Hello everyone, dr. Rhonda Patrick here, today, we're embarking on a deep dive into a fascinating aspect of sleep Health, the potential enhancement of Sleep Quality through heat exposure. It's been my personal experience. That heat exposure along with appropriate cooldown has helped me with aspects of my sleep. I'd like to share with you a little bit about why I think that happens in some of the complex cellular and molecular mechanisms involved, which should equally apply to hot baths saunas and to some degree exercise, these include the release of a
ATP increased adenosine levels and the signaling of sleep regulating cytokines, in other words, aspects of our immune system that can promote sleepiness. Now, you might already be aware of the importance of early bright, light exposure. In resetting our circadian clock and the value of avoiding blue, light exposure at night for optimizing sleep. These are significant elements in the realm of sleep, hygiene. But today, I'd like to temporarily skirt past those fundamentals.
And focus on another intriguing Avenue, the potential of passive body heating. What if the simple Act of raising your body temperature through taking a warm bath or using the hot tub before bed, or spending time in the sun, I could significantly improve Sleep Quality, this isn't just an enticing Theory, there's some scientific research supporting this passive body Heating. In other words, raising your body temperature without exerting yourself, through physical activity, has been shown to
Facilitate sleep onset, likewise taking a warm bath before sleep, increase the proportion of slow, wave, sleep. The Deep restorative phase of our sleep cycle. That is important for staving off. Neurodegenerative diseases like Alzheimer's disease for our older population were sleep issues are very common passive body heating could be an invaluable tool as systematic review. Found that passive body heating can Aid in sleep, initiation and maintenance.
In the elderly, offering a non-pharmaceutical approach to combating sleep disturbances.
So let's dive into heating. So you know, there's heating elevating core body, temperature by exercise. There's also elevating core body temperature through different heat modalities like hot baths and saunas, for example,
But heating visor exercise stimulates ATP release and increases adenosine and signaling a sleep regulating cytokines. So these include tnf Alpha, IL 1. These are released from the periphery or from astrocytes in the brain. So let's talk about ATP release. So exercise increases, the demand for energy in the body, right? That leads to the product to the production and release of adenosine triphosphate. That's a teepee the major
Energy, you know, currency in the body. So, ATP is a molecule that stores and provides energy for all the cellular processes including muscle contractions adenosine. So, as ATP is being used, or utilized during exercise, it breaks down into adenosine, and adenosine is a neuromodulator that plays a role in promoting sleep. So accumulation of adenosine in the brain, particularly in the
Basal forebrain is associated with increased sleep pressure that causes you to feel drowsy sleepy and it promotes the transition from wakefulness to sleep. Sort of. As a side note, caffeine is binding to adenosine receptors and essentially, you know, blunting the effect of adenosine. Any adenosine that's still left over in the morning from binding to those.
Receptors and causing you to feel sleepy. And it's one of the reasons why you get that acute alertness effect from drinking caffeine because you're not, then a feeling that effect of adenosine impact event adenosine binding to those receptors. So sleep regulating cytokines I mentioned also exercise stimulates the production of certain cytokines such as tumor necrosis, Factor Alpha, that's also known as tnf-alpha or interleukin-1 or il-1
These are
actually saamana genic cytokines, they're involved in sleep regulation. These cytokines are released from the periphery or from astrocytes which are type of glial cell in the brain, and they act on specific brain regions to promote, sleep
whole body hyperthermia. A therapeutic technique that involves increasing the body temperature to his level similar to moderate to high fever. Generally through, use of infrared, saunas and warm blankets has also been shown to increase the production of some energetic.
Cytokines tnf-alpha.
And il-1 have both been shown to increase non-rapid eye movement, sleep, non-rem sleep which you know, could could be referring to deep restorative phases of sleep. So in short summary of that set the section, you know, heating the body, particularly through exercise which does stimulate the utilization, the release and utilization of ATP, which then breaks down into adenosine and then that increases
Is the signaling of this sleep regulating cytokines as well. Like, tnf Alpha IL 1. These factors contribute to promoting feelings of drowsiness via the adenosine, the saamana, genic cytokines, they facilitate the transition from wakefulness to sleep. So they potentially then approve improve overall, Sleep Quality, you know, and you know, the also the the deep sleep as well, but it is important to know that exercising
NG too close to bedtime might have the opposite effect. Due to the increased, the acute effects of the increased alertness and the increases in core body temperature without being able to cool down before going to bed. So, it's generally, I think recommended to engage in exercise earlier in the day or just not right before bedtime. So you want to, you want to, at least, do it a couple of hours before bedtime to allow the body to cool down to promote more?
Sleep to allow the alertness and your brain to kind of calm down as well. Of course, like any exercise is better than none but when we're talking about it, in the context is of sleep, it is better to try to not do it literally like right before you're going to go to bed. So the effects of heat and exercise. Let's talk about some very interesting effects that we that we've definitely discussed in the past growth hormone, and prolactin are there too.
Two key hormones that are important in the regulation of slow wave activity.
The relationship between growth hormone and sleep appears to be bi-directional on the one hand, the majority of daily growth hormone, secretion occurs in the initial phase of slow-wave sleep. On the other hand growth hormone and it's releasing hormone growth hormone, releasing hormone have also been shown to promote sleep particularly slow, wave sleep
regular sauna use is probably
Only one of the most powerful stimuli that increases both growth hormone and prolactin. So growth hormone the effects of sauna use on growth. Hormone levels really depend on many factors, including duration, temperature and
frequency. So for instance to
20 minutes sauna sessions at 80 degrees Celsius, with 30 minutes of cooling period, in between can double growth hormone levels basically from their Baseline.
Fine. On the other hand, to 15 minutes on a sessions at about 100 degrees Celsius. Dry heat separated by a 30-minute cooling period
can cause a
five-fold increase in growth hormone levels. So there's also a really remarkable effect when you do sort of repeated sauna use. So repeat its awning. Use, for example, you do one, you do to one our sauna sessions at 80 degrees Celsius. This is very, very high for seven days in a row that leads.
To a 16 fold increase in growth hormone levels in men. That's not something.
It's just, it's kind of just as a
proof of principle, example of how there is a dose-dependent effect of heat stress on growth hormone. And, and that's something again, that is temperature and duration dependent. I don't necessarily think it's good to do that much heat stress. That's pretty intense, but I just wanted to highlight the effect that sauna use does have on growth hormone levels.
The heightened growth
hormone levels typically lasts a few, I would say more like a couple hours after Sean and use their released
after about two hours. They start to go down close to to Baseline levels. It's also kind of interesting that combining exercise with heat stress or sauna. U.s. may also increase growth hormone levels even further than when you just use. For example, sauna alone. And mostly it probably has to do with the again your elevation
Asians in core body temperature going even higher than one than one alone, right?
The release of prolactin alongside growth hormone is one of the classic responses to heat stress prolactin is a hormone produced in the pituitary gland. That is known for its role in lactation and women, but it also has various other functions. One of these is its role in the regulation of sleep prolactin has been found to increase during sleep and particularly during REM sleep, it's also been suggested that it may help to promote slow-wave sleep, the deepest phase of non-rem sleep. So in one study,
This administration of prolactin in humans was found to increase slow-wave sleep. Moreover, some research has suggested that sleep disturbances such as insomnia can occur in conditions with prolactin deficiency.
Prolactin in one study men that use the sauna. They were in the sauna for an 80 degrees Celsius sauna until they felt exhausted, they had a tenfold increase in prolactin levels in another study women who did a 20-minute dry sauna
Twice a week, had a 510 percent increase in prolactin levels after each sauna session. And similar to growth hormone prolactin levels lasted for a couple of hours. There are some other lifestyle factors in addition to sauna, use potentially even hot baths again, something that is going to elevate core body. Temperature exercise is one so exercise can also increase both growth hormone and prolactin. I don't know the exact
Quantitative numbers and how much. But they also do, increase it and then sexual activities. Another one that also increases both both prolactin. So you know the effects of a growth hormone and prolactin also again effect, slow wave deep sleep and so the idea is that you know, doing doing these these activities a couple of hours so you want
To make sure you're not doing again right before bed because you do want to allow your body time to cool down. And if you're if you get this on a literally like like right before bed, you might still be really hot and you won't cool down unless you then you know perhaps get into a cold plunge or do a do a cold shower to cool down but I'm doing it. Like, you know, a couple of hours before bedtime seems Seems like a good time. It's typically when I do my hot tubs, I do a lot of hot tubs.
In the evening and I do them a couple of hours before I go to bed. So that's all I think. Super interesting stuff that we haven't talked about before heating. Activates warm sensitive neurons in the hypothalamus. That promotes the wave. Activity in response to increased core body, temperature and skin temperature, yet again another potential mechanism behind. Why sauna use why hot baths, and even exercise which elevates Core Body.
Aperture May promote slow-wave, deep sleep, and then exercise combined with body Cooling and warm baths combined, you know, with body cooling. Also, you know, may help again to promote slow wave activity in deep sleep.
There are a variety of sauna and hot tub or hot bath. Protocols. That could be derived from the scientific literature on Sony, you some longevity and potential effects on sleep. An example of a sauna protocol could be 20 minutes in a at least 176 degrees Fahrenheit. Sauna, at least one to two hours before bed, allowing the body enough time to cool down before sleep, that may vary. In terms of the time, it takes someone to cool down before sleep. But what if you don't have a sauna
Or even a thermometer, an example of a hot tub or a hot bath protocol would be a temperature of around 104 degrees Fahrenheit for 20 to 30 minutes with as much of the body from shoulders, down submerged as possible. For hot baths, you may need to add more hot water throughout to keep the water temperature at around 104. So in that case, the thermometer may be helpful to monitor the temperature. For me personally, I have a pretty good sense of how hot I feel when I'm in the sauna for 20.
Minutes. So by knowing that I can sort of also make it a proxy approximation with how I feel in a hot bath. So again timing may be important by allowing the body enough time to cool down ideally a couple hours before sleep. Some of you may enjoy a cool shower afterwards, which may also help cool. The body down.
To tie this all together, passive body heating whether through a hot bath or a hot tub, or a sauna, or through physical activity. May be a really useful way to improve Sleep, Quality, especially slow-wave sleep, rather than being a substitute for good sleep. Hygiene, it potentially adds a whole new dimension to it. Learn more on the fundamentals of sleep. Hygiene by listening to my interviews with experts. Dr. Matthew Walker dr. Dan party and dr. Ashley Mason and episodes. 45 8.
67. I'll add a link to those in the description. You can listen to them here on YouTube or get them on Apple podcast or Spotify. Several segments of this episode were taken from a recent live, question-and-answer session, I host one of these, every single month exclusively for my premium members being a premium member, not only gets you access to these Q&A sessions where you can ask questions directly but also a myriad of other benefits. You'll get access to a members-only podcast called the aliquot a twice-monthly.
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