#03 Circadian Rhythms

And indeed, if I were to place electrodes on your head, I could show you this reliable drop in your brain's physiological alertness that happens each and every afternoon. And what this means is that us humans may not have been designed to sleep in a single bout at night, which is what we call monophasic sleep. Rather, we may have been designed to sleep in two bouts. In other words, one longer bout at night and then a siesta-like nap in the afternoon.

Your circadian rhythm, by the way, knows nothing about your levels of adenosine sleep pressure; and your levels of sleep pressure know nothing about your circadian rhythm. They are entirely independent. However, when you're keeping a standard sleep schedule, these two independent factors will beautifully coincide with a synchronicity that any two dance partners would be proud of...

Now, if you were to give your circadian rhythm a personality trait, it would be labeled as a creature of habit. It never stops ticking out its rising and falling rhythm—day after day, night after night.