Understanding Sleep and Wakefulness

ANDREW HUBERMAN: Welcome to Huberman Lab Essentials, where we revisit past episodes for the most potent and actionable science based tools for mental health, physical health, and performance. [MUSIC PLAYING] I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. Today's podcast episode is all about sleep. We're also going to talk about the mirror image of sleep, which is wakefulness. Now, these two phases of our life, sleep and wakefulness govern everything about our mental and physical health. And we're not just going to talk about what's useful about sleep. We're also going to talk about how to get better at sleeping, and that will include how to get better at falling asleep, timing your sleep and accessing better sleep quality. In doing so, we're also going to discuss how to get more focused and alert in wakefulness. So if you're like most people, which includes me, you have some challenges with sleep. At least every third or fifth night or so, and maybe even more often. So we're really going to go tool heavy today and talk about tools that can help you fall asleep, sleep better and emerge from sleep feeling more rested. So what determines how well we sleep and the quality of our wakeful state? It turns out that's governed by two forces. The first force is a chemical force. It's called adenosine. Adenosine is a molecule in our nervous system and body that builds up the longer we are awake. So if you've just slept for eight or nine or ten really deep restful hours, adenosine is going to be very low in your brain and body. If, however, you've been awake for 10, 15 or more hours, adenosine levels are going to be much higher. Adenosine creates a sort of sleep drive or a sleep hunger. And a good way to remember this and think about adenosine is to think about caffeine. Caffeine for most people wakes them up. It makes them feel more alert. Caffeine acts as an adenosine antagonist. What that means is that when you ingest caffeine, whether or not it's coffee or soda or tea or in any other form, it binds to the adenosine receptor. It sort of parks there just like a car would park in a given parking slot. And therefore adenosine can't park in that slot. Now, when caffeine parks in the adenosine receptor slot, nothing really happens downstream of that receptor. The receptor can't engage the normal cellular functions of making that cell and you feel sleepy. So the reason caffeine wakes you up is because it blocks the sleepiness receptor. It blocks the sleepy signal. And this is why when that caffeine wears off, adenosine will bind to that receptor sometimes with even greater what we call affinity. And you feel the crash, you feel especially tired. Caffeine has a lot of health benefits. It also, for some people, can be problematic for health, it can raise blood pressure, et cetera. Caffeine increases this molecule that's a neuromodulator that we call dopamine. We discussed this in episode one, which tends to make us feel good, motivated and give us energy, because as you may have learned in episode one, dopamine is related to another neuromodulator called epinephrine, which gives us energy. In fact, epinephrine is made from dopamine. So let's just take a step back and think about what we're talking about when we're talking about sleepiness. If you've ever pulled an all-nighter, you'll noticed something interesting. As morning rolls around, you'll suddenly feel an increase in your energy and alertness again, even though adenosine has been building up for the entire night. Now, why is that? The reason that is because there's a second force which is governing when you sleep and when you're awake. And that force is a so-called circadian force. Circadian means about a day or about 24 hours. And inside all of us is a clock that exists in your brain and my brain and the brain of every animal that we're aware of that determines when we want to be sleepy and when we want to be awake. That block of sleep and when it falls within each 24 hour cycle is governed by a number of different things. But the most powerful thing that's governing when you want to be asleep and when you want to be awake is light. And in particular, it's governed by sunlight. Now, I can't emphasize enough how important and how actionable this relationship is between light and when you want to sleep. It's quite simple on the face of it, and it's quite simple to resolve. But people tend to make a big mess of this whole circadian literature, frankly. So let's just break it down from the standpoint of what's going on in your brain and body as you go through one 24 hour day. Let's start with waking. So regardless of how well you slept at night or whether or not you were up all night, most people tend to wake up sometime around when the sun rises. When you wake up in the morning, you wake up because a particular hormone called cortisol is released from your adrenal glands. Your adrenal glands sit right above your kidneys and there's a little pulse of cortisol. There's also a pulse of epinephrine, which is adrenaline from your adrenals and also in your brain. And you feel awake. Now, that pulse of cortisol and adrenaline and epinephrine might come from your alarm clock. It might come from you naturally waking up. But it tends to alert your whole system and your body that it's time to increase your heart rate. It's time to start tensing your muscles. It's time to start moving about. It's very important that that cortisol pulse come early in the day, or at least early in your period of wakefulness. When you wake up in the morning and you experience that rise in cortisol, there's a timer that starts going and these are cellular timers and they're dictated by the relation between different organs in your body that says to your brain and body that in about 12 to 14 hours a different hormone. This hormone we're calling melatonin will be released from your pineal gland. So there's two mechanisms here a wakefulness signal and a sleepiness signal. And the wakefulness signal triggers the onset of the timer for the sleepiness signal. OK, so the rhythm of cortisol and melatonin is what we call endogenous. It's happening in us all the time without any external input. In fact, if we were in complete darkness, living in a cave with no artificial lights whatsoever, these rhythms of cortisol and melatonin would continue. So if you were in complete darkness, it would happen once per 24 hour cycle, but it would be somewhat later and later each day. Whereas under normal circumstances, what happens is you wake up. And what happens when you wake up? You open your eyes. When you open your eyes. Light comes into your eyes. Now, the way this system works is that you have a particular set of neurons in your eye. They're called retinal ganglion cells. When light comes into the eye, there's a particular group of retinal ganglion cells or type of retinal ganglion cells that perceives a particular type of light and communicates that to this clock that resides right above the roof of your mouth called the suprachiasmatic nucleus. And the suprachiasmatic nucleus has connections with essentially every cell and organ of your body. Now, it's vitally important that we get light communicated to this central clock in order to time the cortisol and melatonin properly. When I say properly, I can say that with confidence because we know based on a lot of evidence that if you don't get your cortisol and melatonin rhythms right, there are tremendously broad and bad effects on cardiovascular health, metabolic effects, learning, depression, dementia. So let's think about what happens when we do this correctly and how to do it correctly. When we wake up, our eyes open. Now, if we're in a dark room, there isn't enough light to trigger the correct timing of this cortisol melatonin thing. These rhythms, you might say, well, why won't any light do it? Well, it turns out that these neurons in our eye that set the circadian clock and then allow our circadian clock to set all the clocks of all the cells and organs and tissues of our body, responds best to a particular quality of light an amount of light. And those are the qualities of light and amount of light that come from sunlight. So these neurons, what they're really looking for, although they don't have a mind of their own, is the sun at what we call low solar angle. The eye and the nervous system don't know anything about sunrises or sunsets. It only knows the quality of light that comes in when the sun is low in the sky. This system evolved so that when the sun is low in the sky, there's a particular contrast between yellows and blues that triggers the activation of these cells. However, if you wake up a few hours after the sunrise, which I tend to most days personally, you still want to get outside and view sunlight. You don't need the sunlight beaming you directly in the eyes. There's a lot of photons, light energy that scattered from sunlight at this time. But the key is to get that light energy from sunlight ideally into your eyes. It's critically important that you get outside to get this light. I had a discussion with a colleague of mine, Dr. Jamie Zeitzer, who's in the Department of Psychiatry and Behavioral Sciences at Stanford, a world expert in this. And he tells me that it's 50 times less effective to view this sunlight through a window, through a car windshield or through a side window of a car than it is to just get outside with no sunglasses and view light early in the day. Once the sun is overhead, the quality of light shifts so that you miss this opportunity to time the cortisol pulse. And that turns out to be a bad thing to do. You really want to time that cortisol pulse properly. Because we'll get into this a little bit more later. But a late shifted cortisol pulse in particular a 9:00 PM or 8:00 PM increase in cortisol is one of the consequences and maybe one of the causes of a lot of anxiety disorders and depression. So it's kind of a chicken and egg thing. We don't know whether or not it's the correlated with it's the cause or the effect, but it's a signature of depression and anxiety disorder. Bringing that cortisol pulse earlier in your wakeful period, earlier in your day has positive benefits, ranging from blood pressure to mental health etcetera. I'm not going to list them all off because they're just so many of them. But many, many positive things happen when you are getting the cortisol early in the day, far away from your melatonin pulse. So how long should you be outside? Well, this is going to vary tremendously, because some people live in environments where it's very bright. So let's say it's Colorado in the middle of winter, there's a snow field, there's no cloud cover. And you walk outside, there's going to be so much photon light energy arriving on your retina that probably only takes 30 to 60 seconds to trigger the central clock and set your cortisol and melatonin rhythms properly and get everything in lined up nicely. Whereas if you're in Scandinavia in the depths of winter and you wake up at 5:00 AM and the sun is just barely creeping across the horizon and then goes back down again a few hours later, you probably are not getting enough sunlight in order to set these rhythms. So many people find that they need to use sunlight simulators in the form of particular lights that were designed to simulate sunlight. You could say, well, the lights in my house or my phone are really, really bright. Everyone's telling us to stay off our phones at night because they're really bright. But guess what? It turns out that early in the day, your retina is not very sensitive, which means you need a lot of photons, ideally coming from sunlight to set these clock mechanisms. So looking at your phone or artificial lights is fine if you wake up before sunrise, but it's not going to work to set these clock mechanisms. So you want to use sunlight. If you can't see sunlight because of your environment, then you are going to have to opt for artificial light. And in that case, you're going to want an artificial light that either simulates sunlight or has a lot of blue light. Now, without going off course here, you might be saying, wait, I've heard blue light is bad for me. Actually, blue light is great for this mechanism during the day. A lot of people will say I should be wearing blue blockers throughout the day. No, that's the exact wrong thing. That should be reserved for late in the evening. Because light suppresses melatonin. Sunlight inhibits the pineal. It prevents it from releasing melatonin. Darkness allows the pineal to release melatonin. So the pineal is not the gland or the organ of sunlight. It is the gland of darkness. In fact, melatonin can be thought of as a sleepiness signal that's correlated with darkness. So get up each morning, try and get outside. I know that can be challenging for people, but anywhere from two to ten minutes of sunlight exposure is going to work well for most people. If you can't do it every day or you sleep through this period of the early day low solar angle, don't worry about it. The systems in the body, these hormone systems and neurotransmitter systems that make you awake at certain periods of the day and sleepy at other times are operating by averaging when you view the brightest light. Some of you, many of you might be asking, what else can help set this rhythm? Well, it turns out that light is what we call the primary zeitgeber, the time giver. But other things can help establish this rhythm of cortisol, followed by melatonin 12 to 16 hours later as well. The other things besides light are timing of food intake, timing of exercise, as well as various drugs or chemicals that one might ingest. Not illegal drugs, although those will impact circadian mechanisms, as well. The other thing is sunset, when the sun is also at low solar angle low close to the horizon. By viewing sunlight at that time of day, in the evening or afternoon, depending on what time of year it is and where you are in the world. These melanopsin cells, these neurons in your eye signal the central circadian clock that it's the end of the day. There was a really nice study that showed that viewing sunlight around the time of sunset doesn't have to be just crossing the horizon, but circa sunset within an hour or so of sunset prevents some of the bad effects of light in preventing melatonin release later that same night. So let me repeat this viewing light early in the day is key. Viewing light later in the day when the sun is setting or around that time can help protect these mechanisms, your brain and body against the negative effects of light later in the day. So let me talk about how you would do that. You'd go view the sunset or you would go outside in the late afternoon or evening. Again, if you want to do this through a window at work, that's fine, but it'll take 50 times longer. So the best thing to do is just to get outside for a few minutes, anywhere from two to ten minutes also in the afternoon. Having those two signals arriving to your central clock that your body, your internal world knows when it's morning and knows when it's evening is tremendously powerful. There's always a lot of questions about how long? How much How do I know if I've had enough? You'll know because your rhythm will start to fall into some degree of normalcy. You'll start to wake up at more or less the same time each day. You'll fall asleep more easily at night. Generally, it takes about two or three days for these systems to align. So if you've not been doing these behaviors, it's going to take a few days. But they can have tremendous benefits and sometimes rather quickly on a number of different mental and physical aspects of your health. Now let's talk about the bad effects of light. Because light is not supposed to arrive in our system at any time. And nowadays, because of screens and artificial light, we have access to light at times of day and night that normally we wouldn't. Now, earlier I said that you need a lot of light in particular sunlight to set these clock mechanisms. That's true. But there's a kind of diabolical feature to the way all this works, which is the longer you've been awake, the more sensitive your retina and these cells are to light. So that if you've been awake for 10, 12, 14 hours, it becomes very easy for even a small amount of light coming from a screen or from an overhead light to trigger the activation of the clock and make you feel like you want to stay up later, make it harder to fall asleep and disrupt your sleep pattern. OK, so the simple way to think about this is want as much light as safely possible early in the day, morning and throughout the day, including blue light. And you want as little light coming into your eyes, artificial or sunlight after, say 8:00 PM. And certainly you do not want to get bright light exposure to your eyes between 11 PM and 4 AM. And here's why. Light that arrives to the eyes between 11:00 PM and 4:00 AM approximately, suppresses the release of dopamine. This neuromodulator that makes us feel good is sort of an endogenous antidepressant and can inhibit learning and create all sorts of other detrimental effects. It does this through a mechanism for those of you who want to the neural pathways that involves light to the eyes. That's then signaled to a structure called the habenula. When that habenula gets activated, it's actually called the disappointment nucleus because it actually makes us feel less happy and more disappointed and can lead to certain forms of depression in the wakeful state. Now, if you wake up in the middle of the night and you need to use the bathroom or you're on an all night flight and you need to read or whatever it is, fine. Every once in a while it's not going to be a problem to get bright light exposure to your eyes in the middle of the night. But if you think about our lifestyle nowadays and being up late looking at phones, even if you dim that screen, you're triggering this activation because your retinal sensitivity and the sensitivity of these neurons has gone up late in the day. For those of you that are experiencing challenges with mood, those of you that have anxiety, learning problems, issues, focusing, the questions I usually get are how can I focus better? One of the best ways you can support your mechanisms for good mood, mental health, learning, focus, metabolism, et cetera, is to take control of this light exposure behavior at night and not get much or any bright light exposure in the middle of the night. These cells in our eye, these neurons that signal the central clock reside mostly not exclusively, but mostly in the bottom half of our retina. And because we have a lens in front of our retina and because of the optics of lenses, that means that these cells are actually viewing our upper visual field. This is probably not coincidental that these cells were essentially designed to detect sunlight, which is overhead, of course. So if you want to avoid improper activation of these neurons, it's better to place lights that you use in the evening low in your physical environment. So on desktops or even the floor, if you want to go that way as opposed to overhead lights. So overhead fluorescent lights would be the worst. That would be the worst case scenario. Lights that are overhead that are a little bit softer of the yellow or reddish tints would be slightly better. But dim lights that are set low in the room are going to be best because they aren't going to activate these neurons and therefore shift your circadian clock. But let's talk about what light can do in terms of shifting us in healthy ways. So the way to think about this whole system again, is you've got adenosine building up depending on how long you've been awake and it's making you sleepy. And then you've got their circadian mechanisms that are timing your wakefulness and timing when you want to be asleep, mainly through cortisol and melatonin. But there are a bunch of other things that are downstream of cortisol and melatonin like we tend to be hungrier during our wakeful period than late at night. Some people like to eat it late at night. But if you're finding that you can't become a day person or a morning person, shifting your light exposure, exercise and food intake to the daytime will help. Jamie Zeitzer and colleagues did a beautiful study showing that if you turn on the lights before waking up, so around 45 minutes to an hour before waking up. Even if your eyelids are closed provided you're not under the covers. After doing that for a few days, that increases your total sleep time and shifts forward the time at which you feel sleepy. It makes you want to go to bed earlier each night. Now, in a kind of diabolical way, they did this with teenagers who are notorious for wanting to wake up late and stay up late. And what they found was bright light flashes just turning on the lights in their environment, overhead lights, because they're trying to activate the system. And that's why they're using overhead lights even through the eyelids before these kids woke up, then made those kids naturally want to go to bed earlier and they ended up sleeping longer. So that's something you could try. You could put your lights on a timer to go on early in the day before you wake up. You could open your blinds so that sunlight is coming through. And again, if you curl up under the covers, then it's not going to reach these neurons. But it's remarkable, the light can actually penetrate the eyelids, activate these neurons and go to the central clock. That study illustrates a really important principle of how you're built, which is have the capacity for what are called phase advances and phase delays. And I don't want to complicate this too much. So the simplest way to think about phase advances and phase delays is that if you see light late in the day and in particular in the middle of the night, your brain and body, for reasons that now you understand will think that that's morning light, even though it's not sunlight, because you have this heightened sensitivity and it will phase delay, it will delay your clock. It will essentially make you want to get up later and go to sleep later. So the simple way to think about this is if you're having trouble waking up early and feeling alert early in the day, you're going to want to try and get bright light exposure even before waking up because it will advance your clock. It's sort of like turning the clock forward. Whereas if you are having trouble waking up early, you definitely don't want to get too much light exposure or any light exposure to your eyes late in the evening and in the middle of the night because it's just going to delay your clock more and more. And what you're trying to do is provide them anchors. You're trying to provide them consistent, powerful anchors so that your cortisol, your melatonin, and then everything that cascades down from that, like your metabolism and your ability to learn and your sense of alertness, your dopamine, your serotonin, all that stuff is timed regularly. One of the reasons why there's so much challenge out there with focus and anxiety and depression. There are a lot of reasons for that. But one of the reasons is that people's internal mechanisms aren't anchored to anything regular. These systems, again, will average, but if you can provide them consistent light anchors early in the day and in the evening and avoiding light at night, you will be amazed at the tremendous number of positive effects that can come from that at the level of metabolic factors, hormones, and just general feelings of well-being. And this is why whenever people ask me, what should I take? Which is one of the most common questions I get. What supplements should I take? What drugs should I be taking? What things should I be taking? The first question I always ask them is how is your sleep? And 90% of the time they tell me they either have trouble falling asleep or staying asleep or they don't feel rested throughout the day. A brief note about naps. Naps provided that they're less than one ultradian cycle, provided they're 20 minutes or 30 minutes or even an hour can be very beneficial for a lot of people. You don't have to take them, but many people naturally feel a dip in energy and focus late in the afternoon. In fact, if we were going to look at wakefulness, what we would find is that you get that morning light exposure, hopefully your cortisol goes up, people start feeling awake and then around 2 or 3 or 4 in the afternoon, there's a spike in everything from alertness to ability to learn. Some metabolic factors drop and then it just naturally comes back up. And then it tapers off as the night goes on. So for some of you, naps are great. I love taking naps. Some people, they wake up from naps, feeling really groggy. That's probably because they're not sleeping as well as they should at night or as long as they should at night. And so they're dropping into REM sleep or deeper forms of sleep in the daytime. And then they wake up and they feel kind of disoriented. Other people feel great after a nap. So that's another case where just like with caffeine, you sort of have to evaluate for yourself. OK, so naps are going to be good for some people, not for others. I personally like to take a nap around 3 or 4 PM, but there's a practice that I've adopted in the last five years that I've found to be immensely beneficial. That is sort of like napping but isn't napping. It's a thing that they call yoga nidra. Yoga nidra actually means yoga sleep. And it's a sort of meditation that you listen to. Meditation and yoga nidra scripts have been immensely helpful for me in terms of accelerating the transition to sleep. So they involve taking a few minutes, 10 to 30 minutes or so, just like you would for a nap and just listening to a script almost passively, and it has do some particular patterns of breathing and some other kind of body scan things that can really help people learn to relax, not just in that moment, but get better at relaxing and turning off thinking in order to fall asleep when they want to do that at night. In other words, they're always good for you because it's a training mechanism by which you self train your nervous system to go from a state of heightened alertness, that you don't want to heighten, relaxation that you do want. And so it's really teaching you to hit the brake. And that brings us to an even more important point, perhaps, which is we've all experienced that we can stay up if we want to. If we want to stay up late on New Year's or we want to push an all-nighter. Some people can do that more easily than others, but we're all capable of doing that. But it's very hard to make ourselves fall asleep. And so there's a sort of asymmetry to the way our autonomic nervous system, which governs this alertness, calmness thing, the sympathetic and parasympathetic nervous system, there's an asymmetry there where we are more easily able to engage wakefulness and drive wakefulness. We can force ourselves to stay awake than we are able to force ourselves to fall asleep. And one of the things that I say over and over again and I'm going to continue to say over and over again is it's very hard to control the mind with the mind. When you have trouble falling asleep, you need to look to some mechanism that involves the body. And all the things I described meditation, hypnosis, yoga nidra, all involve exhale, emphasized, breathing certain ways of lying down and controlling the body. We're going to get into breathing in real depth at another time. But all of those involve using the body to control the mind rather than trying to wrestle your mind into a certain pattern of relaxation. And when we're having trouble controlling the mind, I encourage people to look towards the body, look toward sunlight, avoid sunlight and bright light if that happens to be late at night. So there's a theme that's starting to emerge, which is in order to control this thing that we call the nervous system, we have to look back to some of the things we discussed earlier, like sensation, perception, etcetera. But we have to ask, what can we control? Well, I'm talking about controlling light exposure, controlling your breathing and body, non-sleep deep rest or what I hereafter we will refer to as NSDR non-sleep deep rest as a way to reset one's ability to be awake after you emerge from NSDR. So to get some more wakefulness and ability to attend some emotional stability reset, as well as make it better and easier to fall asleep when you want to go to sleep at night. Now, non-sleep deep rest does have some research to support it. There's a beautiful study done out of a university in Denmark. I will later provide a link to that study that showed that this meditation and yoga nidra type meditation allows dopamine and other neuromodulators in an area of the brain called the striatum that's involved in motor planning and motor execution to reset itself. In other words, this NSDR can reset our ability to engage in the world in a way that's very deliberate. OK, so what about things that we can and maybe should or should not take in order to control and access better sleep and better wakefulness? There are a couple of things that are directly in line with the biology related to falling and staying asleep and directly in line with the biology of wakefulness. There's a whole category of things like stimulants, cocaine, amphetamine and prescription stimulants that are the prescription ones were designed for the treatment of narcolepsy. So things like modafinil or armodafinil that are designed to create wakefulness, they are all essentially chemical variants of things that increase epinephrine and dopamine. Now, of course, I'm of the standpoint that things like cocaine and amphetamine are just across the board bad. They have so many addictive and terrible effects. In the proper setting prescribed by the proper professional, things like modafinil for narcolepsy might be appropriate. I know that a lot of people out there take Adderall, even though they haven't been prescribed Adderall in order to increase wakefulness. That is essentially, well, it's illegal for one, but it's also abusing the system in the sense that you're pushing back on the adenosine system, slightly differently than you do caffeine. It will make you feel more alert. There tends to be a heavy rebound and they do have an addictive potential. There are also some other effects of those that can be quite bad. But there are some supplements and some things that are safer, certainly safer, and that in cases where you're doing all the right behaviors, you're exercising and eating correctly and you're still having trouble with sleep, that can be beneficial for falling and staying asleep. Now, I want to be very clear. I am not pushing supplements. I'm just pointing you toward some things that have been shown in peer reviewed studies to have some benefit. The first one is magnesium. There are many forms of magnesium, but certain forms of magnesium can have positive effects on sleepiness and the ability to stay asleep, mainly by way of increasing neurotransmitters, like GABA. There are a lot of forms of magnesium out there, but one in particular is magnesium threonate. T-H-R-E-O-N-A-T-E, which you have to check to see if this is right for you. Check with your doctor. The other thing is theanine. T-H-E-A-- T-H-E-A-N-I-N-E. Theanine. 100 to 200 milligrams of theanine for me also helps me turn off my mind and fall asleep. Interestingly, theanine is now being introduced to a lot of energy drinks in order to take away the jitters that are associated with drinking too much caffeine or with some other things that are in the energy drinks. So just a consideration. Again, I'm not here to tell you what to do or not do, but just want to arm you with information. The thing about theanine and magnesium is taken together, they do for some people, they can make them so sleepy and sleep so deeply that they actually have trouble waking up in the morning. So you have to play with these things and titrate them if you decide to use them again, if you decide to go this route, I would not start by taking supplements. I would start by getting your light viewing behavior correct. And then think about your nutrition and then think about your activity and then think about whether or not you want to supplement. We already talked about melatonin earlier. There's another supplement that can be quite useful, which is apigenin. A-P-I-G-E-N-I-N, which is the derivative of chamomile. 50 milligrams of apigenin also can augment or support this kind of creation of a sleepiness to help fall asleep and stay asleep. As an important point, apigenin is a fairly potent estrogen inhibitor. So women who want to keep their estrogen levels high or at whatever levels they happen to be at should probably avoid apigenin altogether. And men take that into consideration as well. Men need estrogen also. You don't want to completely eliminate your estrogen. That can create all sorts of bad effects on libido and cognition, etcetera. So apigenin in some people is going to be a pretty strong estrogen inhibitor. So keep that in mind. So thank you so much for your time and attention. And above all, thank you for your interest in science. [MUSIC PLAYING]

ANDREW HUBERMAN: Welcome to
Huberman Lab Essentials, where we revisit past episodes for
the most potent and actionable science based tools for mental
health, physical health, and performance. [MUSIC PLAYING] I'm Andrew Huberman,
and I'm a professor of neurobiology
and ophthalmology at Stanford School of Medicine. Today's podcast episode
is all about sleep. We're also going to talk about
the mirror image of sleep, which is wakefulness. Now, these two phases of our
life, sleep and wakefulness govern everything about our
mental and physical health. And we're not just going to talk
about what's useful about sleep. We're also going to talk about
how to get better at sleeping, and that will include
how to get better at falling asleep,
timing your sleep and accessing better
sleep quality. In doing so, we're
also going to discuss how to get more focused
and alert in wakefulness. So if you're like most
people, which includes me, you have some
challenges with sleep. At least every third
or fifth night or so, and maybe even more often. So we're really going
to go tool heavy today and talk about tools that
can help you fall asleep, sleep better and emerge from
sleep feeling more rested. So what determines
how well we sleep and the quality of
our wakeful state? It turns out that's
governed by two forces. The first force is
a chemical force. It's called adenosine. Adenosine is a molecule in
our nervous system and body that builds up the
longer we are awake. So if you've just slept for
eight or nine or ten really deep restful hours,
adenosine is going to be very low in
your brain and body. If, however, you've been awake
for 10, 15 or more hours, adenosine levels are
going to be much higher. Adenosine creates a sort of
sleep drive or a sleep hunger. And a good way to remember
this and think about adenosine is to think about caffeine. Caffeine for most
people wakes them up. It makes them feel more alert. Caffeine acts as an
adenosine antagonist. What that means is that when you
ingest caffeine, whether or not it's coffee or soda or
tea or in any other form, it binds to the
adenosine receptor. It sort of parks there
just like a car would park in a given parking slot. And therefore adenosine
can't park in that slot. Now, when caffeine parks in
the adenosine receptor slot, nothing really happens
downstream of that receptor. The receptor can't engage
the normal cellular functions of making that cell
and you feel sleepy. So the reason
caffeine wakes you up is because it blocks
the sleepiness receptor. It blocks the sleepy signal. And this is why when
that caffeine wears off, adenosine will bind
to that receptor sometimes with even greater
what we call affinity. And you feel the crash,
you feel especially tired. Caffeine has a lot
of health benefits. It also, for some people, can
be problematic for health, it can raise blood
pressure, et cetera. Caffeine increases this
molecule that's a neuromodulator that we call dopamine. We discussed this in
episode one, which tends to make us feel good,
motivated and give us energy, because as you may have
learned in episode one, dopamine is related to
another neuromodulator called epinephrine, which
gives us energy. In fact, epinephrine
is made from dopamine. So let's just take a
step back and think about what we're
talking about when we're talking about sleepiness. If you've ever pulled
an all-nighter, you'll noticed
something interesting. As morning rolls
around, you'll suddenly feel an increase in your
energy and alertness again, even though adenosine
has been building up for the entire night. Now, why is that? The reason that
is because there's a second force which is
governing when you sleep and when you're awake. And that force is a
so-called circadian force. Circadian means about a
day or about 24 hours. And inside all of
us is a clock that exists in your
brain and my brain and the brain of every
animal that we're aware of that determines
when we want to be sleepy and when we want to be awake. That block of sleep and when it
falls within each 24 hour cycle is governed by a number
of different things. But the most
powerful thing that's governing when you
want to be asleep and when you want to
be awake is light. And in particular, it's
governed by sunlight. Now, I can't emphasize
enough how important and how actionable this
relationship is between light and when you want to sleep. It's quite simple
on the face of it, and it's quite
simple to resolve. But people tend to make a big
mess of this whole circadian literature, frankly. So let's just break it
down from the standpoint of what's going on in
your brain and body as you go through
one 24 hour day. Let's start with waking. So regardless of how
well you slept at night or whether or not you
were up all night, most people tend
to wake up sometime around when the sun rises. When you wake up
in the morning, you wake up because a
particular hormone called cortisol is released
from your adrenal glands. Your adrenal glands sit
right above your kidneys and there's a little
pulse of cortisol. There's also a pulse
of epinephrine, which is adrenaline from your
adrenals and also in your brain. And you feel awake. Now, that pulse of cortisol
and adrenaline and epinephrine might come from
your alarm clock. It might come from you
naturally waking up. But it tends to alert your
whole system and your body that it's time to
increase your heart rate. It's time to start
tensing your muscles. It's time to start moving about. It's very important
that that cortisol pulse come early in the
day, or at least early in your period of wakefulness. When you wake up in the
morning and you experience that rise in cortisol, there's
a timer that starts going and these are cellular
timers and they're dictated by the relation
between different organs in your body that says
to your brain and body that in about 12 to 14
hours a different hormone. This hormone we're
calling melatonin will be released from
your pineal gland. So there's two mechanisms
here a wakefulness signal and a sleepiness signal. And the wakefulness
signal triggers the onset of the timer
for the sleepiness signal. OK, so the rhythm of
cortisol and melatonin is what we call endogenous. It's happening in us all the
time without any external input. In fact, if we were in complete
darkness, living in a cave with no artificial
lights whatsoever, these rhythms of cortisol
and melatonin would continue. So if you were in
complete darkness, it would happen once
per 24 hour cycle, but it would be somewhat
later and later each day. Whereas under normal
circumstances, what happens is you wake up. And what happens
when you wake up? You open your eyes. When you open your eyes. Light comes into your eyes. Now, the way this
system works is that you have a particular
set of neurons in your eye. They're called retinal
ganglion cells. When light comes
into the eye, there's a particular group of
retinal ganglion cells or type of retinal
ganglion cells that perceives a
particular type of light and communicates that to
this clock that resides right above the roof of
your mouth called the suprachiasmatic nucleus. And the suprachiasmatic
nucleus has connections with
essentially every cell and organ of your body. Now, it's vitally
important that we get light communicated to
this central clock in order to time the cortisol
and melatonin properly. When I say properly, I can
say that with confidence because we know based
on a lot of evidence that if you don't get your
cortisol and melatonin rhythms right, there are
tremendously broad and bad effects on
cardiovascular health, metabolic effects, learning,
depression, dementia. So let's think
about what happens when we do this correctly
and how to do it correctly. When we wake up, our eyes open. Now, if we're in
a dark room, there isn't enough light to
trigger the correct timing of this cortisol
melatonin thing. These rhythms, you might say,
well, why won't any light do it? Well, it turns out
that these neurons in our eye that set
the circadian clock and then allow our
circadian clock to set all the clocks of all the
cells and organs and tissues of our body, responds best to
a particular quality of light an amount of light. And those are the qualities
of light and amount of light that come from sunlight. So these neurons, what
they're really looking for, although they don't have
a mind of their own, is the sun at what we
call low solar angle. The eye and the nervous
system don't know anything about sunrises or sunsets. It only knows the
quality of light that comes in when the
sun is low in the sky. This system evolved so that
when the sun is low in the sky, there's a particular contrast
between yellows and blues that triggers the
activation of these cells. However, if you
wake up a few hours after the sunrise, which I
tend to most days personally, you still want to get
outside and view sunlight. You don't need the sunlight
beaming you directly in the eyes. There's a lot of photons,
light energy that scattered from sunlight at this time. But the key is to get that light
energy from sunlight ideally into your eyes. It's critically important
that you get outside to get this light. I had a discussion with a
colleague of mine, Dr. Jamie Zeitzer, who's in the Department
of Psychiatry and Behavioral Sciences at Stanford,
a world expert in this. And he tells me that it's
50 times less effective to view this sunlight through a
window, through a car windshield or through a side
window of a car than it is to just get outside
with no sunglasses and view light early in the day. Once the sun is overhead,
the quality of light shifts so that you miss
this opportunity to time the cortisol pulse. And that turns out to
be a bad thing to do. You really want to time that
cortisol pulse properly. Because we'll get into this
a little bit more later. But a late shifted cortisol
pulse in particular a 9:00 PM or 8:00 PM increase in cortisol
is one of the consequences and maybe one of the causes
of a lot of anxiety disorders and depression. So it's kind of a
chicken and egg thing. We don't know whether or not
it's the correlated with it's the cause or the
effect, but it's a signature of depression
and anxiety disorder. Bringing that cortisol pulse
earlier in your wakeful period, earlier in your day
has positive benefits, ranging from blood pressure
to mental health etcetera. I'm not going to list them
all off because they're just so many of them. But many, many
positive things happen when you are getting the
cortisol early in the day, far away from your
melatonin pulse. So how long should
you be outside? Well, this is going
to vary tremendously, because some people live
in environments where it's very bright. So let's say it's Colorado
in the middle of winter, there's a snow field,
there's no cloud cover. And you walk outside,
there's going to be so much photon
light energy arriving on your retina that
probably only takes 30 to 60 seconds to
trigger the central clock and set your cortisol
and melatonin rhythms properly and get
everything in lined up nicely. Whereas if you're in Scandinavia
in the depths of winter and you wake up at 5:00 AM and the sun
is just barely creeping across the horizon and then goes back
down again a few hours later, you probably are not getting
enough sunlight in order to set these rhythms. So many people
find that they need to use sunlight simulators in
the form of particular lights that were designed
to simulate sunlight. You could say, well, the
lights in my house or my phone are really, really bright. Everyone's telling us to
stay off our phones at night because they're really bright. But guess what? It turns out that
early in the day, your retina is not
very sensitive, which means you need
a lot of photons, ideally coming from sunlight
to set these clock mechanisms. So looking at your phone
or artificial lights is fine if you wake
up before sunrise, but it's not going to work to
set these clock mechanisms. So you want to use sunlight. If you can't see sunlight
because of your environment, then you are going to have
to opt for artificial light. And in that case, you're going
to want an artificial light that either simulates sunlight
or has a lot of blue light. Now, without going off course
here, you might be saying, wait, I've heard blue
light is bad for me. Actually, blue light is
great for this mechanism during the day. A lot of people will say I
should be wearing blue blockers throughout the day. No, that's the
exact wrong thing. That should be reserved
for late in the evening. Because light
suppresses melatonin. Sunlight inhibits the pineal. It prevents it from
releasing melatonin. Darkness allows the pineal
to release melatonin. So the pineal is not the gland
or the organ of sunlight. It is the gland of darkness. In fact, melatonin
can be thought of as a sleepiness signal
that's correlated with darkness. So get up each morning,
try and get outside. I know that can be
challenging for people, but anywhere from two to ten
minutes of sunlight exposure is going to work
well for most people. If you can't do it
every day or you sleep through this period of
the early day low solar angle, don't worry about it. The systems in the body,
these hormone systems and neurotransmitter
systems that make you awake at certain
periods of the day and sleepy at other
times are operating by averaging when you
view the brightest light. Some of you, many of
you might be asking, what else can help
set this rhythm? Well, it turns out
that light is what we call the primary
zeitgeber, the time giver. But other things
can help establish this rhythm of cortisol,
followed by melatonin 12 to 16 hours later as well. The other things besides light
are timing of food intake, timing of exercise, as well
as various drugs or chemicals that one might ingest. Not illegal drugs,
although those will impact circadian
mechanisms, as well. The other thing is sunset,
when the sun is also at low solar angle low
close to the horizon. By viewing sunlight
at that time of day, in the evening or afternoon,
depending on what time of year it is and where you
are in the world. These melanopsin cells,
these neurons in your eye signal the central
circadian clock that it's the end of the day. There was a really
nice study that showed that viewing sunlight
around the time of sunset doesn't have to be just
crossing the horizon, but circa sunset within
an hour or so of sunset prevents some of the
bad effects of light in preventing melatonin
release later that same night. So let me repeat this viewing
light early in the day is key. Viewing light later
in the day when the sun is setting
or around that time can help protect these
mechanisms, your brain and body against the negative effects
of light later in the day. So let me talk about
how you would do that. You'd go view the sunset
or you would go outside in the late
afternoon or evening. Again, if you want to do this
through a window at work, that's fine, but it'll
take 50 times longer. So the best thing to do
is just to get outside for a few minutes, anywhere
from two to ten minutes also in the afternoon. Having those two
signals arriving to your central
clock that your body, your internal world
knows when it's morning and knows when it's evening
is tremendously powerful. There's always a lot of
questions about how long? How much How do I know
if I've had enough? You'll know because
your rhythm will start to fall into some
degree of normalcy. You'll start to wake up at more
or less the same time each day. You'll fall asleep
more easily at night. Generally, it takes about two
or three days for these systems to align. So if you've not been
doing these behaviors, it's going to take a few days. But they can have
tremendous benefits and sometimes rather
quickly on a number of different mental and
physical aspects of your health. Now let's talk about the
bad effects of light. Because light is not supposed
to arrive in our system at any time. And nowadays, because of
screens and artificial light, we have access to light at times
of day and night that normally we wouldn't. Now, earlier I
said that you need a lot of light in
particular sunlight to set these clock mechanisms. That's true. But there's a kind of
diabolical feature to the way all this works, which is the
longer you've been awake, the more sensitive your retina
and these cells are to light. So that if you've been
awake for 10, 12, 14 hours, it becomes very easy for even
a small amount of light coming from a screen or from
an overhead light to trigger the activation
of the clock and make you feel like you
want to stay up later, make it harder to fall asleep
and disrupt your sleep pattern. OK, so the simple way
to think about this is want as much light
as safely possible early in the day, morning
and throughout the day, including blue light. And you want as little
light coming into your eyes, artificial or sunlight
after, say 8:00 PM. And certainly you do not want
to get bright light exposure to your eyes between
11 PM and 4 AM. And here's why. Light that arrives to the eyes
between 11:00 PM and 4:00 AM approximately, suppresses
the release of dopamine. This neuromodulator
that makes us feel good is sort of an endogenous
antidepressant and can inhibit learning
and create all sorts of other detrimental effects. It does this through a
mechanism for those of you who want to the neural pathways
that involves light to the eyes. That's then signaled to a
structure called the habenula. When that habenula
gets activated, it's actually called the
disappointment nucleus because it actually makes
us feel less happy and more disappointed and can lead to
certain forms of depression in the wakeful state. Now, if you wake up in
the middle of the night and you need to use the bathroom
or you're on an all night flight and you need to read or
whatever it is, fine. Every once in a
while it's not going to be a problem to get bright
light exposure to your eyes in the middle of the night. But if you think
about our lifestyle nowadays and being up
late looking at phones, even if you dim
that screen, you're triggering this activation
because your retinal sensitivity and the sensitivity
of these neurons has gone up late in the day. For those of you that are
experiencing challenges with mood, those of you that
have anxiety, learning problems, issues, focusing, the
questions I usually get are how can I focus better? One of the best ways you
can support your mechanisms for good mood, mental health,
learning, focus, metabolism, et cetera, is to take control
of this light exposure behavior at night and not get much
or any bright light exposure in the middle of the night. These cells in our
eye, these neurons that signal the central
clock reside mostly not exclusively, but mostly in
the bottom half of our retina. And because we have a lens
in front of our retina and because of the
optics of lenses, that means that these
cells are actually viewing our upper visual field. This is probably
not coincidental that these cells
were essentially designed to detect sunlight,
which is overhead, of course. So if you want to avoid improper
activation of these neurons, it's better to place
lights that you use in the evening low in
your physical environment. So on desktops or even the
floor, if you want to go that way as opposed
to overhead lights. So overhead fluorescent
lights would be the worst. That would be the
worst case scenario. Lights that are
overhead that are a little bit softer of the
yellow or reddish tints would be slightly better. But dim lights that
are set low in the room are going to be best
because they aren't going to activate these neurons and
therefore shift your circadian clock. But let's talk
about what light can do in terms of shifting
us in healthy ways. So the way to think about
this whole system again, is you've got
adenosine building up depending on how long
you've been awake and it's making you sleepy. And then you've got their
circadian mechanisms that are timing your
wakefulness and timing when you want to
be asleep, mainly through cortisol and melatonin. But there are a
bunch of other things that are downstream of
cortisol and melatonin like we tend to be hungrier
during our wakeful period than late at night. Some people like to
eat it late at night. But if you're finding that
you can't become a day person or a morning person,
shifting your light exposure, exercise and food intake
to the daytime will help. Jamie Zeitzer and colleagues
did a beautiful study showing that if you turn on
the lights before waking up, so around 45 minutes to
an hour before waking up. Even if your eyelids
are closed provided you're not under the covers. After doing that
for a few days, that increases your total sleep time
and shifts forward the time at which you feel sleepy. It makes you want to go
to bed earlier each night. Now, in a kind of
diabolical way, they did this with
teenagers who are notorious for wanting to wake
up late and stay up late. And what they found was bright
light flashes just turning on the lights in their
environment, overhead lights, because they're trying
to activate the system. And that's why they're
using overhead lights even through the eyelids
before these kids woke up, then made those kids naturally
want to go to bed earlier and they ended up
sleeping longer. So that's something
you could try. You could put your lights on a
timer to go on early in the day before you wake up. You could open your blinds so
that sunlight is coming through. And again, if you curl
up under the covers, then it's not going to
reach these neurons. But it's remarkable,
the light can actually penetrate the eyelids,
activate these neurons and go to the central clock. That study illustrates a
really important principle of how you're
built, which is have the capacity for what are called
phase advances and phase delays. And I don't want to
complicate this too much. So the simplest way to think
about phase advances and phase delays is that if you
see light late in the day and in particular in the
middle of the night, your brain and body, for
reasons that now you understand will think that
that's morning light, even though it's not sunlight,
because you have this heightened sensitivity and it will phase
delay, it will delay your clock. It will essentially make
you want to get up later and go to sleep later. So the simple way
to think about this is if you're having
trouble waking up early and feeling alert
early in the day, you're going to want to try and
get bright light exposure even before waking up because
it will advance your clock. It's sort of like turning
the clock forward. Whereas if you are having
trouble waking up early, you definitely don't want to
get too much light exposure or any light exposure to
your eyes late in the evening and in the middle of the night
because it's just going to delay your clock more and more. And what you're trying to
do is provide them anchors. You're trying to provide them
consistent, powerful anchors so that your cortisol, your
melatonin, and then everything that cascades down from
that, like your metabolism and your ability to learn
and your sense of alertness, your dopamine, your
serotonin, all that stuff is timed regularly. One of the reasons
why there's so much challenge out there with focus
and anxiety and depression. There are a lot of
reasons for that. But one of the reasons is that
people's internal mechanisms aren't anchored to
anything regular. These systems,
again, will average, but if you can provide them
consistent light anchors early in the day and in the evening
and avoiding light at night, you will be amazed at
the tremendous number of positive effects
that can come from that at the level of
metabolic factors, hormones, and just general
feelings of well-being. And this is why whenever people
ask me, what should I take? Which is one of the most
common questions I get. What supplements should I take? What drugs should I be taking? What things should I be taking? The first question I always
ask them is how is your sleep? And 90% of the time
they tell me they either have trouble falling
asleep or staying asleep or they don't feel rested
throughout the day. A brief note about naps. Naps provided that they're
less than one ultradian cycle, provided they're 20
minutes or 30 minutes or even an hour can be very
beneficial for a lot of people. You don't have to take them,
but many people naturally feel a dip in energy and
focus late in the afternoon. In fact, if we were going
to look at wakefulness, what we would find is that you get
that morning light exposure, hopefully your cortisol goes
up, people start feeling awake and then around 2 or 3
or 4 in the afternoon, there's a spike in everything
from alertness to ability to learn. Some metabolic factors drop
and then it just naturally comes back up. And then it tapers off
as the night goes on. So for some of you,
naps are great. I love taking naps. Some people, they wake up from
naps, feeling really groggy. That's probably
because they're not sleeping as well as
they should at night or as long as they
should at night. And so they're dropping into REM
sleep or deeper forms of sleep in the daytime. And then they wake up and
they feel kind of disoriented. Other people feel
great after a nap. So that's another case where
just like with caffeine, you sort of have to
evaluate for yourself. OK, so naps are going to be good
for some people, not for others. I personally like to take
a nap around 3 or 4 PM, but there's a practice that I've
adopted in the last five years that I've found to be
immensely beneficial. That is sort of like
napping but isn't napping. It's a thing that
they call yoga nidra. Yoga nidra actually
means yoga sleep. And it's a sort of meditation
that you listen to. Meditation and
yoga nidra scripts have been immensely
helpful for me in terms of accelerating
the transition to sleep. So they involve taking a few
minutes, 10 to 30 minutes or so, just like you would
for a nap and just listening to a script
almost passively, and it has do some particular
patterns of breathing and some other kind of body
scan things that can really help people learn to relax,
not just in that moment, but get better at
relaxing and turning off thinking in order
to fall asleep when they want to do that at night. In other words, they're
always good for you because it's a training
mechanism by which you self train your nervous system to
go from a state of heightened alertness, that you
don't want to heighten, relaxation that you do want. And so it's really teaching
you to hit the brake. And that brings us to an even
more important point, perhaps, which is we've all experienced
that we can stay up if we want to. If we want to stay up
late on New Year's or we want to push an all-nighter. Some people can do that
more easily than others, but we're all capable
of doing that. But it's very hard to make
ourselves fall asleep. And so there's a sort
of asymmetry to the way our autonomic
nervous system, which governs this alertness,
calmness thing, the sympathetic and
parasympathetic nervous system, there's an asymmetry
there where we are more easily able to
engage wakefulness and drive wakefulness. We can force ourselves
to stay awake than we are able to force
ourselves to fall asleep. And one of the things that
I say over and over again and I'm going to continue
to say over and over again is it's very hard to control
the mind with the mind. When you have trouble
falling asleep, you need to look to
some mechanism that involves the body. And all the things I described
meditation, hypnosis, yoga nidra, all involve
exhale, emphasized, breathing certain ways of lying
down and controlling the body. We're going to get into
breathing in real depth at another time. But all of those involve using
the body to control the mind rather than trying to wrestle
your mind into a certain pattern of relaxation. And when we're having
trouble controlling the mind, I encourage people to
look towards the body, look toward sunlight, avoid
sunlight and bright light if that happens to
be late at night. So there's a theme that's
starting to emerge, which is in order to control
this thing that we call the nervous system,
we have to look back to some of the things
we discussed earlier, like sensation,
perception, etcetera. But we have to ask,
what can we control? Well, I'm talking about
controlling light exposure, controlling your
breathing and body, non-sleep deep rest
or what I hereafter we will refer to as NSDR
non-sleep deep rest as a way to reset one's
ability to be awake after you emerge from NSDR. So to get some more
wakefulness and ability to attend some emotional
stability reset, as well as make it
better and easier to fall asleep when you want
to go to sleep at night. Now, non-sleep deep rest
does have some research to support it. There's a beautiful study done
out of a university in Denmark. I will later provide a
link to that study that showed that this meditation
and yoga nidra type meditation allows dopamine
and other neuromodulators in an area of the brain
called the striatum that's involved in motor planning and
motor execution to reset itself. In other words, this NSDR
can reset our ability to engage in the world in a
way that's very deliberate. OK, so what about things
that we can and maybe should or should
not take in order to control and access better
sleep and better wakefulness? There are a couple
of things that are directly in line
with the biology related to falling and
staying asleep and directly in line with the
biology of wakefulness. There's a whole category of
things like stimulants, cocaine, amphetamine and
prescription stimulants that are the
prescription ones were designed for the
treatment of narcolepsy. So things like
modafinil or armodafinil that are designed to
create wakefulness, they are all essentially
chemical variants of things that increase
epinephrine and dopamine. Now, of course, I'm
of the standpoint that things like
cocaine and amphetamine are just across the board bad. They have so many addictive
and terrible effects. In the proper setting prescribed
by the proper professional, things like modafinil for
narcolepsy might be appropriate. I know that a lot of people
out there take Adderall, even though they haven't been
prescribed Adderall in order to increase wakefulness. That is essentially, well,
it's illegal for one, but it's also abusing
the system in the sense that you're pushing back
on the adenosine system, slightly differently
than you do caffeine. It will make you
feel more alert. There tends to be
a heavy rebound and they do have an
addictive potential. There are also
some other effects of those that can be quite bad. But there are some
supplements and some things that are safer, certainly safer,
and that in cases where you're doing all the right behaviors,
you're exercising and eating correctly and you're
still having trouble with sleep, that can be
beneficial for falling and staying asleep. Now, I want to be very clear. I am not pushing supplements. I'm just pointing you
toward some things that have been shown in
peer reviewed studies to have some benefit. The first one is magnesium. There are many
forms of magnesium, but certain forms of magnesium
can have positive effects on sleepiness and the
ability to stay asleep, mainly by way of increasing
neurotransmitters, like GABA. There are a lot of forms
of magnesium out there, but one in particular
is magnesium threonate. T-H-R-E-O-N-A-T-E, which you
have to check to see if this is right for you. Check with your doctor. The other thing is theanine. T-H-E-A--
T-H-E-A-N-I-N-E. Theanine. 100 to 200 milligrams
of theanine for me also helps me turn off
my mind and fall asleep. Interestingly, theanine
is now being introduced to a lot of energy
drinks in order to take away the jitters
that are associated with drinking too much caffeine
or with some other things that are in the energy drinks. So just a consideration. Again, I'm not here
to tell you what to do or not do, but just want
to arm you with information. The thing about theanine and
magnesium is taken together, they do for some people,
they can make them so sleepy and sleep so deeply that they
actually have trouble waking up in the morning. So you have to play with
these things and titrate them if you decide to use them again,
if you decide to go this route, I would not start by
taking supplements. I would start by getting your
light viewing behavior correct. And then think
about your nutrition and then think
about your activity and then think about whether
or not you want to supplement. We already talked about
melatonin earlier. There's another supplement
that can be quite useful, which is apigenin. A-P-I-G-E-N-I-N, which is
the derivative of chamomile. 50 milligrams of apigenin
also can augment or support this kind of creation of a
sleepiness to help fall asleep and stay asleep. As an important point, apigenin
is a fairly potent estrogen inhibitor. So women who want to keep
their estrogen levels high or at whatever levels
they happen to be at should probably avoid
apigenin altogether. And men take that into
consideration as well. Men need estrogen also. You don't want to completely
eliminate your estrogen. That can create all
sorts of bad effects on libido and
cognition, etcetera. So apigenin in some
people is going to be a pretty strong
estrogen inhibitor. So keep that in mind. So thank you so much for
your time and attention. And above all, thank you for
your interest in science. [MUSIC PLAYING]

Transcript for:Understanding Sleep and Wakefulness

Transcript for:
Understanding Sleep and Wakefulness