Hi friends, today's episode featuring the world renowned expert on high intensity interval training. Also known as hit and author of The 1 minute workout dr. Martin Kabbalah is about the power of having options, the option to be healthy, even on the busiest of days, the option to achieve more by doing less but with greater intensity the option to make every workout minute count, whether you have 5 or 50 when it comes to how best to achieve the profound benefits.
Of cardiorespiratory. Training, the faintest hint, a mere suggestion of controversy has begun to emerge dividing the discourse into two camps, on the one side, proponents extol, the virtues of a conversationally paste lower intensity but higher volume Zone to training on the other side. Advocates argue for the time, efficient and metabolically, intense benefits of high intensity interval training. This begs the question, should you spend more of your overall?
Time at a vigorous intensity high heart rate zone, or should you run slow to run fast as the saying goes in talking to today's guests, I hope to confront that question and those surrounding it had on crucially, in the contest between the message of Zone, 2 versus the arguably competing message of high-intensity training. We must ask ourselves honestly, where along the Spectrum do we most reside? Are we Elite endurance athletes?
It's optimizing for our 20 to 30 hours per week of training or are we the committed exerciser striving to get a few highly effective and impactful hours in every single week. Therein lies a key difference. A crucial piece of context that can help us better understand where we fit in terms of this concept called intensity distribution. Even if you're a committed exerciser you may run the risk of non-response if you're not doing.
High intensity training. That's because a surprising 40% of people might not see improvements in their VO2 max, even if they're meeting the guidelines for moderate intensity exercise, roughly two and a half hours per week, but that picture radically changes. When we increase the physical demands of the work we're putting in high intensity interval training. In many ways is about doing more with less. It's about creating more physiological stress in a very short period of time,
Tapping into a Time. Intensity trade-off where greater intensity yields nearly exponential benefit for the time you put in pioneering studies, including those by dr. Martin Kabbalah underscore the transformative power of hit revealing that short intense. But vigorous burst of exercise can rival. And even at times surpass, many of the benefits derived from prolonged moderate-intensity endurance activities by incorporating, hit into our routines. We not only optimize
Our time, but also catalyze the profound metabolic adaptations. Enhancing mitochondrial capacity and improving cardiovascular and potentially bring Health moreover. Hits ability to elevate vo2max a definitive marker of cardiorespiratory Fitness. That tells us how effectively our body can use oxygen and is a strong predictor of longevity challenges, the traditional paradigms of exercise. Some studies show that there is no upper limit to the
the benefit of cardiorespiratory Fitness on mortality Elite athletes in terms of cardiorespiratory Fitness can have a nearly 80 percent lower risk of mortality than their less fit. Peers of the same age as our lifestyles collectively have become increasingly sedentary. The promise of achieving significant health benefits in shorter durations is not just appealing but essential the science is clear. Hit isn't merely an exercise Trend, but a potent tool in our
Arsenal for longevity and potentially cognitive function. In this episode, we discuss comparisons of various Protocols of interval training such as Sprint interval training versus re-hit versus Tabata. How many minutes or seconds? Your high intensity intervals. Should be Zone. 2 versus Hit for VO2 max, which is better. We talked about whether hit boost metabolism, something, sometimes called the afterburn effect. We address the misconception that high intensity exercise is suboptimal for.
Eating our ability to oxidize fat, this may be counterintuitive, but doing work above and beyond our fat burning zones, actually overall, improves our ability oxidized fat in the big picture, we talked about whether or not high intensity, exercise is a better route to etosha G than fasting. We talk about whether resistance training can be a type of aerobic exercise misconceptions on high intensity, interval training for women, should postmenopausal women do hit, does intense exercise.
Is cortisol, is that a problem? Can we train with osteoarthritis? Does it improve bone, density and more? But this discussion of exercise intensity isn't just about cardiorespiratory Fitness. Some of the areas we focus on which I believe are unique aspects of vigorous exercise are the effects. It has on not only the brain but also cancer metastasis. Vigorous exercise offers unique, perhaps unrecognized benefits that might remain elusive to
Those who seldom step out of their comfort zone beyond the mere time efficiency of hit dr. Caball and I delve into the potential significance of pushing past, the lactate threshold through, vigorous exercise, for Unique, cognitive enhancement and the world of Zone. 2 training, the focus is on maintaining a pace that limits lactate accumulation to a certain point and no further contrast this with high intensity workouts. We're pushing past certain limits leads to more lactate then.
Muscles can use, but herein lies and intriguing question. If that quote unquote access lactate is actually Fuel and a signaling molecule for other tissues, including the brain, are we missing out on cognitive benefits by strictly limiting its cumulation as we would with sewn to it's a thought-provoking conundrum about the realities of a phenomenon known as the lactate shuttle. We also touch on another fascinating.
Area like how exercise intensity affects blood flow Shear force. And the role this plays not only in our brains health and neurodegenerative disease but also metastatic cancer resistance. One of the qualities of cancer cells is that they sometimes have Barnett vulnerabilities that healthy cells, do not one. Such weakness of cancer cells is that of mechanical stress to put it another way when we exercise, we introduced a new type of stress to cancer the turbulence.
Movement creates in our bloodstream. Can reduce the viability of these cells. As they attempt to metastasize, exercise, May reduce the risk of cancer metastasis and it's possible that vigorousness plays a role amplifying the effect. So whether you're an athlete or a fitness Enthusiast or someone simply keen on Aging. Well, and maintaining mental sharpness, today's episode with dr. Kabbalah is a treasure Trove of information on the many unique qualities of vigorous exercise.
Before we jump into the Brilliance of hit with expert, Marty Kabbalah, let's pause a moment to appreciate the energy behind this content, you are Community. This podcast is not sponsored. It's powered by our fans. Every podcast, every topic article, like our new one on photobiomodulation known as red light therapy, even our extensive show notes sent straight to your inbox. Through our free email newsletter is a testament to our shared passion, but for those
Wanting to dive deeper. Our premium membership is the Gateway bi-weekly my team and I craft the science digest an email Roundup of the latest breakthroughs and interests plus each month. I host an interactive Q&A session. Discussing everything from recent episodes to popular health and science queries. These sessions along with the collection of exclusive episodes, find their home, in our members, only podcast feed called the aliquot, organized for easy,
Fleur ation. If you would like to support our mission amplify, our voice and immerse yourself in the premium experience, you can learn more at found my fitness.com, forward slash premium. That's PR e m. I, um, all right enough, introductions, let's embark on this intellectual Journey with dr. Gabor Allah.
Hi everyone. I'm sitting here with dr. Martin Kabbalah who is an exercise physiologist and professor at McMaster University in Hamilton Ontario. I'm pretty excited to be sitting here with Marty perhaps. He's most well known for his research on pioneering research on high intensity interval training. He wrote a very popular book called the one minute workout. As you know Marty I'm very excited to have you here because
I feel like there's a lot of health benefits that can be achieved in a short amount of time. If the right intention is there, if you are pushing hard, you are doing a intense workout and for me, it's very appealing as a full-time mother full-time. You know, I work full time time is the limiting factor for me, so maybe we could just jump right in this high intensity interval training.
And start with defining some of these terms or differentiating between high intensity training HIIT and high intensity interval training. HIIT both short hit right, so, so thanks for the opportunity, lots of different ways to Define things. I think there can be General agreement than when we say high intensity, we're talking a relative heart rate of about eighty percent of your maximum, but there's no Universal definition.
For high intensity training or high intensity interval training, but that would be a typical or average threshold. So about 80% of Max, you're working pretty hard, but it's not an all-out Sprint. Again, the other eye in there is just intermittent so this idea of going relatively hard backing off and repeating that pattern a couple of times and interval training. It's this thing that we seem to ReDiscover every decade or so you know athletes have used it since the turn of the century but it's certainly become popular in the last decade or so or
Dude, popularity, because many people cite time. As a major barrier, some more legitimate than others. Of course, if it's a real-time press issue, or not is interval training. Like when you say interval training because you said, high-intensity Goin, like 80 percent of your max heart rate if you're doing is interval training also that as well as just kind of interchange or is it like you go a little bit less than that? Increasingly? I like the term interval training as a more General catch.
All term. And again that's just relatively harder effort and backing off, but it provides I think more of a broader way of doing that. So if you're just starting out getting into exercise, maybe you just want to start out by walking fast for a few light post and then backing it off. That's a form of interval training. Don't worry at all about whether you're at 80%. So I think of hit high intensity, interval training as one type or one facet of interval training.
As opposed to being the be all and end all got it. So with high intensity interval training, hit. There's, I've heard you talk about and you've published research, you've wrote written about it in a popular book. The health benefits of high intensity interval training on vo2max, which I'm sure you're going to talk all about. But recently there's been a very another form that's become very popular of training for improving.
Geomap VO2 max which is Zone 2 training as defined by a lower intensity sort of lactate threshold training. However that type of training does require a pretty big time commitment. I mean anywhere between three to six hours a week. So can someone achieve similar improvements or really good improvements in VO2 max from doing let's say 20 to 25 minutes of high intensity interval training, 3 to 4 times a week. And
If so you know what are we leaving anything on the table? If you know we're not doing that long-duration sort of Zone to type of training. Yeah. So in short I think you can do more vigorous or high intensity exercise for shorter periods of time and at least see similar improvements in VO2 max. So for the individual who is time pressed, I don't there think there's a need to do three to four hours of what I understand to be Zone to training weekly in order to
surmise improvements and view to maxing. In fact, there's evidence that would suggest that more vigorous intensity exercise higher intensity. Exercise can potentiate ER lead to Greater improvements in VO2 max or eliminate what's known as non response. So some people engage in training and it's very frustrating because their view to Max doesn't change at all and and there's various reasons for that we can talk about. But for example, some evidence has shown that moderate-intensity continuous.
Exercise even for six months. Or so doing guideline based evidence, roughly 40 percent of people don't see a measurable Improvement in their VO2 max. Now, some of that non-response was eliminated in a group that was doing the same total amount of exercise, but engaging in a more vigorous manner. So that would seem to argue against Zone to somewhat, but I think, you know, there's all all roads lead to Rome.
Umm, you know, there's many different strategies that you can engage in successfully and I think a big thing is, what do you like, right? Do you, like and enjoy? Vigorous, intermittent type exercise. Then maybe it's for you. If you prefer continuous lower intensity. Moderate exercise training and that's just what you like and you absolutely hate intervals. That's okay too. Can you talk about what VO2 max is? We hear a lot about it and why it's important for health longevity and maybe why athletes would be interested in it as well? Sure. Soviet
Max is the maximum rate of oxygen uptake by the body. It's typically measured during an incremental exercise test. So you get up to very high work rates and that's where you'll see your highest rate of oxygen uptake, it's determined by many physiological factors and processes but it reflects the peak integrated capacity of the cardiovascular respiratory, the blood the skeletal muscle system to take up and utilize.
Oxygen. It's clearly important for athletes, it sort of sets the ceiling, you know, when a challenge for athletes, in many events is how close to the ceiling. Can you work for a defined period of time? And so, you know, the higher the oxygen uptake, the better. It's also the the clinical correlates of you to Max is Cartier, Spirit or E Fitness. So VO2, max is the best objective measure of cardio Spirit or a fitness and why Fitness is so important epidemiological.
What is show having a hire car? Dear Spirit or a fitness is associated with a reduction in all cause mortality dying from all causes, as well as developing many different chronic diseases, cardiovascular disease, type 2 diabetes. So bottom line is having a higher Fitness is better. It protects you, it reduces your risk of dying and develop diseases. And the best way to measure that is through a VO2 max test. So you mentioned these, these epidemiological studies these
relational studies that are looking at the correlation between higher vo2max and let's say all cause mortality. There's a really I think important paper that was published in Jama in 2018 that showed there was an inverse relationship between vo2max and all-cause mortality with no apparent upper limit. And the elite performing athletes or the leak Elite performers, had a 80% reduction in all cause mortality compared to the
As performers with their VO2 max. So my question for you is, do you think someone who is doing? Let's say, you know, again doing the high intensity interval training, mostly and 20-25 minutes, three or four times a week. Do you think they can be one of those Elite? Is that, like what you would think would be in the lead performer in terms of their VO2, max, or do you have to be an athlete? How can someone do we need to do?
Do extra, you know, types of training on top of the hit to really get to that level at 80%. Yeah, and so there's lots of things there and I think to be clear the way that an individual may choose to engage in physical activity or exercise for their General, Health is completely different from a way that an elite endurance athlete, might rain. And that has to do with lots of things, including What's the total volume of training. So if you're a serious or an elite or very high-level endurance, athlete
You're engaged in 15, 20 sessions of training per week, your training, 25, 30 hours, a week of training, and the best evidence, you know, gleaned with that's, there's some scientific evidence largely, you know, a pinion from high-level coaches and athletes is about an 80/20 split. There is sort of the ideal mixture ratio to optimize endurance performance, so about 80% low to moderate intensity type.
Raining and 20% high intensity training, much of it including interval training again that's the way the an elite athlete might train who's putting in 25 30 hours a week. I think that ratio can change. If we're talking about someone who's engaging in one to two or three to four hours a week of physical activity, and they're looking to optimize how to structure that type of training fit within their regular lives.
I think they're that ratio can change fairly substantially and you can incorporate, I would submit that engaging in more vigorous intensity type exercise. If you're only doing one two, three hours a week May potentiate or give you a further boost in Fitness, so even even potentially 11 our 1/2 hour hours a week because that's that's also something, I mean you mentioned the 80/20 split and that's something I've heard about a lot and I think about it because I am not an athlete, I am
You know, far from an athlete, I am a committed. You know, exerciser, I guess you would call it. I mean, and I, you know, I am also very interested in longevity and improving my VO2 max and I want to talk about measuring that at the, you know, in a minute. But so it's, you know, it's not like finding. If is there a minimum effective dose where we can get 80% of the, you know, improvements in VO2 max, that an athlete would get? I mean that, you know, because if I if I if I can get like eight
80%, you know, I men like that. That's a good amount because there's just, there's no way, I will be an athlete, like that's not my life, I can't do that, you know, but I want to get those improvements in VO2. Max. Correct know and, you know, I would consider myself very similar, I'm a committed exercise, you know, it's in my calendar. I'm sure much like yours is. I'm trying it. But, you know, you're busy, trying to think what's the best way to structure that. But, you know, so, a couple things I think,
Whatever reason you're active or exercising for what's the goal, is it performance? Is it General Health? Is it trying to optimize that time? And I think for a lot of people it does seem to be this is how much time I have, you know, maybe it's one hour a week, maybe it's two hours a week. What's the best way that I can utilize that time to promote my overall health? And for those individuals, again, I would submit that, there is good evidence that engaging in more, vigorous intensity.
Sighs May potentiate the gains that's not to say it's the prescription for everyone and the other thing I think we need to remember about VO2 max is the greatest gains are with the smaller changes in Fitness, right? So we taught Louis look at, you know, people who are have low moderate and high physical activity levels or low moderate, and High View to max levels. The greatest bang for your buck is just getting out of that low range, right? And then they're you continue to gain benefits but you get the
Diminishing returns and the extreme would be the elite athlete who's pretty much doing everything right to maximize their physiology and now they're really just plan on that upper margin. You know, what can I possibly do to e-coat a little bit more gain that the way, that way of thinking and training is not necessarily the way that average everyday people even serious committed. Exercisers who are primary interested in health need to think right likes to, I like stews analogy of like squeezing the wet.
How am I getting the last drops out? You know, you know, that that's something that, you know, maybe if I was more of an elite athlete that I would be interested in doing. But right now, I'm like, how can I get to that? And you know, you know where I'm at least 80, 80 percent of getting that VO2 max, you know, maybe maybe getting all of it if I could. Like I do going going hard and getting it but you do make going hard. You mentioned intensity high intensity interval training, 80%, max heart rate, there's their disease, you know, calculators for me.
Maximum heart rate, you know, I guess it's I would say there's an equation that most people use 220 minus your age but that's doesn't consider Fitness levels. I mean, there's is that would you say that's still kind of the best way for someone who is not going to go out? Or should they like go do an all-out Sprint or something and measure their max heart rate. So I and there, you know, 220 minus your age is still probably the most common. There's a number of other formulas formulas that have been proposed and looked at scientifically. I think the key thing to remember is
There's variability around that. And so if we had 1000 of your listeners and they were all 40 years old, we could be reasonably confident that the average maximum heart rate of those thousand listeners is 180, 220, minus 40. But there's going to be tremendous, inter-individual variability there. And what we call the standard deviation, it's around 10 beats per minute. But what that means is about two-thirds of your listeners would fall somewhere between
Between 170 and 190 95% of listeners would fall somewhere between 160 and 200 and there'd be five percent on either tail, two and a half percent each where their maximum heart rate is actually below 160 or above 200. So, there's a huge range there. And so when you just pick, so, for an individual listener. Now, they're going to work at 220 minus their age. It might be dramatically
Under estimating, intensity or dramatically, overestimating intensity. So, 220, minus your age. It's fine. I think a better way to do it. Is just try and measure it on yourself and there's different ways to do that. The classic would be to go out to a local high school or running track and run a 400-meter or 400-yard Loop 11 time around as hard as you can. You're going to pretty much get to your maximum heart rate by the end or if you're on a bike you know stationary ergometer just ride it.
Higher and higher intensity. So you're increasing the W. Every one minute you're putting it up 10 or 20 watts until you can't go anymore. You're going to be able to measure your individual maximum heart rate, whether you palpate that, whether you're using the hand or whether you have a chest strap or your monitor on. So bottom line is measuring it. Directly on yourself is always going to be better. Well that's those are some good suggestions that I'm going to do myself for sure because I have not done the actual test that
Something. Something they call the stress test to that. Some people do, like, you stress your body to the Limit. Exactly. You know, in so definitely, you know, we have people come into our lab and get tested all the time on a view to Max test and we'll be able to give them their maximum heart rate. Measured very, very accurately but it's also something you can do on your own very cheaply, right? Is as long as you're measuring it with a reasonably accurate device, so it's sort of the, the simple way of getting it. Yeah. For the vo2max like,
Measuring the maximum amount of oxygen. You're taking enduring, I guess, maximal exercise, there's you mentioned to me. Most people are very interested in that and they're not going to get that measured directly either, not going to a lab like yours or to their, you know, physician doing it. But they want to know. Should I do it? Or is there a estimator I can do? That's good. Enough for, how do I decide if I should? Or shouldn't like what, you know, like athletes. Probably maybe they should. But, you know, so this
Count online, calculator, the World Fitness level, you mentioned. Maybe you could talk just briefly about the science behind that and sure so you know I'm not associated with this at all but World World Fitness calculator, is it? It's a valid calculator for estimating vo2max. And so what I mean by that is it's based largely on a lot of research that's been conducted in. Norway in particular Norwegian, Technological University, they've been real Pioneers in a
Lot of interval training research. And so the bottom line is they have a lot of data on measuring things and seeing how they correlate or are related to or can predict vo2max. And so of all of the calculators that are out there, I think this is the one that people could trust the most in terms of answering a few questions about their age, their sex, their typical activity.
Bowls and it will give them a reasonable estimate of their VO2 max, but it's still just an estimate because it's saying you're that typical 40 year old, it's not going to be able to dial in any better individually but at least it's going to give you a marker in the sand or reasonable marker and even if it's not precisely accurate, you can rest assured that it's going to allow you to track changes over time. So you plug your answers into the online calculator, it spits out a value and says your view to Max's.
Is 38 or 45 and then you engage in some sort of training program for three or six months, and then you do it again and that if you see a directional change up, or down, hopefully up, you can be reasonably confident, that, you know, your training program has been effective at increasing your VO2 max, even if the precise number is not 100% accurate. Yeah, that makes sense. You know, I there's a few factors in there that were a little more
Um, on the personalized level, like your resting, heart rate, and your max heart rate and BMI and waist, waist to hip ratio, and are we circumference? I think it was. So it's, you know, there are definitely some some features aside from your rage and everything like that but also the the estimation of physic, like, how intense are you going with your exercise? You know that's that's a net of are there. So subjective component to it where I was like I go hard, you know so
You know, again I think it's kind of good to know that you can use that that online calculator people are interested in probably doing that. But for the average person, do you think measuring it directly? Is really the other way is an in between, if you will is there's submaximal exercise test and there's a number of validated tests that are out there. We could drop those in the show notes, but where you basically are performing a couple of levels of submaximal exercise measuring your heart rate.
And then essentially plug it into an equation that's going to extrapolate and said, okay with this is your rate of increase in heart rate. Once you get up to your maximum, this is what your VO2 max value would be. Or there's no if you have these here but the shuttle run test or a beep test where basically you're running back and forth between asset measured distance and after a point you're not able to keep up but it's called a shuttle run test or a beep test and it basically the more
Power. You're able to exert or the more that you can keep up with, as you have to get faster and faster to run between these two markers. That also correlates with your view to Max. So bottom line is, all of these are submaximal exercise tests. They're better than just an online questionnaire, even that validated one that I mentioned. Because at least it's providing some data about you. You know. So you can't just say, um, engaging in vigorous activity. It's going to actually measure your heart rate a little bit, so
That would sort of be an in-between. But yeah, the gold standard is having a vo2max done in an accredited laboratory and that's going to give you your view to max value directly. And it's also going to give you a lot of data on your power outputs, your heart rate to even your lactate in order to try and look at training zones. For example with respect to other cardiorespiratory adaptations. I mean VO2 max being you know the big one here, right? There's stroke.
Volume increases cardiac output. How does high intensity interval training effect? That's what are those? How does high intensity interval training affect them? May be compared to, you know, moderate-intensity continuous exercise. Yeah, sure. So you know what determines vo2max and as I alluded to earlier it's you know many physiological things but the prime there'd be General. Consensus scientific consensus that the primary factor that
Rates individuals in terms of their VO2, max is their cardiac output. So that's what is the maximum amount of blood and in turn oxygen or the maximum rate of blood and oxygen. It's being pumped out of your heart every minute. And so, a typical untrained individual would have a resting cardiac output of about 5 liters per minute. So if you were to measure how much blood comes out of your heart in a minute, about 5 liters, and maximal cardiac outputs,
We are somewhere around 15 to 20 in, you know, an untrained a moderately. Trained individual Elite athletes have maximal cardiac outputs of 40 liters per minute tremendous. And so again if you could pick one variable that's going to best predict differences between individuals, it would be maximal cardiac output and that's determined by. How often is your heart? Beating every minute, what your maximum heart rate times what you alluded to your stroke volume. And so that's just how much blood with each beat.
Squeezed out of the heart, the other primer determinant would be how well your muscles mainly extract or utilize that oxygen. So your your heart's pumping it out, your circulation is Distributing it through the body and then your muscles. And your mitochondria, ultimately have to use that oxygen and so for a long time, there was tension or debate around is it really the delivery side or the utilization side in terms of oxygen that limits vo2max and
certainly you can put people in situations where one or the other is more important. But generally speaking, it's the delivery side and that's primarily determined by your heart and probably why view too much VO2. Max is such a good measure of things like or predictor of things like all-cause. Mortality cardiovascular disease mortality because probably you know, a failing harder problems with your heart is a major contributor in a lot of those diseases. Yeah, and high.
The interval training. I know it affects cardiac cardiac output, right? And so is that another way of improving cardiac output and it is and so science, you know, now we're talking scientifically VO2 max is easy to measure you know. Basically any exercise physiology laboratory at any University private clinics or medical centers. They can all measure view to Maxwell because it's a relatively non-invasive measure, right? You put a tube in your mouth and you measure.
ER, the amount of oxygen and gas that gets expired. So it's easy to measure all these other things were talked about, certainly cardiac output even just think about what you would have to do to measure the maximum amount of blood that's being pumped out of your heart. Every minute and there are ways to do that, but there are highly specialized. They're very invasive, you know, requiring significant catheterization of your blood vessels. So the point is there's not a lot of direct measures.
Of of cardiac output or stroke volume, but there have been. And there's also ways to reasonable ways we've used in our laboratory to non-invasively assess cardiac output. And so some of those Studies have looked at the effect of interval versus continuous training on cardiac output and and they've shown that more vigorous or more high intensity exercise. May be associated with greater improvements in stroke volume and
Cardiac output as opposed to the same dose or same total amount of continuous moderate intensity training. So maybe if the dose was higher of the continuous moderate training, again, this sort of trade off between duration versus intensity. No, absolutely. And, you know, the other so many points to consider and, you know, I'm sure your audience is getting the sense, you know, there's a lot of nuance to all of this, which is very frustrating for people because they just want to hear, tell me what to do.
Do what is science say and science is always really great, right? It's it's not as clear as we would like often but you know what? It comes even to exercise training studies. Most of my relatively short term, right? A three-month training study is is it long time to measure some of these variables? And so, we don't necessarily know what the maximum potential is for vo2max and most individuals, right? And so if they engaged in longer periods of continuous,
Water training, would they all get to the same level, you know, and maybe hit in the shorter term studies, just get you there. The rate of improvement is a little faster than, with continuous, you know, or are you leaving something off the table by not engaging in the more vigorous effort, you know? I we don't conclude, we could get into a reasonable debate. Put it that way of the answers to all those questions. Yeah. You mentioned the mitochondrial component, the
The the blood getting oxygen being delivered to the muscle. And, you know, mitochondria using that oxygen to produce energy. So maybe we can talk a little bit about some of the skeletal muscle adaptations from high intensity interval training, maybe compare and contrast, when we can to continuous exercise. But mitochondria are very, I mean, the, it's probably one of the most important organelles inside almost of our cells, particularly in must skeletal muscle cells, and I recall
A few studies from your lab and others showing that high intensity interval training was a very potent stimulus for mitochondrial biogenesis or the generation of new mitochondria. So can you talk a little bit about? I mean, how it affects mitochondrial, biogenesis. Maybe the difference between more continuous exercise, why that's important mitochondrial? Biogenesis sure. So you're absolutely right, you know, and I think even if people took high school biology
And to think of mitochondria, these sort of bean shaped things in your in your body. But we now know mitochondria, are this amazing reticular Network? So, it's a bit like, if you can imagine all of your capillaries that go through your, your, your skeletal muscle fibers, the best evidence. Now, it suggests that mitochondria sort of work the same way. It's this network of organelle that goes through muscle and and, and they can change, right? The the size of the organelle, but you can have
Cesare decreases in mitochondrial capacity surprisingly quickly so you can increase mitochondrial content, very, very rapidly. Certainly within a few days or weeks of training and it seems to go the other direction pretty quick as well. So when you d-train you can lose mitochondrial capacity quite quickly as as well, you know, so what is exercise, do any type of exercise? If you can imagine exercise is a stress. And so all of these stress components,
lb or indices of stress change inside your muscles. So you immediately have this large increase in demand for ATP calcium levels. Go up, reactive oxygen, species, lactate hydrogen ions change and many of those, you can think of those as fuel gauges. So the sort of or fuel monitors right there. Seeing oh my goodness, we have an energy crisis, our ATP is going down, this is going to signal that, we need more energy and so many of those compounds, those acute changes have been
Link to Cellular molecular signaling Pathways that are associated with the growth of new mitochondria. So, this is the idea of mitochondrial, biogenesis Genesis, or growth of new mitochondria, and those pathways are really, really well mapped out. Now, a lot of it based on on animal research and, you know, very sophisticated work. But largely, what seen in humans? Is it sort of seems to work the same way. So,
So an acute bout of exercise causes increase in those singling compounds. And, as I mentioned, within a few days or weeks, you can see measurable increases in mitochondria, measured with microscopy or Western blotting. There's lots of methods to to assess that. Now, how does hit and continuous compare? Again, we definitely have studies on this, but all of these require muscle biopsies. So a needle biopsy, a small sample of muscle needs to be taken Often by a physician.
Or at least a highly trained individual under the supervision of a physician. So they're invasive procedures. And what we get is snapshots in time, we don't have real-time changes of how your mitochondria changeover days and weeks. We have these little snapshots but certainly my laboratory a lot of other Laboratories that have compared continuous an interval training. There is some evidence that higher intensity more vigorous exercise. When the total dose is
Matched. Can lead to at least a more rapid or larger increase in mitochondrial content. Again, at least over the short term. So is it just getting you somewhere faster? And if you do enough of it over time, it starts to Plateau. We don't really have a great answer for that right now. If you are generating more, mitochondria, then you know, this kind of goes into the fat oxidation. Mitochondria are the primary place where your oxidizing
You're using fat to produce energy. What do you think of this this concept of, you know, you have to be the substrate you're burning during exercise is. So you have to be burning more fat while you're exercising to have adaptations for better fat, you know, oxidation after you're done with exercise, just you know, at steady state rest. So, in other words like you know, you have to be more in a robic type of state to
To have those adaptations. So, you know, mitochondria consume lots of fuels, right? That the primary ones of course carbohydrate and fat, so whatever you feed it, feed the mitochondria, as long as the capacity has sufficient capacity for that. It will burn either of those fuels, but but you're right, you know, mitochondrial content largely limits or determines fat oxidation by an individual muscle or fat oxidation during exercise is largely.
Determined by mitochondrial content. And in particular, very specific enzyme inside your mitochondria called carnitine, palmitoyl transferase or CPT. That's sort of the gatekeeper that gets fatty acids into the mitochondria, once they're inside the mitochondria, they can be oxidized, but the there's good data to show that that's the critical enzyme. And so with training, you want to increase CPT levels and, you know, people, there's various supplements that are
Good, purported to increase CPT activity. You know, one of the reasons we reasons why carnitine is a popular supplement, is its purported to increase your, your oxidation of fatty acids, the date on that, you know, not great, but we could talk about, we could talk about that as well. But yeah, you know, lots of debate around what's the best way to increase, mitochondrial content because that in turn is going to set the upper limit for fat oxidation capacity and athletes in particular.
Secular want to have a very high rate of fatty oxidized awesome oxidation because even in very lean individuals. There's lots, there's ample fat on board and carbohydrate tends to be a very precious and limited fuel. So ideally we'd like to preserve carbohydrate, you know, until we really need it. Like when we're racing and we need a very high rate of carbohydrate oxidation as well. So if you're going, if you're doing a high-intensity, you know, interval training session and you're going above 80% Max
Heart rate. Your now you know going to this lactate threshold, where you're you're basically producing more lactate quicker than you can consume it potentially your anaerobic maybe. I mean so you know, this, this idea is like that, you're not going to be burning fat during that part of the exercise. But that doesn't necessarily mean that you're not going to be able to burn more fat after. Because it does as you just mentioned, increase, mitochondrial biogenesis so you're actually increasing.
You know, the capacity to oxidize fat later on it mean not. Absolutely. So to me, it's what's important is the increase in mitochondrial content. The overall increase in mitochondria and, you know, I think generally mitochondria have hundreds more than 1,000 different proteins that are all necessary to build the mitochondria and they probably generally all sort of increase in decreasing in parallel, right? So there's not necessarily a specific way to really
I only boost that CPT enzyme that I talked about. So I think that the most important adaptation or a critical adaptation in muscle is increasing mitochondrial content which then will allow a greater fat oxidation capacity as well as a greater carbohydrate oxidation capacity. And you don't have to only work at a high rate of fatty acid oxidation in order to get that boost in mitochondria. So there's there's many different ways.
To stimulate that, including short intensive types, what do just as a sort of side note, I was reading about the effect of like epinephrine norepinephrine which are increased when you're doing more of a higher intensity type of exercise, correct. And that also sort of has some fat, I mean I was at lipolysis, maybe it does. So the catecholamines norepinephrine epinephrine, they're in their involved. And so norepinephrine is an important hormone that will see.
Signal adipose tissue, to start to break down triglyceride and release those fatty acids into the bloodstream. So, you know, much like we were talking about, we use the analogy of oxygen or we talk about oxygen, its delivery of oxygen and its uptake of oxygen. When it comes to fatty acid, use its delivery of the fatty acids and it's the uptake and oxidation of those fatty acids and you can definitely give people supplements that are going to increase lipolysis.
Going to make more fatty acids available, it's going to increase the breakdown of triglycerides, but it's not necessary going to increase oxidation. So there, I think there's quite good evidence that, that has established that the limit for fat oxidation, resides inside the muscle. And it's at that level of the CPT, which is that gatekeeper to get the fatty acids into the mitochondria, where they can then be burned or oxidized. Yeah, that's great. And then mitochondrial, biogenesis is increasing.
That CPT, I mean, if you're looking at least at a Purcell, you know, level right. Is your more mitochondria within that skeletal muscle cell sort of, we were talking about this a little bit earlier off-camera about, you know, the so talking about mitochondrial, biogenesis the other sort of important factor with mitochondrial Health would be my top a g or My Tofu G, which would be the clearance of actual like sort of old damaged mitochondria as you know
Definitely not a lot of evidence, there's animal evidence but how much that can translate to humans is sort of unclear with respect to exercise and particularly high intensity exercise doing that. But what I did want to touch on was a toffee G, which I think we have a little bit, it's he's a little bit, we've got more markers to measure it and it has been measured at least in human skeletal muscle with with respect to response to exercise. And I'm just curious what your thoughts are because it has been
A shown that high intensity exercise is more potent for stimulating autophagy and skeletal muscle than just an overnight fast fast itself. And you don't even have to be in a fasted State when you're doing high intensity exercise, which to me was like, you know, so what is the significance? Do you think for skeletal muscle health and are you do you guys look at that? We don't study that in our laboratory. I think the bottom line there is exercise is good for the routine maintenance.
Turnover of many of these cellular processes including mitochondria so it supports mitochondrial Health. It sort of promotes the sort of breakdown in the the building of new mitochondria. So it's it's important to maintain mitochondrial Health. If you will the overall health or capacity of these mitochondria, you know, clearly I'm a proponent of vigorous intensity exercise. There's some other studies out there that have shown that really vigorous
Exercise can temporarily impair mitochondrial capacity. So if you measure it, immediately post exercise or in the short term after you can engage in to vigorous and effort, you basically really Hammer your cells and they sort of have a decline in function before they start to come back. And so there's some criticism of interval training out there based on those studies, especially very intensive, Wingate style all-out type exercise that can transiently
Reduce mitochondria capacity, we're talking about different things there, you know, out of vision, the various processes. But, you know, I think this is the idea that exercise is a stress. It temporarily disrupt sore damages things, and then it's all about the recovery. That makes the cellular process better, and we continually do that in overtime. Things things get better. But certainly can we acutely over train, or acutely over cause some disruption? Or it takes a prolonged.
On period of time before it recovers. Sure. It's a bit like you know concentric and eccentric weight lifting exercise. We know that eccentric weight lifting exercise is more damaging to tissues yet more sore and so you tend to take a little bit more time to to recover so not as simple as just high-intensity good, continuous nod or less good. There's a lot of nuance there, depending on the process. Yeah I'd love to two-time dive into a little bit more when we when I kind of recover some like protocols because that's really interesting.
Wingate, you know, also just kind of like that's that like an all-out Sprint. It is, you can omit. So if you've never Wingate done at Wingate test, it's the longest 30 seconds of your life. The way to so Wingate test are done on a specialized durometer, specialized bike that allows for very invariable intensity efforts. But the best way to think of it, as if you have a stationary bike is basically getting on it. Setting it, the highest workload possible. So
So it's even hard to get it going. And after 5 Seconds, you feel yourself starting to slow down because it's so challenging. The workload is so high and so you just hang on as long as you can what these specialized bikes do they sort of push back with just the right amount of resistance. And so it will optimize that curve over the 30 seconds, but it's an extremely demanding test. And so some of our early work
I was using that as a stimulus as sort of the one of the most intensive types of short Hard Exercise that you can do. And having people do repeated Wingate test. Very, very challenging, especially late in exercise. You have lots of pH disturbance. Lots of lactic acid production. It hurts. It's uncomfortable. It's not a fun way to train. Yeah, I've never done one of those women have to try one the, the other skeletons.
A muscle adaptations that I think I you know there's some interest particularly like there's so this capillary density. You mentioned mitochondrial Network being sort of like that hit affect capillary density. What is that? Yeah it does, you know II as a muscle physiology. I think you know, the two primary responses in muscle that are critical especially from an aerobic conditioning. Standpoint is the increase in mitochondria and and the increase in capillary ization. So you need more of the blood.
Vessels in order to supply the increase in mitochondria within skeletal muscle. And then of course, there's other adaptations. We see an increase in muscle glycogen content you. So you store more fuel on board, that you can then break down, you increase the transport, for many things, including glucose Transporters. And so one of the reasons why exercise is therapeutic in the treatment of high blood pressure, high blood sugar or
Or diabetes, you know there's lots of reasons but one of the reasons is you increase glucose transport capacity on the cell membrane and so what that means is it allows more glucose to be moved into the muscle, maybe then stored, as muscle glycogen and that helps to lower the blood sugar levels especially if they're chronically. High. And so individuals who start and engage in an exercise program, one of the things that they'll find if they are diabetic, is they have to reduce their diabetic medication because what's happening is
The muscles more fit and rather than needing the drug to try and clear the glucose your muscles doing. It more naturally, if you will, or it's grown, these new glucose Transporters, that helps to clear the glucose the elevated glucose from the bloodstream. What? How does the the difference increasing? The glucose Transporters are good for transfers on muscle differ when you're doing that high intensity exercise versus more moderate? Yeah, so for again, I I think for a lot of these responses, that we might talk about in
In muscle that there is evidence to so show that certainly high intensity exercise can cause changes in these glute for Transporters, we've shown that including in people with type 2 diabetes. But there's just not the body of evidence that we would like to see to definitively say one is better than the other. You know, we've done a number of studies showing that least over the short-term more. Vigorous
Sighs can elicit Superior improvements in some of these markers. But again, the valid criticism is these are relatively short-term studies, they're not always appropriately. Powered, many of these, especially our early studies. Were we like to think of as proof of concept or pilot studies. You know, do these things work and you know, writ large, we really need these randomized, clinical trials, to properly investigate. All of these these questions, what about insulin?
Activity is at all. So I mean so there's like you get this glucose transport. I mean, that's another, I mean, that's one way of glucose regulation and certainly repeated, I mean, acute bouts of exercise or probably when you're talking even throughout the day, that would be so beneficial. But also, like, people are insulin resistant to. How does how does it affect? Yeah. So there's there's various ways to measure insulin sensitivity, but, you know, generally exercise increases insulin sensitivity, there are some systematic.
Who's in meta-analyses that have suggested that maybe more high intensity. Vigorous effort can lead to some greater improvements and markers of insulin sensitivity. But again, even though, you know, we think of oh systematic reviews and meta-analyses. Those are really definitive evidence. But many of the underlying studies tend to be relatively small tend to be relatively low numbers of participants all of the potential bias. You know not that researchers are purposely trying to bias their results but they don't always
include all of the proper controls from a research design standpoint that you might like to see. So sometimes the underlying evidence is, is limited as well which limits the veracity of the systematic reviews and meta-analyses. But certainly, there are there is some evidence to suggest that Vigor intensity more intense exercise may lead to some Superior benefits. They're, you know, just after we might hit on it later, but this idea of multiple boats through the day, one of the things that
And some others are looking at right now or what we termed exercise snacks. So these brief bouts of vigorous intensity exercise that are spread throughout the day and we're running right now to randomized controlled studies at, you know, our lab, in the University of British Columbia, my colleague, professor John little and one of the main outcomes is measures of insulin sensitivity, or blood glucose control in groups that are doing these very short one.
Minute bursts of vigorous effort spread throughout the day to try and get it. Exactly this question, how many times a day? So we're encouraging people to do at least four or five times a day of those snacks. So you know, we Define an exercise snack as lesson or equal to 1 minute of vigorous. Intensity exercise could be jumping on a stationary bike. It could be a series of air squats or body weight style exercise, and we're delivering the intervention. We've partnered with a
Company that's delivering prompts on people's cell phones and so they basically get a prompt that says hey it's time for your exercise snack that links to a little YouTube video that shows the individual what they should do and we're encouraging them to do that four or five times a day. More is better, and we're following them for for three months, 12-week intervention. And we're comparing it to a movement snacks control group. So a group that's getting a very similar intervention but they're not.
Not engaging in vigorous intensity exercise. So it's more stretching Mobility exercise. And so the key variable is changing, there is the intensity of the movements and we're seeing, you know, how to people adhere to that like will people even do that and if they do it, is it enough to move the needle in terms of things like cardiorespiratory, Fitness, blood markers of fat, immune function, glucose and measures of insulin sensitivity as well. One of the studies that we're doing
Going to be using continuous glucose monitoring in individuals with type 2 diabetes. Fantastic, so they're going to be wearing, they're wearing accelerometers as well. Yes, yes, so we're trying to track movement throughout the day and they're going to be wearing continuous glucose monitors before and after the intervention as well. So this this kind of reminds me of some of the, vigorous intermittent lifestyle physical activity, studies Philippa, as you have called it that you've been a part of
So this is, this is there are those studies also considered exercise snacks or no? So, you're right. Viva Villa is, vigorous intermittent, lifestyle physical activity, and very much led by my colleague, Professor Emmanuel. Stamatakis out of the University of Sydney. So I've been fortunate to be part of a, really, an international group that is, that is looking at bill, but, in various ways, but to be clear, we're talking not
Exercise. So you could think of Philippa in some ways is the non-exercise equivalent of an exercise snack. And so, we're talking activities of daily living that you would be doing. Anyway, it's all very give you a very specific example. So to get to the recording studio today, I left my hotel, I had to get here, right, somehow, I had to get here, I took a ride sharing service for most of it, but leaving my hotel room, I had a choice of taking the stairs or taking the elevator
Ater, I could have taken the stairs there or to get to my ride, share service to walk a block. I could have walked to the leisurely Pace or I could have picked up the pace, right? And said I'm going to engage in a vigorous manner here, arrived at the location. Again, it's another minute to get from the Rideshare service, to the front door. I could do that in a vigorous Pace or two pedestrian Pace or I could carry my backpack right and engage in that. And so the question there with Ville de is in the
These activities of daily living that are already part of our Lives. If you embed, vigorous effort in those, you know, another classic example would be to take a five-hour flight, get off the plane, you have the choice, the escalators there or you have the stairs, you know, many people are taking the escalator but you got some heavy backpacks. You could vigorously climb up the stairs or 30 seconds to a minute. That would be a dose of Philippa right there. And so,
Again you got to move from one level to the other, that's not planned and structured exercise, that's just activities of daily living. And the question that's being asked in that research, is if people choose to do that in a vigorous manner is that meaningful. And there's, there's some evidence for that including a large study that was published in December. That was it, mind the UK biobank data. And so what? That allowed the
Vestigators to do was look it over 25,000 individuals who engaged in Villa like efforts. They were accelerometers to try and capture this and they were followed over almost seven years and the outcomes included all-cause mortality, cardiovascular disease mortality cancer mortality. And that work showed revealed that people who engaged in even three to four minutes total a day.
Available like activity, had substantial reductions in all-cause. Mortality, risks were talking 25, 30 percent so that would suggest that even brief, non-exercise, vigorous intermittent, physical activity, can move the needle in terms of health outcomes and of course, we would suspect that maybe it has to do with some of these cardiovascular metabolic changes that we know are associated with health so that's not cause and effect evidence.
It's observational evidence over time, but it was very robustly done. The way the work was was conducted. It's quite compelling, I think I agree. Because after you share those studies with me, I read them and I think even on the higher end. So you mentioned kind of the conservative, you know, three to four minutes a day. When they were getting up to like more like nine, I mean, you're talking. It was like 50 percent reduction in cardiovascular mortality 40 percent reduction in cancer related. Mortality mean that's really
Lee incredible that these people are just doing this, you know, choosing to do these short bursts of, you know, vigorous intensity exercise and then having substantial benefits on, you know, unless you know, longevity and health band, basically, the other, if I can add the other key thing from that study, I think, is that all of these people were self-identified, non exercisers. And so the point is, there are even people who self-identify as non exercisers seemingly are still engaging in vigorous.
Through the day. Now, part of that might be there, their physical capacity is quite low and so what it takes to get them into a vigorous intensity. Ranges is not very much and actually, as part of that study it was repeated in individuals who also identified as exercisers and the same phenomenon we're a parent. So even in exercisers, engaging in Villa like activity was still protective. So again, lots of work to follow up on, you know what actually counts.
As a VIP about, you know, will people do this, you know, but you can imagine again, getting back to this idea of prompts, you know, building envelope alike activities in a smartwatch or an app on a phone and encouraging you to accumulate 3 or 4 or 5, or 10 minutes of bill today. But, you know, three or four minutes of Milpa is, you know, about 30 minutes of vigorous activity a week and large.
In wrist and that is very doable. That is very I mean to say you can do 30 minutes a week is I mean, you're really just saying I don't want to be healthy and, you know, the other it's interesting. I don't want to go on too much of a tangent here but like, you know, you wonder how much also of this of the of these Villas studies and these even exercise snacks has to do with just not being sedentary. Also because that's like an independent risk factor for. I mean independent of exercise, right? So like I said,
I said, at my, I don't consider myself a sedentary person because I engage in physical activity, almost every day. Pretty much seven days. I'm doing something. I'm either doing my palette on and to hit workout. I'm doing resistance training, but I also sit at my desk for a good five hours. I'm sitting there sitting and that is what I am sedentary. So I'm actually trying not to incorporate built by stuff. I guess, you know, in I guess it's more structured. So when it be more of an exercise snack in that case, but I'm doing, you know, the
Burpees or the high knees or something where I'm going to believe me. Like one minute of that I'm like this is the longest minute of my life you know I mean it's like hard so that I can empathize and that I'm very similar. I'm a committed exercise or pretty much. I do something every day but you know as a university Professor you sit at a computer a lot and so trying to build them into my day as as as well. But yeah I think the key there is
You're right. It, there may be a double benefit if you will, you know, all of us should be meeting physical activity. Guidelines, of course, you know, add these in, sprinkle them in, but there may be a double benefit to a villa like approach or an exercise snack approach in that it simultaneously breaks up prolonged periods of sedentary Behavior because, you know, I'm sure like you, I don't like to see that evidence and read those studies that suggest. Even if you're committed, exerciser prolong sedentary is in
Raising your risk, right? You know, we like to think of exercises this Panacea and it's not, it's not a vaccine against ill, health outcomes and reducing sedentary. Behaviors is really important as well as is proper sleep. So I kind of wanted to Circle back just for a moment to the muscle biology aspect because well, one you're an expert in that that Arena and we didn't touch on the how high intensity interval training effects.
The recruitment of muscle fiber. So type one fibers type 2 fibers. What does that mean? How much does individual variation play in that equation. So you know, big picture generally speaking. There's two main types of muscle fibers. They can be Quantified different ways, history, chemically different. There's different ways to measure them but there's slow, twitch and fast, twitch muscle fibers. Those definitions are based on basically how
Quickly, the muscle fibers can shorten or contract and so the fast which are sort of fast, explosive very, very quick. So we think of those associated with variable fast, explosive powerful movements where the, the slow twitch, they don't generate as much force, but they don't fatigue very quickly as as well. Sometimes, those are also known as type 1 and type 2, and those are generally looking at there's ways.
Ways to measure. Basically the oxidative capacity how aerobic each of the muscle fibers are. So there's different ways to categorize them. But generally speaking two types and they differ in their characteristics.
The there's definitely something to the idea that we first recruit and this is known as the size principle in part based on the diameter of the muscle fibers. So these slower twitch fibers. These type one fibers, tend to have, narrower diameters, and they tend to be recruited first. So if I was to get up from the chair right here, we're going to go for a walk around outside. The studio, very low intensity.
Those muscle fibers that we would recruit to do that work or generally these slow twitch or type 1 muscle fibers. They're good for low to moderate levels of force and they last for a long time without fatiguing then we need to get back quickly the studio or we need to run away from a scare that's outside. We suddenly have to engage in very fast movement, we're going to now recruit or call in these fast. Twitch muscle fibers because we need more.
Powerful muscle contractions in order to go faster. We would be able to Sprint away from the danger for very long because we'd eventually fatigue because these muscle these fast, which are type 2 muscle fibers are. That's one of the limitations of them. And so that idea of progressive recruitment of muscle fibers is well-established, what's not? It's not as clean to just be able to say when we do low to moderate exercise, we only recruit slow twitch or type one.
And when we do high-intensity, we certainly don't only recruit type twos. We've already called on our slow twitch and then we start to recruit the fast twitch as well. And the other point is like a lot of things. It's really hard to study. So you know, you take a muscle biopsy site, biopsy sample. That's hard enough, right? Invasive, people have to volunteer. Sometimes, it's a little painful, but yet your biopsy out now you have to separate these muscle fibers. So you literally have to individually identify
Whether muscle fibers are fast or slow and then you separate them into pools and you analyze the type ones and the type twos. Very intricate time-consuming work and so there's not a lot of data out there there. You know, a lot of animal studies that were done previously in rodents. For example, they have much more, clearly defined muscles so they will have fibers muscles that are almost entirely fast-twitch or
is that are almost entirely slow twitch and so in those you can just take samples of specific muscles from a rat hind limb for example and know that you're pretty much looking at fibre type differences. Human muscle is much more variable heterogeneous. And so Elite endurance athletes tend to have a much higher preponderance of slow, twitch muscle fibers, 7080 percent, Elite strength, athletes powerlifters 10,
Have much higher preponderance of fast-twitch muscle fibers but the vast majority of us are walking around somewhere around 50, 50 40 60 and again that that complicates interpretation, when we talk about 5 or type differences, two different types of exercise.
But are we are people more prone to losing one type over the other or what with age? Yes. So and so, definitely, there's evidence to suggest that there's Progressive loss of these fast twitch muscle fibers. May be mainly or sorry may be mainly due to the inherent aging process. But again, you know, we could have a long discussion around whether aging is more a physical inactivity purse, a problem or aging per se, but bottom line is
Tend to lose fast twitch muscle fibers, which is probably why, especially as we age strength training is important in order to maintain the viability of these fast twitch muscle fibers does. Does that, does that have to that correlate also with an increased risk in like Falls? And yeah, you know, I think all of this aligns our certainly, the theories would be that. Yes, right. And so, you know, we mean to maintain flexibility balance all of that, but
Certainly, it maintaining fast-twitch muscle fibers through strength training is going to be important in order to help prevent Falls and other others.
With respect to the metabolism aspect of high-intensity interval training. You know, we talked, we talked, we talked about the insulin sensitivity, the glucose transport increasing. I mean, all these things are good for both people that are in a disease State, like maybe type 2 diabetes or, you know, high glucose, you know, dysregulation metabolics and whatever also for people wanting to prevent also getting type 2 diabetes, right? I mean so there's there's two populations here, right? Yeah, absolutely.
Lutely again. If you know back to the elite athlete they want to optimize all of those processes much as they can write. And the the individual who's very sedentary, they really just need to do something to try and raise the bar. So, you know, we're just talking about a massive Spectrum there from very inactive, very sedentary, very high-risk Behavior to the elite athlete who has maximized almost all of these processes and is just looking for ways to further optimize that
Just to get back to stews analogy wring out the sponge a little bit more and of course most of us fall somewhere. In this this broad range in between what about body, composition weight loss, obviously diet is an important component in those equations but can people use high intensity interval training to help, you know, lose fat also even help, you know, there's there, increase the muscle. Also, you know, is there is there is there a role?
All for high intensity interval training in. So, you're right and that, you know what I tell my students is, this is hardly novel that, you know, we control body mass mainly through nutrition, but we control Fitness through exercise and physical activity. And so clearly exercise generally and high intensity exercise, can play a role a supportive role in terms of weight management body composition changes. We've shown in some of our six and 12 weeks studies, you can change. You can have
Oil changes in body composition. Such that there's a slight loss of fat Mass fat percentage, or a slight increase in lean mass with high intensity interval training. But it tends to be relatively subtle and how it Compares with continuous exercise. Again, I think the biggest thing is, there's probably a time-saving aspect there, and so you can do less total exercise or certainly have a
Lower time, commitment with more vigorous intensity exercise and burn the same number of calories. There is something to the idea of personal trainers, talk about the afterburn effect. This idea of a heightened rate of metabolism and Recovery, we've measured it, you know, you look on the internet, you'll see these massive differences in afterburn, right? Where hit is way up here. And moderates, way down here. It's certainly nothing to that magnitude and but there is a difference, but it tends to be relatively small and it
It's relatively quickly but those small differences can add up over time. And so, you know, people will say well, how can high intensity be effective or how can certainly Sprint type training be effective at this because you don't burn more many calories during the efforts. Well, you do burn a greater rate of calories in recovery and those two things can can play off. But again, I think right now, the best data is like, a lot of things we've talked about, you might get away with some time savings or a smaller.
Our total dose of exercise and still get to the same place with more, vigorous activity. Well, in contrast to that, getting to the same place in my mind, in my opinion, one of the reasons I am so drawn. In addition to the time efficiency aspect of high intensity while training is the brain effects, and there's no doubt that exercise in general has Global effects on the brain.
I mean, there are improvements you do any type of exercise. You look at any observational study exercisers, non exercisers definitely you know, brain benefits lower risk of, you know, age-related diseases neurodegenerative diseases, excuse me. So you know, not that there's not, you know, a role for any type of just getting your blood flow higher. However I'm increasingly convinced when it comes to intensity of exercise there.
Maybe very unique benefits on the brain and that is where I think, you know, high intensity interval training or any type of in high. Intensity training has a special role some of that has to do with actually wanting to increase your lactate levels. So in stead of this lactate threshold training that we were talking about the zone to sort of going, you know, right below the lactate threshold which I guess is defined various ways. Depending on
You're what you're reading or who is doing it. But the lactate shuttle Theory, George Brooks proposed this. You know, it's not a theory anymore. So it kind of the name kind of it's like a lot of date. But can you talk just kind of briefly about the lactate shuttle Theory and maybe like where the brain comes in sure. So you know the lactate shuttle Theory or lactate, you know, many of us. If you look back at your textbooks, your learned that lat
Tate was this metabolic waste product and product and it's just a metabolite like like anything else and it can be an extremely valuable Fuel and we know that and there's elegant studies including from dr. Brooks and others to show that you know, first of all skeletal muscle can produce lactate under fully aerobic conditions. So there's always some lactate production happening and certainly during more intensive exercise where we produce lactate inside the muscles, it can be released
Active skeletal muscle, it can circulate to other places like the heart, like the liver, like the brain, but certainly in heart, heart can be a big consumer of lactate. And so it takes up that lactate can convert it back to glucose and then utilize it during exercise. And so this is the idea of cell to cell or inter organ lactate exchange and I think that's very well established now like you and you would be far ahead of me. But I'm, I'm following this area with with immense.
Interest. I have some colleagues at McMaster where you know both from a cognitive psychology standpoint and also more a hardcore neurophysiology standpoint were engaged in some collaborative research with them but generally looking at this question of physical activity and brain health and probing the role of intensity there. So you know my my understanding is mainly based on talking to my colleagues trying to read reviews.
Of some of this research and my sense is you know very well established potential mechanisms. Now from some of the animal studies and and the human data is certainly intriguing but you know that link between lactate bdnf absolutely. There appears to be a role for intensity there in terms of higher intensities. The better in terms of, you know, potential you didn't F beta.
Aiding the brain. Some of these outcomes associated with neurogenic neurogenesis. Yeah, it's the lactate and we can talk about measuring it but it's interesting because I do measure mine. I do the finger prick and I'm my workouts I'm like trying to go higher for my Lactaid you know and I've read a lot of study for me. I'm very interested in erdheim disease. There's on both sides of my family Alzheimer's and Parkinson's so to me I'm like I need to really focus on brain health.
And so looking at the studies on lactate and even infusing lactate into humans, it increases bdnf just infusing it and I'm like oh I get these levels from I really all out hard workouts. Like this is this is great but also I feel really good. So I start my day with couldn't today, most most days, you know, at least five days a week I'm doing a and will I want to talk about protocols but I'm doing like a 10-minute, you know.
No Tabata. So so I'm doing two back-to-back to bodice actually it's two back-to-back, two bottles and then I have there's some you know minute minute warm-up. And a minute cooldown, I actually don't I use them more for. I'm actually still going hard like half the time and then I like cool down after that minute. So I like at the end, I go and all out, man. It after my two back-to-back devadas and then I'm like and then I cool down. But, you know, I do this for my brain, I feel amazing and there's actually science showing that executive function is
Proved and it's totally correlates in. This isn't humans with lactate after high intensity exercise. And it doesn't correlate with anything else. No glucose like nothing. It's specific to the lactate. And like you said, it's a growing area of research. I'm particularly interested in it. Like I for sure. Notice a difference, in terms of like if I go hard, like, I feel better, I feel smarter I'm like, more on task, you know?
So, for me, it's a very important part of my protocol and I do think there's a lot of benefits for the brain. So I'll have to be in touch with some of your colleagues at McMaster because I love sharing studies and stuff that I find and learning what, you know what other people are doing as well. And so the and maybe there's data out there on this. But, you know, the scientist in me, is innately, curious around things like I, you know, maybe now there's really really good dose-response stuff in terms of exercise dose and beating.
Of increase in some of these other measures. But, you know, so for example, is short sharp large changes, in lactate better than prolonged moderate levels of lactate, right? And I'll tell you something, it's not lactate that I've looked into you, but I've looked into blood flow and Shear force. And I think this is a very, I think it's an emerging field looking at the effects of Shear Force.
And that is where I mean we're talking about a flash flood coming through if you're talking about high intensity versus just, you know, a little trickling and the shear Force itself at least at the blood-brain barrier and just kind of when you were talking about muscle capillary, I was thinking about the shear force it in and of itself. In a dose-dependent manner is responsible for increasing vegf and bdnf, at the blood-brain barrier again, dose-dependent all on the shear Force effects meccano, you know, these mechanoreceptor
Others that are on Solid Surfaces and stuff like these are all sensing things and it's also very important so I think it's another. So there's the lactate part of it where you're increasing the lactate and it's a quick sort of and it is like, I've measured my Lactaid spikes up. You know, I don't get up to levels that my husband, I'm more like a 78 millimolar, and he gets up to like 14, but it's it after 20 minutes. I mean, I'm back down to 1 millimolar and to my Baseline basically. So, you know, is it
It is there something with that, you know lactate you know going intensely up. It also the sheer force. I think there's another interesting component to that that I think needs to be calculated into this equation because I'm seeing increasing data on that not just with respect to brain health but also people that have cancer. So there's a lot of work from Justin Brown. He's at think it's Tulane in New Orleans but the sheer force and how it's affecting the
Circulating tumor cells. So basically people that have been diagnosed with cancer, you'll have a tumor cell that escapes, the the primary tumor site goes into circulation and that's how that's this the potential to metastasize, right? So then goes, you know, is able to travel to another organ and take up camp there or whatever. So there's there's evidence that exercise in general exercise is involved in. Basically anything that gets your blood flow up basically those cancer cells die because they're so like disrupted and
T''v to the mechanical forces, whereas normal cells are fine. But it seems to also again be a dose-dependent effect. The more intense, the exercise, the more blood flow that's going quicker. The more intense the effect and also blood flow to the brain to, right? I mean, just getting that that Shear Force as well. So I think there is a lot of interest there with the brain. It to me is a differentiating factor from more continuous moderate exercise, even longer duration, obviously, there's
Lot of compensation, probably that can happen metabolically when you're going for a longer duration, you know, period of time. But I do see, I do see something unique and I'm, you know, looking, I'm reading the literature, I'm trying to follow it as much. And, you know, I mean, it's emerging, right? I mean we don't really know, you know, just on the topic of interval training there's now seven hundred papers a year coming out. It makes it very challenging to stay on top of the literature you know and that's just in my main area. So absolutely
You know, on the point about vascular stress, we collaborate with some cardiovascular colleagues who are looking at this more and ethelia function flow. Media dilation not in the brain more, in terms of muscle or large arteries leading to a muscle. So parallels there, I think in terms of some of the things you're talking about and Shear stresses and factors that are released, you know, to promote kapler, growth there, the other I want to mention around lactate levels though. It's a bit like heart.
A tin that you know some people just have low maximal, heart rates, some people just have low maximal lactate values. We know it's definitely related to fiber composition more fast-twitch. Muscle fibers have greater potential to drive up lactate, it's related to your enzymatic capacity to produce lactate. So the point I just want to make maybe you're working as hard as your husband, but you just don't have some of the biological.
It's that are going to allow you to get the very, very high lactate levels. You know, what is your Peak lactate level, maybe you're already added or very close to it. So don't beat yourself up too much there. Do you think wearing a continuous lactate monitor, when those exist will help me, maybe right? And so, I, you know, I'm sure we're going to get into zone two, more and lactate, and how we measure things in that. But, you know, I think a challenge with lactate monitoring right now, is it relies on occasional finger prick?
Sampling variability, in the monitors and that when we look at something like continuous glucose monitors and the evolution of that, you know, now we have continuous glucose monitors are combined with insulin pumps amazing, right? So eventually you have real-time monitoring of blood glucose levels and as they change up or down, the insulin can be potentiated or adjusted to get to. And I I'm sure and I know people are working on this techno technically
Lee getting to the point where an athlete would use, a continuous lactate monitor for training and racing, I could see where that could have tremendous value, whether everyone needs that, I don't know. You know, whether you can use heart rate and some other metrics to at least get you reasonably into some zones. But I can see why there would be tremendous interest in among athletes to monitor that and really dial it in to get an idea.
Their metabolic stress know, for sure. I'm not an athlete, but I'll tell you. My interest would also be because before I was doing continuous glucose monitoring, I wore one for around three years or so I was doing finger prick. And, you know, I noticed before my workout, you know, my blood glucose levels were a certain number and then you know, usually sometimes I would do it like three times because of the variation as you mentioned, but after I would go higher up and like what I'm supposed to be like transporting more glucose into my muscles, like, this is
Aeolus, and it wasn't, until I had a continuous glucose monitor on that. I saw the change going way down during the exercise and then gluconeogenesis whatever's kicking in, you know, that it's bike back up, but I wouldn't have known that without that continuous, you know, data and I wonder with the lactate because during exercise the brain consumes consumes it more than glucose. So it actually you know, you have both of them there. It'll go for the lactate over the glucose and I wonder it's like, oh well, what's happening while I'm is it
Really high is my brain consuming more of it or is it might just not producing more, but like you were saying like, what what a continuous lactate model would give me some sort of peek into that, because at least maybe it is going higher. And I just don't see that because I'm not just a snapshot that I'm getting after my workout right now. It's a great point, right? Even just monitoring Venus levels. It's not telling you anything about rates of production and utilization. And so, you know if some it's a really good test question in my senior class, I will ask my students.
It is a high blood lactate, a good or a bad thing from an Exercise capacity standpoint and we tend to think well high blood lactates are bad because you know, it's a so it's a signal that your pH is out of whack and everything like that, but you could also make the case, well actually transporting for a given amount of lactate production. Getting more out of the muscle into the blood might be a good thing because the disturbance to your muscle pH is not going to be as pronounced. Now you've moved the
To where you wanted into the blood is sort of protect the muscle again. It's just a it's a good thinking question. I ask that to them to Challenger thought process around all of the things that control lactate but maybe it's not all about just measuring in the blood either, is it? Yeah. Let's let's dive into that for many brought up some really good points. I think a couple one being, you know, this misconception of, you know, lactate or lactic acid. And you know how, what's actually,
Isabel for, you know, the changes in osmolarity and you know, that that fatiguing feeling I guess in muscle versus basically behind his native will training whether or not it can help. I guess improve muscle fatigue, through changes, you know, regulating the osmolarity better. Yeah. So certain, you know, certainly there you can certainly you can choose to change lactate Transporters with exercise and high intensity training and probably you know go back.
Two athletes that were engaged in high-intensity exercise to engage in high intensity type events, a major adaptation. There is an increase in on our carboxylate Transporters MCT Transporters to help. Get the lactate out of the muscle. And you're right, you know, lactic acid is produced at physiological, pH it rapidly dissociates into the lactate ion and the, the proton, the hydrogen ion and it's the changes in PH associated with the changes in protons.
Ons that we know can interfere with contract out processes, and, and enzymes, and, and things like that. So yeah, complicated physiology. But I think the bottom line is lactate is still a valuable measure and certainly why whether its own to training, or others, the the notion about it's, you know, whether it directly can causes fatigue, probably not, but it's still a really good surrogate marker or index of a lot of other things that are going on. So whether it relates
Osmolality or potassium fluxes or calcium flux has. You know, I think the people that really study muscle fatigue would say it's not about lactate mph all the time but lactate is still something that can be relatively easily monitored and it's a good proxy for, you know, a global look at what might be going on metabolically. And I think that's where my understanding is where its role in zone. 2 training comes into play.
That makes sense. So we talked about some other performance enhancements, you know, that that high intensity interval training complain when he's muscle glycogen like the storage capacity for talking about the muscle fatigue, but and then we talked about vo2max which would be aerobic capacity. There's also the anaerobic is that the anaerobic output is that anaerobic capacity? Correct. And this gets back to this idea of, you know, if if your event is
Multiple short Sprint. So you play a team sport, and your role on the team is to, you know, receive a pass or receive a ball Sprint as hard as you can. And then you have at least a few minutes in between plays to recover or you can, then recover on on the field. Those individuals require very high power outputs that they can achieve repeatedly, but with some Fair bit of time in between. And so those it when we talk about anaerobic capacity the best measure or
The most commonly accepted measure of, anaerobic capacity is a Wingate test and that's because when we do an all-out 30-second effort, a large, majority not all of it. But a large majority of the energy is derived from anaerobic or non oxidative metabolism and so we can quantify power output in terms of wattage on the bike and a large proportion of that power is derived from anaerobic. And so for example you can measure
Or let's say your view to Max test at the end of that test. You had 300 watts so your Peak power output on A View to Max test was 300 watts. Will you can do a 30-second Wingate and Achieve 900, 1000 W, Elite athletes, Elite power athletes, 1500 watts on the bike. So when we talk about someone was exercising, it three hundred percent of VO2 max Pace. That's good. People will Max's Max. How can we exercise above vo2max normally you're
Talking about its power outputs above the VO2 max power output. And when you engage in these short hard efforts that can be multiples of Beauty Max power. So this kind of reminds me of I've heard you talk about this, the Sprint from danger sort of pace or intensity and how I mean you know that that's could be basically the Cornerstone of a highly efficient workout now. What is that can you talk about that? And then maybe compare it to The Windgate or maybe even the Sprint interval training.
Is know for sure. So, again, you know, people think vo2max Will and Max is Max. How can you be above Max? But when we talk about, VO2, max that's maximal, aerobic capacity, and then we could have metrics to that. So, Peak power work peek at view to Max, but Sprint from danger pace. Is just that. So if you had to flee a burning building the pace, you might run at to save your child from an oncoming car. It's well above VO2 max, but you might only have to do it for five seconds. So,
It would equate to top running speed and all-out Sprint over 5 or 10 seconds. You know, even a Wingate test is not true. Max power output. The highest power outputs during a Windgate usually occur within the first few seconds so we're talking five to ten second efforts. What's the highest work rate that you could put out? What's the highest amount of ATP that you could generate much of it non oxidatively over a five, a 10 second?
For at most that's print from danger pace. And you know, if you're an athlete you know, we hear these five Zone training six, own training, for many of us three zones are enough. But when we talk about five and six Zone, what that often is, referring to is, discriminating, were crates or power outputs above view to Max and if you're the athlete, looking to optimize performance,
You know, whether you're working at 150% of you to Max, which you might be able to do for a minute, or two or you working at 250, 300 percent of VO2 max for 5 or 10 seconds. Those might be important in terms of discriminating, fine changes that could further support your performance, where's for most of us, it doesn't really matter. We don't need to get that level of sensitivity in terms of how we structure our training at these very very high intensities are
it's
so do you think there would that mean like it could there be a benefit for sort of changing around our training protocol to incorporate some of that spring? I mean, VO2 max benefit or, you know, soy I do. And, and again, this is not scientific but it makes sense to me at least and it's the old investing analogy, right? And so, you can hit a home run with a hot stock tip, but for most people are better off to, you know, spread it around
Don't put your eggs in different baskets and so I think when it comes to exercise training for many individuals, there's there's an analogy and and that's it maybe do different types of training and and that's going to, you know. So whether you're someone who really responds to Sprint training or really responds to moderate, we can't necessarily predict that and so varying up your training just like we spread out our risk when we invest might be
The the best approach, you know. So should individuals engage in some short sharp hard efforts, I think, you know, ideally speaking. Yes, they should. There's even some recent evidence, I think there's renewed interest in the potential for elite endurance athletes to incorporate sprinting in their training and there's a series of studies that's that's come out Randstad Karsten loon bees work. Showing that when truly world class level.
Cliff's, we throw these terms around highly trained Elite. These are cyclists with starting VO2, max values, 72-73 mils per kilogram per minute. And they randomize them to do either traditional hit 45-minute repeats or effort matched, 30 seconds Sprints and they sort of effort matched. So whichever group you're assigned to you working at the highest effort you could and they were work matched. And what they found was the group that incorporated, the Sprints
Had a further boost to their performance, 20-minute time trial performance and they actually had a small but significant Improvement in VO2 max. And so it would suggest, it may be there might be a place for athletes to incorporate what you know some call rsts repeated Sprint training as a as a ways to further augment their performance. Now you know still relatively small three-week interventions but to go back to your question I think there is
Place for incorporating.
Very vigorous effort sometimes. If you know it again there's some people who shouldn't do sprinting, right? Especially if you're starting out but all things being equal. Yeah, I think varying it up. Your approach is going to be the best for general fitness. I want to talk, let's dive in its in protocols. And this is, this is very like, I'm sitting here, getting very, very intrigued because of my training, which mostly like I mentioned, it's mostly on a pallet on stationary bike and it's, you know,
Again I do a lot of the 22nd on 10 second off you know, back-to-back and I'm thinking like maybe I should also incorporate some you know I could go outside and do he'll Sprint hate them, hate them, hate them, hate them. But I mean it, you know, if I can get if I if I can do it quick it still can be and I just go outside and you know, do this isn't like going around a track or anything which is something that I can conveniently do, but also maybe potentially
It even greater improvements in VO2 max. That's of interest to me. I'm not an athlete, but so are you thought do you think that I'm so, you know, far be it from me to tell you how to train but, you know, from what I've listened to in my awareness of the type of training that you're doing. Actually think, you know, maybe you should do some longer intervals at a little bit lower intensity, you know, maybe you should be incorporating some 3, 4 5 minute intervals as hard as you can go during those rather than almost
Sibley doing Tabata style type training because arguably, you're already doing a ton of Sprint training to bat is are basically Sprint training so I want to be careful here. You know, we could talk let's let's at least for now. Keep it modality-specific. So how you would train on a bike before we start talking about different modes in that because that introduces some other wrinkles. But again from what I understand, what you just said earlier in our interview, most of your training are these for you all out 22nd, Sprint's 10-second recovery.
Efforts, I'd suggest you know and I think dr. Attila recently suggested you might want to do the same thing in those 10, second recovery periods, almost completely stopped or at least go down to very low intensity cycling because part of thing with te bad as you go really hard but those 10 second breaks, you've earned the break, take it. So don't maintain the intensity too high in the 10-second. Valleys before you go hard again. But again, it sounds like much of your interval training right now is already Sprint type training given your
That is we know there's data suggests that all things being equal, three to five-minute repeats at the highest sustainable. Intensity are probably the best way to maximize gains in VO2, max, it's pretty loaded statement but I think you probably want to incorporate some of these longer. Intervals, two, three, four, five minutes again, highest workload, you can and do four of those right now. That's probably going to take you 20.
Minute commitment, some mornings, but I would say or I would encourage you to least think about incorporating some of that style of interval training. Yeah, absolutely. How many times a week, do you think? Yeah. So again, my understanding is you're doing something almost every day and I think you sort of, you know, you go back and forth between some resistance stuff. Well, the resistance is on, I will talk about it. Yeah, well, but it's on the same day as it's just later in the evening. But like, so that, so we mentioned Tabata and then you're saying this this like like longer duration interval,
And it's funny because I had a question about that. Was like What if you let's say, you know time so let's say the interval where you're going all out is or at least high intensity. So 80% is matched. But instead of doing the you know shorter interval, repeated repeated, you do longer ones and sounds to me like the longer one, there is a difference in doing a longer interval, even if you're like, you know, let's say it's six minutes total going all out for Tabata Style versus what you're talking about, which would be
There is, you know, metabolically, the challenge is different, you know, it all. So this is where all interval training is not created equal, right? And again, there's lots of variables, their total volume in particular is important, but I think challenging your metabolic system in different ways is a good strategy. Now, again for you that if you're only doing ten minutes in the morning, some of these days are going to be 20 minutes but maybe some days are you know, 35 minute intervals.
With a little bit of warm up. Cool down recovery in between that could still be a 20-minute workout but you've gotten in there 15 minutes of relatively intense training. Again push as hard as you can go. So they power output say you're working out or going to be different than when you're doing tomatoes and maybe some days do a minute on minute off repeated 10 times even five times, right? There's because that was a protocol that we've used a lot in our studies minute, on minute off repeated ten times took about 25 minutes for
Jules. But now there's studies that have looked at five by one showing that much of the improvements certainly in view to Max is almost as good. So again, when we're doing 10 by one, we're bringing out the sponge a little bit more, but you get a lot of water out of five by one. So I would say very up your your intervals and Recovery periods. Ideally, in order to change up the physiological stress on the body. Now again, you're someone who says I only have 10 minutes in the morning.
Morning and I absolutely love to bodice. Okay, like you're so far ahead of the game compared to many, but I think if you're looking to optimize or maybe that's going to give a different lactate profile to your brain, that may be at least different. I can't guarantee you it's better, but I suspect for improvements in your car, to your spirit, or a fitness and that the different challenge, may maybe a little better. This is great. Marty because I think I am look, if I have 10 minutes, I have 20 and there's certainly some days, I definitely have 20
Others may be 10, you know, like today it was like 10 minutes. I got Marty's coming. I gotta mean I got to do something but you know, I think a lot of people are interested in that because there are different goals. As you mentioned, you know, what are your goals? Are you an athlete? Okay, then 80/20 like, there's lots, I mean, you're putting in the time no matter what, but but there's also people time like anything. So there's those people would like I can't think about, you know, doing you know, maximizing, what I can out of the vo2max and squeezing the cloth and
Every last drop I just gotta like I got 10 minutes or, you know, and I can only do that X many times like, you know, four or five times a week, or maybe some people like 20 minutes. I can do three times a week but then, you know, I am interested in optimizing for vo2max as much as I can while still being time-efficient, you know? And and that I do think there's a, there's a large audience, it's very that's in that camp, where it's like I want to be time-efficient. I want to still really optimized for Bo to me.
And there are really, I would say pretty strong data correlating vo2max. Also with brain health, of course, cardiovascular systems are very related related to the brain, vascular Health, right? So that is really good. We talked about Tabata, we talked about 10 by 1 or 5 by 1. You even talked about some of these longer ones which were like three to five minutes and then your 1 minute. So your was your one minute workout based on the sort where the where the title of the book came from was. So our initial studies, you know,
Fast forward, 15, 20 years of research, our initial studies in this area. We were using the Wingate test. There's a long reasons for that but we were doing these 30-second wingate's. Again, these are uncomfortable people hate them. You need 45 minutes recovery. At least before we can coax you to do another one. But the point is 45, windgates. Still takes 25 or 30 minutes and so it's still a significant time commitment. And so people were saying, well, you know, some of the critics
Rightly pointing out. Well, if it's taking a 30 minutes and you're doing three times a week, you're already getting up there. So really how time efficient is it, and so we wanted to devise protocol where no one would argue that. It was time, efficient. And so, that's where the, and, and the other is it's the last 10 seconds argue, the last 15 seconds of The Windgate that hurt the most. So, you know, basically after about 15 seconds of Wingate, you shut off glycogen utilization. You've just produced so much lactate in your pH changes so much so
If a lot of these responses are in part related to the reduction in glycogen, maybe only need 15 or 20 seconds to trigger some of these responses. So all that to say we came up with a protocol that was three 20 second intervals, five-minute total warm up and cool down and some recovery in between the intervals. So start to finish the protocol took 10 minutes and within that there was one minute a very vigorous exercise, it was the one minute workout.
I think we've at least talked about it before the notion of re hit at the same time as we were sort of coming up with the one minute. Workout, UK researchers Metcalf, vo lured. They've done a lot of this work, they termed what they called. Reduced exertion high intensity training on a very similar theme where they were using a 10-minute start to finish work out. But their protocol involves 10 to 20, only 12 to 10 to 20, s efforts.
So all of this variations on a theme where we're talking, no more than one minute of very intense exercise in a 10-minute time course. And you know that we've done a number of studies. Now looking at that, that work out and showing that certainly, you know, it can prove you too. Many of the things we've talked about, it can improve it to it, at least very similar extent, as more traditional moderate-intensity continuous training, that takes five times longer five,
time's the total exercise volume.
That's a, that's a really big interest. I mean, I think into a lot of people. So I mean that's for me and I mean people that I know a lot of busy people that I know. I mean it's like, you know, so I guess the the the moral of the story here as I think I've the work to rest ratios in a way, do matter to some respect because that was kind of a big question for me. Was the what I'm doing every day was very specific work to rest ratio.
But going going a little bit harder and that really does make sense. And I knew it like, there's something in me that was like, I just need to hear. Marty, tell me so, thank you. You mentioned some of the other protocols like the re-hit. What, how does that, you know, how would you say that really differs from high intensity interval training? I mean, with respect to maybe some of these endpoints were talking about like vo2max. So again, like, you know, first of all, it's all interval training, whether it's hit depends on your definition,
Finished in a little bit. And so that's why again you know I really like this idea this this notion or this terminology of interval training because it covers all the bases. Its just alternating more intense, less intense periods of of work. High intensity for many is 80% or higher heart rate as a metric. And you know and we've done this but to try and because our first work, we called Everything hit, right? Which is much of the field at the time, everything was hit but you know, five minutes at
80% of view to Max is a very different stress as we just talked about from a 20-second about a workout. So at least to try and distinguish the interval training a little bit more there, is this move to try and distinguish hit, which is intense, but submaximal efforts from sit or Sprint, type training, which is much closer to the Sprint from danger, paste type type efforts. So, you know, I would say re-hit is absolutely interval training. It's
Probably closer to Sprint, type training, then traditional hit, which just because of the power outputs, you know, you're working 10/22. But these are very, very high power outputs that you're generating and much higher than vo2max pace. So I was completely confused about that because reduced exertion to me, I was going, oh, this is less than eighty percent. So the reduced exertion, it was 10 or 20.
S. It feels a lot easier than a 30-second Wingate. And it was because, you know, these investigators know, 32nd, wooden gates hurt and all of the lactic acid in the pain and the discomfort, and even the nausea and dizziness, sometimes it can go wrong with 30 seconds. If you're doing 15 or 10 seconds, much of that is is attenuated. So the exertion comes down from the metabolic feelings and it's not the exertion level in terms of the power outputs on on
Like, you know, just to take that one step further, dr. Ed coil, at the University of Texas at Austin. Big name in the field of exercise physiology, doctor coils. Recent work is looking at for second all-out efforts, but doing a fair number of them and it's really just a variation on a theme and dr. Coils point would be you can work, very, very hard even fairly deconditioned people can put out, extremely high power outputs for 4 seconds, then you give them I think.
It's 12 seconds recovery, and they do it again. And so, the point there is these very short, very hard efforts aren't associated with the feeling the perceptions of discomfort. When we initially think of Wingate test, Sprint from danger pace. And you know, I there's a lot of critics certainly on the behavioral side of things who are saying interval training is doomed to failure as a public health priority, because we know that anything above lactate threshold,
Hold it hurts. It makes people uncomfortable, they're less likely to do it, but there's a whole nother group in the exercise Behavior. Fielder going like, well, wait a minute continuous high intensity efforts, even continuous, Sprint efforts are very different from intermittent, high-intensity efforts. And so, there's a lot of certainly, a lot of arguing right now and a lot of Twitter polemics, but I think still a lot of good work to be done. Looking at these perceptual responses to different types of
Well training, it's it's too simplistic to just go, well, Sprint, type training. No one's going to do that because it hurts because now there's evidence to show that. Well, actually, it doesn't when people rate this, they don't find it as unpleasant as uncomfortable as some make it out to claim that it is. So the reduce exertion interval training, the re-hit reduced exertion high intensity training. Is you still there messing around with more the work to rest ratios and you are still going, you still
I'm very hard but you're perceived exertion isn't as high as it would be if you were doing a wing Gator, Sprint, interval training, and so at the end of the day, it really goes to say that you know, perceived exertion isn't necessarily the best way to gauge how hard you're going because if you're still going hard on your 45 seconds, you know, you're doing good and then, you know, it's just this is great. I think this is very clear to me.
Because, you know, the the resume that must be why I'm so drawn to debod to devadas as well, because I'm going hard for 20 seconds versus three minutes. I mean one minute is hard, like it's definitely going to be different and it is, it is, you know, these behavioral psychologist or whatever Twitter polemics that you're talking about, they don't they must not know about David Goggins and the whole movement of you have to suffer to get the to get the gains and you know so there are people that are willing to put in that effort.
There are people that do want to suffer and they will there's some days where you just don't write. There's just some days where you're not going to do that but there are days where some people are very motivated and knowing you know to be clear. These are these are these are very good scientists on both sides who are very careful methodological people you know they so I respect the scientists on both sides of the issue but yeah to your point I think my sense is when it comes to
Higher intensity, especially short duration work the traditional way of thinking. When we think of perceived effort, it's just, it doesn't fit as well, right? Like classic Borg rpe scales are, you know, based on 6220 because that generally correlated with, you know, young fit individuals who had a resting heart rate of 60 in a maximum heart rate of 200. That's where that rating scale comes in. And so, you know, the more
Hence, especially if it's continuous exercise, the higher, the heart rate, the higher, the perceived effort. But we just see such a disconnect between ratings of perceived effort and heart rate. I'll give you a very specific example. We've done a study looking at that 10 by one protocol. So these are 10 one minute efforts at objectively measured, maximal heart rates of 85 to 90 percent of Maximum in older individuals 63 years.
On average obese with type 2 diabetes, on a 10-point rating scale. They started out as a 5 they eventually got to about 1/8 and so the average rpe was about a seven out of ten even though these people were doing very high power outputs at very high percentages of their maximum heart rate so it's just a striking example. In our initial Sprint studies the one-minute Sprint's studies three 22nd efforts. Our first ones we were saying
Go as hard as you can Sprint from danger pace and we and and those we are using a 20 point scale they'd come back 14 15 out of 20. Because now if we ask them to continue that Sprint Pace for a minute, I'm sure we got to 20 but since they're so short. So yeah, to your point is exactly right perceived effort, I don't want to say it, goes out the window but it maybe needs a rethink when we're referring to these very short, very hard, intermittent type efforts,
Where do you think? Let's say someone new to hit, we're like what a good place to start. Be more of these like shorter like in a really good question. And this is where you know, we haven't really talked health risk and all that. I'm sure we'll get into it. But like a standard thing that will just tell people is get out of your comfort zone. So wherever your starting point is your own perceived starting point. Make yourself a little bit more uncomfortable than usual, for a short period. And then
Back off. And so, you know, I use this analogy all the time, if you're only exercise is walking around the block and you want to get into intervals, it's literally for the next to light post. I'm going to pick up the pace a little bit and then I'm going to back off. So I feel a little bit more out of breath. I can feel I'm breathing a little bit more. I can't talk to my partner, like I generally can on our moderate walks, it can be as simple as that, just get it out of your comfort zone. If you're someone who's already dialed in on the bike and you got a smartwatch.
All of that it's like, hey, get your heart rate up, longer or go longer and try and keep your heart rate there. You know, or rather than 20 seconds you're going to go for three minutes as hard as you can and I can be like him. Yeah, I know. And next time we're going to do that but it's going to be a very different challenge for you, right? And this is where I think that the more empowering term interval training. It's okay, because it doesn't matter if you're magically getting to some 80% leveler. Whatever the
Bert's tell you you should be at it's just start with the alternating pattern and then build from there, start to dial it in maybe a little bit more and get more Discerning. But as a starting point, just get out of your comfort zone and back off and repeat that a few times, this kind of reminds me of the was the interval Walker's versus the Walkers solutely. Yes. But you know, excellent data. And these are, you know, relatively small but well controlled randomized. Controlled trials. Looking at interval
Walking versus continuous steady state, walking, including an individuals with type 2 diabetes. 34 month interventions, where individuals were randomly assigned to an interval walking group? Continuous walking or control group the interval and continuous Walker's matched for total exercise, volume total exercise intensity. So you can imagine the, The Continuous Walkers, I think, their average heart rate was around 65% of
Mom, the interval walkers. Got that up to 70 and then down to 60. So we're just talking gentle Hills and Valleys after four months. The interval Walker's greater Improvement in Cartier Spirit, or a fitness greater reduction in a greater change in body, composition greater loss of fat, and most importantly, individuals, type 2, diabetes, greater reduction in 24-hour. Blood sugar measured using continuous glucose monitor.
So it's not to say that continuous walking is bad. I think it's just a little bit of evidence that adding some intervals are varying. The pace even slightly, we're not talking. Sprint training May provide some greater benefit and this kind of relates to something. I was going to ask you about which is you know, interval training for maybe elderly and maybe infirmed. So people that are more sick, you know, like how they can incorporate interval training into their lifestyle and also then like contraindicated
Don't contraindication. Like so you mentioned like like maybe some people you know, is there some people that high intensity interval training is not good for on? How would, you know, sort of all of those? Yeah, so in this, you know, this I always make the point here. I'm a PhD scientists, I read the literature, I'm not a medical doctor, I'm not a cardiologist, I read work like that, I try and stay informed on it and certainly for my book, I interviewed people like dr. Paul Thompson, right noted cardiologist. Who writes many of the guidelines.
Ends around this very, very issue. But first point I always make, is that interval training as we've talked about, a lot comes in many different flavors. So, second point is that many more people than we initially think, can perform and benefit from interval training, and they're just now, there's hundreds and hundreds of studies that have looked at interval training in individuals with cardio, metabolic disease, cardiovascular.
He's heart disease. Type 2, diabetes older individuals, people with metabolic syndrome and a lot of this is not new, you can find studies going back to the 70s and 80s some of the pioneering work looking at interval training and individuals with heart disease. So the notion that people could, you know, individuals with cardiometabolic diseases could engage in benefit from interval. Training is certainly not new. But there remains immense debate and I think it's we're all reading the same size.
Science. And some people, again, I'm talking about the field broadly, some want to see the science get to a certain level before they recommend changes and where that level is is different. So for example, high intensity interval training, my read is, is much more ingrained in Europe and certainly in Scandinavian countries. It's, you know, much of the pioneering work around, high intensity, interval training, and cardiovascular disease was was done in Norway, in the work of Ulrich whistle off and that goes back to the
Calculator that we talked about earlier, but there I think it's much more generally accepted and integrated into cardiac rehab training or I think in North America, it's it's not right, and so that's not necessarily good or bad. I think it's the experts, the cardiologist, the people who write the guidelines looking at the evidence and saying, man, you know, some are more like I say with the there's different viewpoints on that in terms of risk.
And again, I'm not an MD or a cardiologist, but in there's no doubt that more vigorous intensity exercise can transiently increase risk of an event during the exercise bout itself. I think there's there's fairly strong evidence for that. And, you know, in preparing for our interview, I was reading some of the latest guidelines expert. Guidelines around that making that point, you know, and especially in more deconditioned individuals people might already.
Some silent underlying risk factors and so we can't ignore that or downplay it or say that everyone can do interval training, it's fine, but the absolute risk Still Remains low. When you look at events per hours engaged in actual exercise, both moderate and vigorous type effort whether it's continuous or intermittent, the absolute rates remain relatively low, but statistically, there is definitely
An increase in Risk, that's higher with vigorous exercise during the event itself. Now, of course, after the event relative risk is much lower than individuals who would remain sedentary. So, you know, I think the old adage of the greatest risk to your health is just remain. Sedentary is absolutely true, right? And so when I is, was striking phrase that dr. Thompson, used when we interviewed him for the book was, you know, if your choice is between doing hit and doing nothing. Do hit if the choice is between
Hit and moderate, and you're 60, and you've been pretty inactive. You might have some underlying factors and time is not a worry. Do moderate, or at least engage in some water. It is some preconditioning before you start with the, the more intense stuff and then on the, you know, who is absolutely contraindicated atrial fibrillation, is there are some very clearly defined. No go.
Was that if you have certain conditions that you shouldn't be engaging, vigorous intensity exercise. Unstable angina would be another example. Yeah. Sounds like a lot of the I mean things that you would talk to your cardiologist about. You'd already have a cardiologist if you know that you had that sort of disorder. So the last point I would make is, you know, in talking to many Physicians and cardiologists. You know, we think an exercise stress test, sort of gives you that green light or red light to engage in exercise. And in certainly, in our studies
Are individuals had elevated risk people with type 2 diabetes in that. Everyone does a 12-lead ECG stress test before they're recruited into the study. But you know, I naively thought, okay? The person doing the stress, test, the cardiologist reading it. It's going to come back and it's a green light. Good to go in your study red light. Unable what we found was a lot of yellow lights. Hmm. Maybe you know, this person might be contraindicated or there's a change here that might Elevate risk. And so of course we defer
To safety. And so, even those yellow lights, generally, those individuals were not then recruited into the study, which is no doubt influencing outcomes. But I always wonder I'm like, so, are these people just going to sit around and continue doing nothing and is that in itself, raising their their risk. So it's, you know, it even, you know, the standard, you know recommendation, see your doctor get clearance before you change or engage in exercise.
Sighs. It's not always 100% guarantee one way or the other. In terms of, you may deal with a sudden adverse event, we might see it in a twenty-year-old in my lab tomorrow. You can't absolutely rule out these things. I think also mentioning the the Walkers, the interval Walker's versus continuous Walker's was really good. Because, you know, it also kind of highlights the fact that you don't have to go to your 80 percent, max heart rate for interval training and
Perhaps people that are older people that might have some underlying conditions people that are untrained and are starting later in life great. You never, it's never too late to start. They can they can start by, you know, by doing, you know, intervals, that are not necessarily all out, or even submaximal, right? Me just just going a little bit above, what your steady state being able to talk normally sort of conversation is? And you know, I don't think that, you know, my sense is that
Is that many of your listeners are already aware of this? But I think still for a lot of people are certainly the general public, they hear the word hit or interval training and they think, oh my goodness. It's this as hard as you can go, all out Breakneck pace and that's not for me and I think that's a disservice. And, and again, hopefully this
More encompassing term of interval training. It's just this idea of Hills and Valleys, right? And the other point to that is talk to I'm not name-dropping here but just, you know, many people have thought about this for a long time. I also interviewed for the book Karl Foster who has done a lot of work around this and when he first heard, you know, as a scientist in the 80s that there was a group in Germany that was doing interval training in cardiac patients. He saw one of the scientists at a conference
I said oh how many people you killed this week with that crazy stuff and he was relaying that story to a cardiac nurse when he got back to his institution and the nurse. He said sort of tapped him on the cheek and said, oh Carl you're so silly. And she said, look at this patient in the parking lot, who's coming for his cardiac rehab, setting, Earth session. They already engaged in interval training because they can't. They have such low Exercise capacity, they can't get to a continuous moderate pace.
So what they do is they innately interval training, they get out of their car, they take a few steps, they take a break, they take a few more steps. They take a break, it's bit like, Climbers, on Everest, right. And so again, that's a more empowering message, I think you're just starting out. That's okay. You can, you can train like, Elite athletes have trained. We just have to set the workout, approximate level, that's suitable for you rather than, you know, oh my goodness, people are destined to be a failure because very few
Engage in continuous, moderate exercise for a period of even 20 or 30 minutes, because their capacities are so low. So, it's a bit of the behavioral colleagues talk about message framing. I think there's a lot of that we can do with interval training, so for those individuals who just think it's this all out crazy stuff, I'd never do it. It's a, it's a reframing of it for them. Yeah. And also again the the modifying, the work to rest ratios to is another sort of way, I think that it's like although I have to go all out for a minute or two minutes.
It's or three minutes but what about 10 seconds, you know what about 10 seconds. So it's absolutely a lot of there's a lot of ways to sort of modify the you know the hit program in general what about this? The the is it high. The high intensity resistance training or resistance, intensity training, which way it goes different way, you know, some people call functional training but certainly there's high intensity resistance training, you know?
I think can still count, you know, for a lot of resistance training, just because the intensities are so high. You know, we're talking about now very high Force efforts that lasts less than a second sometimes by its definition it's interval training. We just never really think about that. But so I think certainly body weight, style, type interval training, or what used to be traditional calisthenics and that that can play a role.
You're so I think again, using this generic term interval training, I think we can have more aerobic style interval training or resistance style interval training, and again, body weight style interval training, would sort of be the classic one. To me that is interval resistance training and I think it had can have tremendous benefit, you know, it's often a sort of a middle ground, you're not going to see the gains in strength that you would see with.
National heavy, weight, lifting exercise. And you're not necessarily going to see the gains and fitness that you would have with a traditional well-structured aerobic training program, but you can get a lot of both right in the middle, you know, especially if you know we're talking air squats, burpees sets push-ups where you also keep recovery periods, relatively short, you know, you engage in that for 10 to 20 minutes you can keep your maximum, your heart rate up to about 80 percent of Maximum. But you've done a lot of resistance style training,
Again studies including from dr. Brooks and others to show that you know, first of all skeletal muscle can produce lactate under fully aerobic conditions. So there's always some lactate production happening and certainly during more intensive exercise where we produce lactate inside the muscles, it can be released from active skeletal muscle. It can circulate to other places like the heart, like the liver, like the brain, but certainly in heart, heart can be a big consumer of lactate and so it takes up that
At lactate can convert it back to glucose and then utilize it during exercise. And so this is the idea of cell-to-cell or inter organ lactate exchange. And I think that's very well established now like you and you would be far ahead of me. But I'm, I'm following this area with with immense interest. I have some colleagues at McMaster where, you know, both from a cognitive psychology standpoint and also more a hardcore neurophysiology standpoint.
Engage in some collaborative research with them but generally looking at this question of physical activity and brain health and probing the role of intensity there. So you know my my understanding is mainly based on talking to my colleagues trying to read reviews of some of this research and my sense is you know very well established potential mechanisms. Now from some of the animal studies and and the
And data is certainly intriguing, but you know, that link between lactate bdnf, absolutely. There appears to be a role for intensity there in terms of higher intensities. The better in terms of, you know, potential bdnf, bathing the brain. Some of these outcomes associated with neurogenic neurogenesis. Yeah, it's the lactate and we can talk about measuring it but it's interesting because I do measure
And I do the finger prick and I'm my workouts, I'm like trying to go higher for my Lactaid, you know, and I've read a lot of study for me. I'm very interested in erdheim disease there's but on both sides of my family Alzheimer's and Parkinson's. So to me, I'm like I need to really focus on brain health and so looking at the studies on lactate and even infusing lactate into humans, it increases bdnf, just infusing it and I'm like, oh I
Get these levels from, I really all out hard workouts. Like this is, this is great, but also I feel really good. So I start my day with couldn't today, most most days, you know, at least five days a week I'm doing a and will I want to talk about protocols but I'm doing like a 10-minute, you know. Tabata. So so I'm doing two back-to-back to bodice actually it's two back-to-back, two bottles and then I have there's some, you know, minute minute warm-up and a minute cooldown. I actually
Don't I use them more for? I'm actually still going hard like half the time and then I like cool down after that minute. So I like at the end, I go and all out, man. It after my two back-to-back devadas and then I'm like and then I cool down. But, you know, I do this for my brain, I feel amazing and there's actually science showing that executive function is improved and it's totally correlates in. This isn't humans with lactate after high intensity exercise. And it doesn't correlate with anything else. No glucose.
Like nothing. It's specific to the lactate. And like you said, it's a growing area of research. I'm particularly interested in it. Like I for sure. Notice a difference, in terms of like if I go hard like I feel better, I feel smarter I'm like, more on task, you know. So for me, it's a very important part of my protocol and I do think there's a lot of benefits for the brain. So I'll have to be in touch with some of your colleagues at McMaster,
Because I love sharing studies and stuff that I find and learning what, you know what other people are doing as well. And so the and maybe there's data out there on this. But, you know, the scientist in me, is innately, curious around things like I, you know, maybe now there's really, really good dose-response stuff in terms of exercise dose and bdnf increase in some of these other measures. But, you know, so for example, is short, sharp large changes in lactate.
Better than prolonged moderate levels of lactate, right? And I'll tell you something, it's not lactate that I've looked into you, but I've looked into blood flow and Shear force. And I think this is a very, I think it's an emerging field looking at the effects of Shear Force. And and that is where I mean, we're talking about a flash flood coming through. If you're talking about high intensity versus just, you know, a little trickling and the shear Force itself at least at the blood-brain barrier,
Barrier. And this kind of, when you were talking about muscle capillary, I was thinking about the shear force it in and of itself. In a dose-dependent manner is responsible for increasing vegf and bdnf, at the blood-brain barrier again, dose-dependent all on the shear Force effects meccano. You know, these mechanoreceptors that are on Solid Surfaces and stuff like these are all sensing things and it's also very important. So I think it's another. So there's the lactate, a part of it where you're increasing the lactate and it's a quick.
Sort of and it is like I've measured my Lactaid spikes up, you know, I don't get up to levels that my husband, I'm more like a 78 millimolar and he gets up to like 14, but it's it after 20 minutes. I mean, I'm back down to 1 millimolar. I'm to my Baseline basically. So you know is it is there something with that? You know lactate you know going intensely up. It also the sheer force. I think there's another interesting component to that that I think needs to be.
Muscles can use, but herein lies and intriguing question. If that quote unquote access lactate is actually Fuel and a signaling molecule for other tissues, including the brain, are we missing out on cognitive benefits by strictly limiting its cumulation as we would with Zone to. It's a thought-provoking conundrum about the realities of a phenomenon known as the lactate shuttle. We also touch on another fascinating.
Area like how exercise intensity affects blood flow Shear force. And the role this plays not only in our brains health and neurodegenerative disease but also metastatic cancer resistance. One of the qualities of cancer cells is that they sometimes have Barnett vulnerabilities that healthy cells, do not one. Such weakness of cancer cells is that of mechanical stress to put it another way when we exercise, we introduced a new type of stress to cancer the turbulence.
Movement creates in our bloodstream, can reduce the viability of these cells. As they attempt to metastasize, exercise, May reduce the risk of cancer metastasis and it's possible that vigorousness plays a role amplifying the effect. So whether you're an athlete or a fitness Enthusiast or someone simply keen on Aging. Well, and maintaining mental sharpness, today's episode with dr. Gabor Allah is a treasure Trove of information on the many unique qualities of vigorous exercise.
Before we jump into the Brilliance of hit with expert, Marty Kabbalah, let's pause a moment to appreciate the energy behind this content, you are Community. This podcast is not sponsored. It's powered by our fans. Every podcast, every topic article, like our new one on photobiomodulation known as red light therapy, even our extensive show notes sent straight to your inbox. Through our free email newsletter is a testament to our shared passion, but for those
Wanting to dive deeper. Our premium membership is the Gateway bi-weekly my team and I craft the science digest an email Roundup of the latest breakthroughs and interests plus each month. I host an interactive Q&A session. Discussing everything from recent episodes to popular health and science queries. These sessions along with the collection of exclusive episodes, find their home, in our members, only podcast feed called the aliquot, organized for easy,
Fleur ation. If you would like to support our mission amplify, our voice and immerse yourself in the premium experience, you can learn more at found my fitness.com, forward slash premium. That's PR e m. I, um, all right enough, introductions, let's embark on this intellectual Journey with dr. Gabor Allah.
Hi everyone. I'm sitting here with dr. Martin Kabbalah who is an exercise physiologist and professor at McMaster University in Hamilton Ontario. I'm pretty excited to be sitting here with Marty perhaps. He's most well known for his research on pioneering research on high intensity interval training. He wrote a very popular book called the one minute workout. As you know Marty I'm very excited to have you here because
I feel like there's a lot of health benefits that can be achieved in a short amount of time. If the right intention is there, if you are pushing hard, you are doing a intense workout and for me, it's very appealing as a full-time mother full-time. You know, I work full time time is the limiting factor for me, so maybe we could just jump right in this high intensity interval training.
And start with defining some of these terms or differentiating between high intensity training HIIT and high intensity interval training. HIIT both short hit right, so, so thanks for the opportunity, lots of different ways to Define things. I think there can be General agreement than when we say high intensity, we're talking a relative heart rate of about eighty percent of your maximum, but there's no Universal definition.
For high intensity training or high intensity interval training, but that would be a typical or average threshold. So about 80% of Max, you're working pretty hard, but it's not an all-out Sprint. Again, the other eye in there is just intermittent so this idea of going relatively hard backing off and repeating that pattern a couple of times and interval training. It's this thing that we seem to ReDiscover every decade or so you know athletes have used it since the turn of the century but it's certainly become popular in the last decade or so or
Dude, popularity, because many people cite time. As a major barrier, some more legitimate than others. Of course, if it's a real-time press issue, or not is interval training. Like when you say interval training because you said, high-intensity Goin, like 80 percent of your max heart rate if you're doing is interval training also that as well as just kind of interchange or is it like you go a little bit less than that? Increasingly? I like the term interval training as a more General catch.
All term. And again that's just relatively harder effort and backing off, but it provides I think more of a broader way of doing that. So if you're just starting out getting into exercise, maybe you just want to start out by walking fast for a few light post and then backing it off. That's a form of interval training. Don't worry at all about whether you're at 80%. So I think of hit high intensity, interval training as one type or one facet of interval training.
As opposed to being the be all and end all got it. So with high intensity interval training, hit. There's, I've heard you talk about and you've published research, you've wrote written about it in a popular book. The health benefits of high intensity interval training on vo2max, which I'm sure you're going to talk all about. But recently there's been a very another form that's become very popular of training for improving.
Geomap VO2 max which is Zone 2 training as defined by a lower intensity sort of lactate threshold training. However that type of training does require a pretty big time commitment. I mean anywhere between three to six hours a week. So can someone achieve similar improvements or really good improvements in VO2 max from doing let's say 20 to 25 minutes of high intensity interval training, 3 to 4 times a week. And
If so you know what are we leaving anything on the table? If you know we're not doing that long-duration sort of Zone to type of training. Yeah. So in short I think you can do more vigorous or high intensity exercise for shorter periods of time and at least see similar improvements in VO2 max. So for the individual who is time pressed, I don't there think there's a need to do three to four hours of what I understand to be Zone to training weekly in order to
surmise improvements and view to maxing. In fact, there's evidence that would suggest that more vigorous intensity exercise higher intensity. Exercise can potentiate ER lead to Greater improvements in VO2 max or eliminate what's known as non response. So some people engage in training and it's very frustrating because their view to Max doesn't change at all and and there's various reasons for that we can talk about. But for example, some evidence has shown that moderate-intensity continuous.
Exercise even for six months. Or so doing guideline based evidence, roughly 40 percent of people don't see a measurable Improvement in their VO2 max. Now, some of that non-response was eliminated in a group that was doing the same total amount of exercise, but engaging in a more vigorous manner. So that would seem to argue against Zone to somewhat, but I think, you know, there's all all roads lead to Rome.
Umm, you know, there's many different strategies that you can engage in successfully and I think a big thing is, what do you like, right? Do you, like and enjoy? Vigorous, intermittent type exercise. Then maybe it's for you. If you prefer continuous lower intensity. Moderate exercise training and that's just what you like and you absolutely hate intervals. That's okay too. Can you talk about what VO2 max is? We hear a lot about it and why it's important for health longevity and maybe why athletes would be interested in it as well? Sure. Soviet
Max is the maximum rate of oxygen uptake by the body. It's typically measured during an incremental exercise test. So you get up to very high work rates and that's where you'll see your highest rate of oxygen uptake, it's determined by many physiological factors and processes but it reflects the peak integrated capacity of the cardiovascular respiratory, the blood the skeletal muscle system to take up and utilize.
Oxygen. It's clearly important for athletes, it sort of sets the ceiling, you know, when a challenge for athletes, in many events is how close to the ceiling. Can you work for a defined period of time? And so, you know, the higher the oxygen uptake, the better. It's also the the clinical correlates of you to Max is Cartier, Spirit or E Fitness. So VO2, max is the best objective measure of cardio Spirit or a fitness and why Fitness is so important epidemiological.
What
is show having a hire car? Dear Spirit or a fitness is associated with a reduction in all cause mortality dying from all causes, as well as developing many different chronic diseases, cardiovascular disease, type 2 diabetes. So bottom line is having a higher Fitness is better. It protects you, it reduces your risk of dying and develop diseases. And the best way to measure that is through a VO2 max test. So you mentioned these, these epidemiological studies these
relational studies that are looking at the correlation between higher vo2max and let's say all cause mortality. There's a really I think important paper that was published in Jama in 2018 that showed there was an inverse relationship between vo2max and all-cause mortality with no apparent upper limit. And the elite performing athletes or the leak Elite performers, had a 80% reduction in all cause mortality compared to the
As performers with their VO2 max. So my question for you is, do you think someone who is doing? Let's say, you know, again doing the high intensity interval training, mostly and 20-25 minutes, three or four times a week. Do you think they can be one of those Elite? Is that, like what you would think would be in the lead performer in terms of their VO2, max, or do you have to be an athlete? How can someone do we need to do?
Do extra, you know, types of training on top of the hit to really get to that level at 80%. Yeah, and so there's lots of things there and I think to be clear the way that an individual may choose to engage in physical activity or exercise for their General, Health is completely different from a way that an elite endurance athlete, might train and that has to do with lots of things, including What's the total volume of training. So if you're a serious or an elite or very high-level endurance, athlete
You're engaged in 15, 20 sessions of training per week, your training, 25, 30 hours, a week of training, and the best evidence, you know, gleaned with that's, there's some scientific evidence largely, you know, a pinion from high-level coaches and athletes is about an 80/20 split. There is sort of the ideal mixture ratio to optimize endurance performance, so about 80% low to moderate intensity type.
Raining and 20% high intensity training, much of it including interval training again that's the way the an elite athlete might train who's putting in 25 30 hours a week. I think that ratio can change. If we're talking about someone who's engaging in one to two or three to four hours a week of physical activity, and they're looking to optimize how to structure that type of training fit within their regular lives.
I think they're that ratio can change fairly substantially and you can incorporate, I would submit that engaging in more vigorous intensity type exercise. If you're only doing one two, three hours a week May potentiate or give you a further boost in Fitness, so even even potentially 11 our 1/2 hour hours a week because that's that's also something, I mean you mentioned the 80/20 split and that's something I've heard about a lot and I think about it because I am not an athlete, I am
You know, far from an athlete, I am a committed. You know, exerciser, I guess you would call it. I mean, and I, you know, I am also very interested in longevity and improving my VO2 max and I want to talk about measuring that at the, you know, in a minute. But so it's, you know, it's not like finding. If is there a minimum effective dose where we can get 80% of the, you know, improvements in VO2 max, that an athlete would get? I mean that, you know, because if I if I if I can get like eight
80%, you know, I men like that. That's a good amount because there's just, there's no way, I will be an athlete, like that's not my life, I can't do that, you know, but I want to get those improvements in VO2. Max. Correct know and you know, I would consider myself very similar, I'm a committed exercise, you know, it's in my calendar, I'm sure much like, yours isn't. I'm trying it. But, you know, you're busy, trying to think what's the best way to structure that. But, you know, so, a couple things I think,
Whatever reason you're active or exercising for what's the goal, is it performance? Is it General Health? Is it trying to optimize that time? And I think for a lot of people it does seem to be this is how much time I have, you know, maybe it's one hour a week, maybe it's two hours a week. What's the best way that I can utilize that time to promote my overall health? And for those individuals, again, I would submit that, there is good evidence that engaging in more, vigorous intensity.
Sighs May potentiate the gains that's not to say it's the prescription for everyone and the other thing I think we need to remember about VO2 max is the greatest gains are with the smaller changes in Fitness, right? So we taught Louis look at, you know, people who are have low moderate and high physical activity levels or low moderate, and High View to max levels. The greatest bang for your buck is just getting out of that low range, right? And then there you continue to gain benefits but you get the
Diminishing returns and the extreme would be the elite athlete who's pretty much doing everything right to maximize their physiology and now they're really just plan on that upper margin. You know, what can I possibly do to e-coat a little bit more gain that the way that way of thinking and training is not necessarily the way that average everyday people even serious committed. Exercisers who are primarily interested in health need to think right likes to I like stews analogy of like squeezing the wet.
How am I getting the last drops out? You know, you know, that that's something that, you know, maybe if I was more of an elite athlete that I would be interested in doing. But right now, I'm like, how can I get to that? And you know, you know where I'm at least 80, 80 percent of getting that VO2 max, you know, maybe maybe getting all of it if I could. Like I do going going hard and getting it but you do make going hard. You mentioned intensity high intensity interval training, 80%, max heart rate, there's their disease, you know, calculators for me.
Maximum heart rate, you know, I guess it's I would say there's an equation that most people use 220 minus your age but that's doesn't consider Fitness levels. I mean, there's is that would you say that's still kind of the best way for someone who is not going to go out? Or should they like go do an all-out Sprint or something and measure their max heart rate. So I and there, you know, 220 minus your age is still probably the most common. There's a number of other formulas formulas that have been proposed and looked at scientifically. I think the key thing to remember is
There's variability around that. And so if we had 1000 of your listeners and they were all 40 years old, we could be reasonably confident that the average maximum heart rate of those thousand listeners is 180, 220, minus 40. But there's going to be tremendous, inter-individual variability there. And what we call the standard deviation, it's around 10 beats per minute. But what that means is about two-thirds of your listeners would fall somewhere between
Between 170 and 190 95% of listeners would fall somewhere between 160 and 200 and there'd be five percent on either tail, two and a half percent each where their maximum heart rate is actually below 160 or above 200. So, there's a huge range there. And so when you just pick, so, for an individual listener. Now, they're going to work at 220 minus their age. It might be dramatically
Under estimating, intensity or dramatically, overestimating intensity. So, 220, minus your age. It's fine. I think a better way to do it. Is just try and measure it on yourself and there's different ways to do that. The classic would be to go out to a local high school or running track and run a 400-meter or 400-yard Loop 11 time around as hard as you can. You're going to pretty much get to your maximum heart rate by the end or if you're on a bike you know stationary ergometer just ride it.
Higher and higher intensity. So you're increasing the W. Every one minute you're putting it up 10 or 20 watts until you can't go anymore. You're going to be able to measure your individual maximum heart rate, whether you palpate that, whether you're using the hand or whether you have a chest strap or your monitor on. So bottom line is measuring it. Directly on yourself is always going to be better. Well that's those are some good suggestions that I'm going to do myself for sure because I have not done the actual test that
Something. Something they call the stress test to that. Some people do you stress your body to the Limit? Exactly. You know, in so definitely, you know, we have people come into our lab and get tested all the time on a view to Max test and we'll be able to give them their maximum heart rate. Measured very, very accurately but it's also something you can do on your own very cheaply, right? Is as long as you're measuring it with a reasonably accurate device, so it's sort of the, the simple way of getting it. Yeah. For the vo2max like,
Measuring the maximum amount of oxygen. You're taking enduring, I guess, maximal exercise, there's you mentioned to me. Most people are very interested in that and they're not going to get that measured directly either, not going to a lab like yours or to their, you know, physician doing it. But they want to know. Should I do it? Or is there a estimator I can do? That's good. Enough for, how do I decide if I should? Or shouldn't like what, you know, like athletes. Probably maybe they should. But, you know, so this
Count online, calculator, the World Fitness level, you mentioned. Maybe you could talk just briefly about the science behind that and sure so you know I'm not associated with this at all but World World Fitness calculator, is it? It's a valid calculator for estimating vo2max. And so what I mean by that is it's based largely on a lot of research that's been conducted in. Norway in particular Norwegian, Technological University, they've been real Pioneers in a
Lot of interval training research. And so the bottom line is they have a lot of data on measuring things and seeing how they correlate or are related to or can predict vo2max. And so of all of the calculators that are out there, I think this is the one that people could trust the most in terms of answering a few questions about their age, their sex, their typical activity.
Bowls and it will give them a reasonable estimate of their VO2 max, but it's still just an estimate because it's saying you're that typical 40 year old, it's not going to be able to dial in any better individually but at least it's going to give you a marker in the sand or reasonable marker and even if it's not precisely accurate, you can rest assured that it's going to allow you to track changes over time. So you plug your answers into the online calculator, it spits out a value and says your view to Max's.
38 or 45 and then, you engage in some sort of training program for three or six months and then you do it again and that if you see a directional change up, or down, hopefully up, you can be reasonably confident, that, you know, your training program has been effective at increasing your VO2 max, even if the precise number is not 100% accurate. Yeah, that makes sense. You know, I there's a few factors in there that were a little more
Um, on the personalized level, like your resting, heart rate, and your max heart rate and BMI and waist, waist to hip ratio, and are we circumference? I think it was. So it's, you know, there are definitely some some features aside from your rage and everything like that but also the the estimation of physic, like, how intense are you going with your exercise? You know that's that's a net of are there. So subjective component to it where I was like I go hard, you know so
You know, again I think it's kind of good to know that you can use that that online calculator people are interested in probably doing that. But for the average person, do you think measuring it directly? Is really the other way is an in between, if you will is there's submaximal exercise test and there's a number of validated tests that are out there. We could drop those in the show notes, but where you basically are performing a couple of levels of submaximal exercise measuring your heart rate.
And then essentially plug it into an equation that's going to extrapolate and said, okay with this is your rate of increase in heart rate. Once you get up to your maximum, this is what your VO2 max value would be. Or there's no if you have these here but the shuttle run test or a beep test where basically you're running back and forth between asset measured distance and after a point you're not able to keep up but it's called a shuttle run test or a beep test and it basically the more
Power. You're able to exert or the more that you can keep up with, as you have to get faster and faster to run between these two markers. That also correlates with your view to Max. So bottom line is, all of these are submaximal exercise tests. They're better than just an online questionnaire, even that validated one that I mentioned. Because at least it's providing some data about you. You know. So you can't just say, um, engaging in vigorous activity. It's going to actually measure your heart rate a little bit, so
That would sort of be an in-between. But yeah, the gold standard is having a vo2max done in an accredited laboratory and that's going to give you your view to max value directly. And it's also going to give you a lot of data on your power outputs, your heart rate to even your lactate in order to try and look at training zones. For example with respect to other cardiorespiratory adaptations. I mean VO2 max being you know the big one here, right? There's stroke.
Volume increases cardiac output. How does high intensity interval training effect? That's what are those? How does high intensity interval training affect them? May be compared to, you know, moderate-intensity continuous exercise. Yeah, sure. So you know what determines vo2max and as I alluded to earlier it's you know many physiological things but the prime there'd be General. Consensus scientific consensus that the primary factor that
Rates individuals in terms of their VO2, max is their cardiac output. So that's what is the maximum amount of blood and in turn oxygen or the maximum rate of blood and oxygen. It's being pumped out of your heart every minute. And so, a typical untrained individual would have a resting cardiac output of about 5 liters per minute. So if you were to measure how much blood comes out of your heart in a minute, about 5 liters, and maximal cardiac outputs,
We are somewhere around 15 to 20 in, you know, an untrained a moderately. Trained individual Elite athletes have maximal cardiac outputs of 40 liters per minute tremendous. And so again if you could pick one variable that's going to best predict differences between individuals, it would be maximal cardiac output and that's determined by. How often is your heart? Beating every minute, what your maximum heart rate times what you alluded to your stroke volume. And so that's just how much blood with each beat.
Squeezed out of the heart, the other primer determinant would be how well your muscles mainly extract or utilize that oxygen. So your your heart's pumping it out, your circulation is Distributing it through the body and then your muscles. And your mitochondria, ultimately have to use that oxygen and so for a long time, there was tension or debate around is it really the delivery side or the utilization side in terms of oxygen that limits vo2max and
certainly you can put people in situations where one or the other is more important. But generally speaking, it's the delivery side and that's primarily determined by your heart and probably why view too much VO2. Max is such a good measure of things like or predictor of things like all-cause. Mortality cardiovascular disease mortality because probably you know, a failing harder problems with your heart is a major contributor in a lot of those diseases. Yeah, and high.
The interval training. I know it affects cardiac cardiac output, right? And so is that another way of improving cardiac output and it is and so science, you know, now we're talking scientifically VO2 max is easy to measure you know. Basically any exercise physiology laboratory at any University private clinics or medical centers. They can all measure view to Maxwell because it's a relatively non-invasive measure, right? You put a tube in your mouth and you measure.
ER, the amount of oxygen and gas that gets expired. So it's easy to measure all these other things were talked about, certainly cardiac output even just think about what you would have to do to measure the maximum amount of blood that's being pumped out of your heart. Every minute and there are ways to do that, but there are highly specialized. They're very invasive, you know, requiring significant catheterization of your blood vessels. So the point is there's not a lot of direct measures.
Of of cardiac output or stroke volume, but there have been. And there's also ways to reasonable ways we've used in our laboratory to non-invasively assess cardiac output. And so some of those Studies have looked at the effect of interval versus continuous training on cardiac output and and they've shown that more vigorous or more high intensity exercise. May be associated with greater improvements in stroke volume and
Cardiac output as opposed to the same dose or same total amount of continuous moderate intensity training. So maybe if the dose was higher of the continuous moderate training, again, this sort of trade off between duration versus intensity. No, absolutely. And, you know, the other so many points to consider and, you know, I'm sure your audience is getting the sense, you know, there's a lot of nuance to all of this, which is very frustrating for people because they just want to hear, tell me what to do.
Do what is science say and science is always really great, right? It's it's not as clear as we would like often but you know when it comes even to exercise training studies most of my relatively short term, right a three-month training study is is it long time to measure some of these variables? And so, we don't necessarily know what the maximum potential is for vo2max and most individuals, right? And so if they engaged in longer periods of continuous,
Water training, would they all get to the same level, you know, and maybe hit in the shorter term studies, just get you there. The rate of improvement is a little faster than, with continuous, you know, or are you leaving something off the table by not engaging in the more vigorous effort, you know? I we don't conclude, we could get into a reasonable debate, put it that way of the answers, all those questions. Yeah, you mentioned the mitochondrial component. The
The the blood getting oxygen being delivered to the muscle. And, you know, mitochondria using that oxygen to produce energy. So maybe we can talk a little bit about some of the skeletal muscle adaptations from high intensity interval training, maybe compare and contrast, when we can to continuous exercise. But mitochondria are very, I mean, the, it's probably one of the most important organelles inside almost of our cells, particularly in must skeletal muscle cells, and I recall
A few studies from your lab and others showing that high intensity interval training was a very potent stimulus for mitochondrial biogenesis or the generation of new mitochondria. So can you talk a little bit about? I mean, how it affects mitochondrial, biogenesis. Maybe the difference between more continuous exercise, why that's important mitochondrial? Biogenesis sure. So you're absolutely right, you know, and I think even if people took high school biology
And to think of mitochondria, these sort of bean shaped things in your in your body. But we now know mitochondria, are this amazing reticular Network? So, it's a bit like, if you can imagine all of your capillaries that go through your, your, your skeletal muscle fibers, the best evidence. Now, it suggests that mitochondria sort of work the same way. It's this network of organelle that goes through muscle and and, and they can change, right? The the size of the organelle, but you can have
Cesare decreases in mitochondrial capacity surprisingly quickly so you can increase mitochondrial content, very, very rapidly. Certainly within a few days or weeks of training and it seems to go the other direction pretty quick as well. So when you d-train you can lose mitochondrial capacity quite quickly as as well, you know, so what is exercise, do any type of exercise? If you can imagine exercise is a stress. And so all of these stress components,
lb or indices of stress change inside your muscles. So you immediately have this large increase in demand for ATP calcium levels. Go up, reactive oxygen, species, lactate hydrogen ions change and many of those, you can think of those as fuel gauges. So the sort of or fuel monitors right there. Seeing oh my goodness, we have an energy crisis, our ATP is going down, this is going to signal that, we need more energy and so many of those compounds, those acute changes have been
Link to Cellular molecular signaling Pathways that are associated with the growth of new mitochondria. So, this is the idea of mitochondrial, biogenesis Genesis, or growth of new mitochondria, and those pathways are really, really well mapped out. Now, a lot of it based on on animal research and, you know, very sophisticated work. But largely, what seen in humans? Is it sort of seems to work the same way. So,
So an acute bout of exercise causes increase in those singling compounds. And, as I mentioned, within a few days or weeks, you can see measurable increases in mitochondria, measured with microscopy or Western blotting. There's lots of methods to to assess that. Now, how does hit and continuous compare? Again, we definitely have studies on this, but all of these require muscle biopsies. So a needle biopsy, a small sample of muscle needs to be taken Often by a physician.
Or at least a highly trained individual under the supervision of a physician. So they're invasive procedures. And what we get is snapshots in time, we don't have real-time changes of how your mitochondria changeover days and weeks. We have these little snapshots but certainly my laboratory a lot of other Laboratories that have compared continuous an interval training. There is some evidence that higher intensity more vigorous exercise. When the total dose is
Matched. Can lead to at least a more rapid or larger increase in mitochondrial content. Again, at least over the short term. So is it just getting you somewhere faster? And if you do enough of it over time, it starts to Plateau. We don't really have a great answer for that right now. If you are generating more, mitochondria, then you know, this kind of goes into the fat oxidation. Mitochondria are the primary place where your oxidizing
You're using fat to produce energy. What do you think of this this concept of, you know, you have to be the substrate you're burning during exercise is. So you have to be burning more fat while you're exercising to have adaptations for better fat, you know, oxidation after you're done with exercise, just you know, at steady state rest. So, in other words like you know, you have to be more in a robic type of state to
To have those adaptations. So, you know, mitochondria consume lots of fuels, right? That the primary ones of course carbohydrate and fat, so whatever you feed it, feed the mitochondria, as long as the capacity has sufficient capacity for that. It will burn either of those fuels, but but you're right, you know, mitochondrial content largely limits or determines fat oxidation by an individual muscle or fat oxidation during exercise is largely.
Determined by mitochondrial content. And in particular, very specific enzyme inside your mitochondria called carnitine, palmitoyl transferase or CPT. That's sort of the gatekeeper that gets fatty acids into the mitochondria, once they're inside the mitochondria, they can be oxidized, but the there's good data to show that that's the critical enzyme. And so with training, you want to increase CPT levels and, you know, people, there's various supplements that are
Good, purported to increase CPT activity. You know, one of the reasons we reasons why carnitine is a popular supplement, is its purported to increase your, your oxidation of fatty acids, the date on that, you know, not great, but we could talk about, we could talk about that as well. But yeah, you know, lots of debate around what's the best way to increase, mitochondrial content because that in turn is going to set the upper limit for fat oxidation capacity and athletes in particular.
Secular want to have a very high rate of fatty oxidized awesome oxidation because even in very lean individuals. There's lots, there's ample fat on board and carbohydrate tends to be a very precious and limited fuel. So ideally we'd like to preserve carbohydrate, you know, until we really need it. Like when we're racing and we need a very high rate of carbohydrate oxidation as well. So if you're going, if you're doing a high-intensity, you know, interval training session and you're going above 80% Max
Heart rate. Your now you know going to this lactate threshold, where you're you're basically producing more lactate quicker than you can consume it potentially your anaerobic maybe. I mean so you know, this, this idea is like that, you're not going to be burning fat during that part of the exercise. But that doesn't necessarily mean that you're not going to be able to burn more fat after. Because it does as you just mentioned, increase, mitochondrial biogenesis so you're actually increasing.
You know, the capacity to oxidize fat later on it mean not. Absolutely. So to me,
it's
what's important is the increase in mitochondrial content. The overall increase in mitochondria and, you know, I think generally mitochondria have hundreds more than 1,000 different proteins that are all necessary to build the mitochondria and they probably generally all sort of increase in decreasing in parallel, right? So there's not necessarily a specific way to really
I only boost that CPT enzyme that I talked about. So I think that the most important adaptation or a critical adaptation in muscle is increasing mitochondrial content which then will allow a greater fat oxidation capacity as well as a greater carbohydrate oxidation capacity. And you don't have to only work at a high rate of fatty acid oxidation in order to get that boost in mitochondria. So there's there's many different ways.
To stimulate that, including short intensive types, what do just as a sort of side note, I was reading about the effect of like epinephrine norepinephrine which are increased when you're doing more of a higher intensity type of exercise, correct. And that also sort of has some fat, I mean I was at lipolysis, maybe it does. So the catecholamines norepinephrine epinephrine, they're in their involved. And so norepinephrine is an important hormone that will see.
Signal adipose tissue, to start to break down triglyceride and release those fatty acids into the bloodstream. So, you know, much like we were talking about, we use the analogy of oxygen or we talk about oxygen, its delivery of oxygen and its uptake of oxygen. When it comes to fatty acid, use its delivery of the fatty acids and it's the uptake and oxidation of those fatty acids and you can definitely give people supplements that are going to increase lipolysis.
Going to make more fatty acids available, it's going to increase the breakdown of triglycerides, but it's not necessary going to increase oxidation. So there, I think there's quite good evidence that, that has established that the limit for fat oxidation, resides inside the muscle. And it's at that level of the CPT, which is that gatekeeper to get the fatty acids into the mitochondria, where they can then be burned or oxidized. Yeah, that's great. And then mitochondrial, biogenesis is increasing.
That CPT, I mean, if you're looking at least at a Purcell, you know, level right. Is your more mitochondria within that skeletal muscle cell sort of, we were talking about this a little bit earlier off-camera about, you know, the so talking about mitochondrial, biogenesis the other sort of important factor with mitochondrial Health would be my top a g or My Tofu G, which would be the clearance of actual like sort of old damaged mitochondria as you know
Definitely not a lot of evidence, there's animal evidence but how much that can translate to humans is sort of unclear with respect to exercise and particularly high intensity exercise doing that. But what I did want to touch on was a toffee G, which I think we have a little bit, it's he's a little bit, we've got more markers to measure it and it has been measured at least in human skeletal muscle with with respect to response to exercise. And I'm just curious what your thoughts are because it has been
shown that high intensity exercise is more potent for stimulating autophagy and skeletal muscle than just an overnight fast fast itself. And you don't even have to be in a fasted State when you're doing high intensity exercise, which to me was like, you know, so what is the significance? Do you think for skeletal muscle health and are you do you guys look at that? We don't study that in our laboratory. I think the bottom line there is exercise is good for the routine maintenance.
Turnover of many of these cellular processes including mitochondria so it supports mitochondrial Health. It sort of promotes the sort of breakdown in the the building of new mitochondria. So it's it's important to maintain mitochondrial Health. If you will the overall health or capacity of these mitochondria, you know, clearly I'm a proponent of vigorous intensity exercise. There's some other studies out there that have shown that really vigorous
Exercise can temporarily impair mitochondrial capacity. So if you measure it, immediately post exercise or in the short term after you can engage in to vigorous and effort, you basically really Hammer your cells and they sort of have a decline in function before they start to come back. And so there's some criticism of interval training out there based on those studies, especially very intensive, Wingate style all-out type exercise that can transiently
Reduce mitochondria capacity, we're talking about different things there, you know, out of vision, the various processes. But, you know, I think this is the idea that exercise is a stress. It temporarily disrupt sore damages things, and then it's all about the recovery. That makes the cellular process better, and we continually do that in overtime. Things things get better. But certainly can we acutely over train, or acutely over cause some disruption? Or it takes a prolonged.
On period of time before it recovers. Sure. It's a bit like you know concentric and eccentric weight lifting exercise. We know that eccentric weight lifting exercise is more damaging to tissues yet more sore and so you tend to take a little bit more time to to recover so not as simple as just high-intensity good, continuous nod or less good. There's a lot of nuance there, depending on the process. Yeah I'd love to two-time dive into a little bit more when we when I kind of recover some like protocols because that's really interesting.
Wingate, you know, also just kind of like that's that like an all-out Sprint. It is, you can omit. So if you've never Wingate done at Wingate test, it's the longest 30 seconds of your life. The way to so Wingate test are done on a specialized durometer, specialized bike that allows for very invariable intensity efforts. But the best way to think of it, as if you have a stationary bike is basically getting on it. Setting it, the highest workload possible. So
So it's even hard to get it going. And after 5 Seconds, you feel yourself starting to slow down because it's so challenging. The workload is so high and so you just hang on as long as you can what these specialized bikes do they sort of push back with just the right amount of resistance. And so it will optimize that curve over the 30 seconds, but it's an extremely demanding test. And so some of our early work
I was using that as a stimulus as sort of the one of the most intensive types of short Hard Exercise that you can do. And having people do repeated Wingate test. Very, very challenging, especially late in exercise. You have lots of pH disturbance. Lots of lactic acid production. It hurts. It's uncomfortable. It's not a fun way to train. Yeah, I've never done one of those women have to try one the, the other skeletons.
A muscle adaptations that I think I you know there's some interest particularly like there's so this capillary density. You mentioned mitochondrial Network being sort of like that hit affect capillary density. What is that? Yeah it does, you know II as a muscle physiology. I think you know, the two primary responses in muscle that are critical especially from an aerobic conditioning. Standpoint is the increase in mitochondria and and the increase in capillary ization. So you need more of the blood.
Vessels in order to supply the increase in mitochondria within skeletal muscle. And then of course, there's other adaptations. We see an increase in muscle glycogen content you. So you store more fuel on board, that you can then break down, you increase the transport, for many things, including glucose Transporters. And so one of the reasons why exercise is therapeutic in the treatment of high blood pressure, high blood sugar or
Or diabetes, you know there's lots of reasons but one of the reasons is you increase glucose transport capacity on the cell membrane and so what that means is it allows more glucose to be moved into the muscle, maybe then stored, as muscle glycogen and that helps to lower the blood sugar levels especially if they're chronically. High. And so individuals who start and engage in an exercise program, one of the things that they'll find if they are diabetic, is they have to reduce their diabetic medication because what's happening is
The muscles more fit and rather than needing the drug to try and clear the glucose your muscles doing. It more naturally, if you will, or it's grown, these new glucose Transporters, that helps to clear the glucose the elevated glucose from the bloodstream. What? How does the the difference increasing? The glucose Transporters are good for transfers on muscle differ when you're doing that high intensity exercise versus more moderate? Yeah, so for again, I I think for a lot of these responses, that we might talk about in
In muscle that there is evidence to so show that certainly high intensity exercise can cause changes in these glute for Transporters, we've shown that including in people with type 2 diabetes. But there's just not the body of evidence that we would like to see to definitively say one is better than the other. You know, we've done a number of studies showing that least over the short-term more. Vigorous
Sighs can elicit Superior improvements in some of these markers. But again, the valid criticism is these are relatively short-term studies, they're not always appropriately. Powered, many of these, especially our early studies. Were we like to think of as proof of concept or pilot studies. You know, do these things work and you know, writ large, we really need these randomized, clinical trials, to properly investigate. All of these these questions, what about insulin?
Activity is at all. So I mean so there's like you get this glucose transport. I mean, that's another, I mean, that's one way of glucose regulation and certainly repeated, I mean, acute bouts of exercise or probably when you're talking even throughout the day, that would be so beneficial. But also, like, people are insulin resistant to. How does how does it affect? Yeah. So there's there's various ways to measure insulin sensitivity, but, you know, generally exercise increases insulin sensitivity, there are some systematic.
Who's in meta-analyses that have suggested that maybe more high intensity. Vigorous effort can lead to some greater improvements and markers of insulin sensitivity. But again, even though, you know, we think of oh systematic reviews and meta-analyses. Those are really definitive evidence. But many of the underlying studies tend to be relatively small tend to be relatively low numbers of participants all of the potential bias. You know not that researchers are purposely trying to bias their results but they don't always
include all of the proper controls from a research design standpoint that you might like to see. So sometimes the underlying evidence is, is limited as well which limits the veracity of the systematic reviews and meta-analyses. But certainly, there are there is some evidence to suggest that Vigor intensity more intense exercise may lead to some Superior benefits. They're, you know, just after we might hit on it later, but this idea of multiple boats through the day, one of the things that
And some others are looking at right now or what we termed exercise snacks. So these brief bouts of vigorous intensity exercise that are spread throughout the day and we're running right now to randomized controlled studies at, you know, our lab, in the University of British Columbia, my colleague, professor John little and one of the main outcomes is measures of insulin sensitivity, or blood glucose control in groups that are doing these very short one.
Minute bursts of vigorous effort spread throughout the day to try and get it. Exactly this question, how many times a day? So we're encouraging people to do at least four or five times a day of those snacks. So you know, we Define an exercise snack as lesson or equal to 1 minute of vigorous. Intensity exercise could be jumping on a stationary bike. It could be a series of air squats or body weight style exercise, and we're delivering the intervention. We've partnered with a
Company that's delivering prompts on people's cell phones and so they basically get a prompt that says hey it's time for your exercise snack that links to a little YouTube video that shows the individual what they should do and we're encouraging them to do that four or five times a day. More is better, and we're following them for for three months, 12-week intervention. And we're comparing it to a movement snacks control group. So a group that's getting a very similar intervention but they're not.
Not engaging in vigorous intensity exercise. So it's more stretching Mobility exercise. And so the key variable is changing, there is the intensity of the movements and we're seeing, you know, how to people adhere to that like will people even do that and if they do it, is it enough to move the needle in terms of things like cardiorespiratory, Fitness, blood markers of fat, immune function, glucose and measures of insulin sensitivity as well. One of the studies that we're doing
Going to be using continuous glucose monitoring in individuals with type 2 diabetes. Fantastic, so they're going to be wearing, they're wearing accelerometers as well. Yes, yes, so we're trying to track movement throughout the day and they're going to be wearing continuous glucose monitors before and after the intervention as well. So this this kind of reminds me of some of the, vigorous intermittent lifestyle physical activity, studies Philippa, as you have called it that you've been a part of
So this is this is there are those studies also considered exercise snacks or no? So you're right Vic. Villa is vigorous intermittent lifestyle physical activity, and very much led by my colleague Professor Emmanuel. Stamatakis out of the University of Sydney. So I've been fortunate to be part of a, really, an international group that is that is looking at bill, but, in various ways, but to be clear, we're talking not
Exercise. So you could think of Philippa in some ways is the non-exercise equivalent of an exercise snack. And so, we're talking activities of daily living that you would be doing. Anyway, it's all very give you a very specific example. So to get to the recording studio today, I left my hotel, I had to get here, right, somehow, I had to get here, I took a ride sharing service for most of it, but leaving my hotel room, I had a choice of taking the stairs or taking the elevator
Ater, I could have taken the stairs there or to get to my ride, share service to walk a block. I could have walked to the leisurely Pace or I could have picked up the pace, right? And said I'm going to engage in a vigorous manner here, arrived at the location. Again, it's another minute to get from the Rideshare service, to the front door. I could do that in a vigorous Pace or two pedestrian Pace or I could carry my backpack right and engage in that. And so the question there with Ville de is in the
These activities of daily living that are already part of our Lives. If you embed, vigorous effort in those, you know, another classic example would be to take a five-hour flight, get off the plane, you have the choice, the escalators there or you have the stairs, you know, many people are taking the escalator but you got some heavy backpacks. You could vigorously climb up the stairs or 30 seconds to a minute. That would be a dose of Philippa right there. And so,
Again you got to move from one level to the other, that's not planned and structured exercise, that's just activities of daily living. And the question that's being asked in that research, is if people choose to do that in a vigorous manner is that meaningful. And there's, there's some evidence for that including a large study that was published in December. That was it, mind the UK biobank data. And so what? That allowed the
Vestigators to do was look it over 25,000 individuals who engaged in Villa like efforts. They were accelerometers to try and capture this and they were followed over almost seven years and the outcomes included all-cause mortality, cardiovascular disease mortality cancer mortality. And that work showed revealed that people who engaged in even three to four minutes total a day.
Available like activity, had substantial reductions in all-cause. Mortality, risks were talking 25, 30 percent so that would suggest that even brief, non-exercise, vigorous intermittent, physical activity, can move the needle in terms of health outcomes and of course, we would suspect that maybe it has to do with some of these cardiovascular metabolic changes that we know are associated with health so that's not cause and effect evidence.
It's observational evidence over time, but it was very robustly done. The way the work was was conducted. It's quite compelling, I think I agree. Because after you share those studies with me, I read them and I think even on the higher end. So you mentioned kind of the conservative, you know, three to four minutes a day. When they were getting up to like more like nine, I mean, you're talking. It was like 50 percent reduction in cardiovascular mortality 40 percent reduction in cancer related. Mortality mean that's really
Lee incredible that these people are just doing this, you know, choosing to do these short bursts of, you know, vigorous intensity exercise and then having substantial benefits on, you know, unless you know, longevity and health band, basically, the other, if I can add the other key thing from that study, I think, is that all of these people were self-identified, non exercisers. And so the point is, there are even people who self-identify as non exercisers seemingly are still engaging in vigorous.
Through the day. Now, part of that might be there, their physical capacity is quite low and so what it takes to get them into a vigorous intensity. Ranges is not very much and actually, as part of that study it was repeated in individuals who also identified as exercisers and the same phenomenon we're a parent. So even in exercisers, engaging in Villa like activity was still protective. So again, lots of work to follow up on, you know what actually counts.
As a VIP about, you know, will people do this, you know, but you can imagine again, getting back to this idea of prompts, you know, building envelope alike activities in a smartwatch or an app on a phone and encouraging you to accumulate 3 or 4 or 5, or 10 minutes of bill today. But, you know, three or four minutes of Milpa is, you know, about 30 minutes of vigorous activity a week and large.
In wrist and that is very doable. That is very I mean to say you can't do 30 minutes a week is I mean, you're really just saying I don't want to be healthy and you know, the other it's interesting. I don't want to go on too much of a tangent here but like, you know, you wonder how much also of this of the of these Villas studies and these even exercise snacks has to do with just not being sedentary. Also because that's like an independent risk factor for. I mean independent of exercise, right? So like I said,
I said, at my, I don't consider myself a sedentary person because I engage in physical activity, almost every day. Pretty much seven days. I'm doing something. I'm either doing my palette on and to hit workout. I'm doing resistance training, but I also sit at my desk for a good five hours. I'm sitting there sitting and that is what I am sedentary. So I'm actually trying not to incorporate built by stuff. I guess, you know, in I guess it's more structured. So when it be more of an exercise snack in that case, but I'm doing, you know, the
Burpees or the high knees or something where I'm going to believe me. Like one minute of that I'm like this is the longest minute of my life you know I mean it's like hard so that I can empathize and that I'm very similar. I'm a committed exercise or pretty much. I do something every day but you know as a university Professor you sit at a computer a lot and so trying to build them into my day as as as well. But yeah I think the key there is
You're right. It, there may be a double benefit if you will, you know, all of us should be meeting physical activity. Guidelines, of course, you know, add these in, sprinkle them in, but there may be a double benefit to a villa like approach or an exercise snack approach in that it simultaneously breaks up prolonged periods of sedentary Behavior because, you know, I'm sure like you, I don't like to see that evidence and read those studies that suggest. Even if you're committed, exerciser prolong sedentary is in
Raising your risk, right? You know, we like to think of exercises this Panacea and it's not, it's not a vaccine against ill, health outcomes and reducing sedentary. Behaviors is really important as well as is proper sleep. So I kind of wanted to Circle back just for a moment to the muscle biology aspect because well, one you're an expert in that that Arena and we didn't touch on the how high intensity interval training effects.
The recruitment of muscle fiber. So type one fibers type 2 fibers. What does that mean? How much does individual variation play in that equation. So you know, big picture generally speaking. There's two main types of muscle fibers. They can be Quantified different ways, history, chemically different. There's different ways to measure them but there's slow, twitch and fast, twitch muscle fibers. Those definitions are based on basically how
Quickly, the muscle fibers can shorten or contract and so the fast which are sort of fast, explosive very, very quick. So we think of those associated with variable fast, explosive powerful movements where the, the slow twitch, they don't generate as much force, but they don't fatigue very quickly as as well. Sometimes, those are also known as type 1 and type 2, and those are generally looking at there's ways.
Ways to measure. Basically the oxidative capacity how aerobic each of the muscle fibers are. So there's different ways to categorize them. But generally speaking two types and they differ in their characteristics.
The
there's definitely something to the idea that we first recruit and this is known as the size principle in part based on the diameter of the muscle fibers. So these slower twitch fibers. These type one fibers, tend to have, narrower diameters, and they tend to be recruited first. So if I was to get up from the chair right here, we're going to go for a walk around outside. The studio, very low intensity.
Those muscle fibers that we would recruit to do that work or generally these slow twitch or type 1 muscle fibers. They're good for low to moderate levels of force and they last for a long time without fatiguing then we need to get back quickly the studio or we need to run away from a scare that's outside. We suddenly have to engage in very fast movement, we're going to now recruit or call in these fast. Twitch muscle fibers because we need more.
Powerful muscle contractions in order to go faster. We would be able to Sprint away from the danger for very long because we'd eventually fatigue because these muscle these fast, which are type 2 muscle fibers are. That's one of the limitations of them. And so that idea of progressive recruitment of muscle fibers is well-established, what's not? It's not as clean to just be able to say when we do low to moderate exercise, we only recruit slow twitch or type one.
And when we do high-intensity, we certainly don't only recruit type twos. We've already called on our slow twitch and then we start to recruit the fast twitch as well. And the other point is like a lot of things. It's really hard to study. So you know, you take a muscle biopsy site, biopsy sample. That's hard enough, right? Invasive, people have to volunteer. Sometimes, it's a little painful, but yet your biopsy out now you have to separate these muscle fibers. So you literally have to individually identify
Whether muscle fibers are fast or slow and then you separate them into pools and you analyze the type ones and the type twos. Very intricate time-consuming work and so there's not a lot of data out there there. You know, a lot of animal studies that were done previously in rodents. For example, they have much more, clearly defined muscles so they will have fibers muscles that are almost entirely fast-twitch or
is that are almost entirely slow twitch and so in those you can just take samples of specific muscles from a rat hind limb for example and know that you're pretty much looking at fibre type differences. Human muscle is much more variable heterogeneous. And so Elite endurance athletes tend to have a much higher preponderance of slow, twitch muscle fibers, 7080 percent, Elite strength, athletes powerlifters 10,
Have much higher preponderance of fast-twitch muscle fibers but the vast majority of us are walking around somewhere around 50, 50 40 60 and again that that complicates interpretation, when we talk about 5 or type differences, two different types of exercise.
But are we are people more prone to losing one type over the other or what with age? Yes. So and so, definitely, there's evidence to suggest that there's Progressive loss of these fast twitch muscle fibers. May be mainly or sorry may be mainly due to the inherent aging process. But again, you know, we could have a long discussion around whether aging is more a physical inactivity purse, a problem or aging per se, but bottom line is
Tend to lose fast twitch muscle fibers, which is probably why, especially as we age strength training is important in order to maintain the viability of these fast twitch muscle fibers does. Does that, does that have to that correlate also with an increased risk in like Falls? And yeah, you know, I think all of this aligns our certainly, the theories would be that. Yes, right. And so, you know, we mean to maintain flexibility balance all of that, but
Certainly, it maintaining fast-twitch muscle fibers through strength training is going to be important in order to help prevent Falls and other others.
With respect to the metabolism aspect of high-intensity interval training. You know, we talked, we talked, we talked about the insulin sensitivity, the glucose transport increasing. I mean, all these things are good for both people that are in a disease State, like maybe type 2 diabetes or, you know, high glucose, you know, dysregulation metabolics and whatever also for people wanting to prevent also getting type 2 diabetes, right? I mean so there's there's two populations here, right? Yeah, absolutely.
Lutely again. If you know back to the elite athlete they want to optimize all of those processes much as they can write. And the the individual who's very sedentary, they really just need to do something to try and raise the bar. So, you know, we're just talking about a massive Spectrum there from very inactive, very sedentary, very high-risk Behavior to the elite athlete who has maximized almost all of these processes and is just looking for ways to further optimize that
Just to get back to stews analogy wring out the sponge a little bit more and of course most of us fall somewhere. In this this broad range in between what about body, composition weight loss, obviously diet is an important component in those equations but can people use high intensity interval training to help, you know, lose fat also even help, you know, there's there, increase the muscle. Also, you know, is there is there is there a role?
All for high intensity interval training in. So, you're right and that, you know what I tell my students is, this is hardly novel that, you know, we control body mass mainly through nutrition, but we control Fitness through exercise and physical activity. And so clearly exercise generally and high intensity exercise, can play a role a supportive role in terms of weight management body composition changes. We've shown in some of our six and 12 weeks studies, you can change. You can have
Oil changes in body composition. Such that there's a slight loss of fat Mass fat percentage, or a slight increase in lean mass with high intensity interval training. But it tends to be relatively subtle and how it Compares with continuous exercise. Again, I think the biggest thing is, there's probably a time-saving aspect there, and so you can do less total exercise or certainly have a
Lower time, commitment with more vigorous intensity exercise and burn the same number of calories. There is something to the idea of personal trainers, talk about the afterburn effect. This idea of a heightened rate of metabolism and Recovery, we've measured it, you know, you look on the internet, you'll see these massive differences in afterburn, right? Where hit is way up here. And moderates, way down here. It's certainly nothing to that magnitude and but there is a difference, but it tends to be relatively small and it
It's relatively quickly but those small differences can add up over time. And so, you know, people will say well, how can high intensity be effective or how can certainly Sprint type training be effective at this because you don't burn more many calories during the efforts. Well, you do burn a greater rate of calories in recovery and those two things can can play off. But again, I think right now, the best data is like, a lot of things we've talked about, you might get away with some time savings or a small.
Our total dose of exercise and still get to the same place with more, vigorous activity. Well, in contrast to that, getting to the same place in my mind, in my opinion, one of the reasons I am so drawn. In addition to the time efficiency aspect of high intensity while training is the brain effects, and there's no doubt that exercise in general has Global effects on the brain.
I mean, there are improvements you do any type of exercise. You look at any observational study exercisers, non exercisers definitely you know, brain benefits lower risk of, you know, age-related diseases neurodegenerative diseases, excuse me. So you know, not that there's not, you know, a role for any type of just getting your blood flow higher. However I'm increasingly convinced when it comes to intensity of exercise there.
Maybe very unique benefits on the brain and that is where I think, you know, high intensity interval training or any type of in high. Intensity training has a special role some of that has to do with actually wanting to increase your lactate levels. So in stead of this lactate threshold training that we were talking about the zone to sort of going, you know, right below the lactate threshold, which I guess is defined various, you know, ways depending on
You're what you're reading or who is doing it. But the lactate shuttle Theory, George Brooks proposed this. You know, it's not a theory anymore. So it kind of the name kind of it's like a lot of date. But can you talk just kind of briefly about the lactate shuttle Theory and maybe like where the brain comes in sure. So you know the lactate shuttle Theory or lactate, you know, many of us. If you look back at your textbooks, your learned that lat
Tate was this metabolic waste product and product and it's just a metabolite like like anything else and it can be an extremely valuable Fuel and we know that and there's elegant studies including from dr. Brooks and others to show that you know, first of all skeletal muscle can produce lactate under fully aerobic conditions. So there's always some lactate production happening and certainly during more intensive exercise where we produce lactate inside the muscles, it can be released
Active skeletal muscle, it can circulate to other places like the heart, like the liver, like the brain, but certainly in heart, heart can be a big consumer of lactate. And so it takes up that lactate can convert it back to glucose and then utilize it during exercise. And so this is the idea of cell to cell or inter organ lactate exchange and I think that's very well established now like you and you would be far ahead of me. But I'm, I'm following this area with with immense.
Interest. I have some colleagues at McMaster where you know both from a cognitive psychology standpoint and also more a hardcore neurophysiology standpoint were engaged in some collaborative research with them but generally looking at this question of physical activity and brain health and probing the role of intensity there. So you know my my understanding is mainly based on talking to my colleagues trying to read reviews.
Of some of this research and my sense is you know very well established potential mechanisms. Now from some of the animal studies and and the human data is certainly intriguing but you know that link between lactate bdnf absolutely. There appears to be a role for intensity there in terms of higher intensities. The better in terms of, you know, potential you didn't F beta.
Aiding the brain. Some of these outcomes associated with neurogenic neurogenesis. Yeah, it's the lactate and we can talk about measuring it but it's interesting because I do measure mine. I do the finger prick and I'm my workouts I'm like trying to go higher for my Lactaid you know and I've read a lot of study for me. I'm very interested in erdheim disease. There's on both sides of my family Alzheimer's and Parkinson's so to me I'm like I need to really focus on brain health.
And so looking at the studies on lactate and even infusing lactate into humans, it increases bdnf just infusing it and I'm like, oh I get these levels from I really all out hard workouts like this is this is great. But also, I feel really good. So I start my day with couldn't today most most days, you know, at least five days a week. I'm doing a and will I want to talk about protocols, but I'm doing like a 10-minute, you know.
No Tabata, so so I'm doing two back-to-back to bodice. Actually, it's two back-to-back two bottles. And then I have there's some you know minute minute warm-up and a minute cooldown. I actually don't I use them more for I'm actually still going hard like half the time and then I like cool down after that minute. So I like at the end I go and all out man it after my two back-to-back devadas and then I'm like and then I cool down but you know, I do this for my brain. I feel amazing and there's actually science showing that executive function is
Proved and it's totally correlates in. This isn't humans with lactate after high intensity exercise. And it doesn't correlate with anything else. No glucose like nothing. It's specific to the lactate. And like you said, it's a growing area of research. I'm particularly interested in it. Like I for sure. Notice a difference, in terms of like if I go hard, like, I feel better, I feel smarter I'm like, more on task, you know?
So, for me, it's a very important part of my protocol and I do think there's a lot of benefits for the brain. So I'll have to be in touch with some of your colleagues at McMaster because I love sharing studies and stuff that I find and learning what, you know what other people are doing as well. And so the and maybe there's data out there on this. But, you know, the scientist in me, is innately, curious around things like I, you know, maybe now there's really really good dose-response stuff in terms of exercise dose and beating.
Of increase in some of these other measures. But, you know, so for example, is short sharp large changes, in lactate better than prolonged moderate levels of lactate, right? And I'll tell you something, it's not lactate that I've looked into you, but I've looked into blood flow and Shear force. And I think this is a very, I think it's an emerging field looking at the effects of Shear Force.
and that is where I mean we're talking about a flash flood coming through if you're talking about high intensity versus just, you know, a little trickling and the shear Force itself at least at the blood-brain barrier and just kind of when you were talking about muscle capillary, I was thinking about the shear force, it ended up itself in a dose-dependent manner is responsible for increasing vegf and bdnf at the blood-brain barrier again, dose-dependent all on the shear Force effects meccano, you know, these mechanoreceptor
Others that are on Solid Surfaces and stuff like these are all sensing things and it's also very important so I think it's another. So there's the lactate part of it where you're increasing the lactate and it's a quick sort of and it is like, I've measured my Lactaid spikes up. You know, I don't get up to levels that my husband, I'm more like a 78 millimolar, and he gets up to like 14, but it's it after 20 minutes. I mean, I'm back down to 1 millimolar and to my Baseline basically. So, you know, is it
It is there something with that, you know lactate you know going intensely up. It also the sheer force. I think there's another interesting component to that that I think needs to be calculated into this equation because I'm seeing increasing data on that not just with respect to brain health but also people that have cancer. So there's a lot of work from Justin Brown. He's at think it's Tulane in New Orleans but the sheer force and how it's affecting the
Circulating tumor cells. So basically people that have been diagnosed with cancer, you'll have a tumor cell that escapes, the the primary tumor site goes into circulation and that's how that's this the potential to metastasize, right? So then goes, you know, is able to travel to another organ and take up camp there or whatever. So there's there's evidence that exercise in general exercise is involved in. Basically anything that gets your blood flow up basically those cancer cells die because they're so like disrupted and
T''v to the mechanical forces, whereas normal cells are fine. But it seems to also again be a dose-dependent effect. The more intense, the exercise, the more blood flow that's going quicker. The more intense the effect and also blood flow to the brain to, right? I mean, just getting that that Shear Force as well. So I think there is a lot of interest there with the brain. It to me is a differentiating factor from more continuous moderate exercise, even longer duration, obviously, there's
Lot of compensation, probably that can happen metabolically when you're going for a longer duration, you know, period of time. But I do see, I do see something unique and I'm, you know, looking, I'm reading the literature, I'm trying to follow it as much. And, you know, I mean, it's emerging, right? I mean we don't really know, you know, just on the topic of interval training there's now seven hundred papers a year coming out. It makes it very challenging to stay on top of the literature you know and that's just in my main area. So absolutely
You know, on the point about vascular stress, we collaborate with some cardiovascular colleagues who are looking at this more and ethelia function flow. Media dilation not in the brain more, in terms of muscle or large arteries leading to a muscle. So parallels there, I think in terms of some of the things you're talking about and Shear stresses and factors that are released, you know, to promote kapler, growth there, the other I want to mention around lactate levels though. It's a bit like heart.
A tin that
you know some
people just have low maximal, heart rates, some people just have low maximal lactate values. We know it's definitely related to fiber composition more fast-twitch. Muscle fibers have greater potential to drive up lactate, it's related to your enzymatic capacity to produce lactate. So the point I just want to make maybe you're working as hard as your husband, but you just don't have some of the biological.
It's that are going to allow you to get the very, very high lactate levels. You know, what is your Peak lactate level, maybe you're already added or very close to it. So don't beat yourself up too much there. Do you think wearing a continuous lactate monitor, when those exist will help me, maybe right? And so, I, you know, I'm sure we're going to get into zone two, more and lactate, and how we measure things in that. But, you know, I think a challenge with lactate monitoring right now, is it relies on occasional finger prick?
Sampling variability, in the monitors and that when we look at something like continuous glucose monitors and the evolution of that, you know, now we have continuous glucose monitors are combined with insulin pumps amazing, right? So eventually you have real-time monitoring of blood glucose levels and as they change up or down, the insulin can be potentiated or adjusted to get to. And I I'm sure and I know people are working on this techno technically
Lee getting to the point where an athlete would use, a continuous lactate monitor for training and racing, I could see where that could have tremendous value, whether everyone needs that, I don't know. You know, whether you can use heart rate and some other metrics to at least get you reasonably into some zones. But I can see why there would be tremendous interest in among athletes to monitor that and really dial it in to get an idea.
Their metabolic stress know, for sure. I'm not an athlete, but I'll tell you. My interest would also be because before I was doing continuous glucose monitoring, I wore one for around three years or so I was doing finger prick. And, you know, I noticed before my workout, you know, my blood glucose levels were a certain number and then you know, usually sometimes I would do it like three times because of the variation as you mentioned, but after I would go higher up and like what I'm supposed to be like transporting more glucose into my muscles, like, this is
Aeolus, and it wasn't, until I had a continuous glucose monitor on that. I saw the change going way down during the exercise and then gluconeogenesis whatever's kicking in, you know, that it's bike back up, but I wouldn't have known that without that continuous, you know, data and I wonder with the lactate because during exercise the brain consumes consumes it more than glucose. So it actually you know, you have both of them there. It'll go for the lactate over the glucose and I wonder it's like, oh well, what's happening while I'm is it
Really high is my brain consuming more of it or is it might just not producing more, but like you were saying like, what what a continuous lactate model would give me some sort of peek into that, because at least maybe it is going higher. And I just don't see that because I'm not just a snapshot that I'm getting after my workout right now. It's a great point, right? Even just monitoring Venus levels. It's not telling you anything about rates of production and utilization. And so, you know if some it's a really good test question in my senior class, I will ask my students.
It is a high blood lactate, a good or a bad thing from an Exercise capacity standpoint and we tend to think well high blood lactates are bad because you know, it's a so it's a signal that your pH is out of whack and everything like that, but you could also make the case, well actually transporting for a given amount of lactate production. Getting more out of the muscle into the blood might be a good thing because the disturbance to your muscle pH is not going to be as pronounced. Now you've moved the
To where you wanted into the blood is sort of protect the muscle again. It's just a it's a good thinking question. I ask that to them to Challenger thought process around all of the things that control lactate but maybe it's not all about just measuring in the blood either, is it? Yeah. Let's let's dive into that for many brought up some really good points. I think a couple one being, you know, this misconception of, you know, lactate or lactic acid. And you know how, what's actually,
Isabel for, you know, the changes in osmolarity and you know, that that fatiguing feeling I guess in muscle versus basically behind his native will training whether or not it can help. I guess improve muscle fatigue, through changes, you know, regulating the osmolarity better. Yeah. So certain, you know, certainly there you can certainly you can choose to change lactate Transporters with exercise and high intensity training and probably you know go back.
Two athletes that were engaged in high-intensity exercise to engage in high intensity type events, a major adaptation. There is an increase in on our carboxylate Transporters MCT Transporters to help. Get the lactate out of the muscle. And you're right, you know, lactic acid is produced at physiological, pH it rapidly dissociates into the lactate ion and the, the proton, the hydrogen ion and it's the changes in PH associated with the changes in protons.
Ons that we know can interfere with contract out processes, and, and enzymes, and, and things like that. So yeah, complicated physiology. But I think the bottom line is lactate is still a valuable measure and certainly why whether its own to training, or others, the the notion about it's, you know, whether it directly can causes fatigue, probably not, but it's still a really good surrogate marker or index of a lot of other things that are going on. So whether it relates
Osmolality or potassium fluxes or calcium flux has. You know, I think the people that really study muscle fatigue would say it's not about lactate mph all the time but lactate is still something that can be relatively easily monitored and it's a good proxy for, you know, a global look at what might be going on metabolically. And I think that's where my understanding is where its role in zone. 2 training comes into play.
That makes sense. So we talked about some other performance enhancements, you know, that that high intensity interval training complain when he's muscle glycogen like the storage capacity for talking about the muscle fatigue, but and then we talked about vo2max which would be aerobic capacity. There's also the anaerobic is that the anaerobic output is that anaerobic capacity? Correct. And this gets back to this idea of, you know, if if your event is
Multiple short Sprint. So you play a team sport, and your role on the team is to, you know, receive a pass or receive a ball Sprint as hard as you can. And then you have at least a few minutes in between plays to recover or you can, then recover on on the field. Those individuals require very high power outputs that they can achieve repeatedly, but with some Fair bit of time in between. And so those it when we talk about anaerobic capacity the best measure or
The most commonly accepted measure of, anaerobic capacity is a Wingate test and that's because when we do an all-out 30-second effort, a large, majority not all of it. But a large majority of the energy is derived from anaerobic or non oxidative metabolism and so we can quantify power output in terms of wattage on the bike and a large proportion of that power is derived from anaerobic. And so for example you can measure
Or let's say your view to Max test at the end of that test. You had 300 watts so your Peak power output on A View to Max test was 300 watts. Will you can do a 30-second Wingate and Achieve 900, 1000 W, Elite athletes, Elite power athletes, 1500 watts on the bike. So when we talk about someone was exercising, it three hundred percent of VO2 max Pace. That's good. People will Max's Max. How can we exercise above vo2max normally you're
Talking about its power outputs above the VO2 max power output. And when you engage in these short hard efforts that can be multiples of Beauty Max power. So this kind of reminds me of I've heard you talk about this, the Sprint from danger sort of pace or intensity and how I mean you know that that's could be basically the Cornerstone of a highly efficient workout now. What is that can you talk about that? And then maybe compare it to The Windgate or maybe even the Sprint interval training.
Is
know for sure. So, again, you know, people think vo2max Will and Max is Max, how can you be above Max? But when we talk about, VO2, max that's maximal, aerobic capacity, and then we could have metrics to that. So, Peak power work Peak at view to Max, but Sprint from danger pace. Is just that. So if you had to flee a burning building the pace, you might run at to save your child from an oncoming car. It's well above VO2 max, but you might only have to do it for five seconds. So,
It would equate to top running speed and all-out Sprint over 5 or 10 seconds. You know, even a Wingate test is not true. Max power output. The highest power outputs during a Windgate usually occur within the first few seconds so we're talking five to ten second efforts. What's the highest work rate that you could put out? What's the highest amount of ATP that you could generate much of it non oxidatively over a five, a 10 second?
For at most that's print from danger pace. And you know, if you're an athlete you know, we hear these five Zone training six, own training, for many of us three zones are enough. But when we talk about five and six Zone, what that often is, referring to is, discriminating, were crates or power outputs above view to Max and if you're the athlete, looking to optimize performance,
You know, whether you're working at 150% of you to Max, which you might be able to do for a minute, or two or you working at 250, 300 percent of VO2 max for 5 or 10 seconds. Those might be important in terms of discriminating, fine changes that could further support your performance, where's for most of us, it doesn't really matter. We don't need to get that level of sensitivity in terms of how we structure our training at these very very high intensities are
it's
so do you think
there would that mean like it could there be a benefit for sort of changing around our training protocol to incorporate some of that spring? I mean, VO2 max benefit or, you know, soy I do. And, and again, this is not scientific but it makes sense to me at least and it's the old investing analogy, right? And so, you can hit a home run with a hot stock tip, but for most people are better off to, you know, spread it around
Don't put your eggs in different baskets and so I think when it comes to exercise training for many individuals, there's there's an analogy and and that's it maybe do different types of training and and that's going to, you know. So whether you're someone who really responds to Sprint training or really responds to moderate, we can't necessarily predict that and so varying up your training just like we spread out our risk when we invest might be
The the best approach, you know. So should individuals engage in some short sharp hard efforts, I think, you know, ideally speaking. Yes, they should. There's even some recent evidence, I think there's renewed interest in the potential for elite endurance athletes to incorporate sprinting in their training and there's a series of studies that's that's come out Randstad Karsten loon bees work. Showing that when truly world class level.
Cliff's, we throw these terms around highly trained Elite. These are cyclists with starting VO2, max values, 72-73 mils per kilogram per minute. And they randomize them to do either traditional hit 45-minute repeats or effort matched, 30 seconds Sprints and they sort of effort matched. So whichever group you're assigned to you working at the highest effort you could and they were work matched. And what they found was the group that incorporated, the Sprints
Had a further boost to their performance, 20-minute time trial performance and they actually had a small but significant Improvement in VO2 max. And so it would suggest, it may be there might be a place for athletes to incorporate what you know some call rsts repeated Sprint training as a as a ways to further augment their performance. Now you know still relatively small three-week interventions but to go back to your question I think there is
Place for incorporating.
Very vigorous effort sometimes. If you know it again there's some people who shouldn't do sprinting, right? Especially if you're starting out but all things being equal. Yeah, I think varying it up. Your approach is going to be the best for general fitness. I want to talk, let's dive in its in protocols. And this is, this is very like, I'm sitting here, getting very, very intrigued because of my training, which mostly like I mentioned, it's mostly on a pallet on stationary bike and it's, you know,
Again I do a lot of the 22nd on 10 second off you know, back-to-back and I'm thinking like maybe I should also incorporate some you know I could go outside and do he'll Sprint hate them, hate them, hate them, hate them. But I mean it, you know, if I can get if I if I can do it quick it still can be and I just go outside and you know, do this isn't like going around a track or anything which is something that I can conveniently do, but also maybe potentially
It even greater improvements in VO2 max. That's of interest to me. I'm not an athlete, but so are you thought do you think that I'm so, you know, far be it from me to tell you how to train but, you know, from what I've listened to in my awareness of the type of training that you're doing. Actually think, you know, maybe you should do some longer intervals at a little bit lower intensity, you know, maybe you should be incorporating some 3, 4 5 minute intervals as hard as you can go during those rather than almost
Sibley doing Tabata style type training because arguably, you're already doing a ton of Sprint training. Two batters are basically Sprint training so I want to be careful here. You know, we could talk, let's let's at least for now. Keep it modality-specific. So how you would train on a bike before we start talking about different modes in that because that introduces some other wrinkles. But again from what I understand, what you just said earlier in our interview, most of your training are these for you all out, 22nd, Sprint's 10, second recovery,
Efforts, I'd suggest you know and I think dr. Attila recently suggested you might want to do the same thing in those 10, second recovery periods, almost completely stopped or at least go down to very low intensity cycling because part of thing with te bad as you go really hard but those 10 second breaks, you've earned the break, take it. So don't maintain the intensity too high in the 10-second. Valleys before you go hard again. But again, it sounds like much of your interval training right now is already Sprint type training given your
That is we know there's data suggests that all things being equal, three to five-minute repeats at the highest sustainable. Intensity are probably the best way to maximize gains in VO2, max, it's pretty loaded statement but I think you probably want to incorporate some of these longer. Intervals, two, three, four, five minutes again, highest workload, you can and do four of those right now. That's probably going to take you 20.
Minute commitment, some mornings, but I would say or I would encourage you to least think about incorporating some of that style of interval training. Yeah, absolutely. How many times a week, do you think? Yeah. So again, my understanding is you're doing something almost every day and I think you sort of, you know, you go back and forth between some resistance stuff. Well, the resistance is on, I will talk about it. Yeah, well, but it's on the same day as it's just later in the evening. But like, so that, so we mentioned Tabata and then you're saying this this like like longer duration interval,
And it's funny because I had a question about that. Was like What if you let's say, you know time so let's say the interval where you're going all out is or at least high intensity. So 80% is matched. But instead of doing the you know shorter interval, repeated repeated, you do longer ones and sounds to me like the longer one, there is a difference in doing a longer interval, even if you're like, you know, let's say it's six minutes total going all out for Tabata Style versus what you're talking about, which would be
There is, you know, metabolically, the challenge is different, you know, it all. So this is where all interval training is not created equal, right? And again, there's lots of variables, their total volume in particular is important, but I think challenging your metabolic system in different ways is a good strategy. Now, again for you that if you're only doing ten minutes in the morning, some of these days are going to be 20 minutes but maybe some days are you know, 35 minute intervals.
With a little bit of warm up. Cool down recovery in between that could still be a 20-minute workout but you've gotten in there 15 minutes of relatively intense training. Again push as hard as you can go. So they power output say you're working out or going to be different than when you're doing tomatoes and maybe some days do a minute on minute off repeated 10 times even five times, right? There's because that was a protocol that we've used a lot in our studies minute, on minute off repeated ten times took about 25 minutes for
Jules. But now there's studies that have looked at five by one showing that much of the improvements certainly in view to Max is almost as good. So again, when we're doing 10 by one, we're bringing out the sponge a little bit more, but you get a lot of water out of five by one. So I would say very up your your intervals and Recovery periods. Ideally, in order to change up the physiological stress on the body. Now again, you're someone who says I only have 10 minutes in the morning.
Morning and I absolutely love to bodice. Okay, like you're so far ahead of the game compared to many, but I think if you're looking to optimize or maybe that's going to give a different lactate profile to your brain, that may be at least different. I can't guarantee you it's better, but I suspect for improvements in your car, to your spirit, or a fitness and that the different challenge, may maybe a little better. This is great. Marty because I think I am look, if I have 10 minutes, I have 20 and there's certainly some days, I definitely have 20
Others may be 10 you know, like today it was like 10 minutes. I got Marty's coming, I got a mean, I got to do something, but, you know, I think a lot of people are interested in that because there are different goals. As you mentioned, you know, what are your goals? Are you an athlete? Okay, then 80/20 like, there's lots, I mean, you're, you're putting in the time no matter what, but but there's also people time like anything. So there's those people would like I can't think about, you know, doing you know maximizing, what I can out of the vo2max and squeezing the cloth and
Every last drop I just gotta like I got 10 minutes or, you know, and I can only do that X many times like, you know, four or five times a week, or maybe some people like 20 minutes. I can do three times a week but then, you know, I am interested in optimizing for vo2max as much as I can while still being time-efficient, you know? And and that I do think there's a, there's a large audience, it's very that's in that camp, where it's like I want to be time-efficient. I want to still really optimized for Bo to me.
And there are really, I would say pretty strong data correlating vo2max. Also with brain health, of course, cardiovascular systems are very related related to the brain, vascular Health, right? So that is really good. We talked about Tabata, we talked about 10 by 1 or 5 by 1. You even talked about some of these longer ones which were like three to five minutes and then your 1 minute. So your was your one minute workout based on the sort where the where the title of the book came from was. So our initial studies, you know,
Fast forward, 15, 20 years of research, our initial studies in this area. We were using the Wingate test. There's a long reasons for that but we were doing these 30-second wingate's. Again, these are uncomfortable people hate them. You need 45 minutes recovery. At least before we can coax you to do another one. But the point is 45, windgates. Still takes 25 or 30 minutes and so it's still a significant time commitment. And so people were saying, well, you know, some of the critics
Rightly pointing out. Well, if it's taking a 30 minutes and you're doing three times a week, you're already getting up there. So really how time efficient is it, and so we wanted to devise protocol where no one would argue that. It was time, efficient. And so, that's where the, and, and the other is it's the last 10 seconds argue, the last 15 seconds of The Windgate that hurt the most. So, you know, basically after about 15 seconds of Wingate, you shut off glycogen utilization. You've just produced so much lactate in your pH changes so much so
If a lot of these responses are in part related to the reduction in glycogen, maybe only need 15 or 20 seconds to trigger some of these responses. So all that to say we came up with a protocol that was three 20 second intervals, five-minute total warm up and cool down and some recovery in between the intervals. So start to finish the protocol took 10 minutes and within that there was one minute a very vigorous exercise, it was the one minute workout.
I think we've at least talked about it before the notion of re hit at the same time as we were sort of coming up with the one minute. Workout, UK researchers Metcalf, vo lured. They've done a lot of this work, they termed what they called. Reduced exertion high intensity training on a very similar theme where they were using a 10-minute start to finish work out. But their protocol involves 10 to 20, only 12 to 10 to 20, s efforts.
So all of this variations on a theme where we're talking, no more than one minute of very intense exercise in a 10-minute time course. And you know that we've done a number of studies. Now looking at that, that work out and showing that certainly, you know, it can prove you too. Many of the things we've talked about, it can improve it to it, at least very similar extent, as more traditional moderate-intensity continuous training, that takes five times longer five,
time's the total exercise volume.
That's a, that's a really big interest. I mean, I think into a lot of people. So I mean that's for me and I mean people that I know a lot of busy people that I know. I mean it's like, you know, so I guess the the the moral of the story here as I think I've the work to rest ratios in a way, do matter to some respect because that was kind of a big question for me. Was the what I'm doing every day was very specific work to rest ratio.
But going going a little bit harder and that really does make sense. And I knew it like, there's something in me that was like, I just need to hear. Marty, tell me so, thank you. You mentioned some of the other protocols like the re-hit. What, how does that, you know, how would you say that really differs from high intensity interval training? I mean, with respect to maybe some of these endpoints were talking about like vo2max. So again, like, you know, first of all, it's all interval training, whether it's hit depends on your definition,
Finished in a little bit. And so that's why again you know I really like this idea this this notion or this terminology of interval training because it covers all the bases. Its just alternating more intense, less intense periods of of work. High intensity for many is 80% or higher heart rate as a metric. And you know and we've done this but to try and because our first work, we called Everything hit, right? Which is much of the field at the time, everything was hit but you know, five minutes at
80% of view to Max is a very different stress as we just talked about from a 20-second about a workout. So at least to try and distinguish the interval training a little bit more there, is this move to try and distinguish hit, which is intense, but submaximal efforts from sit or Sprint, type training, which is much closer to the Sprint from danger, paste type type efforts. So, you know, I would say re-hit is absolutely interval training. It's
Probably closer to Sprint, type training, then traditional hit, which just because of the power outputs, you know, you're working 10/22. But these are very, very high power outputs that you're generating and much higher than vo2max pace. So I was completely confused about that because reduced exertion to me, I was going, oh, this is less than eighty percent. So the reduced exertion, it was 10 or 20.
S. It feels a lot easier than a 30-second Wingate. And it was because, you know, these investigators know, 32nd, wooden gates hurt and all of the lactic acid in the pain and the discomfort, and even the nausea and dizziness, sometimes it can go wrong with 30 seconds. If you're doing 15 or 10 seconds, much of that is is attenuated. So the exertion comes down from the metabolic feelings and it's not the exertion level in terms of the power outputs on on
Like, you know, just to take that one step further, dr. Ed coil, at the University of Texas at Austin. Big name in the field of exercise physiology, doctor coils. Recent work is looking at for second all-out efforts, but doing a fair number of them and it's really just a variation on a theme and dr. Coils point would be you can work, very, very hard even fairly deconditioned people can put out, extremely high power outputs for 4 seconds, then you give them I think.
It's 12 seconds recovery, and they do it again. And so, the point there is these very short, very hard efforts aren't associated with the feeling the perceptions of discomfort. When we initially think of Wingate test, Sprint from danger pace. And you know, I there's a lot of critics certainly on the behavioral side of things who are saying interval training is doomed to failure as a public health priority, because we know that anything above lactate threshold,
Hold it hurts. It makes people uncomfortable, they're less likely to do it, but there's a whole nother group in the exercise Behavior. Fielder going like, well, wait a minute continuous high intensity efforts, even continuous, Sprint efforts are very different from intermittent, high-intensity efforts. And so, there's a lot of certainly, a lot of arguing right now and a lot of Twitter polemics, but I think still a lot of good work to be done. Looking at these perceptual responses to different types of
Well training, it's it's too simplistic to just go, well, Sprint, type training. No one's going to do that because it hurts because now there's evidence to show that. Well, actually, it doesn't when people rate this, they don't find it as unpleasant as uncomfortable as some make it out to claim that it is. So the reduce exertion interval training, the re-hit reduced exertion high intensity training. Is you still there messing around with more the work to rest ratios and you are still going, you still
I'm very hard but you're perceived exertion isn't as high as it would be if you were doing a wing Gator, Sprint, interval training, and so at the end of the day, it really goes to say that you know, perceived exertion isn't necessarily the best way to gauge how hard you're going because if you're still going hard on your 45 seconds, you know, you're doing good and then, you know, it's just this is great. I think this is very clear to me.
Because, you know, the the resume that must be why I'm so drawn to debod to devadas as well, because I'm going hard for 20 seconds versus three minutes. I mean one minute is hard, like it's definitely going to be different and it is, it is, you know, these behavioral psychologist or whatever Twitter polemics that you're talking about, they don't they must not know about David Goggins and the whole movement of you have to suffer to get the to get the gains and you know so there are people that are willing to put in that effort.
There are people that do want to suffer and they will there's some days where you just don't write. There's just some days where you're not going to do that but there are days where some people are very motivated and knowing you know to be clear. These are these are these are very good scientists on both sides who are very careful methodological people you know they so I respect the scientists on both sides of the issue but yeah to your point I think my sense is when it comes to
Higher intensity, especially short duration work the traditional way of thinking. When we think of perceived effort, it's just, it doesn't fit as well, right? Like classic Borg rpe scales are, you know, based on 6220 because that generally correlated with, you know, young fit individuals who had a resting heart rate of 60 in a maximum heart rate of 200. That's where that rating scale comes in. And so, you know, the more
Hence, especially if it's continuous exercise, the higher, the heart rate, the higher, the perceived effort. But we just see such a disconnect between ratings of perceived effort and heart rate. I'll give you a very specific example. We've done a study looking at that 10 by one protocol. So these are 10 one minute efforts at objectively measured, maximal heart rates of 85 to 90 percent of Maximum in older individuals 63 years.
On average obese with type 2 diabetes, on a 10-point rating scale. They started out as a five. They eventually got to about 1/8 and so the average rpe was about a seven out of ten even though these people were doing very high power outputs at very high percentages of their maximum heart rate, so it's just a striking example. In our initial Sprint, studies the one-minute Sprint's studies, 320, s efforts are first ones. We were saying,
Go as hard as you can Sprint from danger pace and we and and those we are using a 20 point scale they'd come back 14 15 out of 20. Because now if we ask them to continue that Sprint Pace for a minute, I'm sure we got to 20 but since they're so short. So yeah, to your point is exactly right perceived effort, I don't want to say it, goes out the window but it maybe needs a rethink when we're referring to these very short, very hard, intermittent type efforts,
Where do you think? Let's say someone new to hit, we're like what a good place to start. Be more of these like shorter like in a really good question. And this is where you know, we haven't really talked health risk and all that. I'm sure we'll get into it. But like a standard thing that will just tell people is get out of your comfort zone. So wherever your starting point is your own perceived starting point. Make yourself a little bit more uncomfortable than usual, for a short period. And then
Back off. And so, you know, I use this analogy all the time, if you're only exercise is walking around the block and you want to get into intervals, it's literally for the next to light post. I'm going to pick up the pace a little bit and then I'm going to back off. So I feel a little bit more out of breath. I can feel I'm breathing a little bit more. I can't talk to my partner, like I generally can on our moderate walks, it can be as simple as that, just get it out of your comfort zone. If you're someone who's already dialed in on the bike and you got a smartwatch.
All of that it's like hey, get your heart rate up, longer or go longer and try and keep your heart rate, their, you know, or rather than 20 seconds, you're going to go for three minutes as hard as you can. You know, I can be like him. Yeah, I know. And next time we're going to do that but it's going to be a very different challenge for you, right? And this is where I think that the more empowering term interval training. It's okay, because it doesn't matter if you're magically getting to some 80% leveler. Whatever the
Bert's tell you you should be at it's just start with the alternating pattern and then build from there, start to dial it in maybe a little bit more and get more Discerning. But as a starting point, just get out of your comfort zone and back off and repeat that a few times, this kind of reminds me of the was the interval Walker's versus the Walkers solutely. Yes. But you know, excellent data. And these are, you know, relatively small but well controlled randomized. Controlled trials. Looking at interval
Walking versus continuous steady state, walking, including an individuals with type 2 diabetes. 34 month interventions, where individuals were randomly assigned to an interval walking group? Continuous walking or a control group the interval, and continuous Walker's matched for total exercise. Volume total exercise intensity. So, you can imagine the, The Continuous Walker's, I think, their average heart rate was around 65% of
Mom, the interval walkers. Got that up to 70 and then down to 60. So we're just talking gentle Hills and Valleys after four months. The interval Walker's greater Improvement in Cartier Spirit, or a fitness greater reduction in a greater change in body, composition greater loss of fat, and most importantly, individuals, type 2, diabetes, greater reduction in 24-hour. Blood sugar measured using continuous glucose monitor.
So it's not to say that continuous walking is bad. I think it's just a little bit of evidence that adding some intervals are varying. The pace even slightly, we're not talking. Sprint training May provide some greater benefit and this kind of relates to something. I was going to ask you about which is you know, interval training for maybe elderly and maybe infirmed. So people that are more sick, you know, like how they can incorporate interval training into their lifestyle and also then like contraindicated
Don't contraindication. Like so you mentioned like like maybe some people you know, is there some people that high intensity interval training is not good for on? How would, you know, sort of all of those? Yeah, so in this, you know, this I always make the point here. I'm a PhD scientists, I read the literature, I'm not a medical doctor, I'm not a cardiologist, I read work like that, I try and stay informed on it and certainly for my book, I interviewed people like dr. Paul Thompson, right noted cardiologist. Who writes many of the guidelines.
Ends around. This very, very issue. But first point I was make, is that interval training as we've talked about a lot comes in many different flavors. So, second point is that many more people than we initially think, can perform and benefit from interval training, and they're just now, there's hundreds and hundreds of studies that have looked at interval training in individuals with cardio, metabolic disease, cardiovascular.
He's
heart disease. Type 2, diabetes older individuals, people with metabolic syndrome and a lot of this is not new, you can find studies going back to the 70s and 80s some of the pioneering work looking at interval training and individuals with heart disease. So the notion that people could, you know, individuals with cardiometabolic diseases could engage in benefit from interval. Training is certainly not new. But there remains immense debate and I think it's we're all reading the same size.
Science. And some people, again, I'm talking about the field broadly, some want to see the science get to a certain level before they recommend changes and where that level is is different. So for example, high intensity interval training, my read is, is much more ingrained in Europe and certainly in Scandinavian countries. It's, you know, much of the pioneering work around, high intensity, interval training, and cardiovascular disease was was done in Norway, in the work of Ulrich whistle off and that goes back to the
Calculator that we talked about earlier, but there I think it's much more generally accepted and integrated into cardiac rehab training or I think in North America, it's it's not right, and so that's not necessarily good or bad. I think it's the experts, the cardiologist, the people who write the guidelines looking at the evidence and saying, man, you know, some are more like I say with the there's different viewpoints on that in terms of risk.
And again, I'm not an MD or a cardiologist, but in there's no doubt that more vigorous intensity exercise can transiently increase risk of an event during the exercise bout itself. I think there's there's fairly strong evidence for that. And, you know, in preparing for our interview, I was reading some of the latest guidelines expert. Guidelines around that making that point, you know, and especially in more deconditioned individuals people might already.
Some silent underlying risk factors and so we can't ignore that or downplay it or say that everyone can do interval training, it's fine, but the absolute risk Still Remains low. When you look at events per hours engaged in actual exercise, both moderate and vigorous type effort whether it's continuous or intermittent, the absolute rates remain relatively low, but statistically, there is definitely
An increase in Risk, that's higher with vigorous exercise during the event itself. Now, of course, after the event relative risk is much lower than individuals who would remain sedentary. So, you know, I think the old adage of the greatest risk to your health is just remain. Sedentary is absolutely true, right? And so when I is, was striking phrase that dr. Thompson, used when we interviewed him for the book was, you know, if your choice is between doing hit and doing nothing. Do hit if the choice is between
Hit and moderate, and you're 60, and you've been pretty inactive. You might have some underlying factors and time is not a worry. Do moderate, or at least engage in some water. It is some preconditioning before you start with the, the more intense stuff and then on the, you know, who is absolutely contraindicated atrial fibrillation, is there are some very clearly defined. No go.
Was that if you have certain conditions that you shouldn't be engaging, vigorous intensity exercise. Unstable angina would be another example. Yeah. Sounds like a lot of the I mean things that you would talk to your cardiologist about. You'd already have a cardiologist if you know that you had that sort of disorder. So the last point I would make is, you know, in talking to many Physicians and cardiologists. You know, we think an exercise stress test, sort of gives you that green light or red light to engage in exercise. And in certainly, in our studies
Are individuals had elevated risk people with type 2 diabetes in that. Everyone does a 12-lead ECG stress test before they're recruited into the study. But you know, I naively thought, okay? The person doing the stress, test, the cardiologist reading it. It's going to come back and it's a green light. Good to go in your study red light. Unable what we found was a lot of yellow lights. Hmm. Maybe you know, this person might be contraindicated or there's a change here that might Elevate risk. And so of course we defer
To safety. And so, even those yellow lights, generally, those individuals were not then recruited into the study, which is no doubt influencing outcomes. But I always wonder I'm like, so, are these people just going to sit around and continue doing nothing and is that in itself, raising their their risk. So it's, you know, it even, you know, the standard, you know recommendation, see your doctor get clearance before you change or engage in exercise.
Sighs. It's not always 100% guarantee one way or the other. In terms of, you may deal with a sudden adverse event, we might see it in a twenty-year-old in my lab tomorrow. You can't absolutely rule out these things. I think also mentioning the the Walkers, the interval Walker's versus continuous Walker's was really good. Because, you know, it also kind of highlights the fact that you don't have to go to your 80 percent, max heart rate for interval training and
Perhaps people that are older people that might have some underlying conditions people that are untrained and are starting later in life great. You never, it's never too late to start. They can they can start by, you know, by doing, you know, intervals, that are not necessarily all out, or even submaximal, right? Me just just going a little bit above, what your steady state being able to talk normally sort of conversation is? And you know, I don't think that, you know, my sense is that
Is that many of your listeners are already aware of this? But I think still for a lot of people are certainly the general public, they hear the word hit or interval training and they think, oh my goodness. It's this as hard as you can go, all out Breakneck pace and that's not for me and I think that's a disservice. And, and again, hopefully this
More encompassing term of interval training. It's just this idea of Hills and Valleys, right? And the other point to that is talk to I'm not name-dropping here but just, you know, many people have thought about this for a long time. I also interviewed for the book Karl Foster who has done a lot of work around this and when he first heard, you know, as a scientist in the 80s that there was a group in Germany that was doing interval training in cardiac patients. He saw one of the scientists at a conference
I said oh how many people you killed this week with that crazy stuff and he was relaying that story to a cardiac nurse when he got back to his institution and the nurse. He said sort of tapped him on the cheek and said, oh Carl you're so silly. And she said, look at this patient in the parking lot, who's coming for his cardiac rehab, setting, Earth session. They already engaged in interval training because they can't. They have such low Exercise capacity, they can't get to a continuous moderate pace.
So what they do is they innately interval training, they get out of their car, they take a few steps, they take a break, they take a few more steps. They take a break, it's bit like, Climbers, on Everest, right. And so again, that's a more empowering message, I think you're just starting out. That's okay. You can, you can train like, Elite athletes have trained. We just have to set the workout, approximate level, that's suitable for you rather than, you know, oh my goodness, people are destined to be a failure because very few
Engage in continuous, moderate exercise for a period of even 20 or 30 minutes, because their capacities are so low. So, it's a bit of the behavioral colleagues talk about message framing. I think there's a lot of that we can do with interval training, so for those individuals who just think it's this all out crazy stuff, I'd never do it. It's a, it's a reframing of it for them. Yeah. And also again the the modifying, the work to rest ratios to is another sort of way, I think that it's like although I have to go all out for a minute or two minutes.
It's or three minutes but what about 10 seconds, you know what about 10 seconds. So it's absolutely a lot of there's a lot of ways to sort of modify the you know the hit program in general what about this? The the is it high. The high intensity resistance training or resistance, intensity training, which way it goes different way, you know, some people call functional training but certainly there's high intensity resistance training, you know?
I think can still count, you know, for a lot of resistance training, just because the intensities are so high. You know, we're talking about now very high Force efforts that lasts less than a second sometimes by its definition it's interval training. We just never really think about that. But so I think certainly body weight, style, type interval training, or what used to be traditional calisthenics and that that can play a role.
You're so I think again, using this generic term interval training, I think we can have more aerobic style interval training or resistance style interval training, and again, body weight style interval training, would sort of be the classic one. To me that is interval resistance training and I think it had can have tremendous benefit, you know, it's often a sort of a middle ground, you're not going to see the gains in strength that you would see with.
National heavy, weight, lifting exercise. And you're not necessarily going to see the gains and fitness that you would have with a traditional well-structured aerobic training program, but you can get a lot of both right in the middle, you know, especially if you know we're talking air squats, burpees sets push-ups where you also keep recovery periods, relatively short, you know, you engage in that for 10 to 20 minutes you can keep your maximum, your heart rate up to about 80 percent of Maximum. But you've done a lot of resistance style training,
And it's increasing functional strength as well. I think it's a tremendous way to for people to train. It sounds like a lot of CrossFit kind of thinking. Yeah, absolutely. You know, now, maybe not necessarily as intense as some of these programs that you see. But absolutely, that style of functional training, whatever you want to call it or label. It can be extremely beneficial, I think, and in a time efficient way, you get strength gains and some aerobic conditioning as well. Can you get
Get any muscle, muscle math, Mass gains, even strength, gains from high intensity interval training. Let's, let's say if you're on a stationary bike and you're increasing the resistance up. Yeah. So it that one really depends where you're starting level is right. And so if you're already relatively fit and healthy, then the the general belief is that you're not going to see massive changes in muscle protein synthesis or changes in fiber size or anything like that even with fairly
Intensive sprinting. Now, if you're someone just starting out you think of a very deconditioned elderly individual who is going to get on the bike and do some moderate pushes their you know we're not talking all-out Sprint training they could see some improvements in protein synthesis you know. And again are we talking mitochondrial myofibrillar but I think traditional muscle protein synthesis where we're seeing an increase in fiber size in that if your Baseline is very very low. Then I think even
Aerobic style, interval training can be beneficial there. But otherwise, you know, once you get to a certain level, it's not a hypertrophy stimulus generally speaking. Yeah, okay. Because I cranked my resistance up really high on my palate on, and I'm standing and doing it. You know, like, I'm like this test, we do something on my quads and, well, you know, you look at, you know, look at Tour de France cyclists, right? Like, I mean, they're amazingly muscle now. They're very, very lean as well, right? How much of that is. That was covered in a layer of fat. How, how much
With their be there but, you know, I think they're, it's not nothing but, you know, you can get much greater great gains in protein synthesis with some more traditional squat exercise, and things like that with a lot. Lot less volume of work. Can you just lift? I mean, like, can you, you know, like let's say you're doing a more of a resistance training like higher intensity resistance? Remove circuit or like you were talking about
Can you I mean there's can you just get by with just doing that? I mean, yeah, get right compared to what but, you know, so like I don't like only doing heavy resistance training as traditionally practiced. I think you're definitely leaving something on the table in terms of Carter Spirit or a fitness and health benefits and all of that, I think it's a really good question of, you know, again if it's that person like we talked about the classic individual you know, type a limited time still
Engaged in real life with responsibilities family job, things like that and they have an hour a week to train. If they only did high intensity, functional training, calisthenic style, body weight style exercise. I could see a lot of value in that, right? In terms of aerobic conditioning and gains in strength, you know, coming back to what we talked about earlier, you know, if it's if it's four sessions a week, they can do maybe two of those.
Is
our high intensity functional training, or body weight style training, and two or
more
interval training for aerobic conditioning on a bike, on an elliptical, things like that. You know, you only have three. Woohoo. I'm not sure how I defeat those up but still getting some variation in ideally. But yeah, I have a lot of time for high intensity functional training. Yeah. What about the combination of aerobic training with resistance ratings?
This chronic interference effect like heard about. Where if I do my aerobic exercise, right? You know, in conjunction with my my lifting I'm going to blow my gains. I mean, at least that's what I interpreted some of that. Yeah, so I, you know, the I think where the evidence is and if you look at the latest systematic reviews and meta-analyses, what they're going to say is maybe there's a slight interference.
Fact, maybe it's there to a greater extent with high intensity interval training and certainly if you do it within the same session maybe there's some blunting. But if you look at the work right now and there's some evidence to say cycling is okay. But running is not. There's some evidence to say, actually running is okay, but cycling is not. So there's no clear answer. I think the bottom line is there might be a slight interference.
Act in some people especially when they do it very, very close together or in as part of the same session, but it's probably relatively small, it's probably relatively negligible in the big picture. But if you're someone who's really looking to eke out maximal, gains, you probably want to leave a few hours in between your training sessions. Yeah, I was the the interest had kind of sparked because while one because you hear about it, but also from I think it was stews recent study.
Are combining aerobic exercise with resistance training and it was like actually was there a little bit of a beneficial effect in summer regard to blood flow or something like that. So it was you know certainly I think you know it's like a lot of things with interval training. You can pick your study to argue one side of the other but you know I think that and of course meta-analyses are based on all these studies, some good, some less good. But I think that's the sort of state of the field is, it's probably not a big deal for most people including
If look I got half an hour today I can do both. I can't split this up because I can't train tomorrow. Well then do both right? But again if you want to eke out every bit of the drop, then ideally separated by a little bit of time, a couple hours at least, okay. All right. The the guidelines that are set you kind of touched on it a little bit and this is a, this is a big question that people ask all the time. You know, there's these guidelines that are set by a variety of
Is it seems like there's a lot of consensus in terms of the guidelines for moderate-intensity aerobic exercise. Anywhere between 150 to 300 minutes a week or vigorous intensity exercise and that's 75 to 150 minutes a week. I think something like that. Where do you think in your opinion, does high intensity interval training fit into that equation? Is there a new time?
I'm frame and let's say for people that are optimizing for General Health or also for people wanting to also get that, you know, back to the JAMA study, you know, I do want to be closer to that Elite sort of performer level using kit. So for those kind of people there guideline in your opinion or what your opinion also. So there's a ton, they're so so so first thing, you know, let's remember these are physical activity, guidelines or not exercise guide.
And so, we're talking about physical activity, guidelines. You're right, there is General International consensus that hasn't changed that much. If anything, it's just increased the number a little bit in the latest guidelines u.s. skylines for Americans. The The Who World Health Organization guidelines are consistent and they're exactly what you just said, hundred and fifty to three hundred minutes of moderate or half if you're doing it. Vigorous, and how is that defined? Well,
It is defined in an absolute sense of about of not about it's 3 to 5 .9 Mets 3 to 5 .9 metabolic equivalents or five to six on a 10-point rating scale and what that means subjectively is you can talk but you can't sing. So you're exercising with a partner. You could carry on a conversation at a moderate effort but you couldn't sing. Vigorous effort is above six Mets, seven or eight on a 10 point scale.
And you can only say a couple of words so you can carry on a conversation. Say a couple of words, short phrases. So that's sort of the subjective and objective measurements of moderate and vigorous and those are fairly consistent. Now, you know, American College of sports medicine would have some different numbers there at least in terms of percentages of heart rate and things like that but that's generally where we are. Moderate to vigorous
Icarus. And those are for what are deemed substantial health benefits. It's not saying that's the best way to increase your VO2 max. It's saying, there's really good data from a wide variety of sources that if you engage in this level of weekly physical activity, you can expect substantial health benefits brain muscle. You know, lots of lots of things. It's not saying it's ideal either, that's not necessarily the optimal because there's always a
That more is better so you can ring a little bit more out of sponge. If you're going to engage in more and there's not a you know, there's the only other recent change was really that. There used to be this guideline that said you have to accumulate these in boat's lasting at least 10 minutes and that was removed because it was never really supported scientifically. And so at least that change I think has opened up a little window on this notion of all activity counts. And it was
Partly. I think some recognition of there's some studies out there. Showing that very short efforts can be associated with some improvements in some of these Health markers. So the guidelines are just that they're, you know, suggestions or recommended amounts to derive health benefits when we're talking physical activity, they're not saying this is the way that Elite athletes should train in order to optimize their performance. So I think we really need to recognize what the guidelines are.
And the last point in this, my understanding based on talking of these aspirin experts is the tend to be conservative because ideally they would like metrics like doing this amount. We know is associated with a lower risk for all-cause mortality, or is a lower risk for developing cardiovascular disease. And many of these other chronic ailments. And so we just don't have anywhere close to that body of evidence when it comes to interval training. You know, we may eventually
If so, where does hit fit in the big picture I think? And again, I spoke to people for my book. People, like, I'm in Lee at Harvard doctor, I'm in Lee who's engaged with some of these committees? And the point was, well, hit already fits within the guidelines. And I said, well, is it only the hit efforts or the recovery intervals as well? So if you do a 20-minute hit session, but half of that is resting and half of that is the exercise, her point would be no, you
Both, right? Or another example of interval training is so many team sports, right? I like to play Ice Hockey. My wife is a soccer player and so in those four parts of the game you're active and exercising very vigorously. And for the parts, you're not watered or low intensity effort. So with always, if you engage in a one-hour of, pick up ice hockey but you're only playing every other shift. You can probably count the our within that. So I think interval training and
It already Falls within the guidelines and certainly would fall within the guidelines of vigorous activity. Will we ever see the guidelines say
150, men. 150 to 300 of moderate, 75 to 150 of vigorous or 30 to 60 a very vigorous exercise and you know, new breakpoint maybe. But I think the people that write the guidelines will want to see a lot more evidence until we're going to get to that point or, you know, will there be some acknowledgement of these types of Ville? Papa, you know, or at least engage in Bill polite efforts for five minutes?
Day, you know, 30 minutes of Philippa like efforts have also been shown to be associated with this, you know, the UK guidelines. Explicitly refer to hit The Who and the US guidelines, really, do not at least in terms of incorporating it. So it's going to continue to evolve, but I know that's probably a long-winded answer, but that's probably the best perspective that I could offer on that right now. Yeah, I think that's good. And I do think that the alluding to the bill Bessette. He's, I mean, again, like you said, I mean, you're talking
Talking about, you know, to some, I mean, it's a pretty minimum effective dose to get 30 to 40 percent reduction in all cause mortality and cancer mortality, right? I mean, it's not the 80% of the, you know, at least the elite performing people that had the highest VO2 max but and and for that and you know you may you may need to do Dooney probably need to do more but for some people that are just generally wanting to get, you know, 50% reduction or something like maybe
You know, doing doing 60, 75 minutes, a week would and that, you know, because you're I get this question a lot and, you know, you alluded to it earlier whether we like it or not, a lot of people still want that answer is how little can I get away with and the guidelines don't really address that right? Or there at least there's no grudging acknowledgement for saying look, we know most of you have probably aren't going to do this. So at the very least do this, right? They there's been no movement.
Movement on on that if anything were just encouraging people to do more so it is it is may be a gap or at least we should confront that reality that there's a big disconnect there for a lot of
people.
Another sort of I think research Gap is sex differences and it's it's definitely have interest to many many women of all stages of life. So,
Knowledge in the research gaps. I'm still going to ask you some opinions to see if there are any I know I know there's also I think some misconceptions in the general audience in the with the general population also so it'd be nice to kind of even touch on some of those one being, you know, postmenopausal women like is hit good or bad for postmenopausal women, like on the bad side some women are worried about raising cortisol to
Hi, do you have any thoughts on doing, hit for postmenopausal women? So, so specifically on the cortisol level, and again, I think the latest systematic reviews and meta-analyses, you know, the studies vary a little bit but
By and large, I don't think individuals need to worry about chronic increases in cortisol levels, systemically that are going to cause them damage. Clearly cortisol levels can go up just like, catecholamines, go up cutely during exercise. But I think there's some evidence. Now, that would suggest that actually in individuals, that practice interval training basil, cortisol levels actually, stay lower than prior to Baseline. So I don't
It needs to be a major concern, especially given a lot of the other benefits that we can see with this type of approach. So that's that's on the cortisol
issue specifically.
Yeah, and that I mean, given all the benefits we've talked about the cardiorespiratory, the muscle, you know, skeletal muscle, you know, the brain. I mean, there's just, it's pretty clear to me that. I mean, it'd be hard. It'd be a hard sell to say, oh no, it's not beneficial for postmenopausal. Yeah, I know.
And very different is, you know, individuals with PCOS polycystic, ovary can is there's ongoing work. As some really good work out of Norway, looking specifically at hit in individuals with that condition. So showing some some real benefits there on the sex-based differences. You know, writ large, are there sex-based differences in some outcomes? Yes, I think there's subtle.
At least the evidence to this point would suggest there are some differences there, probably subtle differences, but we knew we do need to know a lot more, you know, are there? Massive differences between, for example, phases of the menstrual cycle or oral contraceptive. Users versus naturally cycling. Females again, maybe some, but probably pretty subtle. So that doesn't mean they're not important, but I think the difference is are
Small in most outcomes. But absolutely, we just, you know, need more research. We, we need more research on diversity of responsiveness writ, large, not necessarily, even just biological males. And females, you know, you've talked about this on other episodes, you know, it's an active area of research, and it's a frustrating area of research sometimes. So, I'll give you a very specific example. Some of our research right now is looking at the mechanism,
As for the increase in VO2 max with very short Sprint type interval training, right? And so we know that that increases VO2 max but we're not sure why and actually some of the work would suggest maybe it's more the muscle adaptations than we thought about or at least the cardiac output changes take a while so I have a PhD student immersed in this area and is first study we show that view to Max goes up. Stroke volume was up, cardiac output was up after 12 weeks of training and it looked like there were some differences between the
Males and female participants in the study. So we did a secondary analysis was an appropriately powered. And we thought yeah, actually it doesn't look like the women are responding very much over the females and the man the males are so then we repeat the whole study using more, best practice procedures, properly, controlling for menstrual cycle phase and properly. Expressing Fitness / fat, free mass, and we're basically unable to replicate the
Original fines and we certainly didn't see any evidence of a sex-based difference which tells me something. We've hand wave around a little bit around our conversation. This point there's tremendous enter individual variation in responsiveness. And so at least right now to my mind in terms of potential differences, in responsiveness to specifically Sprint type training, it might be less about a male or female biology issue, and it might just be there's tremendous variability between
Rules and in the almost 40, participants in the combine two studies, it happened to be men people identified as males, that responded to a greater extent, but it might not have anything to do with biological sex and I think that's where a lot many areas are right now. Not all of them. Some of those very clear differences but I think that's where the exercise field is writ large and the vast majority of Studies have not Incorporated these best practices for making.
It comparisons between Sexes, right? Yeah. And also I think you know differences in like at least for me it's like there's invite. There's environmental effects. How much sleep? I got like things that will also affect my ability to perform and you know, things like that. So yeah, I mean there's a lot of gaps in the field and you know, with respect to women and menstrual cycle. It's also a question. I get a lot and I, you know, the I think the reality of it is that, you know, 20 to 30 percent of
And strating women are, you know, during their menstruation are iron deficient and they just don't even know about it. They don't even know about it, they're not thinking about it, they're not increasing their dietary intake of iron the not supplementing with iron during that period and maybe that alone also would affect some irons important for him, right? And that's don't know the others and if you talk to use female athletes or like, even if there is, I don't get to pick when my Race date is. I know I have to peek for this day in 4 months time.
You know, in this location maybe you can structure your training around menstrual cycle a little bit, but I think the real that that's just the reality obviously for women who compete in sport. And so yes, we need to know if there's some differences there but in the big picture it doesn't really matter. It's just one more thing that potentially contributes to variability and responsiveness on the day and you try and control all the other things as well as you can, you know, to Peak as best you can on the day of your
Event or your key event. Does high intensity interval training affect bone mass or bone density? Do you know this is where you know it go like to this point, you know I've encouraged us to think about mode specific when we're making some of these comparisons, I think that's where it depends, right? And so we know that more higher impact events or activities certainly. When We Were Young 10 to, you know, lay down more bone. And so, you know, for talking high-intensity cycling,
NG versus high intensity running, those things are very different, right? Are you running on concrete? Are you running outside and beautiful Trails? All of those things matter, you know, the the flip side to that is, if we talk about injury risk, people say, well, I can't do high intensity training to increase my risk for injury. Well, you know, I'm someone with classic left knee osteoarthritis. I just torn meniscus in my right knee, playing hockey. So, I'm gonna have osteoarthritis and that, and he soon I can engage in very vigorous interval training on the bike.
I can't and I don't run anymore so you know, hit training on the bike. No problem. Any sort of running outside is excruciating for me. So joint problems in general people. People can do you think people can engage in cycling? I do. Yes. And, you know, we know certainly and again, like, I'm not an expert in this area, but, you know, talking to experts and just trying to read and stay abreast of the literature, you know, we know that
people who have joint injuries, certainly meniscal injuries, or osteoarthritis. One of the best things you can do is remain active, and it's obviously frustrating advice for many people because they're like, I want to be active, but it hurts when I'm active. And so moving towards less weight, bearing activities that allow you to be active around the joint and maybe, you know, help with the, the tissues around the joint, but aren't impactful forces. So cycling is a fantastic exercise.
For individuals with osteoarthritis because you can still engage in Fairly vigorous activity without hurting or damaging, you know, specifically your knees in this case. Yeah, that's great. I know there's there's there's quite a few people that are under the misconception that they cannot do any type of high intensity interval training because they have joint issues so they don't to do box jumps, right? But yeah I mean jumping rope which may actually be good great for the bones. I mean that's impactful and you can do certainly do.
High intensity intervals with jumping rope as well. What about? So there's we talk about like some of this, you know we're talking about some of these like misconceptions I guess. And you kind of touched on this a little bit when we were talking about, maybe, you know, people that are shouldn't engage in high intensity interval training like the people with afib or in China, that heart problem, the the
That doing high-intensity interval training could cause a fib or coronary calcification or just even like Elite athletes. In general, like you at the high level, you can see they have a higher tendency for afib and coronary calcification, but on the same in the same breath, they also have a lower risk of you know, cardiovascular related mortality, is there a way to reconcile a thing. So again,
Not expert, but my read of this including you know there's some really there's some really good reviews that have come out recently. And again, we could drop those in the show notes to direct people to reading on this. But you know, the old Latin phrase, the the poison is in the dose right there. There's definitely evidence that individuals who over a lifetime engage in very high intensity. Very high volume exercise may be at greater,
As for some of these issues that you just referred to heart, heart issues, the to my read, in my understanding, while there's theories out there the a definitive cause and effect or mechanistic basis hasn't been definitively established. And the other is it's been pointed out that those date like while clearly that risk is there and you see examples of this, it doesn't fit or doesn't line up with the
Longevity data which is still that, you know, lifetime Runners will still have, you know, a few more years of life compared to others. So I think it's a it's an issue that still really needs to be resolved and probably the safest advice would be, you know, extreme exercise may carry some some consequences right whether it's a u shape or the j-shaped curve, there is something to that and if you're on, you know, this is for the vast majority.
People this isn't an issue but you know, if you are that extreme exerciser, you just need to be mindful of the fact that that may carry some increased cardiovascular risk. Yeah. So I one more Oddball question before my last one which is heavy. What are your thoughts on this like hypoxic training? Like have you heard of like the mouth taping during like hit or so my sense.
Yes, yes, I've definitely heard of it, you know, clearly when you move to more intensive exercise, the vast majority of your ventilation is through your mouth so it's really hard to engage in. Vigorous exercise. When you're restricting, either nasal breathing or mouth breathing, you're going to compromise your performance. It may feel really hard, you know, because you're inducing this added stress, whether it's beneficial, I'm not.
It's of that I you know, I think the data around blood flow restrictor training is much more interesting and there's some really really interesting. We're coming out of out of that, you know, you can make the case that maybe you're going to see some changes in respira Tori or diaphragm muscle or that but getting back to the idea of what limits view to Max. It's generally not a pulmonary limitation. So heart limitation and so
is that are really trying to additionally stress the pulmonary system. So, you know, if people want to try it fine, I don't think there's tremendous evidence that that's going to potentiate training responses. What's the interesting thing about Blood Flow Restriction is it will just you know, like I think deaf, you know as a therapist, so I I'm aware of some ongoing work, I guess that's about and you know, this isn't our work, but I'm also aware of some work looking.
It Blood Flow Restriction exercise and training in very very high level. Endurance athletes showing some interesting changes in performance related metrics or some measures. And yeah so I like I say that work is ongoing. The hard thing with these is it's you can't truly blind. Someone to blood flow restricted training, right? Like many of these interventions we've talked about it's tough to have a true
To control who's completely blinded to the intervention that can influence some some things but you know the idea of blood flow restrictor training, allowing individuals getting back to Joint issues may be working at a lower absolute force or workload but still seeing the metabolic stresses induced with blood flow restrictor training. I've you know, there's some there's some interesting work there. I think so well Cajuns, where do you see this is this is my last question for you. Where do you see the future of
Well, specifically high intensity interval training research, and you know, like the training methodologies, where's where's it going? Like how we can find really, you know, how we can Define good studies to optimize for vo2max to optimize for, like mitochondrial, biogenesis and these these these important measures of longevity and health and performance for the athletes to. But where do you see the field going?
Yeah, so a whole bunch of levels there and I think it you know what's the most it's like how do we spend our tax dollars, right? What's the most important Education? Health all of that but I think given the pervasiveness of physically inactivity writ large. There's a lot of Behavioral work that needs to be done there around. Is it a viable Public Health strategy? What are the best strategies to encourage people to engage in any physical activity Behavior? But
It
brief vigorous physical activity, intermittent, physical activity, non exercise physical activity. Could we have interventions that behavioral interventions, that will finally encourage people to do that. So I think that's a massive area that needs to get looked at number two is, you know, clearly I'm a proponent for interval training, but I fully recognize that we haven't done or just they're not out there, these large-scale randomized, clinical.
All trials making very good comparisons between traditional endurance, exercise and interval type training with proper what we call non-inferiority to designs, which is like, what's the margin of if there is a difference, it doesn't matter, right? So maybe that's half a mat or point two of them at whatever your metric is and design your study. So it's like if we show that margin of non-inferiority then it's good enough, we can basically call these things the same because a lot of the Compares studies to date are relatively.
Small. And so there might be real biological or health-related differences there. But the sample size is just aren't large enough to be able to detect that. And so, certainly in my own work, you know, as I progress into what's the probably the Final Phase of my career is I think we've, we've asked a lot of interesting questions in our work. We've mainly done relatively small scale proof of concept studies. But in our own work, we're thinking a lot more about rigorous research design. And I think the field of exercise
Sighs science, generally is wrestling with this issue of moving towards proper sample, size estimates, proper power calculations registering trials so we don't have systemic bias creeping into results P hacking things like that. So I think that's a very big area of maybe we need fewer smaller studies that generally look the same and a lot more groups. Collaborating larger multicenter trials you know being engaged in some of
It's
work right now, easier said than done, but I think that's where we need to go to, to get to the level of evidence that the people that write the physical activity, guidelines, might say, okay? Now this issue is more informed, right? To make some decisions, they're, you know, probably less important for the general public, but the whole area of Elite Training for athletes, right? Which is you know, invariably almost all of these
Athletes are experiments of one so you know if kipchoge train slightly differently with the marathon record be slightly lower, you know, probably not. You know who am I to question? Kipchoge is training but I think we continue to wrestle with this. Like we don't really know all these experiments of NF1 and Elite coaching, is that blend of Art and Science but we don't have these large, you know, Interventional studies. And athletes saying exactly what's the best way?
To train. We have some of them we touched on them but they're really, really hard to do, but if you're interested in the Elite Performance and then maybe the, I'm sure I'm missing Lots but probably the final one would be technological advancements, right? There's just been huge advancements, obviously around, sleep research, activity, tracking, things like that, you know, continuous lactate monitoring and athletes, will that really move the needle or, you know, revolutionize training using
Some of these markers, maybe you want to and also data and activity tracking for everyday people as well, you know, the ubiquity of smartphones and watches and things like that, getting back to the behavior, you know, can we encourage people with activity prompts and things like that? Like, is that a viable strategy or is that? It's never really going to work in the real world. So these sort of translational studies that continue to move research out of the laboratory into
Old world settings so that we can truly move towards Effectiveness studies as opposed to efficacy studies. I think is where the field needs to go. Awesome. Well, Marty, thank you so much for taking quite a bit of time to have this discussion with me today. I mean, I learned quite a bit and I know people are going to really enjoy learning this, you know, everything that we talked about today. I know. So you we talked about your book, the one minute workout people can find that Amazon, I mean anywhere, right?
Ebook. Form hard copy? Yeah it's available everywhere as we say and then you also have a website Martin Maher. Is it Martin Martin kabbalah.com/rh? Calm and then a Twitter Twitter handle is at Gible. Mm, Kabbalah M. So GI be a LM. So I'm surname. First initial. Okay, awesome. So people can go to those places to learn more about high intensity, interval training, your website, your book and also follow me on Twitter if they want to get out.
Absolutely, you know, really I started the website just so is a One-Stop shop. In terms of you can learn about our research, you can learn. I put up, Podcast interviews, like this links to the book links to dr. Phillips. And I have a free online course that people can can take called hacking exercise for for health. You know. And let me just add one last thing is opportunities like this to engage in knowledge translation science communication. It's huge right and
In writing the book, one of the things I had to get comfortable with, you know, and in science, we want to control everything. And if you move, you know, when you're writing research papers, you get a little controversial or you move outside a little bit and you just get whacked, right? Whereas, I think when you're boiling down or trying to boil down information, for the general public or other knowledge users and we don't have all the answers. We just have to sort of give our best guesses. Not move outside the lanes too much, but say, this is the best evidence right now. It's not
Fact. And so the way you do a podcast interviewer, write a book for the general public. It's very different from your right, how you write a scientific article and that's okay, right? There's some people who will only write scientific articles, never move outside their area as fine. We all do, what you're comfortable with but you know that also has limitations right? Because that many of these things are still behind pay walls. People can't get to them and so science, communication knowledge translation is really, really important. So thanks for this opportunity.
Opportunity and and the work that you do on on this podcast, I think it's tremendously important. Thank you so much, and it's nice to know that other scientists will be listening. And there are collaborations that can also happen out of podcasts as well. So, it's been a pleasure, Marty, and thank you for everything you do. And for coming on podcast today, thank you, very much. As we wrap up this deep dive into the world of interval training. I'd like to offer you an opportunity to continue your journey of understanding and insight.
Don't Human Health and Living better through scientific understandings. Consider joining, my email newsletter, it's not just about updates, it's a commitment to deeper knowledge. You'll be the first to receive episode summaries detailed timelines and other valuable resources. Visit found my fitness.com forward, slash newsletter, that's newsletter1 sign up today. Also, if you're Keen to explore how genes
Is can influence Fitness ranging from endurance and the potential to enhance vo2max with endurance training to reduce lactate transportation out of muscles susceptibility? To muscle fatigue and Men, and A predisposition to soft tissue injuries. Like Achilles tendon, ACL tennis elbow, consider exploring. Our free Fitness genetic report to get started. All you need is your raw DNA data, which you may have, if you've Used Services like 23andMe or ancestry,
Ena. You can find that free report at found my fitness.com forward slash genetics forward, slash Fitness. That's found my fitness.com, forward slash genetics forward, slash Fitness fitn ESS, or you can just scroll to the bottom of the genetics page, and look for the big list of free. Basic reports. All you need is your DNA data file.
Until next time, continue your pursuit of scientific wisdom, talk to you soon.
