Essentials: Sleep Toolkit for Optimizing Sleep & Sleep-Wake Timing

Welcome to Huberman Lab Essentials, where we revisit past episodes for the most potent and actionable science based tools for mental health, physical health, and performance. I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. Today, we're talking all about sleep and how to optimize your sleep. Let's consider what the perfect twenty four hour cycle would look like. Regardless of when you wake up in the morning, one of the first things that happens is that your body temperature is increasing, and that's just going to happen naturally. That increase in body temperature, in turn, causes an increase in the release of a hormone called cortisol. Cortisol is often demonized and considered this bad thing, and indeed, you don't want cortisol to be chronically or consistently elevated throughout the day or night. But you do want cortisol to reach its peak early in the day right about the time you wake up. One way that you can ensure that that cortisol peak occurs early in the day right about the time that you wake up is to view bright light ideally from sunlight within the first thirty to sixty minutes after waking. The reason for that is very simple. You want to trigger that cortisol increase to occur very early in your day, and you don't want that cortisol peak to happen later, which is what will happen if you wait to get outside and see sunlight. The reason for this is that you have a set of neurons, nerve cells in your eye, they're called intrinsically photosensitive melanopsin cells, but you do not need to know that name. Those neurons respond best to bright light, and especially right after waking early in the day, they are best able to signal to a set of neurons that reside over the roof of your mouth called the suprachiasmatic nucleus, which is a cluster of neurons that then sends a huge number of other signals, electrical and chemical, out to your entire body that triggers that cortisol increase, provides a wake up signal for your brain and body, and sets in motion a timer for you to fall asleep later that night. Here's what you do, or at least here's what I do. I wake up in the morning, and I want to reach for my phone. But I know that even if I were to crank up the brightness on that phone screen, it's not bright enough to trigger that cortisol spike and for me to be at my most alert and focused throughout the day and to optimize my sleep at night. So what I do is I get out of bed and I go outside, and if it's a bright, clear day and the sun is low in the sky or the sun is starting to get overhead, what we call low solar angle, then I know I'm getting outside at the right time. Especially on cloudy days, you want to …