Andrew Huberman's complete sleep optimization toolkit covering light, temperature, caffeine, food, and supplements
Andrew Huberman presents a solo episode on sleep science and practical tools for optimizing sleep and wakefulness across a full 24-hour cycle.
Summary
Andrew Huberman, neuroscientist and professor at Stanford School of Medicine, presents a comprehensive toolkit for optimizing sleep by structuring behavior across three critical periods of each 24-hour cycle. He argues that the foundations of great sleep are laid in the first 60–90 minutes after waking — through morning sunlight exposure, cold water, exercise, and timed caffeine intake — not just in the hours before bed. He explains the biological mechanisms behind each tool, including the roles of cortisol, melatonin, adenosine, and core body temperature in regulating the sleep-wake cycle. He also introduces the concept of "temperature minimum" as a precise, personalized tool for managing jet lag, shift work, and circadian clock adjustment. For those who have optimized their behavioral tools and still struggle with sleep, he outlines a specific supplement stack — magnesium threonate, apigenin, and theanine — with dosage guidance and caveats.
Key Takeaways
FULL TRANSCRIPT
The Foundation: Why the First Hours After Waking Determine Sleep Quality
Andrew Huberman: Today we're talking all about sleep and how to optimize your sleep. Let's consider what the perfect 24-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. 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 a 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. 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 — called intrinsically photosensitive melanopsin cells, though 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 the 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.
Critical Period One: Morning Sunlight, Temperature, Caffeine, and Food
Andrew Huberman: 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, 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. If it's a bright clear day and the sun is low in the sky — what we call low solar angle — then I know I'm getting outside at the right time. Especially on cloudy days, you want to get outside and get as much light energy, or photons, in your eyes.
Now, if it's a very clear day and I can see where the sun is, I do not need to stare directly into the sun. The way to get this sunlight viewing early in the day is to look toward the sun. Never look at any light — sunlight or otherwise — that's so bright it's painful to look at, because you can damage your eyes. But for this morning sunlight viewing, it's best to not wear sunglasses. It is absolutely fine to wear eyeglasses or contact lenses — so-called corrective lenses. In fact, those will serve you well in this practice because they will focus the light onto your neural retina and onto those melanopsin intrinsically photosensitive ganglion cells.
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.
If you wake up before the sun is out, you can and probably should flip on artificial lights in your home environment or apartment or wherever you happen to live — if your goal is to be awake. If you wake up at 4 in the morning and you need to be awake, then turn on artificial lights. But if you're asking whether turning on artificial lights can replace sunlight at those hours, unfortunately the answer is no. Unless you have a very special light — we'll talk about what kind — the bright artificial lights in your home environment 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, 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 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.
On cloudy days, you especially need to get outside. On overcast days, you especially need to get outside and get sunlight — you just need to get more of it. How much light viewing do you need? This is going to vary depending on the person and the 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 to give an absolute prescription, but we can give some general guidelines.
On a clear day — 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. About five minutes. On a day where there's cloud cover, so the sun is just peeking through the clouds or there's more dense cloud cover, you want to get about ten minutes of sunlight exposure to your eyes early in the day. And on days that are really densely overcast, or maybe even rainy, you're going to want to get as much as 20 or 30 minutes of sunlight exposure.
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.
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, there are sunlight simulators or daylight simulators that you can purchase. Those are quite expensive in general. Therefore, I suggest cheaper options that work just as well because they get just as bright — things like ring lights that are sold for people to take selfies and that kind of thing. An 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, especially on cloudy days. Many listeners live in locations throughout the world where during the winter it gets very, very dark, so they can't get sufficient sunlight. But get that morning light, ideally from sunlight, and take into account all the specific points I've given you here.
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. 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. 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 interacting with the adenosine system and washing out some of the adenosine that might still be residual if you didn't sleep enough.
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.
Using Temperature and Exercise to Accelerate Morning Wakefulness
Andrew Huberman: 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 if you were to just shuffle around outside, get your sunlight, maybe read a little bit, etc. There are two main ways you can do that.
The first way is to get into cold water of some sort. 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 specifically designed for deliberate cold exposure. Get under some cold water. One to three minutes of cold water exposure will wake you up because of that adrenaline release — and it will serve to increase your core body temperature. That's right. 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 — acts as a thermostat and says, "The external of my body is cold, and therefore I'm going to heat up my core body temperature." So this is a little bit paradoxical. People think that 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 a cold shower for one to three minutes, your core body temperature will increase. So this is great for waking up.
And we have exercise. One of the best ways to increase your core body temperature early in the day is to exercise. The best time to exercise, at least what the research points to, is immediately when you wake up in the morning. 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. But try and get your core body temperature increased first thing in the morning, and a great way to do that is with cold water and/or with exercise. And again, it doesn't have to be your full-blown workout for the day if you're doing workouts consistently — which I hope everybody is, because everybody really should exercise.
Caffeine Timing and Its Effect on Sleep Architecture
Andrew Huberman: The next category of tool for use early in the day is caffeine. You do not have to drink caffeine. What I'm about to describe are ways to leverage caffeine use to optimize sleep and wakefulness if you are comfortable with caffeine.
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. Caffeine effectively works as an adenosine antagonist and limits sleepiness. For many people, shifting that caffeine intake from immediately after waking in the morning to 90 to 120 minutes after waking 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 100 milligrams if you are interested in getting into the best possible sleep. 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 and still fall asleep fine. There are more and more papers all the time pointing to the fact that caffeine intake late in the day — after 4:00 p.m. — 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 bout of exercise first thing in the morning and you want your caffeine before that bout of exercise. In that case, go for it. I absolutely respect the fact that people have different work schedules, kids' schedules, etc. So if you want to do some or none or all of these tools, that's really up to you. I'm just providing them to you in the simplest form that I can.
Food Timing, Meal Volume, and the Circadian Clock
Andrew Huberman: The other lever or tool that you have available to you is food — not just what you eat, but when you eat. 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 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 12:00 noon. 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 lunchtime.
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.
Now, food is an interesting lever because it's not just about when you eat but also about what you eat. If you eat a very large meal — it doesn't matter if you slept terrifically well ten 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, and 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 if you eat a huge breakfast, it's likely that you're going to be tired immediately after eating that breakfast, unless of course you exercised very hard prior to that and you metabolize all that food very quickly.
If you do decide to eat in the first few hours of the morning, understand that you are helping to set what's called a food-entrained circadian clock. Light, temperature, timing of food intake, movement, and exercise — all of these things literally funnel into this thing that we call the circadian clock, and they let that clock, that set of neurons, predict when you are likely to be eating and active and viewing sunlight the next day and the next day and the next day. So what all these tools do is they really set up a cascade — think of it as a wavefront of wakefulness and focus throughout the day.
Critical Period Two: Midday Through Evening
Andrew Huberman: Really, there are three critical periods throughout each 24-hour cycle. During each of those critical periods, you're going to want to do as many specific things as you can to optimize your wakefulness, focus, and mood throughout the day and your sleep at night.
The first critical period is the one we've been talking about — things like morning sunlight viewing, caffeine 90 to 120 minutes after waking, exercise, and so on. It encompasses the time from which you wake up until about three hours after waking.
The second critical period is the time throughout the day and afternoon leading into evening. What are the things you can do throughout 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 a few don'ts.
First of all, be careful about ingesting too much caffeine throughout the middle of the day. Second, if you are a napper — and I raise my hand here because I love naps, I've always loved naps — should you nap or not? That's a question 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 bout.
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 and don't make them longer than 90 minutes, but then all the non-nappers get really worried — "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.
So this critical period throughout the day is one in which most people are doing a lot of stuff — emailing, picking up kids, exercising, commuting, taking phone calls and Zooms, etc. 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 100 milligrams after 4:00 p.m. if your goal is to fall asleep at a reasonably normal time.
For those of you who exercise in the afternoon, understand that if you exercise very intensely — weight training, running, or some other very intense exercise — that's typically going to further increase your body temperature and it's going to 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 you prefer, great. Just know that you are delaying your circadian clock, making it such that you will naturally want to go to sleep later and wake up later. Contrast that with exercising early in the day, say immediately after waking or in the first zero to four hours after waking — in most cases, that's not going to shift your circadian clock much.
Afternoon Sunlight as a Second Circadian Anchor
Andrew Huberman: This second critical period raises the question of whether you should also be getting a lot of light — in particular sunlight — throughout the day. On the face of it, you might just think yes: sunlight is great, provided we're not getting a sunburn and we're not staring at the sun and damaging our eyes. However, because light is such a powerful stimulus for controlling the timing of your sleepiness 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.
Well, it turns out it's not so straightforward. Getting some sunlight in your eyes in the late afternoon — again, maybe five or ten, maybe thirty minutes depending on how much cloud cover there is — serves an additional beneficial purpose. It inoculates 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.
To make it very clear: 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 low solar angle, when it starts to descend in the sky. 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 that tells your brain and body, "Hey, it's evening. The sun is descending." Those yellows and blues and oranges that you see in evening sunsets signal to your brain and body that evening is there and that nighttime is coming. They're really establishing a second reference point or wavefront of biological signals that are going to optimize your nighttime hours and your transition into really terrific sleep.
Critical Period Three: Evening and Nighttime — Light, Temperature, and Substances
Andrew Huberman: So now let's talk about what I'm calling critical period three of each 24-hour cycle. This would be the period of late evening — it might be 6:00 p.m. for some, depending on when you go to sleep, or 7:00 p.m. — extending into the hours in which you decide to get into bed and go to sleep, and then throughout the night. There are a number of things you're going to want to do, and a number of things you are going to want to avoid doing, in order to optimize your sleep.
First of all, you're going to want to avoid bright artificial lights of any color. Once the sun goes down, you would be wise to try and dim the lights in your indoor environment. If you are going to use light at night — and most people do — I would encourage you to use as little artificial light as is required to carry out the activities you need to carry out safely. If you're watching a television show or something on your computer, dim that screen way, way down, as dim as possible while still being able to view what you need to view. That bright light exposure will absolutely quash any melatonin that happens to be circulating in your brain and body.
Now, melatonin — a lot of people think of it as a supplement, but melatonin is naturally released as the evening comes about and into the nighttime hours. It's a hormone that makes you feel sleepy and allows you to fall asleep. So viewing bright light in the late evening hours and nighttime hours is really not good for your sleep quality and your ability to fall and stay asleep. For most people, a simple rule of thumb is going to be: avoid bright artificial lights of all colors, and in particular overhead bright artificial lights, between the hours of 10:00 p.m. and 4:00 a.m. Use only as much light as is absolutely necessary in order to carry out the routines and activities you need to carry out safely.
Now, that's light. But as you recall, we also have this tool related to temperature. You're probably not going to be surprised that the way to leverage temperature in the evening is the exact opposite of the way that you want to leverage temperature early in the day. Early in the day, temperature increases from cold showers or exercise wake you up. What that means is that taking a cold shower late at night is probably a bad idea. Rather, taking a nice hot bath or a sauna — you might think that would heat up your body, and indeed that's what happens if you stay in for a very long time. But if you do a hot tub or a hot bath or a sauna in the evening and you don't stay in for more than 20 or 30 minutes, and you get out and take maybe a coolish or warm shower, then what happens is there's a compensatory cooling off of your core body temperature. Your body temperature will drop by one to three degrees, and it will make it much easier to get into sleep. So if you're somebody who enjoys hot baths, hot showers, or hot tubs, evening and nighttime is going to be the best time to do that if your goal is to facilitate sleep.
Similarly, you should try and make your sleeping environment pretty cool, if not cold. Now, that doesn't mean you need to be cold while you're asleep — you can get under as many blankets as you need. But it's a good idea to make your sleeping environment cool. Drop the temperature in that sleeping environment by at least three degrees. You'll be happy that you did.
You're going to want to sleep in a relatively cool or cold sleeping environment and then layer on the blankets as needed to stay asleep. If you lower the temperature in your sleeping environment — lower the temperature in that room, or use a controllable mattress cover that can cool down — it's naturally going to make your sleeping environment cooler. And if you're too warm under the blankets, all you have to do is extend a hand or a foot out from under those blankets. Whereas if the sleeping environment is too warm, there's very little you can do to cool off besides push off those blankets. But if the room itself is too warm, well, what are you going to do? You'd probably have to put your hands into some cool water or take a coolish shower for a couple of seconds — not very practical.
I would be remiss if I didn't touch on alcohol and CBD and THC. In many places — but not all — THC is illegal, although there are medical uses and some places it's decriminalized or legal. Alcohol, of course, is consumed almost as frequently as caffeine. The sleep that one gets after drinking alcohol is greatly disrupted sleep. THC and alcohol do help some people fall asleep and maybe even stay asleep, but the architecture of that sleep is suboptimal compared to the sleep they would get without alcohol or THC in their system. I'm not here to tell you what to do or not to do — I'm certainly not the substance police. That's not my role. I'm just reporting to you the biology. If your sleep is not restoring you to the extent that you feel it should, or if you are regularly relying on a drink or two in order to fall asleep, or THC in order to fall asleep, that is disrupting your total pattern of sleep.
Supplements for Sleep: The Three-Part Stack
Andrew Huberman: Okay, so you've done everything correctly up until now. You got your morning routine from critical period one. You got your afternoon routine. You saw some sunlight in the afternoon. You avoided caffeine in the eight to ten hours before bedtime. You're not drinking alcohol. You've cooled down the room. You've dimmed the lights, etc. What else can we do in order to optimize our sleep?
I always say behavioral tools first, then look to nutrition, then if necessary look to supplementation, and then if still necessary look to prescription drugs — obviously prescribed by a board-certified physician.
There are supplements that for most people will greatly improve their ability to fall and stay asleep. The three main supplements in that category — the sleep supplement stack — are magnesium threonate (T-H-R-E-O-N-A-T-E), apigenin (A-P-I-G-E-N-I-N), and theanine (T-H-E-A-N-I-N-E). You don't necessarily need to take all three, although many people get a synergistic effect from taking all three. You may not even need to take even one.
What I recommend is that if you're already doing all the behavioral tools regularly and you're still having trouble falling asleep and staying asleep, then you might try one of the supplements within this sleep stack. They do have fairly wide margins for safety, although I should also say that anytime you're going to add or remove something from your supplement protocol or your nutritional program, you definitely want to talk to your physician. I don't just say that to protect us — I say that to protect you.
For most people, the margins of safety on these things are going to be pretty broad. For some people, the dosage of any one or several of the supplements I mentioned will be zero — that is, you won't need them in order to get and stay asleep most nights of your life. For many people, however, taking 145 milligrams of magnesium threonate can be very beneficial. Some people need to go a little higher, some a little lower. 50 milligrams of apigenin — and again, you could just take the apigenin on its own. And 100 to 400 milligrams of theanine, taken alone or in combination with the other supplements mentioned in this stack. Many people find that this allows them to get really drowsy, fall asleep, sleep really deeply, feel much more refreshed the next day, and not have any grogginess.
About 5% of people report that magnesium threonate really disrupts their gut — it gives them diarrhea or gastric distress — in which case, don't take it. And in a slightly different way, many people who can tolerate magnesium threonate and like apigenin might find that theanine, even at the lowest dose of 100 milligrams, gives them such vivid dreams that they actually find it disruptive. They wake up in the middle of the night, or they find that the sleep they're getting is kind of anxiety-ridden because of the intensity of those dreams. So some people might choose to leave theanine out of the sleep stack and just take magnesium threonate or apigenin. Again, some people might leave magnesium threonate out of the sleep stack. All of this is really about finding the supplementation protocol that's ideal for you.
The ideal time to take those supplements is 30 to 60 minutes before bedtime.
That sleep stack can be very beneficial to people, and I do think it's preferable to melatonin. First of all, melatonin is a hormone that you endogenously make. The dosages of melatonin contained in most commercial products are far, far, far greater than what we would make endogenously — so it's really supra-physiological, and that's of concern because melatonin is not just responsible for making us sleepy and helping us fall asleep. It also does things like interact with other hormone systems — testosterone and estrogen, even the puberty system in kids. Is taking melatonin every once in a while a problem for adjusting to jet lag, etc.? Probably not — I would even say no. But taking it chronically over time, especially kids taking it chronically over time, can potentially be problematic.
Consistency, Weekends, and the Temperature Minimum Tool
Andrew Huberman: I do want to mention a couple of broad contour tools that will impact your ability to sleep really well on a consistent basis. The one that impacts the most number of people is weekends. It turns out that most everybody feels the impulse to sleep in on the weekend, especially if they've been out late the night before. However, the data show that keeping relatively consistent sleep and wake times is really going to enhance the quality and depth of your sleep. So if you stay out late one night, sure, you might allow yourself to sleep in an extra hour or so, but you should really try to avoid sleeping in longer than an hour beyond your normal wake-up time. It would be better to wake up at a consistent time — plus or minus an hour — and get a nap in the afternoon, provided that nap again isn't too long.
Now, a couple of final points and additional tools that I think are going to be useful to everybody — in particular people who have young children, or are following a shift work schedule, or who are experiencing jet lag. Keep in mind that jet lag can be due to travel, which is obvious, but jet lag can also be due to getting woken up in the middle of the night. Your body doesn't know the difference between flying to a new time zone and getting woken up in the middle of the night.
The tool I'd like to offer you is an understanding of something called temperature minimum. Here's the question you need to ask yourself: what is your typical wake-up time? If your typical wake-up time most days is 7:00 a.m., then your temperature minimum is 5:00 a.m. Your temperature minimum is not a temperature — it's a time within your 24-hour cycle. Approximately two hours before your typical wake-up time, your body is at its lowest temperature that it will ever be in the 24-hour cycle. That's why it's called your temperature minimum.
Here's what you need to know about your temperature minimum. If you view bright light, exercise, or drink caffeine — or all of the above — in the two to four hours before your temperature minimum, that will delay your clock. What that means is it will make you want to go to sleep later and wake up later the following night.
Let's run this exercise for you — the person waking up at 7:00 a.m. on a regular basis. I can predict with almost certainty that your body is going to be at its lowest temperature at 5:00 a.m. So what that means is that if you get up at 3:00 a.m. or 4:00 a.m. and you flip on bright lights in your house or in your bathroom, or you have a cup of coffee, or you do any kind of exercise, or you get up and head to the airport, the mechanisms in your brain and body that control timing of sleep and timing of waking will shift. They will delay. It's as if you put your clock on hold for a little while and then let it start again. And you will tend to want to go to sleep later and wake up later the following night.
Now, the opposite is true if you view bright light, drink caffeine, exercise, or socialize in the hours immediately after your temperature minimum. So for you in this example — the person who wakes up at 7:00 a.m., whose temperature minimum is 5:00 a.m. — if you view bright light, exercise, maybe have a snack, or socialize and move about at 5:30 or 6:00 a.m. or 7:00 a.m., that will tend to phase advance your clock. It will tend to make you want to go to bed earlier and wake up earlier the following night.
I use this example of a person who wakes up typically at 7:00 a.m., but of course you need to adjust that for yourself if you're somebody who wakes up at 9:00 a.m. or at 5:00 a.m., etc.
Applying Temperature Minimum to Jet Lag and Shift Work
Andrew Huberman: Why do I offer this as a tool? This is an immensely powerful tool if, for instance, you are headed to a time zone where you need to go to bed earlier and wake up earlier once you arrive. What it means is that in the day or two before you leave, you can force yourself to exercise, drink caffeine, maybe even eat a meal early in the morning. You force yourself to do the activities that are going to phase advance your clock. Whereas if you're traveling to a time zone where you are going to need to go to sleep much later and wake up much later, you can do those things in the hours prior to your temperature minimum.
And I should say for everybody — people who are jet-lagged, engaged in shift work, or not — if you need to be awake in the middle of your sleep cycle, you know, you're feeding a baby or taking care of a loved one or need to do something critical or need to work, use red light. Now, for shift workers who really are trying to stay awake all night and sleep all day, this is not going to be ideal. But for people who, for instance, need to stay up really late one night, or wake up especially early — like 3:00 a.m. to prepare for an exam or to head to the airport — using red light has been shown to allow people to be awake enough to see what they need to see and perform their activities safely, but it does not seem to disrupt the cortisol rhythm — the healthy, normal cortisol rhythm.
So that's a lot of information and a lot of tools, and I really want to encourage everybody to get your behaviors right, get your nutrition right for you. I promise that if you start to implement some — or ideally all — of these tools, the quality of your sleep will increase tremendously. And of course, in doing so, the quality of your daytime alertness and your ability to focus will improve tremendously. Sleep is the absolute foundation of your mental health, your physical health, and your performance in all endeavors.