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

Channel: Andrew Huberman / Huberman Lab
URL: https://www.youtube.com/watch?v=RTgJSQtvo88

Transcript

[00:00] Welcome to Hubberman Lab Essentials,
[00:01] [music] where we revisit past episodes
[00:04] for the most potent and actionable
[00:06] science-based tools for mental health,
[00:08] physical health, and performance.
[00:11] I’m Andrew Huberman, and I’m a professor
[00:13] of neurobiology and opthalmology at
[00:16] Stanford School of Medicine. Today,
[00:18] we’re talking all about sleep and how to
[00:20] optimize your sleep. Let’s consider what
[00:22] the perfect 24-hour cycle would look
[00:26] like. Regardless of when you wake up in
[00:28] the morning, one of the first things
[00:30] that happens is that your body
[00:31] temperature is increasing. And that’s
[00:33] just going to happen naturally. That
[00:35] increase in body temperature in turn
[00:38] causes an increase in the release of a
[00:40] hormone called cortisol. Cortisol is
[00:42] often con demonized and considered this
[00:44] bad thing. And indeed, you don’t want
[00:46] cortisol to be chronically or
[00:48] consistently elevated throughout the day
[00:49] or night. But you do want cortisol to
[00:52] reach its peak early in the day, right
[00:54] about the time you wake up. One way that
[00:57] you can ensure that that cortisol peak
[00:59] occurs early in the day, right about the
[01:01] time that you wake up, is to view bright
[01:04] light, ideally from sunlight, within the
[01:06] first 30 to 60 minutes after waking. The
[01:09] reason for that is very simple. You want
[01:12] to trigger that cortisol increase to
[01:14] occur very early in your day, and you
[01:17] don’t want that cortisol peak to happen
[01:19] later, which is what will happen if you
[01:21] wait to get outside and see sunlight.
[01:23] The reason for this is that you have a
[01:26] set of neurons, nerve cells in your eye.
[01:28] They’re called intrinsically
[01:29] photosensitive melanopsin cells, but you
[01:31] do not need to know that name. Those
[01:32] neurons respond best to bright light and
[01:35] especially right after waking early in
[01:37] the day. They are best able to signal to
[01:40] a set of neurons that reside over the
[01:42] roof of your mouth called the super kisa
[01:44] nucleus which is a cluster of neurons
[01:46] that then sends a huge number of other
[01:48] signals electrical and chemical out to
[01:50] your entire body that triggers that
[01:52] cortisol increase provides a wakeup
[01:54] signal for your brain and body and sets
[01:56] in motion a timer for you to fall asleep
[01:58] later that night. Here’s what you do, or
[02:00] at least here’s what I do. I wake up in
[02:01] the morning and I want to reach for my
[02:03] phone. But I know that even if I were to
[02:06] crank up the brightness on that phone
[02:07] screen, it’s not bright enough to
[02:09] trigger that cortisol spike and for me
[02:12] to be at my most alert and focused
[02:15] throughout the day and to optimize my
[02:16] sleep at night. So, what I do is I get
[02:18] out of bed and I go outside and if it’s
[02:22] a bright clear day and the sun is low in
[02:25] the sky or the sun is, you know,
[02:27] starting to get overhead, what we call
[02:28] low solar angle, then I know I’m getting
[02:31] outside at the right time. Especially on
[02:33] cloudy days, you want to get outside and
[02:35] get as much light energy or photons in
[02:37] your eyes. But let’s say it’s a very
[02:39] clear day and I can see where the sun
[02:41] is. I do not need to stare directly into
[02:44] the sun. So, the way to get this
[02:46] sunlight viewing early in the day is to
[02:49] look toward the sun. Never look at any
[02:52] light, sunlight or otherwise, that’s so
[02:54] bright that it’s painful to look at
[02:55] because you can damage your eyes. But
[02:57] for this morning sunlight viewing, it’s
[03:00] best to not wear sunglasses. That’s
[03:02] right, to not wear sunglasses. It is
[03:04] absolutely fine to wear eyelasses or
[03:07] contact lenses, so-called corrective
[03:09] lenses. In fact, those will serve you
[03:11] well in this practice or this tool
[03:13] because they will focus the light onto
[03:14] your neural retina and onto those
[03:16] melanopsin intrinsically photosensitive
[03:17] ganglen cells. This is grounded in the
[03:20] core of our physiology. There are
[03:22] literally hundreds if not thousands of
[03:23] quality peer-reviewed papers showing
[03:25] that light viewing early in the day is
[03:28] the most powerful stimulus for
[03:29] wakefulness throughout the day and it
[03:32] has a powerful positive impact on your
[03:34] ability to fall and stay asleep at
[03:35] night. So, this is really the
[03:37] foundational power tool for ensuring a
[03:40] great night’s sleep and for feeling more
[03:42] awake during the day. If you wake up
[03:44] before the sun is out, you can and
[03:47] probably should flip on artificial
[03:49] lights in your internal home environment
[03:51] or apartment or wherever you happen to
[03:53] live. If your goal is to be awake,
[03:55] right? If you wake up at 4 in the
[03:56] morning and you need to be awake, well,
[03:57] then turn on artificial lights. If
[03:59] you’re asking whether or not turning on
[04:00] artificial lights can replace sunlight
[04:02] at those hours. Unfortunately, the
[04:04] answer is no. Unless you have a very
[04:07] special light, we’ll talk about what
[04:09] kind of light. The bright artificial
[04:11] lights in your home environment are not,
[04:14] I repeat, are not going to be
[04:15] sufficiently bright to turn on the
[04:19] cortisol mechanism and the other wake up
[04:21] mechanisms that you need early in the
[04:23] day. The diabolical twist, however, is
[04:25] that those lights in your home or
[04:26] apartment or even on your phone are
[04:29] bright enough to disrupt your sleep if
[04:32] you look at them too late at night or in
[04:34] the middle of the night. So, there’s
[04:35] this asymmetry in our retinal, our eye
[04:38] biology, and in our brains biology
[04:40] whereby early in the day, right around
[04:42] waking, you need a lot of light, a lot
[04:44] of photons, a lot of light energy. And
[04:46] artificial lights generally just won’t
[04:48] accomplish what you need them to
[04:50] accomplish. But at night, even a little
[04:53] bit of artificial light can really mess
[04:55] up your so-called circadian, your
[04:57] 24-hour clocks and all these mechanisms
[04:59] that we’re talking about. On cloudy
[05:00] days, you especially need to get
[05:02] outside. I repeat, on cloudy days,
[05:05] overcast days, you especially need to
[05:06] get outside and get sunlight. You just
[05:08] need to get more of it. Now, how much
[05:10] light and how much light viewing do you
[05:12] need? This is going to vary depending on
[05:14] person and place. I mean, literally
[05:16] where you live on Earth, whether or not
[05:17] there’s a lot of tree cover, whether or
[05:19] not you’re somebody who has sensitive
[05:21] eyes or less sensitive eyes, it’s really
[05:23] impossible for me to give an absolute
[05:25] prescriptive, but we can give some
[05:26] general guidelines. In general, on a
[05:28] clear day, meaning no cloud cover or
[05:30] minimal cloud cover, you want to get
[05:32] this sunlight exposure to your eyes for
[05:36] about five minutes or so. Could be 3
[05:39] minutes one day, could be 7 minutes the
[05:40] next day. about 5 minutes. On a day
[05:44] where there’s cloud cover, so the sun is
[05:46] just peeking through the clouds or it’s
[05:47] more dense cloud cover, you want to get
[05:50] about 10 minutes of sunlight exposure to
[05:53] your eyes early in the day. And on days
[05:55] that are really densely overcast or
[05:57] maybe even a rainy, you’re going to want
[05:59] to get as much as 20 or 30 minutes of
[06:02] sunlight exposure. Just don’t try and
[06:04] get this sunlight exposure through a
[06:06] windshield of a car or a window, whether
[06:09] or not it’s tinted or otherwise. it
[06:10] takes far too long. It’s simply not
[06:13] going to trigger the relevant
[06:14] mechanisms. Now, if you live in a part
[06:16] of the world where it’s extremely dark
[06:18] and overcast or the weather won’t let
[06:19] you outside or you live in a cave, there
[06:22] are sunlight simulators or daylight
[06:24] simulators that you can purchase. Those
[06:26] are quite expensive in general.
[06:28] Therefore, I suggest cheaper options
[06:31] that work just as well because they get
[06:33] just as bright. things like ring lights
[06:35] that are sold in order for people to
[06:37] take selfies and this kind of thing. A
[06:40] LED tablet will work pretty well. I
[06:42] actually have one of those and I put it
[06:43] on my desk all morning even though I
[06:45] still get outside and look at sunlight
[06:47] first thing in the morning. Again, also
[06:50] especially I should say on cloudy days.
[06:52] Many of our listeners live in locations
[06:53] throughout the world where for instance
[06:54] during the winter it gets very very
[06:56] dark. So they can’t get sufficient
[06:57] sunlight. But get that morning light,
[07:00] ideally from sunlight, and take into
[07:02] account all the specific points that
[07:04] I’ve given you here. When you start
[07:06] doing this, you’ll notice that your body
[07:09] will start to feel more energized and it
[07:11] will feel more energized more quickly.
[07:14] You’ll actually start to notice this
[07:16] mechanism kicking in each day,
[07:17] especially if you’re paying attention to
[07:18] your physiology. It’s that diffuse, very
[07:20] bright sunlight, that photon energy that
[07:22] you really want. That’s going to set all
[07:24] the rhythms of your brain and body in
[07:25] the proper way. Not just that cortisol
[07:28] peak, but it’s going to trigger proper
[07:30] metabolism. It’s going to set a timer
[07:32] for you to be able to fall asleep about
[07:34] 16 hours later. It’s also going to
[07:35] suppress any melatonin, a hormone that
[07:38] makes you sleepy that happens to be
[07:39] swimming around in your bloodstream at
[07:41] the time you wake up. It does a number
[07:43] of other things too, including interact
[07:44] with the adenosine system and kind of
[07:46] wash out some of the adenosine that
[07:48] might still be residual if you didn’t
[07:49] sleep enough. Fundamentally speaking,
[07:52] get that morning sunlight viewing. I
[07:54] promise you will be grateful that you
[07:57] did. It makes everybody feel better,
[07:59] feel more alert, and it will greatly
[08:01] assist with your ability to fall and
[08:03] stay asleep later that night. You will
[08:05] also want to leverage not just light but
[08:08] temperature as a tool. If you are
[08:11] inclined, it would be wise to try and
[08:13] increase your core body temperature a
[08:16] bit more quickly than it would otherwise
[08:19] if you were to just, you know, shuffle
[08:20] around outside, get your sunlight, maybe
[08:22] read a little bit, etc. And there are
[08:24] two main ways you can do that. The first
[08:25] way is to get into cold water of some
[08:29] sort. So this could be a cold shower of
[08:30] anywhere from 1 to 3 minutes. This could
[08:32] be an ice bath if that’s your thing. It
[08:34] could be a cold tub or if you own a a
[08:36] cold tub uh that’s specifically designed
[08:39] for deliberate cold exposure. Get under
[08:41] some cold water. 1 to 3 minutes of cold
[08:43] water exposure will wake you up because
[08:44] of that adrenaline release. And and I
[08:47] want to highlight the and it will serve
[08:50] to increase your core body temperature.
[08:53] That’s right. If you put something cold
[08:54] on the surface of your body, your brain,
[08:56] a little cluster of neurons in the
[08:57] so-called medial preoptic area, act as a
[09:00] thermostat and say, “Ah, the external of
[09:02] my body is cold and therefore I’m going
[09:04] to heat up my core body temperature.”
[09:06] So, this is a little bit paradoxical.
[09:07] People think, oh, if you get into cold
[09:09] water or an ice bath, your body
[09:10] temperature is going to drop. And
[09:11] indeed, that’s true. If you stay in for
[09:12] a while, but if you just get in for
[09:14] about 1 to 3 minutes or under the cold
[09:16] shower for 1 to 3 minutes, your core
[09:17] body temperature will increase. So, this
[09:20] is great for waking up. And we have
[09:23] exercise. One of the best ways to
[09:24] increase your core body temperature
[09:26] early in the day is to do exercise. I
[09:28] always say the best time to exercise, at
[09:30] least what the research points to, is
[09:32] immediately when you wake up in the
[09:33] morning. It could be a walk. So you can
[09:35] get your sunlight exposure while you’re
[09:37] taking a walk first thing in the
[09:38] morning. It could be a light jog. It
[09:40] could be skipping rope. But try and get
[09:42] your core body temperature increased
[09:44] first thing in the morning. And a great
[09:46] way to do that is with a cold water and
[09:49] or with exercise. And again, it doesn’t
[09:51] have to be your full-blown workout for
[09:53] the day if you’re doing workouts
[09:55] consistently, which I hope everybody is
[09:56] because everybody really should
[09:58] exercise. Right now, you’ll notice we’re
[09:59] only focused on this early part of the
[10:01] day. And you might be saying, “Wait a
[10:02] second. I thought this was an episode
[10:03] about tools for sleep.” Well, everything
[10:05] that we’re talking about doing in these
[10:07] first 60 to 90 minutes of the day really
[10:10] set in motion a wave of biological
[10:13] cascades that carry through the entire
[10:15] day and into the evening and into the
[10:17] night and really do serve to optimize
[10:19] sleep. So just hang in there with me. So
[10:20] the next category of tool for use early
[10:23] in the day is caffeine. You do not have
[10:25] to drink caffeine. So what I’m about to
[10:27] describe are ways to leverage caffeine
[10:29] use to optimize sleep and wakefulness if
[10:32] you are comfortable with caffeine.
[10:34] Caffeine is something that a lot of
[10:35] people consume early in the day. How
[10:37] much depends on your tolerance and
[10:40] there’s a lot of individual variability
[10:41] here. Again, caffeine is a denosine
[10:43] antagonist or effectively works as a
[10:45] denosine antagonist and limits
[10:47] sleepiness. And for many people,
[10:49] shifting that caffeine intake from
[10:51] immediately after waking in the morning
[10:52] to 90 to 120 minutes gives them a much
[10:55] longer arc of energy throughout the day
[10:57] and they don’t feel the need to drink
[10:59] more caffeine later in the afternoon. If
[11:02] you do drink caffeine later in the
[11:03] afternoon, really try and limit the
[11:05] total amount or drink decaf. Certainly
[11:07] keep the total amount to less than 100
[11:10] milligrams if you are interested in
[11:11] getting into the best possible sleep.
[11:13] And I say this knowing that many people,
[11:15] including myself, can drink a double
[11:16] espresso with 200 milligrams of caffeine
[11:19] or more at 5:00 p. p.m. or even 6 PM or
[11:21] after dinner and still quote unquote
[11:24] fall asleep fine or still sleep fine.
[11:26] There are more and more papers all the
[11:27] time that point to the fact that
[11:28] caffeine intake late in the day after 4
[11:32] p.m. that is can really disrupt the
[11:34] architecture of your sleep. So you might
[11:35] think you’re sleeping well, but you’re
[11:37] not sleeping nearly as well as you could
[11:38] if you avoided caffeine in those
[11:40] afternoon hours. Now, some of you might
[11:42] be doing your main bout of exercise
[11:44] first thing in the morning and you want
[11:46] your caffeine before that bout of
[11:47] exercise. In that case, I say go for it.
[11:50] I absolutely respect the fact that
[11:52] people have different work schedules,
[11:54] kids schedules, etc. So, if you want to
[11:57] do some or none or all these tools,
[11:58] that’s really up to you. I’m just
[12:00] providing them to you in the simplest
[12:02] form that I can possibly provide them.
[12:04] Now, the other lever or tool that you
[12:06] have available to you is food. Not just
[12:08] what you eat, but when you eat. And it
[12:10] turns out that if you eat early in the
[12:12] day, you support a biological clock
[12:15] mechanism that will make you more alert
[12:17] early in the day. That said, many people
[12:19] choose to fast in the early morning
[12:21] hours of the day or in the first part of
[12:23] the day. I’m one such person. I
[12:24] generally don’t ingest any food until
[12:27] about 11:00 a.m. or 12:00 noon.
[12:29] Sometimes I’ll have breakfast. If people
[12:30] are meeting for brunch or breakfast, I
[12:32] will have breakfast for social reasons
[12:34] every once in a while, but most of the
[12:35] time I don’t eat until about lunchtime.
[12:38] However, some people are really hungry
[12:40] when they wake up in the morning. Just
[12:41] know that if you eat early in the day,
[12:44] you are further triggering an increase
[12:46] in metabolism and in temperature that
[12:49] will make you more alert. So, you don’t
[12:51] have to eat early in the day, but you
[12:54] can start to see how these different
[12:55] tools layer together. Sunlight viewing,
[12:57] exercise, cold water, eating, many of
[13:00] them are converging on the same
[13:01] mechanisms. In fact, when you drink
[13:02] caffeine, there’s also a small increase
[13:04] in body temperature due to the
[13:05] adrenaline increase that it stimulates.
[13:07] So all of these things can be layered on
[13:09] top of one another or you can use them
[13:11] individually or think about them
[13:12] individually. Now food is an interesting
[13:14] lever or tool because it’s not just
[13:17] about when you eat, but it’s also about
[13:18] what you eat. And I’ve talked a lot
[13:21] about eating for energy and what that
[13:23] means in terms of caloric energy versus
[13:25] neural energy, etc. in previous podcast
[13:27] episodes. We’re not going to focus on
[13:28] that now because that’s very nuanced.
[13:31] All that said, if you eat a very large
[13:33] meal, it doesn’t matter if you slept
[13:36] terrifically well 10 hours the night
[13:38] before or if you are about to go to
[13:40] sleep or if it’s the middle of the
[13:42] afternoon, if your gut is full of food,
[13:44] there’s just a large volume of food in
[13:46] your gut, it’s going to divert a lot of
[13:49] blood and other critical resources away
[13:52] from other organs of your body, in
[13:54] particular your brain, and you’re going
[13:55] to be sleepy after eating a big meal. So
[13:57] this is sort of a duh, but I think
[13:59] oftentimes in the discussions about what
[14:01] to eat for energy, people neglect to
[14:04] consider food volume as a strong
[14:06] parameter or variable in that
[14:08] discussion. So if you eat a huge
[14:10] breakfast, it’s likely that you’re going
[14:11] to be tired immediately after eating
[14:13] that breakfast, unless of course you
[14:14] exercise very hard prior to that and you
[14:17] metabolize all that food very quickly.
[14:18] So if you do decide to eat in the first
[14:20] few hours of the morning, just
[14:21] understand that you are setting or you
[14:23] are helping to set a food entrained as
[14:26] it’s called circadian clock. Light,
[14:30] temperature, timing of food intake,
[14:32] movement, and exercise. All of these
[14:34] things literally funnel in in a neural
[14:38] sense. They funnel into this thing that
[14:40] we call the circadian clock. and they
[14:42] let that clock, that set of neurons,
[14:44] predict when you are likely to be eating
[14:47] and active and viewing sunlight the next
[14:50] day and the next day and the next day.
[14:51] So, what all these tools do is they
[14:53] really set up a cascade. Think of it as
[14:56] kind of a wavefront of wakefulness and
[14:58] focus throughout the day. It’ll take you
[14:59] through the middle of the day in the
[15:01] afternoon stages we’ll talk about in a
[15:02] few minutes, but really they take you to
[15:05] this period that is about 5:00 p.m.
[15:08] until your bedtime. A second critical
[15:10] period in which you need to leverage
[15:12] particular tools in order to get and
[15:14] stay asleep optimally and to be able to
[15:17] sleep through the night. So really,
[15:19] there are three critical periods
[15:20] throughout each 24-hour cycle. And
[15:22] during each of those critical periods,
[15:24] you’re going to want to do as many
[15:26] specific things as you can to optimize
[15:28] your wakefulness and focus and mood
[15:30] throughout the day and your sleep at
[15:32] night. The first critical period is the
[15:34] one that we’ve been talking about up
[15:34] until now. Things like morning sunlight,
[15:36] viewing caffeine, 90 to 120 minutes
[15:38] after waking, exercise, and so on. And
[15:40] it really encompasses the time from
[15:42] which you wake up until about 3 hours
[15:45] after waking. The second critical period
[15:47] is the time throughout the day and
[15:50] afternoon leading into evening. So you
[15:52] may ask, what are the things that you
[15:53] can do throughout the day, the middle of
[15:55] your day and into the afternoon and
[15:56] evening hours that are really going to
[15:58] set you up for the best possible sleep
[15:59] later that night? Well, there are a few
[16:02] dos and there are a few don’ts. First of
[16:04] all, be careful about ingesting too much
[16:06] caffeine throughout the middle of the
[16:08] day. That’s kind of an obvious one for
[16:09] the reasons that we talked about
[16:10] earlier. Second of all, if you are a
[16:12] napper, and I raise my hand now for
[16:14] those of you listening, I’m raising my
[16:15] right hand because I love naps. I’ve
[16:17] always loved naps. Should you nap?
[16:19] Should you not nap? That’s a question
[16:21] that I get asked a lot and that I asked
[16:22] Dr. Matthew Walker when he was a guest
[16:24] on this podcast. Here was his answer.
[16:26] And here’s what the data support. It is
[16:28] fine to nap in the afternoon, but don’t
[16:31] nap so late in the day or for so long
[16:33] that it disrupts your ability to fall
[16:36] and stay asleep at night for your major
[16:38] sleep bout. I should also say you do not
[16:40] have to nap. It’s kind of an interesting
[16:42] phenomenon that happens on these
[16:44] podcasts and on social media where we’ll
[16:46] talk about naps and the fact that naps
[16:47] are great and don’t make them longer
[16:49] than 90 minutes, but then all the
[16:51] non-nappers get really worried like,
[16:53] “Wait, am I supposed to nap? I don’t
[16:54] like naps. I wake up groggy.” You do not
[16:56] have to nap. In fact, if you can make it
[16:58] through your whole day without napping,
[16:59] great. More power to you. So, this
[17:01] critical period throughout the day is
[17:03] one in which most people are doing a lot
[17:04] of stuff. They’re emailing and picking
[17:06] up kids and they’re exercising and
[17:07] they’re commuting and doing all sorts of
[17:09] things, taking phone calls and Zooms,
[17:11] etc. But if you can get that period of
[17:13] deep relaxation through a nap or NSDR,
[17:16] that’s going to serve you well. Try not
[17:18] to drink too much caffeine, certainly no
[17:19] more than 100 milligrams of caffeine
[17:22] after 4 p.m. if your goal is to fall
[17:24] asleep at a reasonably normal time. And
[17:26] for those of you that exercise in the
[17:28] afternoon, understand that if you
[17:31] exercise very intensely, so this might
[17:33] be weight training or running or some
[17:34] other very intense exercise, typically
[17:37] that’s going to further increase your
[17:39] body temperature and it’s going to
[17:40] so-called delay your circadian clock.
[17:43] It’s going to make it such that you want
[17:45] to fall asleep a little bit later, maybe
[17:48] even a lot later. So if you’re
[17:49] exercising in the afternoon or evening
[17:52] and that’s the only time you can
[17:53] exercise or that’s the time that you
[17:54] prefer to exercise, great. Just know
[17:56] that you are delaying your circadian
[17:58] clock, you are making it such that you
[18:00] will naturally want to go to sleep later
[18:02] and wake up later. Contrast that with if
[18:04] you exercise early in the day, say
[18:07] immediately after waking up or in the
[18:09] first 0 to 4 hours after waking. In most
[18:13] cases, that’s not going to shift your
[18:14] circadian clock much. This critical
[18:17] period two or second critical period I
[18:19] should say during the middle of the day
[18:20] is a time in which you should be doing
[18:22] certain things and avoiding doing
[18:23] certain things. So that raises the
[18:24] question of whether or not you should
[18:25] also be getting a lot of light in
[18:27] particular sunlight throughout the day.
[18:28] Now on the face of it you might just
[18:30] think yes you know sunlight’s great
[18:31] provided we’re not getting a sunburn and
[18:33] we’re not staring at the sun and
[18:34] damaging our eyes we should get as much
[18:36] sunlight as we possibly can. However,
[18:39] because light is such a powerful
[18:40] stimulus for controlling the timing of
[18:42] your sleepfulness or sleepiness, I
[18:44] should say, and wakefulness,
[18:47] we might want to be cautious about how
[18:48] much light we are viewing in the
[18:50] afternoon, in particular, in the early
[18:52] evening hours. Well, turns out it’s not
[18:55] so straightforward viewing. So, sunlight
[18:57] to the eyes, sunlight in the late
[18:59] afternoon and evening hours. So again,
[19:01] depends on time of year, depends on
[19:03] location that you happen to be in. But
[19:05] getting some sunlight in your eyes for
[19:06] again maybe 5 or 10, maybe 30 minutes
[19:10] depending on how much cloud cover there
[19:12] is. Doing that in the afternoon serves
[19:14] an additional beneficial purpose, which
[19:17] is you inoculate your nervous system
[19:19] against some of the negative effects of
[19:22] bright artificial light or even dim
[19:24] artificial light in the nighttime hours
[19:28] between 10 p.m. and 4:00 a.m., which is
[19:30] really critical period 3. And we’ll talk
[19:31] about what to do and what to not do
[19:33] during critical period 3 of every
[19:35] 24-hour cycle. But to make it very clear
[19:37] what I’m saying here, get that morning
[19:39] sunlight in your eyes, but also get some
[19:42] sunlight in your eyes in the late
[19:44] afternoon and evening hours when the sun
[19:46] is at so-called low solar angle, when it
[19:47] starts to descend in the sky. Getting
[19:49] that sunlight in your eyes in the late
[19:51] afternoon and evening signals to that
[19:54] clock that it’s evening time and that
[19:57] sleep is coming. It also serves as a
[20:00] second anchor that tells your brain and
[20:02] body, hey, it’s evening. The sun is
[20:04] descending. Those yellows and blues and
[20:07] oranges that you see in the evening
[20:08] sunsets, those signal to your brain and
[20:10] body that evening is there and that
[20:12] nighttime is coming. And they’re really
[20:14] establishing a second reference point or
[20:16] wavefront of biological signals that are
[20:19] going to optimize your nighttime hours
[20:21] and your transition into really terrific
[20:23] sleep. So now let’s talk about what I’m
[20:25] calling critical period three of each
[20:28] 24-hour cycle. So this would be the
[20:29] period of time of late evening. So, it
[20:32] might be 6:00 p.m. for some, depending
[20:34] on when you go to sleep, or 7:00 p.m.
[20:36] extending into the hours in which you
[20:39] decide to get into bed and go to sleep.
[20:41] And then throughout the night, there are
[20:42] a number of things that you’re going to
[20:44] want to do, and there are a number of
[20:45] things that you are going to want to
[20:47] avoid doing in order to optimize your
[20:49] sleep. First of all, you’re going to
[20:51] want to avoid bright artificial lights
[20:54] of any color. Once the sun goes down,
[20:57] you would be wise to try and dim the
[20:59] lights in your indoor environment. If
[21:01] you are going to use light at night, and
[21:03] most people do, I would encourage you to
[21:06] use as little artificial light as is
[21:08] required to carry out the activities you
[21:10] need to require safely. If you’re
[21:12] watching a television show or you’re
[21:14] watching something on your computer, dim
[21:16] that screen way, way down, as dim as
[21:18] possible while still, of course, being
[21:19] able to view what you need to view. That
[21:21] bright light exposure will absolutely
[21:23] quash any melatonin that happens to be
[21:26] circulating in your brain and body. Now,
[21:27] melatonin a lot of people think of as a
[21:29] supplement, but melatonin is naturally
[21:31] released as the evening comes about and
[21:33] into the nighttime hours. It’s a hormone
[21:35] that makes you feel sleepy and allows
[21:37] you to fall asleep. So, viewing bright
[21:39] light in the late evening hours and
[21:41] nighttime hours is really not good for
[21:44] your sleep quality and your ability to
[21:46] fall and stay asleep. So, for most
[21:48] people, a simple rule of thumb is going
[21:50] to be avoid bright artificial lights of
[21:52] all colors and in particular overhead
[21:55] bright artificial lights between the
[21:56] hours of 10 p.m. and 4:00 a.m. Use only
[21:59] as much light as is absolutely necessary
[22:01] in order to carry out the routines and
[22:03] activities you need to carry out safely.
[22:06] Now, that’s light, but as you recall, we
[22:08] also have this tool related to
[22:09] temperature. And you’re probably not
[22:12] going to be surprised that the way to
[22:14] leverage temperature in the evening is
[22:16] the exact opposite of the way that you
[22:17] want to leverage temperature early in
[22:19] the day. Early in the day, temperature
[22:21] increases from cold showers or exercise,
[22:23] etc. wake you up. What that means is
[22:25] that taking a cold shower late at night
[22:27] is probably a bad idea. Rather, taking a
[22:30] nice hot bath or a sauna you might think
[22:32] would heat up your body. And indeed,
[22:34] that’s what happens if you stay in a
[22:35] very long time. But if you do hot tub or
[22:37] a hot bath or a sauna in the evening and
[22:40] you don’t stay in for more than 20 or 30
[22:41] minutes and you get out, you take maybe
[22:43] a coolish shower or a warm shower, then
[22:46] what happens is there’s a compensatory
[22:48] cooling off of your core body
[22:49] temperature for the reasons we discussed
[22:51] earlier and your body temperature will
[22:52] drop by 1 to 3° and it will make it much
[22:55] easier to get into sleep. So if you’re
[22:57] somebody that enjoys hot baths, hot
[22:58] showers or hot tubs, evening and
[23:01] nighttime is going to be the best time
[23:02] to do that if your goal is to facilitate
[23:05] sleep. Similarly, you should try and
[23:07] make your sleeping environment pretty
[23:08] cool, if not cold. Now, that doesn’t
[23:10] mean you need to be cold while you’re
[23:12] asleep. You can get under as many
[23:14] blankets as you need, but it’s a good
[23:15] idea to make your sleeping environment
[23:17] cool. In fact, drop the temperature in
[23:19] that sleeping environment by at least
[23:20] 3°. You’ll be happy that you did. You’re
[23:23] going to want to sleep in a relatively
[23:24] cool or cold sleeping environment and
[23:26] then layer on the blankets as needed to
[23:29] stay asleep. If you lower the
[23:31] temperature in your sleeping
[23:32] environment, so lower the temperature in
[23:33] that room or use a controllable mattress
[23:36] cover that can cool down like eight or
[23:38] something of that sort, it’s naturally
[23:39] going to make your sleeping environment
[23:41] cooler. And if you’re too warm under the
[23:44] blankets, all you have to do is extend a
[23:45] hand or a foot out from under those
[23:47] blankets. Whereas, if the sleeping
[23:49] environment that you’re in is too warm,
[23:50] there’s very little you can do to cool
[23:52] off besides push off those blankets. But
[23:54] if the room is too warm, well, what are
[23:56] you going to do? You’d probably have to
[23:57] put your hands into some cool water,
[23:58] take a coolish shower or something for a
[24:01] couple of seconds. That’s not very
[24:02] practical. I would be remiss if I didn’t
[24:04] touch on alcohol and CBD and THC. Many
[24:08] places, but not all. THC is illegal,
[24:11] although there are medical uses and some
[24:13] places it’s um decriminalized. Other
[24:15] places it’s legal. Alcohol, of course,
[24:17] is consumed almost as frequently as
[24:20] caffeine is consumed. The sleep that one
[24:22] gets after drinking alcohol is greatly
[24:25] disrupted sleep. THC and alcohol do help
[24:29] some people fall asleep and maybe even
[24:32] stay asleep. The architecture of that
[24:33] sleep is suboptimal compared to the
[24:36] sleep they would get without alcohol or
[24:38] THC in their system. So, I’m not here to
[24:40] tell you what to do or not to do. I’m
[24:42] certainly not um the substance police.
[24:45] That’s not my role. I’m just reporting
[24:46] to you the biology. If your sleep is not
[24:49] restoring you to the extent that you
[24:51] feel it should or if you are regularly
[24:53] relying on a drink or two in order to
[24:56] fall asleep or THC in order to fall
[24:58] asleep that is disrupting your total
[25:01] pattern of sleep. Okay? So you’ve done
[25:03] everything correctly up until now. You
[25:05] got your morning routine from critical
[25:06] period one. You got your afternoon
[25:08] routine. You saw some sunlight in the
[25:10] afternoon. You avoided caffeine in the
[25:12] eight hours or 10 hours before bedtime.
[25:14] You’re not drinking alcohol. you’ve
[25:16] cooled down the room, uh you’re doing
[25:18] all these things right, you’ve dim the
[25:19] lights, etc., etc. What else can we do
[25:22] in order to optimize our sleep? I always
[25:24] say behavioral tools first, then look to
[25:28] nutrition, then if necessary, look to
[25:30] supplementation, and then if still
[25:32] necessary, look to prescription drugs,
[25:35] obviously prescribed by a
[25:37] board-certified physician. There are
[25:38] supplements that for most people will
[25:40] greatly improve their ability to fall
[25:43] and stay asleep. And the three main
[25:45] supplements in that category or that kit
[25:48] of sleep supplements, and I’ve talked
[25:50] about these before, are magnesium
[25:52] thriionate. So, T h reo n a t e,
[25:57] apagenine, api g- e n i n, and theonine.
[26:01] T h e a n i n e. Theonine. You don’t
[26:04] necessarily need to take all three.
[26:06] Although many people get a synergistic
[26:08] effect from taking all three. You may
[26:09] not even need to take even one. What I
[26:12] recommend is that if you’re already
[26:14] doing all the behavioral tools regularly
[26:16] and you’re still having trouble falling
[26:18] asleep and staying asleep, well then you
[26:21] might try one of the supplements within
[26:24] this sleep stack. They do have fairly
[26:26] wide margins for safety. Although I
[26:27] should also say anytime you’re going to
[26:30] add or remove something from your
[26:32] supplement protocol, your nutritional
[26:33] program, you definitely want to talk to
[26:35] your physician. I don’t just say that to
[26:36] protect us. I say that to protect you.
[26:38] For most people, the margins of safety
[26:39] on these things are going to be pretty
[26:40] broad. For some people, the dosages of
[26:42] any one or several of the supplements I
[26:44] mentioned will be zero. That is, you
[26:46] won’t need them in order to get and stay
[26:48] asleep most nights of your life. For
[26:50] many people, however, taking 145
[26:53] milligrams of magnesium 3en8ate can be
[26:56] very beneficial. Some people need to go
[26:58] a little higher. Some people need to go
[26:59] a little bit lower. 50 milligrams of
[27:02] apagenine. And again, you could just
[27:04] take the apagenine on its own. And 100
[27:07] to 400 millig of theanine taken again
[27:11] alone or in combination with the other
[27:13] supplements mentioned in this stack many
[27:15] people find allows them to get really
[27:17] drowsy and fall asleep sleep really
[27:19] deeply and they feel much more refreshed
[27:21] the next day and they don’t have a
[27:22] groggginess. About 5% of people report
[27:26] that magnesium 3 and8 really disrupts
[27:29] their gut. It gives them diarrhea or
[27:31] gastric distress in which case don’t
[27:32] take it. Now in a slightly different
[27:34] way, many people who can tolerate
[27:37] magnesium 3 and8 or really thrive on
[27:39] magnesium 3 and8 and like epigenine
[27:42] might find that theanine even at the
[27:45] lowest dose of 100 milligrams because
[27:46] again the range is 100 to 400 milligrams
[27:48] that theanine gives them such vivid
[27:51] dreams that they actually find it
[27:52] disruptive or they wake up and in the
[27:54] middle of the night or they find that
[27:55] the sleep that they’re getting is kind
[27:56] of anxietyridden because of the
[27:58] intensity of those dreams. So some
[28:00] people might choose to leave theanine
[28:01] out of the sleep stack and just take
[28:03] magnesium 3in8 or rapenine. Again, some
[28:05] people might leave magnesium 3 and8ate
[28:07] out of the sleep stack. All of this is
[28:09] really about finding the supplementation
[28:11] protocol that’s ideal for you. I should
[28:13] mention that whether or not you’re
[28:14] taking one or two or three of the
[28:16] components of the sleep stack. The ideal
[28:18] time to take those is 30 to 60 minutes
[28:20] before bedtime. That sleep stack can be
[28:22] very beneficial to people. And I do
[28:24] think that it’s preferable to melatonin.
[28:26] First of all, melatonin is a hormone
[28:28] that you indogenously make. The dosages
[28:30] of melatonin that are contained in most
[28:32] commercial products is far far far
[28:34] greater than what we would make
[28:35] indogenously. So, it’s really supra
[28:38] physiological. So, that’s of concern
[28:40] because melatonin is not just
[28:41] responsible for making us sleepy and
[28:44] fall asleep. It also does things like
[28:47] interacts with other hormone systems,
[28:49] testosterone and estrogen, even in the
[28:50] puberty system in kids. Is taking
[28:52] melatonin every once in a while a
[28:54] problem for adjusting to jet lag, etc.?
[28:56] Probably not. I would even say no. But
[28:58] taking it chronically over time,
[29:00] especially kids taking it chronically
[29:02] over time, can potentially be
[29:03] problematic. I do want to mention a
[29:05] couple of broad contour tools that will
[29:08] impact your ability to sleep really well
[29:11] on a consistent basis. And the one that
[29:13] impacts the most number of people is
[29:15] weekends. Turns out that most everybody
[29:18] feels the impulse to sleep in on the
[29:20] weekend, especially if they’ve been out
[29:21] late the night before. However, the data
[29:24] show that keeping relatively consistent
[29:27] sleep and wake times is really going to
[29:29] enhance the quality and depth of your
[29:31] sleep. So, if you stay out late one
[29:32] night, sure, you might allow yourself to
[29:35] sleep in an extra hour or so, but you
[29:37] should really try to avoid sleeping in
[29:39] longer than an hour beyond your normal
[29:43] wake up time. it would be better to wake
[29:44] up at a consistent time plus or minus an
[29:46] hour and get a nap in the afternoon
[29:48] provided that nap again isn’t too long.
[29:51] Now, a couple of final points and
[29:52] additional tools that I think are going
[29:54] to be useful to everybody in particular
[29:56] people who have young children or are
[29:59] following a shift work schedule or who
[30:02] are experiencing jet lag. Keep in mind
[30:05] jet lag can be due to travel, which is
[30:07] obvious, but jet lag can also be due to
[30:10] getting woken up in the middle of the
[30:11] night, right? Your body doesn’t know the
[30:12] difference between flying to a new time
[30:14] zone and getting woken up in the middle
[30:16] of the night. The tool that I’d like to
[30:18] offer you is an understanding of
[30:19] something called temperature minimum.
[30:21] And I’m going to make this as simple as
[30:23] possible, and I’m confident that
[30:24] everyone can understand this, even if
[30:25] you don’t have any science background.
[30:27] Here’s the question you need to ask
[30:28] yourself. What is your typical wake up
[30:32] time? If your typical wake up time most
[30:34] days is 7 a.m., well, then your
[30:37] temperature minimum is 5:00 a.m. That’s
[30:39] right. Your temperature minimum is not a
[30:41] temperature. It’s a time within your
[30:43] 24-hour cycle. Approximately 2 hours
[30:46] before your typical wake up time, your
[30:48] body is at its lowest temperature that
[30:50] it will ever be in the 24-hour cycle.
[30:53] That’s why it’s called your temperature
[30:54] minimum. Here’s what you need to know
[30:56] about your temperature minimum. If you
[30:58] view bright light, exercise or drink
[31:02] caffeine or all of the above in the two
[31:05] to four hours before your temperature
[31:08] minimum, that will delay your clock.
[31:11] What that means when I say delay your
[31:13] clock is it will make you want to go to
[31:15] sleep later and wake up later the next
[31:18] night. Okay, so let’s run this exercise
[31:20] for you, the person waking up at 7 a.m.
[31:22] on a regular basis. I can predict with
[31:25] almost certainty that your body is going
[31:27] to be at its lowest temperature at 5:00
[31:30] a.m. So, what that means is that if you
[31:32] get up at 3:00 a.m. or at 4:00 a.m. and
[31:36] you flip on bright lights in your house
[31:38] or in your bathroom or you have a cup of
[31:40] coffee or you do any kind of exercise or
[31:42] you get up and head to the airport, the
[31:45] mechanisms in your brain and body that
[31:47] control timing of sleep and timing of
[31:49] waking will shift. They will delay. It’s
[31:51] as if you put your clock on hold for a
[31:54] little while and then let it start
[31:55] again. Okay, that’s the simplest way I
[31:57] can describe it. And you will tend to
[31:58] want to go to sleep later and wake up
[32:01] later the following night. Now, the
[32:04] opposite is true if you view bright
[32:07] light, drink caffeine, or exercise or
[32:10] socialize, I should say, in the hours
[32:13] immediately after your temperature
[32:15] minimum. So for you in this example, the
[32:17] person who’s waking up at 7:00 a.m.,
[32:19] your temperature minimum is 5:00 a.m. If
[32:21] you view bright light, exercise, maybe
[32:23] have a snack, maybe not, or socialize,
[32:26] move about at 5:30 or 6:00 a.m. or 7:00
[32:30] a.m., that will tend to phase advance
[32:33] your clock. It will tend to basically
[32:36] make you want to go to bed earlier and
[32:38] wake up earlier the following night.
[32:39] Now, I use this example of a person who
[32:41] wakes up typically at 7:00 a.m. whose
[32:43] temperature minimum is 5:00 a.m. But of
[32:45] course, you need to adjust that for
[32:47] yourself if you’re somebody who wakes up
[32:48] at 9:00 a.m. or at 5:00 a.m., etc. Why
[32:50] do I offer this as a tool? Well, this is
[32:52] an immensely powerful tool if, for
[32:54] instance, you are headed to a time zone
[32:56] where you need to go to bed earlier and
[32:58] wake up earlier once you arrive in that
[33:00] time zone. What it means is in the day
[33:01] or two before you leave, you can force
[33:04] yourself to exercise, drink caffeine,
[33:08] maybe even to eat a meal early in the
[33:10] morning, or maybe you still fast early
[33:11] in the morning. That’s really up to you.
[33:13] But you force yourself to do the act the
[33:15] activities that are going to phase
[33:17] advance your clock. Whereas, if you’re
[33:19] traveling to a time zone where you are
[33:21] going to need to go to sleep much later
[33:23] and you’re going to need to wake up much
[33:26] later, even a little bit later, you can
[33:28] do those things in the hours prior to
[33:30] your temperature minimum. And I should
[33:33] say for everybody, people who are doing
[33:35] jet who are jetlagged and engaged in
[33:38] shift work or not, but just for
[33:39] everybody, if you need to be awake in
[33:42] the middle of your sleep cycle, you
[33:43] know, you’re feeding a baby or you’re um
[33:46] you’re taking care of a loved one or you
[33:47] need to do something that’s critical or
[33:48] you need to work, use red light. Okay.
[33:51] Now, for shift workers who really are
[33:53] trying to stay awake all night and sleep
[33:55] all day, this is not going to be ideal.
[33:57] But for people that for instance need to
[33:59] stay up really late one night or wake up
[34:01] especially early like 3:00 a.m. to
[34:02] prepare for an exam that you’re just not
[34:04] ready for or to head to the airport etc.
[34:07] Using red light has been shown to allow
[34:10] people to be awake enough that and
[34:11] obviously see what they need to see in
[34:13] order to perform their activities safely
[34:15] but it does not seem to disrupt the
[34:17] cortisol rhythm that is the healthy
[34:20] normal cortisol rhythm. Okay. So, that’s
[34:22] a lot of information and a lot of tools,
[34:24] and I really want to encourage everybody
[34:25] to get your behaviors right, get your
[34:27] nutrition right for you. I promise that
[34:29] if you start to implement some or
[34:31] ideally all of these tools, the quality
[34:34] of your sleep will increase
[34:35] tremendously. And of course, in doing
[34:38] so, the quality of your daytime
[34:39] alertness and your ability to focus will
[34:41] improve tremendously. Again, sleep is
[34:44] the absolute foundation of your mental
[34:47] health, your physical health, and your
[34:48] performance in all endeavors. And last,
[34:51] but certainly not least, thank you for
[34:53] your interest in science.
[34:55] [music]