Sleep Toolkit: Tools for Optimizing Sleep & Sleep-Wake Timing | Huberman Lab Podcast #84

0:00 - Welcome to The Huberman Lab Podcast, where we discuss science and science-based tools for everyday life. [bright music] 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. This is a topic we've covered previously on this podcast in the episode called "Master Your Sleep." However, since the airing of that episode, there's been some terrific new science to come out. I've also received thousands, yes, literally thousands of questions related to the specific protocols covered in that episode as well as in the episode on jet lag and shift work. And while today's episode is not specifically about jet lag and shift work, we are going to cover tools that will allow you to shift your schedule

0:46 if you need to for work or travel, and we will also cover tools that will allow you to fall back asleep if you happen to wake up in the middle of the night or if you get a poor night's sleep, how to actually recover from that poor night's sleep more quickly, and yes, indeed, even replace sleep that you've lost. So today's episode is going to be filled with practical tools. We will touch on some of the underlying science, but it's really designed to be a practical toolkit for optimizing your sleep depending on your specific sleep needs. Various times throughout today's episode, I will refer to studies that form the backbone of the tools that I'll be describing. But whereas most of the podcast episodes here tend to be deep scientific mechanism and then tools, scientific mechanism, then tools, today I'm mainly going to focus on the practical tools

1:32 that anyone, indeed, all people, I believe, should use in order to optimize their sleep. Why should everybody want to optimize their sleep and put considerable effort into optimizing their sleep? Well, put simply, sleep is the foundation of mental health, physical health, and performance of all kinds, cognitive performance, physical performance, et cetera. It also controls things like our immune system, wound healing, our skin health and our appearance, whether or not we can think clearly or not, whether or not we will live as long as we possibly can or not, whether or not we suffer from dramatic age-related cognitive decline or not. In other words, whether or not we keep our memory as we age. I could go on and on about all the terrible things that can happen to somebody if they don't sleep well.

2:17 Thanks to the great work of Professor Matt Walker at University of California, Berkeley, and the wonderful book that he wrote, "Why We Sleep," I think the world is largely onboard now that sleep is critical to our health, our mental health, our physical health, and our performance, but what's not often discussed is how great life is, that is, how much more focused and energetic and how positive our mood gets, when we are sleeping for the appropriate amount of time at the appropriate depth and when we are doing that regularly. Basically everything in life gets better when we're sleeping well. So today I'm going to teach you the tools that will allow you to optimize your sleep. That is, get to sleep and stay asleep, fall back asleep if you wake up in the middle of the night, and adjust your sleep given the various life demands you may be experiencing. I'm pleased to announce that The Huberman Lab Podcast

3:04 is now partnered with Momentous supplements. We partnered with Momentous for several important reasons. First of all, they ship internationally, because we know that many of you are located outside of the United States. That's valuable. Second of all, and perhaps most important, the quality of their supplements is second to none, both in terms of purity and precision of the amounts of the ingredients. Third, we've really emphasized supplements that are single-ingredient supplements and that are supplied in dosages that allow you to build a supplementation protocol that's optimized for cost, that's optimized for effectiveness, and that you can add things and remove things from your protocol in a way that's really systematic and scientific. This is really hard to do if you're taking blends of different supplements or if the dosages are such that you can't titrate, or that is, adjust the dosages of a given supplement.

3:51 So by using single-ingredient supplements, you can really build out the supplement kit that's ideal for you and your specific needs. If you'd like to see the supplements that we partner with Momentous on, you can go to livemomentous.com/huberman. There you'll see those supplements. And just keep in mind that we are constantly expanding the library of supplements available through Momentous on a regular basis. Again, that's livemomentous.com/huberman. Before we begin, I'd like to emphasize that this podcast is separate from my teaching and research roles at Stanford. It is, however, part of my desire and effort to bring zero-cost-to-consumer information about science and science-related tools to the general public. In keeping with that theme, I'd like to thank the sponsors of today's podcast. Our first sponsor is InsideTracker. InsideTracker is a personalized nutrition platform that analyzes data from your blood and DNA

4:38 to help you better meet your health goals. I've long been a believer in getting regular blood work done for the simple reason that many of the factors that impact your immediate and long-term health can only be analyzed from a quality blood test. And nowadays, with the advent of modern DNA test, you can also get insight into, for instance, what your biological age is and compare that to your chronological age. And, of course, your biological age is really the age that counts. The problem with a lot of blood tests and DNA tests out there, however, is that you get information back about the levels of metabolic factors, lipids, hormones, et cetera, but you don't know what to do with that information. InsideTracker makes that all very easy to navigate. They have a personalized platform. So this is a web portal where you can go, you'll see the numbers from your blood tests and DNA tests, and then it will tell you, for instance, how you could adjust various aspects of your nutrition

5:23 or your exercise or supplementation in order to bring those numbers into the ranges that are best for you. If you'd like to try InsideTracker, you can go to insidetracker.com/huberman to get 20% off any of InsideTracker's plans. That's insidetracker.com/huberman to get 20% off. Today's episode is also brought to us by Eight Sleep. Eight Sleep makes smart mattress covers with cooling, heating, and sleep tracking capabilities. It turns out that your body temperature and your ability to fall and stay asleep are very closely related. If your body does not drop by one to three degrees, you are simply not going to get into deep sleep or stay in deep sleep. And waking up, it also turns out, is related to body temperature. Every time you wake up in the morning, your body is warming up in order to wake you up, and this has an enormous number of hormonal and metabolic

6:10 and other cascades that are vitally important, not just to what happens while you sleep, but your health and your energy and focus throughout the day. Eight Sleep is an incredible device. It's one that I've been using for six months or so, and it's completely transformed my sleep. And I already thought I was sleeping pretty well. The way it works is that you can cool or heat your mattress according to different times throughout the night. So for instance, you can cool your mattress if you tend to run warm and that will help you fall and stay deeply asleep and then toward morning, you can have the mattress programmed or, I should say, the mattress cover programmed, so that you warm up your sleeping environment and you wake up when you want to wake up. If you've been sleeping pretty well but waking up in the middle of the night, you might also find that by cooling your mattress even further toward the middle of your sleep about, well, you'll stay in deep sleep much longer.

6:57 If you'd like to try Eight Sleep, you can go to eightsleep.com/huberman to check out the Pod Pro Cover and save $150 at checkout. Eight Sleep currently ships within the US, Canada, and the United Kingdom. Again, that's eightsleep.com/huberman to save $150 at checkout. Today's episode is also brought to us by LMNT. LMNT is an electrolyte drink that has everything you need in order to get your brain and body to function at its best, but none of the things you don't, in particular, sugar. Electrolytes are vitally important to the way that your neurons, your nerve cells, work and, indeed, to the way that all the cells of your body work. But your nervous system and your neurons particularly depend on electrolytes because you need the electrolytes, sodium, magnesium, and potassium, in the proper ratios, in order for those nerve cells to fire what are called action potentials,

7:42 which are the electrical signals that allow your neurons to work and to allow you to do everything from remembering information to moving your muscles deliberately. When you exercise, or even if you don't, you can get quite low on electrolytes, especially on a hot day. You can get dehydrated. There are lot of different ways to replenish your fluids and electrolytes and there are a lot of different electrolyte drinks out there, but many of them contain a lot of sugar. And some of those that don't contain a lot of sugar don't have the proper ratios of sodium, magnesium, and potassium. If you'd like to try LMNT, you can go to drinklmnt, that's L-M-N-T, .com/huberman to claim a free LMNT Sample Pack with your first purchase. Again, that's drinklmnt.com/huberman to claim a free sample pack. Let's talk about sleep and tools to optimize your sleep.

8:28 I want you to conceptualize yourself as contained within a room that has only very few windows or very few entry points. What do I mean by this? Well, your brain and your nervous system control whether or not you move or don't move. They control whether or not you're digesting food or you're not digesting food. They control whether or not you're stressed or not stressed, happy or sad, et cetera. All of that stuff that controls all that stuff is housed inside your skin and skull, et cetera. That might seem pretty obvious, but what that means is that for your brain and body to feel alert and focused, ready to move and exercise or do some work, or if your brain body are going to lie down and go to sleep,

9:17 well, that brain and body needs cues, it needs inputs, to determine when to do those different things. And those cues and inputs arrive through a defined set of what I'll call stimuli, but you can also think of these as levers or tools. The main levers and tools that are going to allow you to control when you are awake and when you are asleep and to get better sleep every single night are light, literally photons, light energy, could be from sunlight, could be from artificial light, we will discuss those particulars in a moment, as well as darkness. That is the absence of light. So we've got light and dark. Those are two very powerful tools to encourage your nervous system

10:03 to be in one state or another, meaning awake or asleep. Temperature is another tool or lever. Turns out that when your body is cooling down, you have a greater tendency to fall and stay asleep. In fact, every night when you actually sleep, your body is dropping by one to three degrees and that drop in temperature is required. It's like a gate that your body has to go through in order for you to get into sleep. And in fact, the converse is also true. If your body heats up by one to three degrees or so, you will wake up. So you've got light, dark, temperature, food. And when we say food, we mean what we eat, when we eat,

10:48 and the amount that we eat. Okay, so light, dark, temperature, food, exercise. And of course, exercise comes in different forms. We can do cardiovascular exercise that can be low-intensity, long-distance exercise. It can be high intensity, so-called high intensity interval training. It could be weight training. It could be yoga. It could be swimming, any number of different activities. But exercise, in general, causes an increase in body temperature and tends to make us more alert, not just during the exercise, but in the immediate hours after that exercise. Exercise does some other things that relate to our sleep as well and we'll talk about those today and how you can leverage them. Another potent lever for adjusting your sleepiness and wakefulness is caffeine.

11:33 This, of course, comes as no surprise to people, but why and how caffeine works might come as a surprise. Very briefly, we have a molecule in our body called adenosine and the longer we have been awake, the more adenosine builds up in our brain and body and adenosine is part of the reason why we get sleepy. Caffeine effectively operates as a adenosine antagonist. It works by basically occupying the receptor for adenosine. So it's a little bit of a convoluted mechanism. But basically all you need to know is that caffeine prevents the actions of adenosine. That's one of the reasons why caffeine makes us feel alert. But how much caffeine we drink and when we drink caffeine turns out to be vitally important for adjusting our wakefulness and for optimizing our sleep. So we'll talk about that as well.

12:20 The other category of lever or tools which are immensely powerful for optimizing sleep are supplements. There now exist as many as eight different supplements that can powerfully modulate sleep in healthy ways and that have huge margins for safety. So we're going to talk about what those supplements are. In previous episodes of this podcast and as a guest on other podcasts, I've talked about three particular supplements, magnesium threonate, apigenin, and theanine, which together can really enhance the speed at which one falls asleep and people's ability to stay asleep and to really get into those deep stages of sleep that are particularly restorative. Today we're going to talk a little bit more about each of those three and how they can best be used in combination, but we are also going to touch on some other supplements

13:05 that I have not talked about much before, if at all. Things like glycine and GABA, as well as inositol. Many people are going to find inositol interesting and of particular use to them, especially if they're following a low-carbohydrate diet or if they are fasting before sleep or just trying to avoid eating too close to bedtime and yet they're having a hard time falling asleep. Inositol also turns out to be especially useful for people who have a tendency to wake up in the middle of the night and have a hard time falling back asleep. It also has some interesting and potent effects on anxiety throughout the day. So we're going to talk about inositol as a tool as well. And then last in our list of general categories of levers and tools for optimizing sleep are digital tools. Now, when we say digital tools,

13:51 I don't necessarily mean devices. What I mean are things like non-sleep deep rest scripts. These are zero-cost scripts that you listen to that take your body through some deep relaxation and that can help people both fall asleep, stay asleep, fall back asleep, and get better at sleeping. And also going to talk about digital tools related to self-hypnosis. This is distinctly different from stage hypnosis. So I know some of you hear hypnosis and you think, oh, you know, people clucking like chickens and doing things that are outside their control. That's not at all what I'm referring to here. I'm talking about clinically and research-supported tools that have been shown to enhance people's ability to fall and stay asleep and that can get you far better at sleeping. So again, to recap the list of levers and tools,

14:36 we've got light and dark, and that includes the intensity of light, the timing of light, et cetera. We've got temperature. We have food. We have exercise, caffeine, supplements, and digital tools, not just limited to devices, but zero-cost tools that you can access on YouTube and elsewhere in various apps that can really help you optimize your sleep. So today we're going to talk about all of these. I really want to provide you as many tools as possible, give you the logic behind each of those tools and when and how best to apply them so that you can develop the sleep toolkit that's ideal for your sleep needs. As we head into our description of tools for optimizing sleep, let's consider what the perfect 24-hour cycle would look like. Let's start this 24-hour cycle with when you wake up in the morning.

15:23 So for some of you, that will be 5:00 a.m. For others of you, that will be 10:00 a.m. Most people, I believe, wake up sometime between 6:30 a.m. and 8:30 a.m. But 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. Some of it is going to be the consequence of your moving around a bit, but really the increase in body temperature is one of the main triggers for why you woke up in the first place. That increase in body temperature in turn causes an increase in the release of a hormone called cortisol. Cortisol is often discussed as a stress hormone, but it's not just associated with stress. It also enhances your immune system provided cortisol is elevated at the right times,

16:09 and the right time for cortisol to be elevated is when you first wake up in the morning. That increase in cortisol is also going to increase metabolism. It's also going to increase your ability to focus mentally and for you to move your body. So again, cortisol is often demonized and consider 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 30 to 60 minutes after waking.

16:55 That's right, view bright sunlight within the first 30 to 60 minutes after waking. I'll get into all the caveats about what happens if you wake up before the sun is out, what if you live in the UK where there is no sun, or people claim there is no sun. Hate to tell you this, folks, but there is sun in the UK. We'll talk about all that. But everybody, whether or not you live in a cloudy place or a sunny place, whether or not there's cloud cover or not that day, should really strive to get bright light in your eyes, ideally from sunlight, within the first 30 to 60 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

17:40 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. So again, we're not trying to go into too much mechanism today. We are trying to really hammer on tools

18:25 and I'll substantiate those tools just a bit with some mechanism. But 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, you know, starting to get overhead, what we call low solar angle, then I know I'm getting outside at the right time. If there's cloud cover and I can't see the sun, I also know I'm doing a good thing because it turns out, especially on cloudy days,

19:11 you want to get outside and get as much light energy or photons in your eyes. But let's say it's a very clear day and I can see where the sun is. I do not need to stare directly into the sun. If it's very low in the sky, I might do that because it's not going to be very painful to my eyes. However, if the sun is a little bit brighter and a little bit higher in the sky, sometimes it could be painful to look at. So the way to get this sunlight viewing early in the day is to look toward the sun. If it's too bright to look at directly, well, then don't do that. You just look toward it, but not directly at it. It's absolutely fine to blink. In fact, I encourage you to blink whenever you feel the impulse to blink. Never look at any light, sunlight or otherwise, that's so bright that it's painful to look at 'cause you can damage your eyes.

19:57 But for this morning sunlight viewing, it's best to not wear sunglasses, that's right, to not wear sunglasses, at least for this morning sunlight viewing. It is absolutely fine to wear eyeglasses or contact lenses, so-called corrective lenses. In fact, those will serve you well in this practice or this tool because they will focus the light onto your neural retina and onto those melanopsin intrinsically photosensitive ganglion cells. If your eyeglasses or contact lenses have UV protection, that's okay. There's so many different wavelengths of light coming from the sun and they are bright enough that they will trigger the mechanisms that you want triggered at this early time of day. So try and get outside, ideally within the first five minutes of waking or maybe it's 15 minutes, but certainly within the first hour after waking.

20:44 I want to share with you three critical things about this tool of morning sunlight viewing. First of all, this is not some woo biology thing. This is grounded in the core of our physiology. There are literally hundreds, if not thousands, of quality peer-reviewed papers showing that light viewing early in the day is the most powerful stimulus for wakefulness throughout the day and it has a powerful, positive impact on your ability to fall and stay asleep at night. So this is really the foundational power tool for ensuring a great night's sleep and for feeling more awake during the day. Second of all, if you wake up before the sun is out, you can, and probably should, flip on artificial lights in your internal home environment or apartment

21:30 or wherever you happen to live if your goal is to be awake, right? If you wake up at four in the morning and you need to be awake, well, then turn on artificial lights. Once the sun is out, however, once the sun has risen, then you still want to get outside and view sunlight. Some of you will wake up before the sun comes out. And if you're asking whether or not turning on artificial lights can replace sunlight at those hours, unfortunately, the answer is no. Unless you have a very special light, and we'll talk about what kind of light, the bright artificial lights in your home environment are not, I repeat, are not going to be sufficiently bright to turn on the cortisol mechanism and the other wake-up mechanisms that you need early in the day. The diabolical twist, however,

22:16 is that those lights in your home or apartment or even on your phone are bright enough to disrupt your sleep if you look at them too late at night or in the middle of the night. So there's this asymmetry in our retinal, our eye biology, and in our brain's biology, whereby early in the day, right around waking, you need a lot of light, a lot of photons, a lot of light energy, and artificial lights generally just won't accomplish what you need them to accomplish. But at night, even a little bit of artificial light can really mess up your so-called circadian, your 24-hour clocks, and all these mechanisms that we're talking about. So if you wake up before the sun is out and it's still dark, please turn on as many bright artificial lights as you possibly can or need, but then get outside once the sun is out.

23:02 On cloudy days, you especially need to get outside. I repeat, on cloudy days, overcast days, you especially need to get outside and get sunlight. You just need to get more of it. Now, how much light and how much light viewing do you need? This is going to vary depending on person and place, literally where you live on earth, whether or not there's a lot of tree cover, whether or not you're somebody who has sensitive eyes or less sensitive eyes. It's really impossible for me to give an absolute prescriptive, but we can give some general guidelines. In general, on a clear day, meaning no cloud cover or minimal cloud cover, you want to get this sunlight exposure to your eyes for about five minutes or so. Could be three minutes one day, could be seven minutes the next day, about five minutes. On a day where there's cloud cover,

23:48 so the sun is just peeking through the clouds or it's more dense cloud cover, you want to get about 10 minutes of sunlight exposure to your eyes early in the day. And on days that are really densely overcast or maybe even are rainy, you're going to want to get as much as 20 or 30 minutes of sunlight exposure. Another key thing is do not, forget about, just don't try and get this sunlight exposure through a windshield of a car or a window, whether or not it's tinted or otherwise. It takes far too long. It's simply not going to trigger the relevant mechanisms. You would be standing there all day trying to get enough light into your eyes from the morning sunlight and by then the sun will have already moved from low solar angle to overhead and it simply won't work for all sorts of mechanisms related to your circadian rhythm functions.

24:34 So just don't try and do it through a windshield, sunglasses, or a window. It's just not going to work. Get outside. If the weather is really bad or for whatever reason, safety reasons, you cannot get outside, well, then I suppose try and get near a window. That would be the last, last resort. But you really want to get outside to get this sunlight exposure. Now, if you live in a part of the world where it's extremely dark and overcast or the weather won't let you outside or you live in a cave or some other small box that does not allow any natural light into it for whatever reason, well, then you're going to need a replacement for that sunlight. And there are sunlight simulators or daylight simulators that you can purchase. Those are quite expensive in general and therefore I suggest cheaper options

25:21 that work just as well because they get just as bright. Things like ring lights that are sold in order for people to take selfies and this kind of thing. A drawing LED tablet will work pretty well. I actually have one of those and I put it on my desk all morning even though I still get outside and look at sunlight first thing in the morning, again, also, especially, I should say, on cloudy days. We do not have any affiliation to any ring lights or LED lights or these panels. So we will provide a link to a couple of different options if you want to explore the various options. I don't know what people's different budgets are. I don't know where people live. I just know that many of our listeners live in locations throughout the world where, for instance, during the winter, it gets very, very dark, so they can't get sufficient sunlight. But get that morning light, ideally from sunlight,

26:07 and take into account all the specific points that I've given you here. And, I should say, enjoy this practice. It's really nice to get outside first thing in the morning and get this sunlight. In fact, when you start doing this, you'll notice that your body will start to feel more energized and it will feel more energized more quickly. You'll actually start to notice this mechanism kicking in each day, especially if you're paying attention to your physiology. So enjoy this practice of getting outside. Yes, you can take your morning beverage outside. Yes, you can take your dog with you. In fact, animals intuitively know to get this morning sunlight. They actually seek it out at the right times of days. We human beings need to be told by podcasters and other people about the science that supports these kinds of practices. Our pets apparently do not. But get outside alone or with somebody,

26:54 with your kids, with your dog. However you go about this practice, make sure you do this practice at least 80% of the days of your life. That's right. If you miss a day, for instance, you're bedridden for a day, try and get next to a window. Let's say you are traveling, or for whatever reason, you are not able to get outside first thing in the morning, well, then try to get twice as much sunlight in your eyes, or I should say extend the duration of sunlight viewing in the morning for twice as long the following day. This is a slow, integrative mechanism that underlies this whole thing of wakefulness during the day and sleep at night due to sunlight viewing and if you miss a day, you can make up for it the next day, but you have to get twice as much light or twice as much duration of light. If you really want to get technical

27:40 and you really want to measure how much light is in your environment, you can download a free app, something like Light Meter, and that will allow your phone to act as a bit of a light meter. It'll give you a pretty accurate measurement of how many lux, which is a measure of brightness, are in your environment in the morning. And in general, that's just going to be a good tool for evaluating your environments. Here's what I suggest you do. Wake up in the morning, take Light Meter, point it at the brightest light in your home, and take a measurement, and what you'll probably find is it's about a thousand lux. Now go outside and if there's some sunlight out and there's cloud cover, point it at the sky and press that button. You can actually hold it down and it'll give you a dynamically updated lux measurement. And what you'll find is like 5,000, 10,000, sometimes even 90,000 lux,

28:26 even though you don't experience it as so much brighter, and that's because an indoor artificial light is very concentrated over a small spatial area whereas the sunlight is very diffuse. But it's that diffuse, very bright sunlight, that photon energy, that you really want that's going to set all the rhythms of your brain and body in the proper way. Not just that cortisol peak, but it's going to trigger proper metabolism, it's going to set a timer for you to be able to fall asleep about 16 hours later, and on and on and on. And I should mention within the on and on and on, it's also going to suppress any melatonin, a hormone that makes you sleepy that happens to be swimming around in your bloodstream at the time you wake up. It does a number of other things too, including interact with the adenosine system and kind of wash out some of the adenosine that might still be residual if you didn't sleep enough.

29:11 Fundamentally speaking, get that morning sunlight viewing. I promise you will be grateful that you did. It makes everybody feel better, feel more alert, and it will greatly assist with your ability to fall and stay asleep later that night. Before we continue with today's discussion, we're going to take a brief pause to acknowledge our sponsor, Athletic Greens, also called AG1. I started taking Athletic Greens way back in 2012. So I'm delighted that they've been a sponsor of this podcast. Athletic Greens contains vitamins, minerals, probiotics, digestive enzymes, and adaptogens. So it's got a lot of things in there. That's actually the reason I started taking it and the reason I still take it once or twice a day. It essentially covers all of my nutritional bases. And the probiotics in particular are important to me because of the critical importance

29:57 of what's called the gut-brain axis, that is neurons and other cell types in the gut, in the digestive tract, that communicate with the brain and the brain back to the digestive tract in order to control things like mood, immune function, hormone function, and on and on. Whenever somebody has asked me what's the one supplement they should take, I always answer Athletic Greens. I gave that answer long before I ever had this podcast and it's the answer I still give now for all the reasons that I detailed just a moment ago. If you'd like to try Athletic Greens, you can go to athleticgreens.com/huberman to claim a special offer. They'll give you five free travel packs that make it really easy to mix up Athletic Greens while you're on the road, plus a year's supply of vitamin D3K2, which are also very important for a huge number of bodily factors and brain factors that impact your immediate and long-term health.

30:42 Again, that's athleticgreens.com/huberman to claim that special offer. Okay, so now we're still focusing on this early part of the day when you've woken up, the first hour or so after waking. And we can go to our list of other levers and tools, right? We have light and dark. We already talked about light and sunlight in particular. We've got temperature, food, exercise, caffeine, supplements, and digital tools. Now, once you've woken up and you want to be awake, okay? So this is likely to be early in the day if you're following a more standard schedule. You will also want to leverage not just light, but temperature as a tool. If you are inclined, it would be wise to try and increase your core body temperature a bit more quickly than it would otherwise

31:30 if you were to just, you know, shuffle around outside, get your sunlight, maybe read a little bit, et cetera, and there are two main ways you can do that. The first way is to get into cold water of some sort. So this could be a cold shower of anywhere from one to three minutes. This could be an ice bath if that's your thing. It could be a cold tub, or if you own a cold tub that's specifically designed for deliberate cold exposure. Get under some cold water. That will certainly wake you up. And if you've ever jumped into cold water or had a cold shower, you know it really wakes you up because you release adrenaline, epinephrine, from both your brain and body, the body from your adrenals and your brain from a little cluster of neurons called locus coeruleus. Again, the names don't matter. One to three minutes of cold water exposure will wake you up because of that adrenaline release

32:16 and, and I want to highlight the and, it will serve to increase your core body temperature. That's right, your body and brain interact as a bit of a thermostat system where if you put something cold on the surface of your body, your brain, a little cluster of neurons in the so-called medial preoptic area, act as a thermostat and say, "Ah, the external of my body is cold and therefore I'm going to heat up my core body temperature." So it's a little bit paradoxical. People think, oh, if you get into cold water or an ice bath, your body temperature is going to drop. And indeed, that's true if you stay in for a while, but if you just get in for about one to three minutes, or under the cold shower for one to three minutes, your core body temperature will increase. So then when you get out of that cold water, your body temperature is increasing at a rate, at a slope, that's steeper than it would otherwise

33:03 and you're going to feel more alert. It also has the advantage of increasing not just adrenaline, but dopamine, which is a molecule involved in motivation, focus, et cetera. So this is great for waking up. So we've got sunlight, we've got temperature triggered by cold water, and we have exercise. One of the best ways to increase your core body temperature early in the day is to do exercise. Now, some of you might choose to do your full-blown workout for the day first thing when you wake up in the morning, I would say the best time to exercise, at least what the research points to, is immediately when you wake up in the morning or three hours after waking or 11 hours after waking. But that's really getting down into optimization for sake of muscular strength and grip strength and it's very hard to give a strict prescriptive. Here's what I suggest.

33:48 If you want to be alert early in the day and you want to sleep great at night, get that bright sunlight, get into some cold water, and if you don't want to get into some cold water, try and get some movement. It could be a walk. So you can get your sunlight exposure while you're taking a walk first thing in the morning. It could be a light jog. It could be skipping rope. These days, I skip rope for about 10 minutes or 20 minutes while looking at the sun. So I'm trying to layer in these different things for waking up. And then I take a cold shower afterwards. This is what I've been doing as of lately, but I don't do that all year long necessarily. Or some of you are going to be working out mid-morning. I sometimes do that. But try and get your core body temperature increased first thing in the morning, and a great way to do that is with the cold water and/or with exercise. And again, it doesn't have to be your full-blown workout

34:35 for the day if you're doing workouts consistently, which I hope everybody is because everybody really should exercise at least, I believe, five or six, or maybe even seven days a week. For me, it's six days a week, sometimes five, rarely is it seven. So get that exercise or even just a modest amount of movement, walking, jogging, skipping rope, some light calisthenics. That will further increase your core body temperature and help you feel more awake. Then we have the category of caffeine. And again, we're just talking about this early part of the day, and you might be saying, "Wait a second, I thought this was an episode about tools for sleep." Well, everything that we're talking about doing in these first 60 to 90 minutes of the day really set in motion a wave of biological cascades that carry through the entire day and into the evening and into the night and really do serve to optimize sleep.

35:20 So just hang in there with me. And for those of you that are interested in focus and attention, your ability to learn, all of these tools and practices are going to greatly enhance those as well. So the next category of tool for use early in the day is caffeine. Caffeine is a very important compound to think about. I do realize that some people who are prone to anxiety, especially panic attacks, anxiety attacks, might avoid caffeine entirely. That's absolutely fine. You do not have to drink caffeine. So what I'm about to describe are ways to leverage caffeine use to optimize sleep and wakefulness if you are comfortable with caffeine, if you like caffeine, I happen to love caffeine. I like it in the form of coffee or espresso or yerba mate tea, in particular non-smoked varieties of yerba mate tea. Non-smoked because the smoked varieties seem to carry

36:07 some carcinogenics, some cancer causing risk. There's increasing data on that. So non-smoked varieties of yerba mate. So caffeine is something that a lot of people consume early in the day. How much depends on your tolerance, and there's a lot of individual variability here. Again, caffeine is an adenosine antagonist, or effectively works as an adenosine antagonist and limits sleepiness. I highly recommend that everybody delay their caffeine intake for 90 to 120 minutes after waking. However painful it may be to eventually arrive at that 90 to 120 minutes after waking, you want, and I encourage you, to clear out whatever residual adenosine is circulating in your system in that first 90 to 120 minutes of the day. Get that sunlight exposure, get some movement to wake up, and then, and only then, start to ingest caffeine

36:55 because what you'll do if you delay caffeine intake until 90 to 120 minutes after waking is you will avoid the so-called afternoon crash. And you may still get a little bit of dip in energy in the afternoon, but it's not going to be that massive crash. I've talked about the reasons for that crash on previous episodes. But if you delay your caffeine intake 90 to 120 minutes after waking, you are doing yourself a great service towards wakefulness and to avoid the crash. And the afternoon crash has another liability to it, which is typically people will emerge from that afternoon crash either grumpy or groggy and then they'll lean into drinking more caffeine, which can then disrupt their sleep. So wait 90 to 120 minutes after waking in the morning to drink caffeine. And if you drink caffeine at any point throughout the day,

37:40 really try and avoid any caffeine, certainly avoid drinking more than a hundred milligrams of caffeine after 4:00 p.m. and probably even better to limit your last caffeine intake to 3:00 p.m. or even 2:00 p.m. And for many people, shifting that caffeine intake from immediately after waking in the morning to 90 to 120 minutes gives them a much longer arc of energy throughout the day and they don't feel the need to drink more caffeine later in the afternoon. If you do drink caffeine later in the afternoon, really try and limit the total amount or drink decaf. Certainly keep the total amount to less than a hundred milligrams if you are interested in getting into the best possible sleep. And I say this knowing that many people, including myself, can drink a double espresso with 200 milligrams of caffeine or more at 5:00 p.m. or even 6:00 p.m. or after dinner

38:28 and still, quote, unquote, fall asleep fine or still sleep fine. However, there are terrific data, Matt Walker and I talked about this, and there are more and more papers all the time that point to the fact that caffeine intake late in the day, after 4:00 p.m. that is, can really disrupt the architecture of your sleep. So you might think you're sleeping well, but you're not sleeping nearly as well as you could if you avoided caffeine in those afternoon hours. Now, some of you might be doing your main about of exercise first thing in the morning and you want your caffeine before that about of exercise. In that case, I say, go for it. Drink your caffeine, do your workout right after waking up. I don't have a problem with that. You will find, however, that you're going to get an early afternoon dip in energy and that dip in energy is going to be substantial because it's going to be a dip in energy

39:14 that naturally follows that workout from the morning. So it's dependent on temperature, and it's going to be related to the elimination of that adenosine blockade by caffeine. So you're getting a kind of a one-two punch on your energy levels by taking a lot of caffeine and exercising early in the day. You can sort of expect that you're going to get a drop in energy in the early afternoon. That's okay if that works for you, but just know that delaying that caffeine 90 to 120 minutes after waking would be the ideal scenario most days and most scenarios. All that said, I absolutely respect the fact that people have different work schedules, kid schedules, et cetera.

40:00 So if you want to do some or none or all these tools, that's really up to you. I'm just providing them to you in the simplest form that I can possibly provide them. Now, the other lever or tool that you have available to you is food. Not just what you eat, but when you eat. And it turns out that if you eat early in the day, you support a biological clock mechanism that will make you more alert early in the day. That said, many people choose to fast in the early morning hours of the day or in the first part of the day. I'm one such person. I generally don't ingest any food until about 11:00 a.m. or 12 noon. Sometimes I'll have a protein shake. Sometimes I'll have some almonds. Sometimes I'll have breakfast. If people are meeting for brunch or breakfast, I will have breakfast for social reasons every once in a while. But most of the time I don't eat until about lunch time.

40:47 However, some people are really hungry when they wake up in the morning. Just know that if you eat early in the day, you are further triggering an increase in metabolism and in temperature that will make you more alert. So you don't have to eat early in the day, but you can start to see how these different tools layer together. Sunlight viewing, exercise, cold water, eating. Many of them are converging on the same mechanisms. In fact, when you drink caffeine, there's also a small increase in body temperature due to the adrenaline increase that it stimulates. So all of these things can be layered on top of one another or you can use them individually or think about them individually. Now, food is an interesting lever or tool because it's not just about when you eat, but it's also about what you eat. And I've talked a lot about eating for energy and what that means in terms of caloric energy

41:33 versus neural energy, et cetera, in previous podcast episodes. We're not going to focus on that now because, frankly, to get into a description of whether or not somebody should eat fruits or vegetables or animal proteins or dairy, et cetera, early in the day, that's very nuanced. What you eat for your breakfast, or if you choose to not eat breakfast, is really up to you. All that said, if you eat a very large meal, it doesn't matter if you slept terrifically well 10 hours the night before or if you are about to go to sleep or if it's the middle of the afternoon, if your gut is full of food, there's just a large volume of food in your gut, it's going to divert a lot of blood and other critical resources away from other organs of your body, in particular, your brain, and you're going to be sleepy after eating a big meal. So this is sort of a duh, but I think oftentimes in the discussions

42:20 about what to eat for energy, people neglect to consider food volume as a strong parameter or variable in that discussion. So if you eat a huge breakfast, it's likely that you are going to be tired immediately after eating that breakfast unless of course you exercise very hard prior to that and you metabolize all that food very quickly. So it's up to you whether or not to eat first thing in the morning or not. But if you do eat in the first few hours of the morning, just understand that you are setting or you are helping to set a food entrained, as it's called, circadian clock. Light, temperature, timing of food intake, movement and exercise, all of these things literally funnel in in a neural sense, they funnel into this thing that we call the circadian clock and they let that clock, that set of neurons,

43:08 predict when you are likely to be eating and active and viewing sunlight the next day and the next day and the next day. I say all this because there are some beautiful studies, and I'll highlight one, again, in the show note captions, that show that if people are having a hard time waking up in the morning, one of the things they can do is maximize sunlight viewing, exercise in the morning, drink caffeine. Although, again, I support the idea that that would best be done about 90 to 120 minutes after waking. Eating some food in those early morning hours, et cetera, et cetera. You can layer in multiple levers or tools in order to be more alert. And that's what these levers and tools are really there for in this sense of what we're talking about today, which is optimizing sleep.

43:54 Yes, they will make you more alert. Yes, they will provide some adrenaline and dopamine, for instance, the cold water, et cetera, et cetera. But the reason we're talking about these things in the context of sleep is that they start to give your body some predictable autonomic timing. What is predictable autonomic timing? Well, your autonomic nervous system is the components of your brain and body that cause wakefulness and sleepiness and you can start to create some predictability in that autonomic timing. You can start to do things that really make it such that you naturally wake up at six in the morning or five in the morning. That's right, if you're somebody who naturally is a night owl, who likes to stay up until two in the morning and sleep until 10:00 a.m., and you now have a job or you have to go to school or you have a partner that likes to get up early

44:40 and go to sleep early, well, you can make that happen and you can make that happen pretty painlessly if you take a week or so and go to sleep 30 minutes or an hour earlier each night, set an alarm and wake up 30 minutes or an hour earlier each morning until, of course, you're waking up at the time you want to wake up, and then even in that groggy state, get some exercise, get some sunlight viewing. If the sun's not out, turn on those bright artificial lights. Have some breakfast, even if you're not hungry. In fact, for those of you that engage in shift work because you have to, or travel and you're jet lagged, one of the quickest ways to shift your circadian clock and get onto the local schedule is to eat on the local schedule. So what all these tools do is they really set up a cascade. Think of it as kind of a wavefront of wakefulness and focus

45:27 throughout the day. It'll take you through the middle of the day and the afternoon stage we'll talk about in a few minutes, but really they take you to this period that is about 5:00 p.m. until your bedtime. I realize some people are going to bed very early, like 8:00 p.m. or 9:00 p.m., which to me seems very early, but very few people go to sleep at 5:00 p.m. right? Unless you're doing that for shift work or other reasons. But from 5:00 p.m. until bedtime is really a critical period in which you need to leverage particular tools in order to get and stay asleep optimally and to be able to sleep through the night. So really there are three critical periods throughout each 24-hour cycle. And during each of those critical periods, you're going to want to do as many specific things as you can to optimize your wakefulness and focus and mood throughout the day

46:12 and your sleep at night. The first critical period is the one that we've been talking about up until now. Things like morning sunlight viewing, caffeine 90 to 120 minutes after waking, exercise, and so on. We can call that critical period one and it really encompasses the time from which you wake up until about three hours after waking. Although, I should just mention 'cause there are always those people that say, "Wait, I wake up at 4:00 a.m. and the sun isn't out until 8:00 a.m.," okay, so it might be four hours. But really it's those early morning hours of your day once you're awake. The second critical period is the time throughout the day and afternoon leading into evening. So you may ask what are the things that you can do throughout the day, the middle of your day and into the afternoon and evening hours, that are really going to set you up for the best possible sleep later that night. Well, there are a few dos and there are a few don'ts.

47:00 First of all, be careful about ingesting too much caffeine throughout the middle of the day. That's kind of an obvious one for the reasons that we talked about earlier. Second of all, if you are a napper, and I raise my hand now, for those of you listening, I'm raising my right hand because I love naps. I've always loved naps. Nowadays I do NSDR or a Reveri sleep hypnosis almost every day. And I tend to do that, as I mentioned, in the early afternoon hours if I'm feeling kind of sleepy, because even though I optimize my caffeine intake timing, et cetera, I tend to get a little sleepy in the afternoon. Most people get a little sleepy in the afternoon. Some of that is related to hitting that peak of body temperature. And you might think, wait, I thought high body temperature is associated with alertness, and it is, but right as you crest that high body temperature and your body temperature starts to drop,

47:46 there's a tendency to be a little bit sleepy. So some of you might opt to take a nap in the afternoon. Should you nap, should you not nap? That's a question that I get asked a lot and that I asked Dr. Matthew Walker when he was a guest on this podcast. Here was his answer and here's what the data support. It is fine to nap in the afternoon, but don't nap so late in the day or for so long that it disrupts your ability to fall and stay asleep at night for your major sleep about, okay? So naps are fine, but don't sleep so long during the day or too late in the day that it disrupts your ability to fall and stay asleep. I should also say you do not have to nap. It's kind of an interesting phenomenon that happens on these podcasts and on social media where we'll talk about naps and the fact that naps are great, but don't make them longer than 90 minutes,

48:31 but then all the non-nappers get really worried. Like, wait, am I supposed to nap? I don't like naps. I wake up groggy. You do not have to nap. In fact, if you can make it through your whole day without napping, great, more power to you. But if you do nap and you find that naps serve you well, keep those naps shorter than 90 minutes for reasons related to ultradian cycles and so forth, and make sure that you don't nap too late in the day that you are then staying up too late at night and having a hard time waking up the next morning. I will say that for a lot of people who do not like naps or that find they wake up really grumpy from naps or groggy from naps, I encourage you to try the Reveri app, try an NSDR script, try yoga nidra. Try something of that sort for anywhere from 10 to 20 to 30 minutes.

49:16 I tend to do this every day now. I'll just lie down, and I love yoga nidra, I love NSDR scripts, I love using the Reveri app. In particular, the portion of the Reveri app that gets you better at sleeping. It really is beneficial for me because it serves as very replenishing while I'm doing that hypnosis, but it's also gotten me much better at falling and staying asleep and falling back asleep in the middle of the night. So this critical period throughout the day is one in which most people are doing a lot of stuff. They're emailing and picking up kids and they're exercising and they're commuting and doing all sorts of things, taking phone calls and Zooms, et cetera. But if you can get that period of deep relaxation through a nap or NSDR, that's going to serve you well. Try not to drink too much caffeine, certainly no more than a hundred milligrams of caffeine, after 4:00 p.m

50:02 if your goal is to fall asleep at a reasonably normal time. And for those of you that exercise in the afternoon, understand that if you exercise very intensely, so this might be weight training or running or some other very intense exercise, typically that's going to further increase your body temperature. Makes sense, right? Based on everything we know about metabolism and body temperature. And it's going to so-called delay your circadian clock. It's going to make it such that you want to fall asleep a little bit later, maybe even a lot later. So if you're exercising in the afternoon or evening and that's the only time you can exercise or that's the time that you prefer to exercise, great, but be careful about ingesting too much caffeine in order to get the energy to do that exercise 'cause that caffeine will disrupt your sleep and just know that you are delaying your circadian clock.

50:49 You are making it such that you will naturally want to go to sleep later and wake up later. Contrast that with if you exercise early in the day, say, immediately after waking up or in the first zero to four hours after waking, in most cases, that's not going to shift your circadian clock much. And toward the end of the episode, we'll talk a little bit about forced exercise prior to wake-up times. That doesn't mean doing exercise in your sleep. That means deliberately setting an alarm and getting out of bed much earlier than you naturally would. That turns out to be a very potent tool to so-called advance your circadian clock. So we can talk about that a little bit later in the episode. But this critical period, too, in the middle of the day is when you're going to want to leverage specific tools, and we've talked about those:

51:35 limiting caffeine intake; being mindful of the clock-delaying effects of exercise; the fact that, also, if you're going to nap, you don't want to nap too long or too late into the day otherwise you'll disrupt your nighttime sleep. So this critical period two, or second critical period, I should say, during the middle of the day is a time in which you should be doing certain things and avoiding doing certain things. So that raises the question of whether or not you should also be getting a lot of light, in particular, sunlight, throughout the day. Now, that's something that hasn't been explored too much in the literature until recently when Dr. Samer Hattar who's the director of the chronobiology unit at the National Institutes of Mental Health, decided to do a number of experiments exploring the effects of light on mood and other aspects of brain function and body function when that light is delivered not just in the morning, which is great for us,

52:21 but also throughout the day. So should you be looking at sunlight or bright artificial lights throughout the day? Now, on the face of it, you might just think, yes, you know, sunlight's great. Provided we're not getting a sunburn and we're not staring at the sun and damaging our eyes, we should get as much sunlight as we possibly can. In fact, we talked about this in the episode on hormones about how getting light onto as much of our skin as we can throughout the day can really help in the production of testosterone and estrogen in both men and women in healthy ways that improves mood and libido and all sorts of things that are associated with wellbeing. However, because light is such a powerful stimulus for controlling the timing of your sleepfulness, or sleepiness, I should say, and wakefulness, we might want to be cautious about how much light we are viewing in the afternoon, in particular, in the early evening hours, right?

53:09 Well, turns out it's not so straightforward. Viewing, so sunlight to the eyes, sunlight in the late afternoon and evening hours, so again, depends on time of year, depends on location that you happen to be in, but getting some sunlight in your eyes for, again, maybe five or 10, maybe 30 minutes, depending on how much cloud cover there is, doing that in the afternoon serves an additional beneficial purpose, which is you protect or you inoculate your nervous system against some of the negative effects of bright artificial light or even dim artificial light in the nighttime hours between 10:00 p.m. and 4:00 a.m., which is really critical period three. And we'll talk about what to do and what to not do during critical period three of every 24-hour cycle.

53:54 But to make it very clear what I'm saying here, get that morning sunlight in your eyes, but also get some sunlight in your eyes in the late afternoon and evening hours when the sun is at so-called low solar angle, when it starts to descend in the sky. Again, you don't have to stare directly at the sun, although if you can catch a nice, beautiful sunset, go for it. But as the sun starts to descend, it triggers those same neurons in your eye that communicate with your circadian clock, but it communicates with a different component or different compartment within the circadian clock. That circadian clock is not just one thing. It's multiple things. And you have what are called morning oscillators and evening oscillators. And to make a long story short, the tool that I'm describing of looking at the sun in the late afternoon and evening, again, blinking is fine,

54:41 don't stare at the sun, but getting that sunlight in your eyes in the late afternoon and evening signals to that clock that it's evening time and that sleep is coming. It also serves as a second anchor or reference point for your body and your brain to know where it is in time. Remember back to the beginning of the episode when I said your brain and your body and all your organs are locked inside this skin and this skull and they don't know what's going on in the outside world. Well, that morning sunlight viewing and the other things you do during critical period one, those provide one strong set of signals that it's wake-up time and time to be alert and time to be focused. And then in the evening, by getting sunlight in your eyes again, in particular, sunlight that comes from low solar angle sunlight,

55:27 well, that provides a second stimulus or a second reference point that tells your brain and body, "Hey, it's evening. The sun is descending." Now, you might say, "Wait, how does the brain and these neurons know the difference between morning light and evening light?" It turns out has to do with the particular wavelengths of light that are present in morning versus evening. It's an incredible mechanism. And you are probably familiar with the fact that when the sun is directly overhead,

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