Master Your Sleep & Be More Alert When Awake | Huberman Lab Essentials

welcome to hubman lab Essentials where we revisit past episodes for the most potent and actionable science-based tools for mental health physical health and performance I'm Andrew huberman and I'm a professor of neurobiology and Opthalmology 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 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 10 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 a Denine creates a sort of sleep drive or a sleep hunger and a good way to remember this and think about a Denine 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 not it's coffee or soda or tea or in any other form it binds to the adenosine receptor it's 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 Etc 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 neur modulator 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 sleep sleepiness if you've ever pulled an allnighter you'll notice 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 why is that the reason that is 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 got 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 in 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 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 okay 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 Norm under normal circumstances what happen 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 gangling cells or type of retinal gangling 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 supermatic nucleus and the supermatic 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 uh 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 and 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 in 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 the 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 zeiter who's in the uh 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 proper L because we'll get into this a little bit more later but a late shifted cortisol pulse in particular a 9 p.m. or 800 p.m 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 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 Etc I'm not going to list them all off because there 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 okay 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 uh it's Colorado in the middle of winter there's a snow field there's no cloud cover and you walk outside you 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 uh lined up nicely whereas if you're in Scandinavia in the depths of winter and you wake up at 5:00 a.m. and the Sun is just barely creeping across the Horizon 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 right 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 oh 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 2 to 10 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 these 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 zeit Giver 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 sunet 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 these neurons in your eyes signal the 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 sunet 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 as 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 2 to 10 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 normaly 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 2 or 3 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 okay so the simple way to think about this is you want as much light as 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 p.m. and certainly you do not want to get bright light exposure to your eyes between 11:00 p.m. and 4:00 a.m. and here's why light that arrives to the eyes between 11:00 p.m. and 4:00 a.m. approximately suppresses the release of dopamine this neuromodulator that makes us feel good is sort of an ant endogenous anti depressant 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 know the neural Pathways that involves light to the eyes that's then signal 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're uh you know you're need to read or whatever it is fine it's you know 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 Etc 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 uh 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 if that's 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 sort of 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 that are Downstream of cortisol 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 zeiter and colleagues had 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 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 a 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 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 um early in the day before you wake up you could open your blind so that sunlight is coming through again if you you know curl up under the covers then it's not going to reach uh 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 buildt which is you 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 in 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 will ENT 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's 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 the reasons why there's so much uh you know 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 Factor 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's 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 knps naps provided that they're less than one ultradian cycle provided their 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 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 go 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 okay so naps are going to be good for some people not for other I personally like to take a nap around 3:00 or 400 p.m. but there's a practice that I've adopted in The Last 5 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 you do some particular patterns of breathing and some other um kind of body scan like 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 break 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 right 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 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 you know 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 if 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 Etc 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 he after 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 okay 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 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 modafanil or armodafinil that are designed to create wakefulness they are all essentially um chemical variants of things that increase epinephrine and dopamine now of course I'm of the the standpoint that things like cocaine 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 modao for narcolepsy um might be appropriate I know that a lot of people out there take Aderall even though they haven't been prescribed Aderall in order to increase wakefulness that is essentially uh you know well it's illegal for one but it's also it's abusing the system in the sense that you're pushing back on the adenosine system slightly differently than you do caffeine um it will make you feel more alert there tends to be a heavy rebound and they do have an addictive potential there 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 towards 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 te which you have to check to see if this right is right for you check with your doctor the other thing is theanine t h e a uh th a n i NE 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 an 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 the thing about theanine and magnesium is taken together they do uh for some people they can make it 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 then think about whether or not you want a supplement we already talked about melatonin earlier there's another supplement that could be quite useful which is appenine API GE n i n which is a derivative of chamomile 50 milligrams of appenine also can augment or support this kind of um creation of a sleepiness uh to help fall asleep and stay asleep as a important point appenine 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 appenine altogether and men take that into consideration as well uh 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 Etc so um appenine 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]