Transcript: Diary Of A CEO Interview w/ Neuroscientist Andrew Huberman

How do they test this?

ANDREW HUBERMAN: (00:07:05 – 00:07:20) This healthy curve, as it’s called, was measured through just consistent blood draws around the 24-hour cycle. And then it’s been looked at in response to everything from caffeine to cold plunges to exercise to sunlight. And there’s this very— so protocol number 1 is hydrate.

STEVEN BARTLETT: (00:07:21 – 00:07:21) Okay.

Protocol 1: Hydrate

ANDREW HUBERMAN: (00:07:21 – 00:07:52) Your mind is exceedingly more sharp when you’re well hydrated, and it actually helps boost your morning cortisol. There’s a very interesting interaction between the bladder being emptied — usually after people wake up, they use the restroom, they urinate, and then hydrating. There’s an ascending pathway along the vagus nerve that serves to wake up the brain, and I’ll talk about this a few times. Part of that has to do with hydration first thing in the morning. You wake from bed to urinate in the middle of the night because of an arousal phenomenon of hydration and the bladder being full.

STEVEN BARTLETT: (00:07:52 – 00:07:55) When you say hydrate, do you mean electrolytes or just water?

ANDREW HUBERMAN: (00:07:55 – 00:07:59) 16 to 32 ounces of good clean water is fine. If you want to add electrolytes, great.

STEVEN BARTLETT: (00:08:00 – 00:08:01) How much is that? Is that a cup or is that—

ANDREW HUBERMAN: (00:08:02 – 00:08:04) This is 16 ounces, maybe 18 ounces.

STEVEN BARTLETT: (00:08:04 – 00:08:05) Okay. So like a big mug.

Protocol 2: Sunlight or Bright Light

ANDREW HUBERMAN: (00:08:05 – 00:12:17) Yeah. You want to consume about 80 ounces of water throughout your day. It’s a lot, but basically everything you want to do in the early part of the day, you want to do less in the evening part of your day.

The next thing, and this is really key, it could have gone first, but you want to view sunlight or a 10,000 lux artificial light. I could spend 3 hours talking about this, but I’ll keep it really brief. When you view sunlight, there’s this beautiful phenomenon. It activates these melanopsin intrinsically photosensitive ganglion cells, the major focus of my work for many, many years, so I’ll resist saying more. They literally extend physical wires that we call axons into your hypothalamus. Your master circadian clock resides there. We call that your suprachiasmatic nucleus.

And when you view low solar angle sunlight — sun low in the sky — there’s an abundance of, yes, UV, but it’s lower when it’s low in the sky. You actually can look at the morning sun more easily than you can the overhead sun. Why? The morning sun looks more yellow, orange, or even some red tones. Compared to the overhead sky, well, the light coming from the sky is the same, right? But the specific wavelengths of light, as we call them, that are coming from the sun when it’s low in the sky are the optimal stimulus for these melanopsin intrinsically photosensitive cells that tell your central clock it’s time to wake up. The day is beginning.

There’s also something incredible that happens if you get bright light in your eyes in that first, ideally 30 minutes, but even 60 minutes of your day. There are 2 pathways by which your brain circadian clock wakes you up. One is it sends signals through peptides it releases and neural signals, but it’s able to activate what we call the HPA axis, hypothalamus pituitary gland, which sort of hangs outside the brain, and then adrenals — you release adrenaline. There’s a unique window that passes after about an hour following waking where your suprachiasmatic clock can trigger an alternate pathway that literally goes down your spinal column and triggers your adrenals to release additional cortisol.

In fact, viewing sunlight in the first hour of your day takes this peak higher. Here’s what it would look like if you didn’t view bright light in the first hour of your day — it would be lower, which is bad, and your stress responses then would be bigger and longer. This increase in cortisol is driven by viewing sunlight.

Now, when I say sunlight, people say, especially in the UK, “there’s no sun where I live.” Okay, this could easily say daylight. Why? Because there’s always daylight out. If you look at how bright it is on an overcast day in the middle of December, even in the UK, at 8:00 AM versus midnight the night before, it’s different. It’s obvious when there’s overcast skies, less of the long wavelength light, the oranges and reds are coming through. But you want daylight in your eyes in the first hours of your day. Go out on your balcony if that’s all you can do. If you’re in a car, roll down the window. It’s not good to try and do this through a window or windshield.

There’s so much data showing that spiking your morning cortisol this way establishes low cortisol and high sleepiness hormones at night, which is great, buffers stress, and moreover kickstarts your immune system to protect you against bacteria and viruses you can encounter during the day. It is great for your metabolism, mood, ability to learn, and on and on. And in the book, I explain a number of different ways how this peak relates to this trough if people are interested.

If you don’t have access to sunlight or daylight, using a 10,000-lux artificial light can be very beneficial. These 10,000-lux lights have been shown to significantly offset the symptoms of seasonal affective disorder, et cetera. But what we’re finding from this huge study from the UK Biobank is that you want bright days and you want dark nights, and they’re additive. Having bright days is great for your mental health and physical health along a huge number of parameters, significantly improves them. But having dark nights, even if you were in dim light all day, people are healthier if it’s dark at night. The risk of dying early if you have bright nights goes up immensely, and we don’t talk about this enough. If you don’t have access to enough daylight — like you wake up before the sun comes out and you’re up for 2 hours, let’s say, before the sun comes out — I highly recommend getting a 10,000 lux artificial light.

STEVEN BARTLETT: (00:12:17 – 00:12:21) And last time we spoke, you took me outside after the conversation and you had an app on your phone.

ANDREW HUBERMAN: (00:12:21 – 00:12:24) Right, a light meter. I have no relation to the app, but I use it.

STEVEN BARTLETT: (00:12:24 – 00:12:27) And that is able to tell you how much lux of light you’re getting at the moment.

ANDREW HUBERMAN: (00:12:27 – 00:13:36) Yes, but it’s additive. So one thing that’s important to note is let’s say you miss a day, right? The next day, get outside for twice as long. How long should you do it? On a very clear morning with the sun rising. And by the way, you don’t need to see the sun cross the horizon. You can just wait till it’s elevated, but it’s low in the sky. People who are concerned about UV damage should know that when the sun is low in the sky, the UV index is much lower, and there’s a reason for that. It’s a phenomenon called Rayleigh scattering. Sunrises and sunsets are very beautiful and colorful. When the sun’s overhead, it’s hard to look at, it’s this big ball of light, it’s so bright because you’re getting all the wavelengths, the UV all the way out to the infrared, coming at you in more or less equal intensities. When the sun is low in the sky, the UV is not completely scattered, but not as much of that is reaching your eyes. Much lower risk of sunburn, much lower risk of eye damage, and so on.

So here’s the diabolical thing. Your screens are not nearly bright enough to kickstart this increase in cortisol in the morning, but they are very capable of increasing your cortisol levels at night, because this low level of cortisol makes you vulnerable to big increases in cortisol.

STEVEN BARTLETT: (00:13:36 – 00:13:44) It’s a little bit of a detail that you explain in the book, but I was going to say on this point, is it just exposing my eyes to the light or does my body need to be exposed to it?

Light on Skin and Blood Sugar

ANDREW HUBERMAN: (00:13:44 – 00:14:46) Great point. And one of the protocols in there, it’s not one of the 10 I listed, is about the importance of getting sunlight on as much of your skin as possible, as is socially appropriate. Beautiful work from Glen Jeffery’s lab at University College London. You know, I can believe this. They do a glucose tolerance test — they fast people, they have them drink a glucose drink, they measure how fast blood sugar rises. And if they shine red light — so long wavelength is red, this would be medium wavelength because it’s yellow, red would be, I’m guessing, somewhere between 500 and 600 nanometers of light — actually, red would be probably somewhere between 580 and 700, and then infrared goes out further into the 800s and 1,000s. The sun emits all of those. So this is long wavelength light.

They shine long wavelength light on people’s backs and they do the glucose tolerance test, and they observe a more than 25% reduction in the peak. And they also look at the rate of rise of blood glucose. It’s buffering blood glucose rise, which we know is a good thing.

STEVEN BARTLETT: (00:14:46 – 00:14:51) Just to summarize, they shine red light on someone’s back while they have a glucose shot and their glucose spike is lower.

ANDREW HUBERMAN: (00:14:51 – 00:17:57) That’s right. And you can do this onto bare skin or you can do it through a t-shirt. Turns out that these people’s metabolism rose significantly. Why? How? Well, long wavelength light can actually go into and through your body. It gets absorbed and it can go about 8 centimeters into the body. Red light, long wavelength light of infrared, can pass all the way through the body. They show that beautifully in this study.

So that’s not good? No, it’s fantastic, because along the way it makes conformational changes in the way that your mitochondria handle the electrons. Basically, this long wavelength infrared light that comes from the sun — it’s the heat that you feel from the sun or from a long wavelength light device — allows your mitochondria to function more effectively, more efficiently.

Now, it’s not to say that short wavelength light, blues and greens and ultraviolet light, are bad. We need ultraviolet light. We need it on our skin to make vitamin D. What you want is full spectrum balanced light, but not so much UV that you get a sunburn, and you don’t want a lot of short wavelength light in the absence of long wavelength light. Best way to do that: sunlight in the early and later part of the day, because the UV index is low. You’re getting the full spectrum. Indoor LED lights like this, which we all spend a lot of time under, there’s now evidence from Glen Jeffery’s lab and others that it actually may damage the mitochondria.

We talked about melatonin coming from the pineal gland that makes you sleepy at night. You also have melatonin in most all of the cells of your body, and there it doesn’t make you sleepy — it serves as an antioxidant, but it’s sort of captured, and the way to liberate it is through long wavelength light. So you have a protective mechanism that’s kicked on with long wavelength light that protects you against the oxidative stress and damage to cells, and this has many, many positive effects.

Glen’s lab has done experiments where they literally take a light like this and have people look at it for 1 to 3 minutes, a couple times a week. They look at people, different ages, different eye conditions. He’s a serious vision scientist — he’s not a biohacker, he has no interest in commercial products, although sometimes I wish he did. People over 40 who experience age-related vision loss — we all do a little bit — experience improvements in vision when they do this simple thing. And why would that be? Well, it turns out that your photoreceptors, which absorb light and convert it into electrical signals that allow you to see, are the most mitochondrial-rich and metabolically active cells in your entire body.

Now, biologists love to play this game where they go, “your tongue is the most metabolically active,” then someone else makes a different claim. The photoreceptors, my friends, are the most metabolically active cells in your entire body. So they have a ton of mitochondria, and they need to protect themselves against the oxidative damage that comes with generating a bunch of downstream products from ATP. So long wavelength light is what protects them. You can see significant improvements in vision for people that view long wavelength light a couple times a week, but only in people older than 40. And get this, only in people that do that in the first 3 hours of their day.

STEVEN BARTLETT: (00:17:58 – 00:17:58) What?

ANDREW HUBERMAN: (00:17:59 – 00:19:09) Yes. Your eyes and your body and brain are not the same in this first third of your day versus this middle third of your day versus the last third of your day. And at night, they’re not. Your sensitivity to bright light causing bad effects on you after sundown increases — not immediately, but it increases gradually. Your need for bright light in your eyes in the early part of the day is immense. You need this, you want this. And if you miss a day, get out the next day and view some more light.

You asked, will light to other parts of the body work? Not for setting this system in motion, but it’s a great idea to get out 2 to 3 times per week when the UV index is low. You can just look on your phone, what’s the UV index. In general, be out in the earlier or the later half of your day when the UV index is lower, and get some light onto your skin. You don’t have to be naked or in a swimsuit — great if you are and that’s appropriate, but you can also just wear a t-shirt because the long wavelength light will go all the way through. So Glen Jeffery and Roger Seheult — he’s a physician who talks about the immense benefits of getting sunlight onto the skin for getting over disease, for enhancing immune system function, and on and on.

STEVEN BARTLETT: (00:19:10 – 00:19:13) There’s going to be a lot of people right now thinking, I’m not going to go buy a red light lamp.

ANDREW HUBERMAN: (00:19:13 – 00:19:14) Not necessary.

STEVEN BARTLETT: (00:19:14 – 00:19:15) Not necessary.

ANDREW HUBERMAN: (00:19:15 – 00:21:13) No — sunlight. Pink Floyd album. Pass sunlight through a prism, it bends the light and you see the rainbow: red, orange, yellow, green, blue, indigo, violet. But also in that sunlight is ultraviolet light. Some UVB exposure each day to the skin increases testosterone and estrogen in both women and men and is important for libido. It actually reinforces romantic relationships for reasons other than sexual interactions, attractiveness, et cetera — strong effects. So sunlight has it all. What you don’t want is to go outside when there’s so much UV that you get a sunburn. And you don’t want to think that red light’s the only light you need. You want that warmth from the sun.

And it gets better, because — and notice I’m sort of like, it gets better like a salesman, I’m selling nature — when you go outside and there’s a lot of greenery, greenery reflects long wavelength red and infrared light. Throw on some infrared goggles and you’re not going to do this, but you’d look and all that stuff would be glowing white in those goggles. Greenery reflects down infrared light. How do you know it reflects light? I’m stealing Roger’s words as I say this, but where’s the coolest place to be on a hot day? Under a tree. Why is that? Because it’s reflecting the heat, the infrared light. But when you’re out in greenery, you’re getting all that long wavelength light and it bounces around and it goes through you.

So get out into nature, walk outside. If you work and live in a city, get outside, take off a brimmed hat because you do want the sun getting down onto your face. People are so terrified about accelerating aging based on UV, but we’re not talking about baking yourself in UV light all day. The health benefits of this are immense. There’s a Swedish study that actually showed that the more sunlight people got, the longer they lived. In fact, smokers who got a lot of sunlight — this isn’t my favorite study, but we have to admit it’s there — lived longer than nonsmokers who didn’t get enough sunlight. And there are other things too, like exercise, et cetera. But don’t smoke — but get sunlight.

Night Shift Workers and Evening Light

STEVEN BARTLETT: (00:21:14 – 00:21:15) There’ll be a lot of night shift workers listening.

ANDREW HUBERMAN: (00:21:16 – 00:22:18) I have a section specifically for night shift workers, because here are the 2 scariest things: night shift workers live shorter lives, cancer rates go up, they’re metabolically unhealthy, and it’s very hard to mitigate. But I provide some tools specifically for night shift workers and for jet lag, by the way, because people travel.

Here’s the really scary thing. You and I qualify as night shift workers, because the studies on night shift work, barring some of the more extreme ones — most of them were on how many people after 6:00 PM are on devices getting artificial LED exposure or doing activities besides eating and socializing with their family or in bed. If you work at night at home, you’re still a night shift worker. You don’t have to work all night to be a night shift worker. So we have a generation of kids that are metabolically sick, and I don’t like to be one of these fearmonger people, but here’s the cool thing. I’m going to skip to number 6.

STEVEN BARTLETT: (00:22:18 – 00:22:18) Okay.

Protocol 6: Evening Light — the “Netflix Inoculation”

ANDREW HUBERMAN: (00:22:18 – 00:23:42) Okay. As the sun is going down, you don’t have to watch the sunset — that would be cool to watch, everyone loves sunsets — but try and get some daylight in your eyes in the late afternoon or evening if you’re going to be working indoors from after lunch until nightfall. Try and get near a window. Do your best. Go out on a balcony. Take a quick walk around the building. Do what you can to get some sunlight in your eyes without sunglasses.

When you get some sunlight in your eyes in the late part of your day — let’s just say in the last third of your day, and the clock times don’t matter here because we all get up and go to sleep at different times — you buffer those cells in your eye against the negative effects of artificial light at night. This is your Netflix inoculation, as I call it. You can be on your computer at 9 or 10 at night without it damaging your melatonin levels quite as much, without it disrupting your blood glucose levels and your sleep, if you get some bright light in your eyes in the later part of your day.

But there’s one population of people for whom this doesn’t work, and it seems to be adolescents. You can’t buffer them against the negative effects of screen light at night. What happens if you view screen light at night? You get big bumps in cortisol. And people say, well, I can fall asleep just fine after being on my iPad or screen — true, some people don’t have as much of a negative effect from blue light at night, but the blood glucose effects and the next morning cortisol effects are the problem. Remember I said high cortisol sets you up for low cortisol?

STEVEN BARTLETT: (00:23:42 – 00:23:42) Yeah.

ANDREW HUBERMAN: (00:23:43 – 00:24:20) Low cortisol sets you up for high cortisol. So you’ve got a population of people, kids, whose cortisol is slightly but significantly higher in the evening and at night because they’re on devices, and the next morning their cortisol levels are struggling to get up. This is a tough one because teens socialize that way and you don’t want to take their phones away, and they cling to their iPads like my new bulldog Strummer clings to a chew toy — you take it away from them and they hate you for it. So I said view daylight, because you can’t always see the sun, but even if it’s overcast, just get out for a few minutes and take a walk. Your sleep will be better. I feel like I’m giving a lecture in class.

STEVEN BARTLETT: (00:24:20 – 00:24:21) That’s amazing.

Protocol 3: Exercise Early

ANDREW HUBERMAN: (00:24:21 – 00:24:37) Okay, so we said hydrate, sunlight. And then number 3 — I know everyone’s heard it, but if you can exercise in the first 3 to 4 hours of your day — you could do it in the afternoon without problem, but there’s a huge advantage to doing cardiovascular resistance training in the first 3 hours of your day.

STEVEN BARTLETT: (00:24:37 – 00:24:39) Cardiovascular or resistance training?

ANDREW HUBERMAN: (00:24:39 – 00:25:43) Yeah. In the book, I devote an entire chapter, chapter 2, to exercise, and I explain what I think personally is the best way to structure an exercise program for somebody who doesn’t want to be the most jacked, but wants muscle and definition and strength. Somebody that doesn’t need to run a marathon for a record time but wants endurance. Somebody who wants to be able to sprint reasonably fast and has middle distance ability too.

It’s basically structured, you either lift or do cardio on alternating days. 3 days total of lifting, warm-up, reasonably low volume of work sets, 2 to 3 work sets per exercise, emphasizing compound movements. So not a preacher curl or a tricep kickback — those are fine, but you’re going to get a lot more bang for your buck if you’re doing pull-ups, rows, dips, multiple presses at once, multiple joints moving at once as a compound exercise. Some hip hinge movement, so it could be squat, hack squat, some deadlifts. And I talk about how to get specific aesthetic effects in there too. I’m by no means an exercise physiologist, but I’ve been resistance training since I was 16. I’m now 50, I’ll be 51 in a month, so I feel great.

STEVEN BARTLETT: (00:25:43 – 00:25:46) Cardio at the start if you’re doing resistance training, or not at all?

ANDREW HUBERMAN: (00:25:46 – 00:28:03) I warm up for 5 minutes of cardio and then resistance train. But I do the cardio on alternate days, 3 days total of cardio. 1 day of cardio is long and slow for about an hour. 1 is about 30 minutes at moderate intensity. 1 is a short one, like I did this morning — jumped on the AirDyne bike, pedal easy for a minute, then go all out for 30 seconds, easy for 10, 30, 10, 30, 10, 30, 10, and then you’re off the bike. Basically max heart rate training. And the day after leg day, if you do your legs right, take a rest day.

Here’s the interesting thing about exercise — you’ll notice I didn’t say deliberate cold exposure. You want to blow some minds? I will go toe to toe with anybody on the internet or off the internet: deliberate cold exposure does not raise cortisol this much. It’s amazing to me that the same people that are suggesting moderate to high-intensity exercise are saying that deliberate cold exposure raises cortisol. It’s simply not true — not true for women either. A lot of people asked, is your book going to be for women and men? I distinguish between data. When there are data showing that it’s different for women and men, I acknowledge it. When there’s no data in women, I acknowledge that too. And the data are very clear in women and men: trivial increases in cortisol, magnificent, huge increases in adrenaline, norepinephrine, and dopamine from deliberate cold exposure. And those so-called catecholamines are great to have rolling into your day — they’re the things of alertness and focus.

The appropriate stressor for cortisol — appropriate meaning the one that you want — is a psychological stressor. We know that: working out with weights for 45 minutes, taking your sets near to failure, going for a run for 30 minutes. So the point being, if you do this exercise in the first 3 hours of your day, you’re getting a big inflection in cortisol — again, this is what you want.

Now, some people can’t exercise first thing in the day. They either don’t want to or they can’t by way of schedule. And if you go into exercise in the later part of your day, that’s fine. Your cortisol will come back down. You can do some long exhale breathing to slow your heart rate — Andy Galpin talks about that. Take a hot shower, which paradoxically lowers your core body temperature and then helps you sleep. When you heat up the surface of your body, you have a thermostat in your brain called the medial preoptic area, and it goes, “the surface of my body is warm, I should probably cool my core body temperature down,” and you fall asleep better. This is like the putting-socks-on effect or the hot bath effect.

STEVEN BARTLETT: (00:28:03 – 00:28:05) I assume a massage or something like that also.

ANDREW HUBERMAN: (00:28:05 – 00:28:10) Great. You have access to that in the last hour of your day? We need to learn more about your life.

STEVEN BARTLETT: (00:28:11 – 00:28:14) My fiancée used to be a masseuse for many years, so she—

ANDREW HUBERMAN: (00:28:14 – 00:29:08) Awesome. So when you exercise for a few days early in the first 3 hours of your day, let’s say you do that 2 times, the next morning you wake up feeling a little bit more willing to exercise. Did your willpower change? Well, in some sense, yes, but what happened was your cortisol entrainment mechanisms changed. Your suprachiasmatic nucleus all day is clocking what you’re doing. Let’s say you eat at 9, 12, snack at 3 and 6:30 — you have a food anticipatory signal. Ghrelin is secreted, makes you hungry. We are clocks, and the synchronization of those clocks is very, very important. When you exercise at roughly the same time of day, early in the day, you will have more energy to exercise. In the first 15 minutes before that, you’ll notice you kind of start stirring around. Yes, part of it is cognitive, but a lot of it actually is your brain anticipating exercise is coming. That’s why I teach neuroanatomy — this is fun.

The Anterior Midcingulate Cortex

STEVEN BARTLETT: (00:29:09 – 00:29:14) I have a brain here in front of me. It does open up in case you want to open it up. But you just reminded me of something.

ANDREW HUBERMAN: (00:29:14 – 00:29:14) Yeah.

STEVEN BARTLETT: (00:29:15 – 00:29:25) You reminded me of something that I saw you talk about, which was the anterior midcingulate cortex. And I think you described this as being one of the most interesting discoveries of neuroscience.

ANDREW HUBERMAN: (00:29:26 – 00:30:54) So cingulate cortex — I mean, it’s not directly exposed here, but the anterior midcingulate cortex would sit somewhere like there. This is an amazing structure. Just to remind people, when we feel some sort of pressure — social pressure, physical pressure, traffic that we hate — and we decide, “I’m going to lean into this, I’m going to compete, I’m going to push through this internal or external resistance,” neurons in the anterior midcingulate cortex are just firing away. And if that area is stimulated — my colleague Joe Parvizi at Stanford showed this, he’s a neurosurgeon — people say, “I feel like a challenge is coming on and I’m going to lean into it.” This is the brain area of tenacity.

And the amazing thing is it has connections all over the brain with reward systems, et cetera. So it’s collecting information about when it gets activated, what’s going on in the world that makes you feel pressure, when you feel like pushing back, when you don’t. But the best part is it is highly subject to plasticity. People who diet successfully, their anterior midcingulate cortex gets bigger and more active. People who embark on a new exercise program, adding some component of exercise — for me, it’s mobility work because I’ve gotten a little stiff over the years — when you do something that you don’t want to do, that you don’t reflexively do, your anterior midcingulate cortex gets bigger and more willing to engage in challenging things going forward.

STEVEN BARTLETT: (00:30:54 – 00:31:00) Yeah, so that’s the key point, which is that sets you up to be able to do more challenging things in the future.

Protocol 4: Deliberate Cold Exposure and Stress Tolerance

ANDREW HUBERMAN: (00:31:00 – 00:34:00) That’s right. Why would you do deliberate cold exposure? I’ll tell you why. Because your ability to sit calmly, or even not so calmly, when your system is flooded with adrenaline and norepinephrine, and to be able to trigger that with cold water safely — like a cold shower, getting into a cold ice bath, it’s safe as long as it’s not so cold, as long as you’re not hyperventilating beforehand on purpose — that carries over to your ability to keep your head straight when other things trigger adrenaline. You don’t get 10 stress systems, you get one. And stress looks like this: your adrenaline goes up and it comes down slowly. There’s a hallmark of stress: cortisol goes up, goes down.

So I came up with a model for arousal. When people hear “arousal” they think it’s got to be romantic arousal — it can be, but arousal is really just how alert or sleepy you are. You can be really sleepy, like in a coma, or you can be in full-blown panic. Nobody wants that. A seesaw is the right analogy here, because we have this thing called the autonomic nervous system. The autonomic nervous system is made up of 2 parts, parasympathetic and sympathetic. They’re in different parts of the body, they both connect to most every organ, but in general, when you are relaxed, that’s the reflection of parasympathetic tone going up. When you’re stressed, it’s the reflection of sympathetic tone going up. As you get sleepy, your parasympathetic nervous system starts to dominate a bit, and as you get really sleepy, it dominates more. When you wake up in the morning, and then if you do the right things like hydrate, get sunlight and some exercise, your cortisol goes up and you’re going to be more alert.

The ability to navigate stress of all kinds depends on your ability to control the tightness of this hinge. When you train your ability to think, breathe, stay calm when your system is flooded with adrenaline — and that happens later in a way that was non-voluntary, something happened that you didn’t want to happen — your brain immediately flits to the understanding of that place, and you are able to maintain thoughtfulness. You can know not to speak. That’s often the best thing you can do — to react or not react.

In fact, when you get into a cold plunge, one of the beautiful things about cold is that your prefrontal cortex, which is involved in strategy setting and making meaning out of what’s going on, its activity is greatly suppressed for the first 20 to 30 seconds. Know this about every stressful circumstance: in the first 20 to 30 seconds, you are brain damaged. You are in that mode where you could react physically — sometimes that can save your life, but most times you just don’t want to do anything. Step out of the way of the car, get away from the aggressor, whatever. But most times you’re best off not saying a darn thing. And then your prefrontal cortex slowly starts coming back online, and then you’re back again because you ruminate.

STEVEN BARTLETT: (00:34:00 – 00:34:01) This is good relationship advice.

ANDREW HUBERMAN: (00:34:02 – 00:34:30) Very good relationship advice. I wish I had learned it long ago. Actually, last night I looked on Twitter and I saw something that was both perplexing and a little bit upsetting to me. And I went to sleep, like — I know how to deal with this, some long exhale breathing, which will slow your heart rate, and we’ll talk about that. But I woke up this morning, turns out it was a complete misunderstanding and everything was reversed. But last night I thought about sending a text, and I thought, later at night the prefrontal cortex is already diminished. This is why stress feels so much harder to deal with at night.

STEVEN BARTLETT: (00:34:30 – 00:34:34) And prefrontal cortex, we should describe that thing. Logic and stuff.

ANDREW HUBERMAN: (00:34:34 – 00:35:28) So frontal cortex — here it’s logical, you have the frontal and motor areas here, and your prefrontal cortex is basically a big patch of real estate behind your forehead that in humans is greatly expanded compared to other mammals. I don’t like calling them lower, but they have less prefrontal cortex, so they’re more driven by their impulses.

One of the most incredible things that every child and adult needs to develop is what’s called top-down inhibition. You feel an impulse, but you resist the impulse. The way I’ve mostly trained my dog Strummer, because it works, is I taught him at 9 weeks of age — put down a piece of food, of course he goes for it, he loves food. And you teach him “wait,” and he sits there, and you teach him to look at you. Now I can have him moving toward a piece of food, and I say “wait,” and his nose can be this far, and he’ll just stop. He has great top-down inhibition. Is it about food?

STEVEN BARTLETT: (00:35:28 – 00:35:28) No.

ANDREW HUBERMAN: (00:35:28 – 00:36:00) Am I trying to torture him? Of course not. It’s so that if I say “wait,” he can suppress his arousal. This is one of the most valuable skills. People with frontal damage show an inability to do that, which is why sometimes they’re violent or they say inappropriate things. People who are tired, stressed, drunk — prefrontal cortex activity is suppressed. Get in a cold shower, first 20, 30 seconds, it’s kind of fun. You’re like, “here I am with less of a brain than I had getting in.” And then 30 seconds later, you’re like, “I can do this.”

STEVEN BARTLETT: (00:36:01 – 00:36:03) This explains why you shouldn’t do things tired.

ANDREW HUBERMAN: (00:36:03 – 00:36:05) Don’t do things tired. Don’t say things tired.

STEVEN BARTLETT: (00:36:05 – 00:36:06) Oh my God.

ANDREW HUBERMAN: (00:36:06 – 00:36:08) Impulse control is way worse.

STEVEN BARTLETT: (00:36:08 – 00:36:32) So when I heard you talk about the anterior midcingulate cortex, and that there was this part of the brain that was kind of like the willpower, or you described it then as the tenacity muscle, it completely changed my relationship with hard things, because it made me realize, at some conceptual level, that every hard thing I overcome is better equipping me — like when I curl weights in the gym — to do harder things tomorrow.

ANDREW HUBERMAN: (00:36:32 – 00:36:32) Yes.

STEVEN BARTLETT: (00:36:33 – 00:36:42) When I heard that, I thought, oh, there’s like a neurological — I’m making a neurological investment in my future. And then you talked there about doing voluntary difficult things, like the cold plunge, whatever.

ANDREW HUBERMAN: (00:36:43 – 00:37:04) Or learning a new language. It can be cognitive in nature. It can be learning to dance if that’s stressful for you. It can be anything that creates some internal resistance for you. This is a beautiful structure because it’s wired into cognitive capacities and our ability to build them, and emotional challenges too.

STEVEN BARTLETT: (00:37:04 – 00:37:10) We’re kind of optimizing our lives towards comfort though, aren’t we? That’s like a winning formula — more comfortable things.

On Convenience, Striving, and Overoptimization

ANDREW HUBERMAN: (00:37:11 – 00:38:51) I think Jack Dorsey said it best. There’s this great video of him online — it was a small lecture he was giving where he said, anytime we exchange ourselves, our money, our time for convenience, we are almost always giving up something that’s fundamentally useful for us neurologically. And it’s okay to do. I order food on DoorDash because there’s great food and I don’t have a lot of time to cook. I’d like to devote my time to other things. I’m trading for convenience. But if you’re aware of the trade-off, you’re much better off. And the real question is what you’re going to do with that additional time.

While I’m against overoptimization to the point that it pulls you out of life, that diminishes life, I am all for striving and optimization, quote unquote, in ways that allow you to lean into the rest of your life with more vigor. I think Arthur Brooks says it best — we are wired, and meaning comes from striving, and within striving is some struggle, and within struggle is also the release from struggle, and that’s also very satisfying.

Here’s the overoptimization thing to me in a nutshell: there are people for whom doing 2 of the things I described for 5 minutes each per day will experience a significant improvement in their mental and physical health. There are people for whom they’re sort of like junkyard dogs — they can live on anything, they have a ton of vigor, and they’re going to be like, “yeah, I didn’t feel that much from drinking some water and getting sunlight, cool.” I got you, you’re one of those people who can fall asleep in front of the screen, get up, and just keep going on a sugary muffin, great. But everyone can afford to take a look at what they’re doing now and try and move the needle toward more vigor, wellbeing, happiness, peace by doing certain things.

STEVEN BARTLETT: (00:38:51 – 00:38:55) Do you become more sensitive to the thing when you stop doing the thing?

Nutrition

ANDREW HUBERMAN: (00:38:55 – 00:42:16) Depends on the thing. So for instance, I talk about nutrition in there, and I really go into the literature — I cover everything from the all-meat diet to vegan diets — so people can choose. But if you look at what most people could benefit from doing, and you could do this with a vegan or vegetarian diet, it’s a little harder, but the best diet is going to be the following.

Not too many calories, not too few — that’s individual, you can calculate that, it’s an easy thing to do, and I provide a way to do that. You need to get high complete-protein-to-calorie-ratio proteins. This is a concept I came up with, because if you look at the literature, yes, we need the essential amino acids, so that’s a complete protein — you can get that from beans and rice, but to get 30 grams of complete protein from beans and rice, you’re going to consume about 4 to 5 times as many calories as is required if you get it from a chicken breast. This is a factor that’s kind of obvious, but no one ever talks about it. So you want to eat some high complete-protein-to-calorie-ratio protein — eggs, lean meat, fish. And then everyone knows you need fiber — vegetables and fruits.

But what I will say is that many people who remove starches entirely, or remove vegetables entirely, will find that their autoimmune issues resolve, and there are reasons for that, and we have to acknowledge that. But most people should be eating some vegetables and fruit for micronutrients and fiber. Low-sugar fermented foods — very clear, Justin Sonnenburg’s work from Stanford, very clear — lowers the inflammatome. In fact, when they had people eat more fiber, for many people, inflammatory markers went up. No one likes to talk about that, especially not the vegans, but too much fiber can be noxious for some people and pro-inflammatory. So low-sugar fermented foods like sauerkraut, kimchi, beet kvass — delicious. Problem is they tend to be expensive, but you can make your own, and there’s recipes online.

I don’t want to get into the seed oil debate. Just use olive oil, it’s delicious, it’s relatively inexpensive nowadays to get real olive oil. Small amounts of butter. Why are we even debating seed oils? It’s so dumb — it’s like the fastest way to kill neurons that I’m aware of. It’s like, the studies are not well done — you’re comparing a processed food diet that includes seed oils versus a high meat diet with processed meat. It’s a mess. As a scientist, you just look at this and go, this field sucks. 90% of the studies — you don’t even have to be trained in nutrition to see it — there are 5 different variables here and 4 over here. This is what you would call a bad experiment. So olive oil, the data are great, it’s impressive.

And starches are great for fueling muscles and glycogen and brain, but you don’t want to overdo them. And the way that people tend to overdo starches is by eating starches combined with a lot of fats. Sourdough bread is great. Sourdough bread with butter is even better, if you ask me. Sourdough bread with equal amounts of butter and bread, you’re starting to get into problems. It’s very hard for people to overeat starches unless they have a lot of fats with them or sugar with them.

STEVEN BARTLETT: (00:42:17 – 00:42:22) On starches, is there an impact? I think I’ve heard you talk about an impact on your sleep with what you eat late at night.

ANDREW HUBERMAN: (00:42:23 – 00:43:49) Many people who don’t eat enough starches find that they have sleep issues, and there are reasons for this. We talk about comfort foods — typically people think junk foods when they think comfort foods, but foods that increase glucose lower cortisol. That’s weird — starches lower cortisol, and you want your cortisol low at night, it helps you fall and stay asleep. Now, you don’t want to eat too close to bedtime, and you don’t want to have gnawing hunger at bedtime either. We talk about that.

But here’s the interesting thing — what is cortisol? I should have mentioned this earlier. Is it a stress hormone? No, it’s a hormone that’s released during stress. Cortisol’s job is not to deal with stress — cortisol’s job is to mobilize energy in the body. When cortisol goes up, glucose is mobilized, and other fuels too. So when you eat starches, you buffer cortisol. There’s a very clear relationship here. So people who are not eating enough starches, who then allow themselves that bowl of rice or a bowl of pasta in their final meal of the day, or a little bit at lunch and at dinner, maybe even a bowl of oatmeal at breakfast — they feel more even psychologically, they have more physical energy. Sometimes people with chronic stress issues notice they stop shaking. People with autoimmune issues sometimes see those resolve, because your cortisol is buffered, because your blood glucose is elevated, and so your body isn’t tapping into the survival system to try and mobilize glucose.

STEVEN BARTLETT: (00:43:49 – 00:44:04) So I have this outstanding question I have to ask you. It goes back to the picture you drew of the graph. You said high cortisol in the morning is a good thing. So what if I pick up my phone first thing in the morning and I look at my worst emails?

ANDREW HUBERMAN: (00:44:05 – 00:44:10) In some sense, from the perspective of spiking your cortisol, it’s a good thing, but can you do it outside while getting sunlight?

STEVEN BARTLETT: (00:44:10 – 00:44:16) Please. I was wondering if it matters how the cortisol comes, because what if I stress myself in the morning? It doesn’t matter? Really?

ANDREW HUBERMAN: (00:44:16 – 00:44:16) It doesn’t matter.

STEVEN BARTLETT: (00:44:16 – 00:44:16) Interesting.

ANDREW HUBERMAN: (00:44:17 – 00:44:18) The problem is the rumination that comes with stress.

STEVEN BARTLETT: (00:44:18 – 00:44:18) Okay.

ANDREW HUBERMAN: (00:44:19 – 00:44:47) Right. So the nice thing about physical stressors that we control, like a workout or a cold plunge, is that they have an onset and an offset. Yes, they start faster than they end — you have stress and it kind of carries over, you ruminate. But psychological stressors tend to bang around in our brain a lot, and late at night, they tend to come back. I will say this: I think 2027 is going to be the year that we close the coffin on this “cortisol is bad” thing.

STEVEN BARTLETT: (00:44:48 – 00:44:51) So how should I think about cortisol? Because right now I think of it as the stress hormone.

ANDREW HUBERMAN: (00:44:52 – 00:44:53) It’s to mobilize energy.

STEVEN BARTLETT: (00:44:53 – 00:44:53) Okay.

ANDREW HUBERMAN: (00:44:54 – 00:44:54) So you can use it.

STEVEN BARTLETT: (00:44:55 – 00:44:55) Okay.

ANDREW HUBERMAN: (00:44:55 – 00:45:00) And if you’re going to sleep at night, you don’t need to mobilize energy, so you can use it — you need to rest and reset your body.

STEVEN BARTLETT: (00:45:00 – 00:45:01) Okay.

ANDREW HUBERMAN: (00:45:01 – 00:45:04) Cortisol is an energy-promoting hormone.

STEVEN BARTLETT: (00:45:04 – 00:45:10) So if I walk up on stage, my cortisol level — like before I go up on stage and there’s a big audience, whatever — my cortisol level’s going to go up then.

ANDREW HUBERMAN: (00:45:10 – 00:45:35) Yeah, if you’re stressed about it, maybe a little bit more, but it’s a preparation hormone. You’re preparing for adversity, but also great things. There are these beautiful studies from a guy named James McGaugh and Larry Cahill, which showed — do you know that if you want somebody to learn something, you spike their cortisol before, during, or after that thing, and it should work? Why not? Trauma does that, and you never forget. All you do is work on trying to remove the emotional load of that traumatic thing.

STEVEN BARTLETT: (00:45:36 – 00:45:44) Wait, so does that mean that someone who’s listening to this podcast right now in the gym is going to have better knowledge recall of what we talked about than someone who’s listening in bed?

Learning, Focus, and the Anterior Midcingulate Cortex

ANDREW HUBERMAN: (00:45:44 – 00:46:40) Great question. So I have a chapter that’s all about learning, motivation, and plasticity. We’ve all heard exercise makes your brain better — how, why? Turns out it’s very important to understand there are 2 ways it does that, or at least 2. One is it raises your levels of arousal. Exercise doesn’t make you smarter — exercise makes you more alert coming out of the exercise so you can go learn things, because it turns out you have to be alert to learn things. In particular, you need adrenaline and cortisol elevated to learn things.

So when people say weightlifting is good for your brain, cardio is good for your brain — turns out long, slow cardio, my endurance friends aren’t going to like this, is not that great for your brain. It’s not bad for your brain, but it’s not that great either. Turns out an intense weightlifting session or high-intensity interval training session, in the 4 hours after that, you are primed for learning. Why? You’ve got a lot of stimulatory molecules in your body and you can focus better.

STEVEN BARTLETT: (00:46:41 – 00:46:50) What about if I’m a podcaster and I want to be able to ask good questions and use my mouth and my brain in that context, but not necessarily just learning — performance of my cognition?

ANDREW HUBERMAN: (00:46:50 – 00:47:29) So the performance curve is basically an inverted U. If you’re not alert enough, you can’t do what you need to do. If you’re too alert, you can’t do what you need to do or learn. So you want to be at the top of that inverted U. A lot of what learning is about, and a lot of what the anterior midcingulate cortex is about, is getting from “I don’t want to do it” up to the top of that U. Then it’s usually about not getting too stressed.

Now, I learned the best trick for this — the 2 best tricks — and that will take us to number 5. You can use it any time of day, which is: use physiological sighs to reduce stress fast. I have a chapter on stress mitigation, and it’s essentially 2 components. One is how to limit stress in the moment.

STEVEN BARTLETT: (00:47:29 – 00:47:30) Okay.

ANDREW HUBERMAN: (00:47:30 – 00:47:33) Very, very important to know how to limit stress in the moment. And here—

STEVEN BARTLETT: (00:47:34 – 00:47:34) Why is it so important?

Protocol 5: The Physiological Sigh

ANDREW HUBERMAN: (00:47:35 – 00:48:51) Oh, gosh. Because meditation, a great night’s sleep, massage, social relations, being well-fed, hydrated — all of that helps you buffer stress. But when something happens and your heart rate is too high, or you’re shaking and you can’t organize your thoughts the way you want, none of that helps. You’ve gone over the line, you’re too far on the arousal spectrum towards alert.

It was about 2016 that I realized I’m going to take a significant portion of my lab and work on this problem. I wanted to find real-time tools for mitigating stress. So I started hanging around with people from special operations who spend time in ice baths and cold water — they don’t actually do ice baths in the SEAL teams, by the way, they spend a lot of time in cold water during their training. And I started talking to people in performance fields, in particular neurosurgeons, people who deal with life-or-death circumstances for many, many years and maintain immense calm. One of my closest childhood friends — you should have him on this podcast — his name is Dr. Eddie Chang, and he’s a neurosurgeon at UCSF. He’s the chair of neurosurgery, and he’s brought people out of locked-in syndrome to speak through AI. He’s also a bioengineer, and he’s been my friend since we were 7 years old, and we talk 3 times a week these days about science. I actually visited his laboratory and got to see him take a golf-ball-sized tumor out of a guy’s forebrain while the guy was awake.

STEVEN BARTLETT: (00:48:51 – 00:48:51) Wow.

ANDREW HUBERMAN: (00:48:52 – 00:49:44) Eddie is the calmest guy you’ll ever meet. Why? Because a movement of less than a millimeter in the wrong direction for him could cost a patient’s life. People have ways to calm down in real time.

So I teamed up with a colleague, David Spiegel. At that time he was our associate chair of psychiatry, and he studies hypnosis — clinical hypnosis for smoking cessation, pain management, and anxiety. And I should say, mainly Melis Yilmaz Balban in my lab did a study where she built a stress lab with VR and stress — that’s a whole other thing. And then we did this study where about 100 or so subjects were fitted with trackers that measured heart rate, heart rate variability, and sleep. People were in one of 4 groups. They either meditated for 5 minutes a day, or they did box breathing — inhale, hold, exhale, hold — for 5 minutes.

STEVEN BARTLETT: (00:49:44 – 00:49:45) Like 4 seconds each or something.

ANDREW HUBERMAN: (00:49:45 – 00:55:30) There’s a way you can measure it, which is the carbon dioxide tolerance test — how well you can control an exhale will tell you a little bit about how stressed you are. When you’re stressed, you tend to blow off carbon dioxide very quickly, and when you’re less stressed, it tends to shift towards long exhales becoming easier.

So one of the groups — and then I’ll say what the mechanism is — did cyclic hyperventilation. Some people call this Wim Hof breathing, Tummo breathing, pranayama breathing. Big inhales, passive exhales, repeated for 5 minutes. Massively spikes adrenaline, which isn’t a bad thing, you’re controlling it anyway. Does not spike cortisol very much, incidentally. And when you do those exhales, you’re blowing off a lot of carbon dioxide, so it shifts your internal state and tends to make people very alert.

Or there was a 4th condition where they did a double inhale, long exhale, repeat — the so-called physiological sigh. Jack Feldman at UCLA and some other folks in the 1930s had observed that animals and people, when they’re very relaxed, would do this kind of strange pattern of breathing — a double inhale, long exhale. Jack’s lab discovered there’s a brain area called the parafacial nucleus, which is specifically there to generate this double inhale-exhale pattern in animals and in humans.

Turns out there are 2 breathing centers. One is called the Prebötzinger complex, named after a bottle of wine — a pattern of breathing where you inhale, exhale, and you alternate. This other structure, the parafacial nucleus, which we all have, is involved any time you double up the inhales or exhales, and it’s involved in breathing while you speak or sing or eat. It generates these physiological sighs, which get triggered in environments where there’s not enough oxygen, or when you get claustrophobic, or when you get very stressed. Carbon dioxide goes up, your brain senses that, and it triggers the gasp reflex. That double inhale maximally inflates the millions, hundreds of millions of little sacs in the lungs. And then when you exhale, you offload the greatest amount of carbon dioxide. A single inhale doesn’t offload as much carbon dioxide, but that second short inhale takes these little sacs in your lungs, which are like balloons at a kid’s party — they’re empty, but they’re fluid-lined on the inside, so there’s some surface tension inside them, they’re sticking together. It’s the double inhale that opens those up, and then you offload the carbon dioxide.

Now, that’s great, but the real magic of deliberate long exhales is that they slow your heart rate down through a process called respiratory sinus arrhythmia. This is one of the most important things for anyone interested in stress, exercise, sleep, and wellness, because we have this vagus nerve. Everyone likes to talk about the vagus nerve — it’s a massive nerve bundle that collects sensory and chemical information from the organs of the body and sends it up to the brain. And it’s classified as parasympathetic, calming. But you know what’s funny? Neuroscientists, when they want to wake up a person during an experiment, like a neurosurgery experiment, they stimulate the vagus. A treatment for depression is to stimulate the vagus. Guess what that does? Makes people more alert. So it’s a mixed nerve.

But the really cool part about the vagus is that it’s not all ascending. 85% of the information is going up from the body through the vagus, but there’s another pathway too, and it goes down to your heart, and it controls the slowing of the heart rate when you exhale. Heart rate variability is the slowing of your heart rate when you exhale. You want to increase your HRV? Do a few deliberate exhales during the day. People ask, how do I get my HRV up? Well, you do some VO2 max training, some max heart rate training, some HIIT workouts, et cetera. But you really want to increase your HRV in sleep and while waking — just do some deliberate exhales during the day, because that’s the parasympathetic, the calming arm of the vagus pushing down on your heart rate.

All of the groups I described saw benefits, but it was the people who did these physiological sighs that benefited the most. So then I started exploring, well, how fast does heart rate slow down with physiological sighs? And it turns out you don’t need to do it for 5 minutes — you do it once. You’re feeling stressed, you’re going on stage, you’re waiting for a diagnosis, you feel too alert relative to how you want to feel for whatever reason, good or bad, you’re about to get married, whatever — you just breathe until your lungs are empty, and it’s immediate.

For me, that was immensely gratifying — yes, because it’s fun to publish papers. We published it in Cell Reports Medicine, and Melis gets the lion’s share of the credit for that. There were other people on the paper, but she did so much hard work on that and the analysis. I was so gratified, because I’m like, oh, finally — if I didn’t sleep well, or if something stressful happened even though I slept well, I could calm myself down like that. I thought real-time tools for stress are what we all need.

The interesting thing is that you can also raise your stress threshold, and a lot of the stress mitigation chapter is also about how to do that. We need to train for discomfort so that the little things don’t feel so big.

STEVEN BARTLETT: (00:55:31 – 00:55:31) Yeah.

ANDREW HUBERMAN: (00:55:31 – 00:56:04) This is also important in survival situations. You need to be able to think very clearly about what order of operations to take, what direction to escape through. This is not about setting yourself up to tolerate more pain and abuse — this is about the exact opposite. This is about safety, this is about self-protection. This is about noticing when we’re alert but calm — we can notice the subtle ripples in people around us, who needs our attention, who we really don’t like but never really realized it. You can notice that stuff.

STEVEN BARTLETT: (00:56:04 – 00:56:12) A lot of people wake up at like 2:00, 3:00 AM in the morning in the middle of the night, and they don’t really know why. They don’t know how to get back to bed. They start worrying and ruminating.

ANDREW HUBERMAN: (00:56:12 – 00:56:13) Very common.

STEVEN BARTLETT: (00:56:13 – 00:56:16) Yeah. So they can use this as a tool in that moment?

ANDREW HUBERMAN: Definitely.

Falling Back Asleep: The Eye Movement Trick

ANDREW HUBERMAN: (00:56:16 – 00:58:44) 10 long, deliberate exhales. There’s also this really crazy trick that I put in the book that has indirect scientific support. Best way to fall back asleep — you want to hear this? This is so nuts.

To fall asleep or to fall back asleep, you need to stop thinking about your body position. Turns out there’s a direct relationship through a few steps, but there’s a dedicated circuit between your eyes, their movements, and your cerebellum, which is involved in proprioception and balance and a number of other things. We call the cerebellum the mini brain — these hyperfoliated lobes back here. “Foliated” is just nerd speak for foldy, bumpy. It’s involved in balance, it’s involved in learning. It’s actually very important for generating and responding to the error signals between what you’re trying to do and what you can do. That error signal turns out to be one of the most important things for generating learning — to make errors through genuine attempts. Your cerebellum is critical for that. It’s also involved in timing.

So you need to kind of turn off your recognition of your own limbs to fall asleep. How do you do that? You know what works with babies? Walk back and forth at a particular pace — this was defined in a Japanese study — and have people swing the baby back and forth gently as they do it, and the baby falls asleep. Guess what? Parents figure out the exact cadence with a very small margin of error through trial and error, to figure out how to get their kid to sleep. It’s like a natural experiment, and it’s been looked at in the lab.

Turns out when you rock back and forth, your eyes move. This is a very, very ancient system that exists in all jawed animals, including us, that as we move through space — walking, running, swimming, whatever — the world is gliding by, what we call optic flow. You would see the world blurry, but you have a compensatory eye movement that, unbeknownst to you, because of a connection between your eyes, these brainstem areas, and your cerebellum, creates a visual slip error, and your eyes automatically offset that error. So when I move, the world seems stable.

And it turns out there’s a pattern of eye movement that can shut down the proprioceptive circuits in the cerebellum, which make you forget your limb position, and it greatly facilitates the speed at which you fall back asleep. Okay — you’re going to close your eyes.

STEVEN BARTLETT: (00:58:45 – 00:58:46) Great.

ANDREW HUBERMAN: (00:58:46 – 00:59:58) You’re going to move your eyes slowly to one side underneath your eyelids, then to the other side, then up, then down. Now you’re going to move them counterclockwise in a circle-ish, and then clockwise in a circle-ish. And now, still with your eyes closed, you’re going to kind of point them towards your nostrils — you’re not going to cross your eyes — and you’re going to do a long exhale.

That, done 2 or 3 times, generally has people waking up the next morning like, “what happened?” What happened is your proprioceptive circuits are shut down. That’s kind of fun to do, it costs nothing, and it generally works. Some people, if they’re really stressed, it might not work. But this is what I do if I wake up in the middle of the night — I usually go to the bathroom, get back in bed, do long exhale breathing, and I do that, and I wake up the next morning. It really works well. So well, in fact, that there’s a company based on work done by 2 MIT scientists — they have a sleep mask that generates this pattern of eye movements through a little electrode behind the ear. It stimulates the extraocular muscles in just the right pattern. I tried it, and you fall right asleep.

STEVEN BARTLETT: (00:59:58 – 00:59:58) You’re joking.

ANDREW HUBERMAN: (00:59:59 – 01:00:43) No. And it monitors REM. We monitor REM through an Eight Sleep or a Whoop or some other device through changes in heart rate and breathing — this is direct monitoring of REM. It’s wild, and it can control your eye movements to induce more REM if you want more REM. There will be a time very soon, within the next 12 to 14 months, when, because of devices like the one they and others are making, you’re going to be able to say, “I want 2 hours of deep sleep, I want 2 hours of REM across a 6-hour night, because I can’t afford to sleep my ration of 8.” And you will be generating those eye movements during sleep in order to facilitate, not force, but facilitate those patterns of sleep.

Peptides, Hormones, and GLP-1 Drugs

ANDREW HUBERMAN: (01:02:49 – 01:03:41) Yes, I have no affiliation to it — it’s called pinealon. I will tell you, in the book, I do not talk about hormone therapies, peptides, or psychedelics. The book is about what I know for sure. Hormones, peptide therapies, and psychedelics are at the front edge right now. I’m very much involved in looking at the research, talking to the people that are doing these things, and yes, I dabble in these things. I’m very interested, I experiment on myself, and I’m an adult, I can do that.

So pinealon is very interesting, because I found that if I took a tiny bit every third night — I tried this experiment for about a month — I got massive amounts of REM sleep that night, but also on subsequent nights. I hosted Dr. Abed Bakri on my podcast, who’s, in my view, the most knowledgeable physician on the topic of peptides.

STEVEN BARTLETT: (01:03:41 – 01:03:43) Oh, I saw that episode. It’s amazing.

ANDREW HUBERMAN: (01:03:43 – 01:03:58) He’s amazing, and I think you guys would have an even better conversation, frankly. But in any event, he tells me that pinealon is potentially involved — there are some data supporting its use for encouraging pinealocyte health, so the actual health of the pineal—

STEVEN BARTLETT: (01:03:58 – 01:03:59) Pineal gland.

ANDREW HUBERMAN: (01:03:59 – 01:04:20) Yeah, the pineal gland, which makes melatonin and does other things too. So I think pinealon is a great tool to use sporadically — I don’t use it regularly. As long as we’re talking about peptides, I’m peptide curious, you know, I’m from the Bay Area, peptide curious. I have not tried any GLPs yet, but I’m getting curious about very, very low dose tirzepatide or retatrutide.

STEVEN BARTLETT: (01:04:20 – 01:04:26) I’m peptide curious, but I’m scared, because you’ve got to inject most of them, right?

ANDREW HUBERMAN: (01:04:27 – 01:04:29) It’s a tiny little thing.

STEVEN BARTLETT: (01:04:29 – 01:04:34) What’s your take on peptides as a category? It’s a big category, isn’t it? Everything seems to be a peptide these days.

ANDREW HUBERMAN: (01:04:34 – 01:05:26) Here’s my opinion. It will be popular with some people, unpopular with others, but obviously, as with hormone therapies or anything else, or supplements, sleep, hydration, sunlight, exercise, nutrition — you need all that stuff. The behavioral tools are the foundation. Great things can happen when you build on a foundation. Okay things can happen when you build on a non-foundation, but it doesn’t last long. The combination of the two can be pretty awesome, especially if somebody has the means and the interest.

So the GLPs, which are the weight loss drugs — I think retatrutide is amazing. It’s not just a GLP, it also hits the glucagon and GIP pathway. This is the one that Eli Lilly invested hundreds of millions of dollars, if not more, into researching, and it went through phase 3. People lost approximately one-third of their body weight in about a year or so.

STEVEN BARTLETT: (01:05:27 – 01:05:29) Is that a good thing for everybody?

ANDREW HUBERMAN: (01:05:29 – 01:06:22) No. So what’s happening is — the psychedelic community talked about microdosing, and that microdosing phrase has now been incorporated into GLPs, and people realized they could bypass a lot of the side effects and the cost by microdosing GLPs. These are anecdotes, so I want to be clear, and I’m not pushing peptides or selling peptides. I have a friend who’s very, very skeptical about anything that’s not fully FDA approved — she says, “I don’t want to hear about your biohacking nonsense,” this kind of thing. But she has chronic fatigue syndrome, and she talked to me about what can I do. She’s seen all these physicians — physicians at Stanford, physicians at UCSF. She’s a very smart, nuanced person, but she’s hit a wall. She’s started taking a very, very low dose of tirzepatide once every 10 days.

STEVEN BARTLETT: (01:06:22 – 01:06:23) And tirzepatide is—

ANDREW HUBERMAN: (01:06:23 – 01:06:55) It’s one of the GLP-1 drugs. We could talk about Mounjaro, Ozempic, but it’s not touching GIP or glucagon, it’s mainly just increasing levels of glucagon-like peptide, which suppresses hunger and appetite but also seems to lower inflammation. Yes, there are concerns about vision loss in people who have certain structural abnormalities of the eye. Yes, there are concerns about apathy if people take too much of them. It seems to reduce alcohol craving for people that like alcohol, and sugar craving more generally, and it can reduce craving for everything if you take enough of it.

STEVEN BARTLETT: (01:06:55 – 01:06:55) Yeah.

ANDREW HUBERMAN: (01:06:56 – 01:08:52) Keep in mind, these drugs are ramping up levels of GLP-1 1,000-fold or more. The body has never seen this level of glucagon-like peptide in the history of humans. And remember, this whole thing was discovered because a smart biologist was studying why Gila monsters — these reptiles that I think are ugly, he probably thinks are beautiful — only have to eat a couple times a year. It’s because they make a peptide called exendin, which turned out to be homologous to glucagon-like peptide-1 in humans. The reason these reptiles don’t have to eat very often is because they always feel satiated, because they have very high levels of glucagon-like peptide-1 circulating. We don’t.

And it works through 2 mechanisms. It tells the brain’s mechanisms for satiety to ramp up their activity — so your brain is telling you, I don’t really want food. And it also makes people feel full, which is the basis of some of the side effects of nausea and other things.

So she’ll tell you, “oh my God, my energy’s back, my inflammation markers are way lower, I’m not cured, but I feel so much better.” Very, very hard to dispute that kind of experience if you’re the patient. We could talk about safety and sourcing, et cetera, but anyway, people are starting to realize they can microdose stuff, but you won’t see randomized controlled trials that are going to push this kind of notion — you can tell it’s terrible for business.

So then there are things like pinealon for sleep, epitalon perhaps for DNA repair — I haven’t dabbled with that one yet. And then there are the so-called growth hormone secretagogues — we’re talking about tesamorelin, ipamorelin, CJC-1295. These will promote more growth hormone release and sleep. They’ll have a negative feedback effect where they’re going to shut down some of your own production, and people get a bit leaner and claim their deep sleep is better, and it can increase insulin sensitivity. I’ll tell you, I’ve tried semaglutide, I’ve tried a few of these other ones. They nuke my REM sleep. They give me a ton of deep sleep.

STEVEN BARTLETT: (01:08:52 – 01:08:52) Cheap.

ANDREW HUBERMAN: (01:08:52 – 01:10:00) I don’t like them. I’ve tried pinealon, I’ll take it now and again, I don’t do it right now. And BPC is the one that gets everybody talking, because Body Protection Compound 157 is made in the gut. People claim — and I do think their claims are accurate — that they feel, notice what I said right there, that they feel as if their recovery from injury was accelerated. And I believe them, because I’ve spent a lot of time with the animal data, whether it’s an Achilles tendon transection, or nerve regrowth, or tendon or ligament regrowth, and vascular — yes, it does seem to accelerate healing across the board, but the concern is you could vascularize tumors. Now, would I take it? No, I don’t have an injury right now, I don’t have any reason to take it.

So I don’t think people should ask, “should I take peptides?” You should ask, “what effect in your life am I trying to achieve?” And then maybe BPC makes sense, maybe it doesn’t. You’re not going to find many clinical trials on it. It has a very, very high, maybe infinite, LD50, meaning no one has really figured out how much can kill you. But that’s not a good way to run your life. It’s somewhere between a drug and a supplement.

STEVEN BARTLETT: (01:10:00 – 01:10:10) I think this is one of the concerns, or one of the conversations I often hear around GLPs at the moment, is that they’ve just not been around long enough for us to know the side effect profile over a long period of time. Is there any truth to that?

ANDREW HUBERMAN: (01:10:11 – 01:10:47) Well, do you want to be in the experiment or out of the — do you want to be in the control group or the experimental group? For somebody who has serious obesity issues, the tirzepatides and Mounjaro and Ozempics and retatrutide could potentially save their life. Vision loss is a serious consideration, although I’ll go on record — vision is my home, and I’ll just be direct, I don’t tap dance around this, and I’m not trying to start any battles, David and I can talk about it directly — David Sinclair recently went on Rogan and said the amount of blindness caused by GLPs has doubled, which scared everybody.

STEVEN BARTLETT: (01:10:47 – 01:10:47) I heard that.

ANDREW HUBERMAN: (01:10:48 – 01:10:56) But there’s a structural abnormality in the eye of a subset of people for whom that’s true. And it’s a great idea to get your eyes scanned.

The Eye, Glaucoma, and GLP-1 Vision Risk

ANDREW HUBERMAN: (01:10:56 – 01:13:15) Oh, man, this is fun — it’s a good thing you only come on here every once in a while, because I’ll do this all day, every day. So light obviously comes in, you’ve got that cornea on the outside of the eye, and the lens focuses the light onto your retina, which is this pie-crust-like structure that lines the back of your eye. An amazing structure, 3 cell layers thick, catches light, absorbs light. The photoreceptors turn that into electricity through phototransduction. Then that electricity is cast forward to a set of cells that line the inner part of the retina that we call retinal ganglion cells, and they send their wires, their axons, out the optic nerve into your brain. They course along the bottom of the brain and enter your brain, including your circadian clock. You get vision, you get sleep-wake rhythms, you get hormone regulation by light — it’s incredible.

Well, where they exit the eye is called the optic nerve head. And if the optic nerve head is a nicely shaped and sized tube for them to exit, great. Too big, that’s not good. Too tight’s not good either, because those wires get pinched off. This is part of what happens in the disease glaucoma, where the eye pressure goes up and those axons die away, these cells die away — it’s the second leading cause of blindness in the world.

So in some people who have a structural feature of the optic nerve head where these wires leave the eye, it does seem that the GLPs put them at greater risk for causing some cinching off of those cells, and there have been cases of blindness. But the thing that wasn’t really fair, David, is this: he is developing some very potentially impressive tools to rescue vision in glaucoma, et cetera, but meanwhile, GLPs are not making many people go blind. That’s about as true as masturbation making people go blind — I’m not saying you should do either one, that’s your personal choice — but the point here is that he scared the daylights out of people, pun intended, telling them that they can make you go blind. But everyone should get this area of their eye imaged, and it turns out it’s very easy — you can go to your ophthalmologist or optometrist, ask for an eye pressure test. Usually insurance covers it, but definitely worth paying for.

STEVEN BARTLETT: (01:13:16 – 01:13:18) That was number 5!

ANDREW HUBERMAN: (01:13:18 – 01:13:19) We got into peptides. Yeah.

STEVEN BARTLETT: (01:13:19 – 01:13:20) Yeah, we’ve done quite a few.

ANDREW HUBERMAN: (01:13:20 – 01:13:22) Good thing we’re not talking about psychedelics. We’ll do that another time.

STEVEN BARTLETT: (01:13:22 – 01:13:22) Oh, gosh.

ANDREW HUBERMAN: (01:13:22 – 01:13:25) We won’t do them another time. I don’t do psychedelics publicly.

STEVEN BARTLETT: (01:13:26 – 01:13:28) Listen, I’m open-minded. I didn’t care.

ANDREW HUBERMAN: (01:13:28 – 01:13:30) Not as open-minded as you’d be if we do psychedelics.

STEVEN BARTLETT: (01:13:30 – 01:13:31) No, I’m just kidding.

ANDREW HUBERMAN: (01:13:32 – 01:13:35) You took DMT in a faraway land where it was very legal.

Psychedelics, Reality, and Religion

STEVEN BARTLETT: (01:13:35 – 01:14:01) Because, you know, I sit here and talk about these things, and psychedelics — I actually worked in a psychedelics company for about a year. It was deeply, deeply fascinating, and the reason I was compelled by it is the efficacy as it relates to mental health, and the studies being done out of London around things like psilocybin and ibogaine and DMT treatments. And I just thought, wow, some of the clinical data is unbelievable. I’d love to learn more. So I did psilocybin, and then I did DMT, and it was really just—

ANDREW HUBERMAN: (01:14:02 – 01:14:03) I’ve not done DMT.

STEVEN BARTLETT: (01:14:03 – 01:14:04) You’ve never done DMT?

ANDREW HUBERMAN: (01:14:04 – 01:14:23) No, no. I’ve done clinical MDMA and psilocybin. I think I’m done with that, not because I had a negative experience, but I got what I wanted out of it, and I found it to be immensely beneficial — the combination of MDMA and psilocybin, with therapy going in, therapy during, and therapy coming out of it.

STEVEN BARTLETT: (01:14:23 – 01:14:55) Do you know what — it’s one of the things that made me think a lot about religion, was having a DMT experience where what I experienced felt indistinguishable from this reality, in terms of the vividness and the realness of it. And me just pondering this concept, that a tiny little inhale of smoke could completely change my material reality — so therefore I concluded that my material reality is literally, tell me if my logic’s wrong, a small amount of chemicals being uninterrupted. Does that make logical sense?

ANDREW HUBERMAN: (01:14:56 – 01:18:40) Yeah. So I think about this way too much. I guess we are going to talk about psychedelics, reality, and religion. A couple short statements about this — I’m fascinated by this, so I’d love to hear you talk more about it. But here are a couple ways that I think about it in a non-dismissive way.

Most all of biology is just compartmentalized chemistry. Whether it’s the flow of electricity along neural circuits to generate tenacity, for instance, or learning, you’re just guiding chemistry in particular ways. That’s not a way to trivialize it, it’s kind of a way to think about it. There are 2 ways that you can change brain function, behavior, and chemistry. One is mechanical — I can breathe differently, I can get a massage, I could poke myself with a knife. So there are mechanical forces that change our physiology, and then there are chemical forces — pharmacology, things we eat, and chemicals within us, serotonin, et cetera. That’s really it, there’s no other thing.

In many ways, you’re absolutely right, it’s compartmentalized chemistry, and mechanics and other chemicals are what control that chemistry. I think organizing one’s thoughts sometimes in that way can be helpful, because you realize the stress response is really just a bunch of chemicals happening in certain places and so on.

I personally am intrigued about the idea of things outside of our conscious understanding in biology that maybe things like DMT give us access to, or maybe just prayer gives us access to, or faith gives us access to. And it comes from my recognition, both as a neuroscientist and just a human who’s been alive for 50 years and some change, that our biology and psychology, let’s mold those together, are extraordinarily good at accomplishing certain things. But there are certain things that are outside the abilities of our psychology and biology. And if we are asking our psychology and biology to satisfy something that they simply cannot satisfy, we’re going to miss out on a lot of potential meaning in life.

And to be very direct about it — at the point where I decided to really embrace the idea of faith, of a God, that there are powers outside of human understanding, that can be very useful, everything got better. It relieved me of the pressure to control everything internally and externally. And I find it not just intriguing, but absolutely captivating, that a force outside of us — some people call it God, the universe, some people might think it’s Jesus, some people might think it’s something else — might actually hold some power in how we could potentially behave, be better. Wouldn’t it be wonderful if there’s this thing planted in us, or some of us, which is a question about things outside of us that, if we were to embrace, could allow us to get to a better place as a species? Why would we think that a technology like AI would do that? AI is wonderful, but why would we think it would come from computers, from anything that humans and only humans could do?

To me, embracing the notion of a God and having faith, which, by the way, is about having doubt but still doing the practices — prayer — is to me one of the most liberating and educating things, not just about God and the universe, but about the human brain.

STEVEN BARTLETT: (01:18:40 – 01:18:41) Okay, I’ve got some questions.

ANDREW HUBERMAN: (01:18:41 – 01:18:45) Yeah. I mean, it’s like we’re not meant to solve this on our own.

STEVEN BARTLETT: (01:18:45 – 01:18:46) Do you believe in God?

ANDREW HUBERMAN: (01:18:46 – 01:18:47) Absolutely.

STEVEN BARTLETT: (01:18:47 – 01:18:49) When did God come into your life?

ANDREW HUBERMAN: (01:18:50 – 01:21:20) Very early, but I was very good at suppressing the notion that it was real. I would pray in private, I would hide it, and not just in bad times. And then I think I lived enough and observed enough hardship — we’ve talked about some of this on a previous podcast, I talk a little bit about it in the book — but I observed it out there too, not just in my own life. I started to realize, especially if you stick your hands in enough brains, and you see my good friend Eddie Chang record from the brain of an awake human and remove a tumor and save that person’s life, and you also realize that brain areas are controlling things, because when they’re stimulated, that person feels and responds in a certain way — you realize that we’re not all meat and potatoes in there. There’s something else, but I’m not sure that it all comes from us. It’s sort of hard to explain.

The best way I kind of wriggle out of this is that I brought my dad on my podcast. My dad and I, for many years, had a choppy relationship — we have a great relationship now. He’s 83 years old, he’s super vigorous, he loves ideas, he’s into quantum computing, and he’s a theoretical physicist. And I asked him to explain quantum mechanics — I go, “tell my audience how relativity works.” He worked on chaos theory, so, “tell us how chaos works.” And he said he’ll do that, but I have to understand that one of the most important things about understanding quantum mechanics is that early on you learn that the human brain can’t wrap its head around quantum mechanics with logic, with human understanding — you have to rely on the math. And he says anyone who talks about the quantum field who can’t show you the math, can’t show you the proofs, is lying. He loves it when people are like, “oh, the quantum this and the quantum that,” which often happens in the meditative communities, but others too. And he goes, people throw this word around because very few people actually understand quantum biology — there’s some logic, but there are gaps in their logic that the math doesn’t line up with. And the math doesn’t lie.

So what he was saying, and we were having a discussion about God, is that at some point, if you’re going to have faith in a higher power or God, you have to depart this notion that your logical brain can go from A to B to C and boom, you’re there. But in quantum mechanics, it’s the same thing — but on the basis of quantum mechanics, you can build stuff. You can engineer stuff in the real world, like that red light, or a rocket.

STEVEN BARTLETT: (01:21:21 – 01:21:23) Are you saying you don’t know all of this?

ANDREW HUBERMAN: (01:21:23 – 01:28:34) There’s no math to prove this thing that I call the existence of God. There’s no math, and it’s not worth torturing yourself over. What I believe is worth torturing yourself over — and there’s also great beauty in there — is embracing the practice of prayer, embracing the questions, opening the aperture of your beliefs just for a moment, going, “maybe I’m going to just believe in God for 10 seconds, see what that’s like.” And I started to experience beauty and peace around not trying to control things that obviously were not under my control, not just within me but in other people. And I really started to see what I could only describe as miracles. By miracles, I mean I would pray for some indication of what the right path might be on something where it wasn’t clear to me, and then 2 or 3 days later, something would happen which would seem almost completely unrelated, and the answer would come in that thing. And then I just locked in — I’m like, listen, I’m a disciplined guy when I really want to be, I’m going to pray every night before I go to sleep. If I fall asleep, I’ll get out of bed and pray if I wake up in the middle of the night. I’ve not missed a night in nearly 3 years.

I was recently invited up to Stanford to give a talk with Arthur Brooks, who’s a lifetime Catholic, he’s in Mass every morning. He and I have very different experiences of God and religion. My family was mixed religion. I got to sit up there and just say, “listen, I’ll tell you, I’m for sure the person who’s least knowledgeable, least versed in this room, but what I can tell you is my experience with prayer, what I can tell you is what I’ve observed in myself when I open the aperture for faith.” The reason I did that talk is because our former director of neurosciences at Stanford had written to me and said, “I think you should consider talking to this group.” He did some of the most important experiments in the history of neuroscience linking neuronal activity to perception. It really showed that if you stimulate certain brain areas, people perceive things a certain way regardless of what’s happening out in the world. There’s a brain area I could trigger right now, and I could show you a movie of a bunch of dots moving up, and everyone here would be like, “they’re moving up.” And if I tickled the right neuron in your brain, you’d say, “they’re moving down.” And I’m like, that’s wild. Then I turn it off and you’d say, “oh yeah, of course they’re moving up.” Your understanding of the world is an abstraction that occurs inside your skull on the basis of photons that come in through your eyes, sound waves that hit your ears, mechanical forces that hit your skin, and chemicals that go in your nostrils and in your mouth. And then you abstract reality in here. Now, the laws of physics dictate how those things — photons have properties, sound waves have properties — are transformed into signals, but then you abstract the world with enough accuracy so that I can pick up this pen and not miss it, at least for now.

So if you understand neuroscience that way, and then you go, we don’t see infrared in this room because we don’t have the sensors, but a pit viper does — does that mean that there’s a God? No, not necessarily, that alone doesn’t prove that. But what it does prove is that we only have access to the physical events in the world that we have the filters within us to extract, which is a kind of mealy-mouthed way of saying you can’t see it because you can’t see it, you don’t have the sensors. You can throw on infrared goggles and then you can see it, but that’s a technology. I don’t think there will ever be the “God goggles.” The emotional goggles, so to speak, come from this thing that we call faith. Faith is the infrared goggles of human understanding about why we’re here.

And the challenge for people is, I feel like people come in 3 categories, at least 3. They either were forced into religion in a bad way, so they hate it. They never had access to it in a way that gently pulled them toward it — it was like people knocking on their door, it felt like a disturbance, and I’m not against proselytizing if it’s done kindly and delicately. Or they’re absolutely convinced that it can’t be, which I look at as sort of a spiritual anorexia. There are regions of the brain that, when stimulated, people get a godlike experience — the experience of God, not as themselves, but they feel it. You’ve had this. And so people have said, well, then there’s a God region of the brain, and it’s just a brain region. That can’t be. But we have brain regions — Arthur says this much more eloquently than I could — there are brain regions for thirst, which in the philosophical way, again this is coming from him, not me, would say, well, that proves the existence of water. The thirst proves the existence of water. So I have a thirst circuit for gaining understanding of this thing that we call life, and whatever comes after it. And in that thirst, I decided to open the aperture to the idea that the thing, the stimulus, the water, the photons, I’m not able to extract that through thought, through my eyes, through my ears — just like my dad couldn’t come to understand quantum mechanics by thinking really hard about it, you have to do the math. And there are gaps in my reasoning here, it’s not a perfect one-to-one.

But also, life’s just so much better, man. I don’t think anxiety sticks in us very long if we’re feeling anxious, you pray, “God, please, help me remove this.” It’s not “do this for me,” it’s “help me put energy in me to do the right things today, put energy in me to serve people.” I prayed before I came in here — really, I get on my knees before every podcast, guest or host, and I prayed. I said, “please help me move my ego out of the room.” We all have an ego. “Help me move my ego out of the room. I would hope that people could learn useful information that might help them and that they would propagate that information. Please make sure that I maintain humility, maintain — help me strive for clarity. And help Steven and I do something that we’re not predicting would happen, but that you want to happen, that we don’t understand.” And maybe that’s this part of the conversation, right? I don’t know, and the point is not to know.

It’s also fun as a scientist who loves mechanisms and cells and circuits and neuromodulators — it’s enriching to have a part of life that I can just explore in. I like mysteries. Science is about mysteries, and it’s about solving mysteries, but it’s also about being in awe of the mystery. And I’m all in, man. I mean, I’m all in, differently than other people talk about being all in. And I don’t tell people what to do morally, I’m really just trying to navigate my own path. But it’s one of the best things that ever happened to me. It’s so liberating. And life is still plenty hard, but I love it.

STEVEN BARTLETT: (01:28:35 – 01:29:16) It seems to be an antidote that a lot of people are reaching for now, based on the way that we’ve kind of designed our lives over the last couple of decades — the individualism, the loneliness, the nihilism, the me-me-me, the material success, the low-level narcissism of being on social media and trying to get as many followers as you can. We’ve become islands. And I’ve been thinking a lot about this idea of God and meaning, because it does appear to me that we are meant to be anchored to ourselves, and then our family, and then, I don’t know, our community, and then maybe our city, and then maybe our country, and then maybe the planet, and then something above.

ANDREW HUBERMAN: (01:29:16 – 01:29:19) I mean, you’re an ambitious guy. Go bigger, man. I’m not trying to push you.

STEVEN BARTLETT: (01:29:19 – 01:29:20) No, no, please.

ANDREW HUBERMAN: (01:29:21 – 01:32:41) The biggest thing is that there is a non-human force in the universe that wants goodness and can exemplify perfection. And you and I, if I may, by virtue of being human, by virtue of having circuits — I mean, the famous studies, like people get to stimulate different areas of their brain. You know the area that people like to stimulate a lot? The area that generates frustration and anger, that arousal. I saw that result and I was like, oh man, that’s disappointing. Why not beauty, giddiness, or even feelings of being drunk? They found that too, but they weren’t as interested in that.

Are we bad? No, we’re not bad. We are wired with an animal part of our brain, and we are wired with a conscious, thoughtful part of our brain. And it’s a lot of work to ascend — I know that word is like in the looks-maxing thing now — but to ascend as a human to a place where you’re living in a controlled and thoughtful and peaceful way with yourself and with your pursuits, and you’re striving to put goodness in the world and take care of people, and to do that with a little less friction. I know from experience that comes from trying not to control every aspect of every process, and somehow everything just goes much better.

So people will be like, “oh, he really drank the Kool-Aid.” I don’t know, I actually think this was pumping in my veins from the start. Yes, I worked on a lot of topics — stress, vision, et cetera — but I studied neural development for a long time, and, you know, sperm meets egg and cells start dividing and you get a human. We understand induction factors, I teach developmental neurobiology, cell migration, axon guidance, mesoderm, ectoderm, et cetera. Great — compartmentalized chemistry can give you a human, but there are gaps in our understanding, and there’s magic in that orchestration that goes beyond what the science can even begin to understand. It’s nothing short of spectacular.

Also, who doesn’t want more awe in their life? Dr. Keltner is like the awe guy at Berkeley — he said awe is when you go from small aperture to big aperture, and from big aperture to small aperture. That transition induces awe, and you can hear it in sound too. Like when you walk in off the street and go into — Stanford has this incredible church, Memorial Church, unbelievably beautiful with this giant organ, and you walk in there and people change, not just because it’s a church. There’s this high ceiling, and you go, “wow, this is incredible.” And of course I know humans made it, I’m not an idiot, but there’s this transition from day aperture to holy aperture. And you can get this other ways too, I’m not saying you can’t get this other ways, but I like the idea that if we dial out really far, there’s something much greater than us. I don’t know exactly what form it takes, or exactly what shape it takes, or exactly what ways God would exert influence over our minds, but—

STEVEN BARTLETT: (01:32:42 – 01:32:42) You don’t need to.

ANDREW HUBERMAN: (01:32:42 – 01:32:43) You don’t need to.

STEVEN BARTLETT: (01:32:43 – 01:32:59) This is the thing that I think I have to come to terms with — I go, “okay, this is really interesting, there’s lots of meaning and benefits to my life, if we’re just thinking about benefits.” And then I go, “okay, so which Bible have I got to believe?” And then I start looking at the Bibles and I’m like, “okay, Noah’s Ark—”

ANDREW HUBERMAN: (01:32:59 – 01:34:14) Look at a bunch of them, I think one will call to you more than the others. It may end up being atheism for some people. But when I said “spiritual anorexia” earlier — anorexia is the most deadly of the psychiatric illnesses, it’s incredibly deadly, and something happens to the neural circuits where people with true anorexia feel some sort of sense of, quote unquote, reinforcement — reinforcement is better than reward, reinforcement from avoiding food as opposed to eating it. That runs against our evolution as a species and our health.

But the desire for food, as Arthur would say, proves the existence of food. The desire, the thirst, proves the existence of water. And there are atheists who are like, “yeah, I don’t need it, not for me,” and then there are atheists who have a kind of spiritual anorexia — their spirituality is not believing in a God. And I look at them and go, well, you’re kind of on the same extreme. It’s almost like it wraps around so far that the truly religious people and the atheists kind of meet right there. They both have the same sort of thing, but there’s kind of an inversion of the circuit right there. I don’t know, someone will work out the neuroscience or not. I’m going to keep praying, because my life is that much better.

STEVEN BARTLETT: (01:34:15 – 01:34:18) When I heard you talk about it, I started praying a little bit.

ANDREW HUBERMAN: (01:34:18 – 01:34:18) Oh, right on.

STEVEN BARTLETT: (01:34:19 – 01:35:05) Not all the time, but there have been several moments where I thought, you know what, now would be a good time to just pray. Because someone like you saying that you do it gives a lot of other people permission to try and to investigate for themselves. Because if I’m in the Huberman camp, maybe I’m someone who really cares about scientific rigor and precision, and then if you change that camp to also be open-minded to spirituality and religion and these other pursuits, I can still be ideologically who I believe I am while also investigating these other things. So when I heard you talk about prayer, it was really impactful for me — it gave me permission, I should say, at some level, to also investigate. And yeah, I report the same findings as you, that it helps.

ANDREW HUBERMAN: (01:35:05 – 01:37:02) Yeah, it helps. My former chair and director of neurosciences at Stanford, who encouraged me to do that talk at Veritas, where I mostly talked about how ignorant and naive I am on these topics — he’s a brilliant neuroscientist, he has faith, and I respect him and I respect his mind.

I also think there’s maybe a kind of fun analogy here that just came to mind. This happens in every dimension, like audience and podcasters, but this happened during the pandemic with the health community, and we’re seeing the long tail of that now. But, you know, when you’re a kid, you think your parents are everything, you think they can do no wrong. And then there’s this thing called being an adolescent teenager, and you catch them lying or saying things occasionally, or doing things, and you go, “wait, you said that,” and all of a sudden you’re like, “you don’t know anything.” Then you gain some, hopefully, agency and velocity in life, and you get to this point where you think you know everything and you accept that they don’t, but you’re really the one that understands. I think that as adults, we eventually get to the place after that where we go, “oh wait, it’s outside of me, I’m going to look outside of me.” Then you go, no, everyone — all these adults, we all went through it. And it’s really going, “oh wait, no, I’m looking to humans for something that isn’t going to come from human beings. We’re all flawed, we’re all imperfect.” And so the notion, the belief, that perfection exists outside us, and that we can strive for certain things through works, through practices — that’s not just compelling, that’s downright fantastic to me, because you fully embrace the woes and the beauty of being human in embracing God. It’s kind of a weird thing. So listen, more power to the atheists if they can pull it off without all that. Great. I’m going to keep at it.

STEVEN BARTLETT: (01:37:02 – 01:38:34) Amen. Okay, so we haven’t done number 7, and what’s number 8? We haven’t done number 8.

ANDREW HUBERMAN: (01:38:34 – 01:38:35) Yeah.

STEVEN BARTLETT: (01:38:35 – 01:38:36) And we haven’t done—

Protocol 7: A Dark Sleep Environment

ANDREW HUBERMAN: (01:38:36 – 01:38:41) Well, we sort of did this. So at night, once you’re asleep, try and keep your sleeping environment as dark as possible.

STEVEN BARTLETT: (01:38:41 – 01:38:41) Okay.

ANDREW HUBERMAN: (01:38:41 – 01:39:08) A good eye mask is useful, some people like earplugs too. If you wake up in the middle of the night, do some long exhale breathing, or do the wacky eyes-to-the-side, eyes up, and then counterclockwise and clockwise thing. So at night, dim the lights. Why? Bright lights stimulate cortisol release, and you want your cortisol low at night. Everyone says, “yeah, dim the lights because it suppresses melatonin” — that’s true, but that’s just half of the story. The other reason is it increases cortisol, and you want your cortisol low at night.

STEVEN BARTLETT: (01:39:09 – 01:39:12) What about this whole conversation around phones at night, and blue light?

ANDREW HUBERMAN: (01:39:13 – 01:39:31) Dim your phone, or triple-click program it to go to the red screen. I think, let’s be reasonable, the last 30 minutes before sleep, no screens. First 30 minutes after waking, you should be looking at the sun and exercising, hydrating, and doing that kind of thing.

STEVEN BARTLETT: (01:39:31 – 01:39:33) And chuck the partner out the bed. I’ve had—

ANDREW HUBERMAN: (01:39:33 – 01:39:35) I’ve had some really — oh, they’re sleeping.

STEVEN BARTLETT: (01:39:35 – 01:39:36) Babe, I’m joking.

ANDREW HUBERMAN: (01:39:36 – 01:39:38) I’m the opposite, I’m a spooner.

STEVEN BARTLETT: (01:39:38 – 01:39:40) So am I. You know, I’ve read some studies.

ANDREW HUBERMAN: (01:39:40 – 01:39:42) I sleep best as big spoon. Yeah, with a human.

STEVEN BARTLETT: (01:39:42 – 01:39:50) I have no choice. No, but I did hear a study that it does impact sleep, but who cares?

ANDREW HUBERMAN: (01:39:50 – 01:39:59) I don’t know. The bed cooling thing is very helpful because I tend to run warm, so having another person in there is like really warm. It’s like sleeping with a—

STEVEN BARTLETT: (01:39:59 – 01:39:59) It’s so funny.

Protocol 8/9: Focus and Neuroplasticity

ANDREW HUBERMAN: (01:39:59 – 01:44:17) I don’t want to diminish — I don’t want to do a giant hot water bottle, but she runs really warm, so having the cooling mattress helps.

But okay, you really want to do these 2 things — they actually go very well together. You need to do a bout of work of 90 minutes to 2 hours. You’ve got to strive and try and learn something, do something hard every day mentally. This is critical for your ability to focus.

And by the way, you asked about phones — an awesome study came out. They had people with their phone off, upside down on the table, or in their bag underneath their chair, or in the opposite room, a separate room. What they found is people can focus just fine in all 3 conditions, but if the phone is anywhere in the room, the amount of cognitive flexibility they have with the material they’re focusing on is diminished. In other words, it requires more energy to focus, even if they’re not getting calls and notifications. There’s a subscript running in the brain, apparently, that’s anticipating that this thing is going to reach for me, it’s going to call me. So it’s calling you even if it’s not calling you, which is pretty interesting. And so the way to increase focus and cognitive capacity is actually to just get the phone out of the room. That’s a big part of it.

Visual field matters a lot too — like the kid in school with the hoodie who’s not asleep, that actually is helpful. I talk about some of the history of tools for focus, pharmacology, but also physical devices — they used to design helmets for kids to try and help them focus, the kids that had trouble. The problem is now with the phone, you’ve moved the whole world right in front of you, so focusing just here doesn’t work. But get the phone out of the room and do some effortful learning bout, and it should feel like a fight. Keep in mind the friction you feel trying to learn something — that’s adrenaline. How do we block learning? We block adrenaline and its downstream effects with propranolol. Being alert but calm, or a little stressed, and making errors through deliberate attempts to do something, not just throwaway errors — that’s how you learn.

Why? If I can reach out and grab this pen, my brain doesn’t change. One of the biggest lies in public education about neuroscience is that every experience changes your brain. By the time I’m done saying this, your brain will be different. No, that’s absolutely not true, that’s a bunch of nonsense. I studied neuroplasticity, I teach neuroplasticity. I’ll tell you, you know what induces neuroplasticity? Being a baby who’s trying to learn, or being an adult who’s forcing yourself to try and learn and you can’t do the thing. The error is what stimulates the plasticity. And the appropriate level of difficulty, say the computational modeling, is somewhere around 15% on average.

Now, what does that mean? There are 2 kinds of practice. One is practicing doing things I already know how to do — there you’re aiming for 100% performance, you’re reinforcing what you already know how to do. Talk to a great dancer and they’ll tell you they drill, drill, drill, drill the things they already know how to do. But when you’re trying to learn a new language, a new emotional skill, a new physical skill, a new cognitive-emotional skill, you need to make genuine attempts, and you need to fail some of the time. And those failure signals are relayed to your cerebellum, and your cerebellum propagates through networks that say “change.”

So there’s a set of conditions in the chapter on plasticity that say you need to be alert — I talk about all the ways you can get alert, including pharmacology, supplements, and behavioral tools. Then you need to be focused — I talk about all the tools for focus, which you can devote to anything, not just learning. And then I talk about the conditions for plasticity — you need to get this friction and these errors, and then you need to stop. You need to come back a day or two later, do it again, and then you need to make sure that you reinforce what you learned.

Here’s where AI is going to be a wonderful tool, already is a wonderful tool. The best way to learn is to not forget — meaning if you test yourself mentally, or you could use any one of the LLMs — I’ll go into ChatGPT and say, “generate a short test of graduate-student-at-Stanford-level questions about neuroplasticity,” and I go, “oh, I remember this, there’s this one thing I don’t remember.” That’s how you maintain and build knowledge over time — self-testing. People hear the word “test” and they think of an external tester. You’re the test taker. Self-testing.

STEVEN BARTLETT: (01:44:18 – 01:44:22) That’s a really interesting idea for this podcast episode, which we should definitely run, team.

ANDREW HUBERMAN: (01:44:22 – 01:44:23) Should we generate a quiz?

STEVEN BARTLETT: (01:44:24 – 01:44:28) Yeah. So we can take the transcript and we can turn it into a test.

ANDREW HUBERMAN: (01:44:28 – 01:44:28) Cool.

STEVEN BARTLETT: (01:44:28 – 01:44:34) Of the 10 protocols that you’ve talked through, and we’ll link it below if you want to take the test.

ANDREW HUBERMAN: (01:44:34 – 01:44:35) Awesome.

ANDREW HUBERMAN: (01:44:35 – 01:45:39) ChatGPT is great at doing this. You can change the difficulty, and you can actually say, “I’m a professor of neuroscience, and I want a 15% error rate on average.” It’s pretty cool.

The study I love that really backs this up is that there have been a lot of studies of learning where they have students read the same passage 1, 2, 3, or 4 times, and then they also have them highlight or take notes, or they just have them read it once and self-test. And they look 6 months and 2 years later — reading it once, no notes, no highlighting, and self-testing a week later, looking up what you got wrong or couldn’t remember, led to much more stable learning over time. This doesn’t work so well for physical endeavors, because there you have to actually do the physical thing, you have to test yourself physically. But I love that set of experiments, because it tells us everything we should be doing.

So I think in doing this, for me, it could be a book, or lately I’ve been podcasting and recording my audiobook. Have you done a book?

STEVEN BARTLETT: (01:45:39 – 01:45:41) Yes, and I did the audiobook, which was horrific.

ANDREW HUBERMAN: (01:45:41 – 01:45:42) Are you due for another one?

STEVEN BARTLETT: (01:45:43 – 01:45:47) I am. I’ve actually written it already — I finished writing it last year, but I—

ANDREW HUBERMAN: (01:45:47 – 01:45:47) Oh man, what’s it about?

STEVEN BARTLETT: (01:45:48 – 01:45:57) It’s called Just Fing Do It*. I asked the audience multiple times what they wanted — I showed them multiple covers of books, hundreds of them, and asked them what they wanted, and that was the one that most of them tried to buy.

ANDREW HUBERMAN: (01:45:57 – 01:45:57) Okay.

STEVEN BARTLETT: (01:45:57 – 01:46:17) So it’s really a breakdown of how to do the thing. And actually, I reference you in there, in the chapter about the anterior midcingulate cortex, and what you said about — well, to be clear, I didn’t discover that structure, but I’m happy to expound on all its incredible abilities. I just quote what I heard you say about it on your podcast, but I’ll show you what I wrote.

ANDREW HUBERMAN: (01:46:17 – 01:46:17) Cool.

ANDREW HUBERMAN: (01:46:17 – 01:46:52) I’ll get a copy, I’m late to the train, obviously. I think it’s enriching as a person, it’s not about optimization per se — it’s about being a human being, and effort that’s followed by learning and reward, especially for things that may not immediately benefit you, but just enrich your mind. If you’re interested in the history of medicine, read a hard book, The Prince of Medicine, about Galen. If you’re interested in light, there are a bunch of cool books about sunlight coming out now from people other than me about how cool sunlight is. There are just cool books out there.

STEVEN BARTLETT: (01:46:52 – 01:46:56) But this is linked to brain health and dementia, these kind of things, no?

ANDREW HUBERMAN: (01:46:57 – 01:47:21) To some extent, yeah. The data on dementia say that people who stay mentally and physically active and are socially enriched do much better. In fact, Masud Husain, who is this brilliant neurologist from Oxford, has been talking about patients who, it turns out, live a very long time, have lots of plaques and tangles — the signature anatomical features of Alzheimer’s dementia — but no dementia.

STEVEN BARTLETT: (01:47:21 – 01:47:22) Oh yeah.

ANDREW HUBERMAN: (01:47:22 – 01:48:30) And these people are exercisers, and they stay very avidly engaged in learning. So there are a lot more people with Alzheimer’s walking around — they have all the diagnostic features of Alzheimer’s except the memory loss and dementia. This says that to some extent, the physical ramifications of Alzheimer’s, and the consequence of those changes in neurons, are somewhat separable.

To be fair, he also told me that there are patients with Parkinson’s who can’t generate smooth movement, but if they have to escape a burning building, they can. Which is interesting — a little frustrating as a message, because it could potentially send the wrong message, like they’re just not motivated enough. But it points to the fact that if motivational systems are high enough, there may be alternate motivational systems, in the same way that kids with very severe ADHD, if you give them a video game they love, they are locked and loaded, they’re in a focus tunnel for 2 hours — which tells you they can focus, but not on things they’re not really interested in. And a lot of life is about forcing yourself to be interested in things you don’t really want to do.

STEVEN BARTLETT: (01:48:30 – 01:48:32) So that’s number 4. We got one left — number 10.

ANDREW HUBERMAN: (01:48:32 – 01:48:33) Yeah.

STEVEN BARTLETT: (01:48:33 – 01:48:34) You said they were linked.

Protocol 10: Personal Development — Shut Up, Suit Up, Show Up

ANDREW HUBERMAN: (01:48:34 – 01:54:29) To frame this a little bit — the last chapter of my book is on personal development. I thought a lot about whether I should write a chapter on relationships, and that seemed like a no. Not because I haven’t had them, or because I haven’t had some great ones, but because I think people who work on that as their academic focus should fundamentally be the ones to do that. Then again, I had a chapter on nutrition and exercise too. But in any event, I decided to write about relationship to self.

And then I thought, no, personal development is something we’re all trying to do. Here’s the key question I set up at the beginning. I talk about grief, and what the science of grief is, and how to navigate grief. But early on in that chapter on personal development, I set it up the following way. I look out on the landscape of all the personal, psychological, and relationship development stuff out there — online, in books, in papers, et cetera — and it looks like there are sort of 2 bins. One is how to find what’s important to you, do what’s best for you, and be the person you’re supposed to be for the world, and maybe for yourself too. And then there’s this other bin, which is that we need to be very careful about pursuing things and fulfilling roles, because we can get very far off track from our core, what Martha Beck would call our essential self. I’m a huge fan of her work, in no small part because she talked about that in her books, which were very impactful for me. She also has 3 degrees from Harvard, so this isn’t somebody who can’t get stuff done. She’s a mom, and she’s navigated complicated life landscapes.

So I was like, okay, this is kind of it. And then I hosted James Hollis, this 84-year-old Jungian analyst, on my podcast, and he just wowed the heck out of all of us. He basically said this — mind you, this guy’s written books like The Eden Project, on relationships, books like Under Saturn’s Shadow, on the healing and trauma of men, he’s a brilliant thinker — he said, look, there are 3 things you’ve got to do every day. He encourages his patients to write this on their refrigerator or carry it around with them.

First, he said, “shut up.” I’m like, what? I thought it was going to be like this nice Jungian analyst. He goes, “shut up, because there’s always somebody suffering more than you. You have to have gratitude, you have to have a gratitude practice.” So I spend some time talking about what that really looks like, because there’s a science of gratitude, and then there’s the common understanding of what that is. It’s really about receiving gratitude — or, yes, having a gratitude practice of all the things that are good in your life, but really it’s about giving gratitude and receiving gratitude. I talk about that and how to accomplish it.

Second thing he said — so I go, okay, now he’ll kind of soften up — and he says, “suit up.” You’re not going to be able to do well in anything in life unless you prepare, take care of it. Get up in the morning, take care of your health, do what you need to do — shower, brush your teeth, get organized. This sounds a little bit like Jordan Peterson’s “clean your room,” but it was even edgier than that. It was like, how in the world could you perform well on an exam, or in a relationship, or in a sport, or at work, if you don’t actually do your homework? I was like, oh man, this is some boomer knowledge right here.

And then he says, “and show up.” He said happy people fulfill outward roles for the world — they fulfill roles, father, mother, sister, brother — and this is not the totality of it, but they look at themselves as somebody who needs to fulfill roles: teacher, mechanic, whatever, engineer, podcaster. But you have to shut up, suit up, and show up. You need to fulfill roles. There is no human being that doesn’t have to do stuff for the world, you can’t freeload.

But then he said, there’s this other bin, which is: if you carry on like that for 10, 20, 30 years, you can end up quite happy. But most of the time, if people just do those things, they end up pretty miserable. And I was like, oh man. He said the other piece is: once a day, you need to get out of role fulfillment, you need to get out of preparation, suiting up, and you need to get out of trying to be more grateful. You still need to do that, but you need to get out of that, and go into what he called exiting the stimulus-response mode of being — which could be sitting quietly in meditation, it could be drawing, listening to music. You’re not trying to accomplish anything, you’re just letting your unconscious mind feed you information about what he called your deepest heart’s desires.

I was like, “yes, this is why we go camping.” He said, “yes, you can take longer extended breaks, you can go backpacking, you can run, you can do that. You can allow this to happen in any number of ways. But once a day, take some space for yourself and just touch in with self.” Now, if you’re sitting there going, “okay, what do I want to be when I grow up,” it should happen — it’s not the way it works. Your unconscious mind speaks to you in emotions, in analogies, and it sets you up to go back into life to be able to see connections and start navigating in new and interesting ways, ways that are unique to your heart’s desires about what you like and what you don’t like, and to know that those choices are in goodness and in keeping with who you are.

I can’t tell you what your deepest heart’s desires are, only you can come to that clarity, but you need to do it through a practice where you’re not trying to be the football coach, the mom, the best this. You need to listen to yourself, but you also need to keep fulfilling those roles, because he and I both agree, and I get asked all the time, “how do I find my calling?” You find it while working your butt off doing something else. That’s how. You don’t sit around going, “oh, that’s my calling.” You work your butt off doing something else, and you hate it, so you do something you hate a little less, then you do something you hate a little less maybe, and eventually you get pulled forward to this thing that is your key self.

STEVEN BARTLETT: (01:54:29 – 01:54:42) And there’s not necessarily — because people often, when they talk about finding your passion, “passion” is a word that happens to be singular, which can be somewhat distorting, because then you think almost like an Easter egg — I have to go search for it, and there’s going to be one of them somewhere.

ANDREW HUBERMAN: (01:54:43 – 01:55:04) I can handle 5-year chunks. Maybe this just reflects my years and years of getting degrees, where it’s like 3 to 5 years for this, then 3 to 5 years for that — postdoc, graduate school, et cetera. I’m navigating from 50 to 55 now. That’s what I know. I know what I’m going to carry forward — exercise, faith, hydration. So I know what I’m going to carry forward, but I don’t know what’s coming next. I’ve never been 60 before.

Sleep Position, Glymphatic Clearance, and Meditation

STEVEN BARTLETT: (01:55:05 – 01:55:19) So at the end of the day, there were 2 questions that I had for you here based on some of the research. The first is, I’ll say it’s a technical one, but sleeping on your side — I heard there’s different outcomes for your brain based on how you sleep at night.

ANDREW HUBERMAN: (01:55:19 – 01:55:35) Yeah. When you sleep, you have a washout of waste products from the brain — very important for offsetting dementia, very important for feeling rested. And if that’s not enough incentive, very important for getting rid of bags under your eyes. In the morning, when you’ve — have you ever seen yourself after one night’s terrible sleep?

STEVEN BARTLETT: (01:55:35 – 01:55:35) Oh my gosh.

ANDREW HUBERMAN: (01:55:36 – 01:55:38) Sleep 2 nights well, you see yourself.

STEVEN BARTLETT: (01:55:38 – 01:55:38) Yeah, you’re like, what the hell?

ANDREW HUBERMAN: (01:55:38 – 01:55:48) Yeah, you’re your handsome self again, Steven. So what is that? That’s accumulation of lymph and other fluids and waste products that’s getting flushed out.

STEVEN BARTLETT: (01:55:49 – 01:55:49) Really?

ANDREW HUBERMAN: (01:55:49 – 01:59:06) So during sleep, there’s this glymphatic clearance, and it does seem it can be slightly but significantly improved by sleeping on your side with your head slightly elevated. We used to think it was slightly inverted, now we think it’s slightly elevated. When you get up in the morning — I’m actually a big fan, I’ve got one of these inversion tables, but most people won’t, where you lie back and go upside down. This feels good on my back. But some people get the shaker, some people do some jump rope, you can just kind of shake out and move.

Because the lymphatic system is really incredible. It’s one-way valves stacked up from your feet all the way up to your brain. People think about the role of lymph and lymph nodes in immune checkpoints and the immune system — that’s all true, of course, but the lymph system is taking liquid and dumping it back into your blood circulation, and it can accumulate when you’re lying down, or when you’re — this is lymphedema, swelling of the lower limbs, et cetera. So you need to move. When you move, you’re essentially squeezing the lymph in these one-way valves up to dump back into the general circulation.

Your brain doesn’t have that mechanism, so miraculously, in sleep, the astrocytes, the glial cells, actually create a bit of extra space in the brain between neural tissue that allows the waste products — the glymph, as we call it, glia-lymph, glymph — to flow up and out towards the surface of the brain, and then it dumps out of the brain, still in the body, of course, and down and out. Actually, the puffiness of the eyes, the anterior chamber of the eye, some of the cloudiness of the eye — these systems are shared. And actually, some of it comes out through the nose, which is wild.

But get upright, move around. There’s a bunch of ways of, like, tapping, shaking — it looks silly, it looks kind of crazy, looks like you’ve been in California too long if you do these things, but it can help move lymph out. But sleeping does that too, clears glymph.

The other thing that’s — there’s a recent study published in Proceedings of the National Academy of Sciences that I detail in the book, which is that a short meditation, believe it or not, increases glymphatic clearance in the daytime. Now, this is super interesting, because folks like you and me always want to figure out how we can get by with less sleep and still feel awesome and not short-circuit our health. Turns out that regular meditators are probably able to shave an hour off their sleep — 20 minutes a day of meditation — because they’re getting the glymph clearance during their meditation. And so in sleep, the timing of sleep and how long you sleep has a lot to do with body temperature, but there also seems to be a drive for glymph clearance that says you need to sleep longer, which is one of the reasons why when you’re sick, you sleep a lot more. That’s one of the reasons, there are others as well.

So I’m now back to meditating, and my meditation practice is pretty feeble compared to many, but here’s what I do. I wake up in the morning, and the first thing I do is 10 breaths of meditation. I tell myself, if I can’t concentrate for 10 breaths without my mind going elsewhere, what kind of day am I going to have? And also, what kind of human am I if I can’t organize myself for 10 breaths? Then I get out of bed. I usually go straight to the bathroom, pee, then I hydrate, then I get sunlight, then I try and get some movement. Although these days, because of the dog, I get a walk in, then I come back, drink some caffeine, exercise.

STEVEN BARTLETT: (01:59:07 – 01:59:08) And the 10-step starts.

ANDREW HUBERMAN: (01:59:08 – 01:59:16) Yeah, it starts all over again. We are this rhythm. No human being has ever escaped these circadian influences in cortisol and melatonin.

STEVEN BARTLETT: (01:59:16 – 01:59:20) You don’t really talk in depth about supplements or recommend supplements.

Supplements

ANDREW HUBERMAN: (01:59:20 – 01:59:45) Oh, I do. I always get asked, “what should I take?” I talk about alpha-GPC, L-tyrosine. I talk about theanine, and theanine’s use with low-dose caffeine for enhanced task switching, which is a very interesting literature. I talk about ways to improve sleep — everything from tart cherry to apigenin, to Quviviq, which is one of the DORAs, one of these orexin drugs. I—

STEVEN BARTLETT: (01:59:46 – 01:59:47) But what do you take every day?

ANDREW HUBERMAN: (01:59:48 – 01:59:51) You got another 3 hours? No, no, no, no, not really.

STEVEN BARTLETT: (01:59:51 – 01:59:57) What if you had to pick 5? If they said, “you can only do 5 for the rest of your life,” what 5 supplements would it be?

ANDREW HUBERMAN: (01:59:57 – 02:00:16) Well, if somebody’s sleeping terrifically well, I’d say nothing for sleep. If they’re not sleeping terrifically well, I would suggest they try magnesium threonate or magnesium bisglycinate — they’re interchangeable for sleep. Okay, that’s one. I’m a big believer in getting at least 1 gram per day of EPA omega-3.

STEVEN BARTLETT: (02:00:16 – 02:00:16) Okay.

ANDREW HUBERMAN: (02:00:17 – 02:00:31) I suggest getting it because it’s now available generic and cheap, but in prescription form — Lovaza EPA — the form of omega-3 that you want for brain health, and probably also for cardiovascular health and reduced inflammation.

STEVEN BARTLETT: (02:00:31 – 02:00:32) How do I know if that’s the omega-3 that I have?

ANDREW HUBERMAN: (02:00:33 – 02:00:34) You need a prescription.

STEVEN BARTLETT: (02:00:34 – 02:00:35) Oh, you need a prescription.

ANDREW HUBERMAN: (02:00:35 – 02:00:39) But here’s what’s awesome about it — it’s very high concentration EPA, and it’s cleared of all heavy metals.

STEVEN BARTLETT: (02:00:40 – 02:00:40) Okay.

ANDREW HUBERMAN: (02:00:41 – 02:01:26) And it’s very, very inexpensive. So the challenge is getting a doctor to prescribe it for you — just tell them you want Lovaza, or else you’re going to take a bunch of stuff over the counter and might get mercury poisoning. Don’t threaten your doctor, but you get the idea. So that’s for mental health, physical health — big believer in boosting omega-3s. Also, I don’t eat fatty fish, I don’t like salmon unless it’s sushi, and I’m just not good at eating seafood. So that’s 2.

Vitamin D — 5,000 to 10,000 IUs per day. People will say, “oh, you don’t know that, you need a blood test, you don’t want to overdo it” — okay, don’t take 25,000, but most people are underdosing vitamin D. And I know it annoys people, but I’m not trying to hit the RDA.

STEVEN BARTLETT: (02:01:27 – 02:01:28) The recommended daily allowance.

ANDREW HUBERMAN: (02:01:28 – 02:02:29) Yeah. I’m not just trying to hit the RDA, and I’m also not trying to blow a gasket by taking too much — let’s be rational here. I’m trying to get to a point where I can derive safety but additional benefits. And it’s clear that dosing of 5,000 IU per day has some additional benefits that go way beyond the conventional benefits of vitamin D that are discussed — for instance, hormone health. I can see my blood work getting better when I take 5,000 as opposed to 3,000 IU of vitamin D, and I’m not changing anything else. So vitamin D, and I get sunlight — maybe 10,000 was a little high, but I take 5,000 to 10,000. So that’s 3.

And then the other 2 would be, if you’re going to exercise or work intensely late in the day, or if you really want a stimulant to go with your caffeine — by the way, 90% of the world consumes caffeine every day, so that’s a foregone conclusion that they’re already taking it — I am a big fan of alpha-GPC. 600 milligrams or 900 milligrams of it.

STEVEN BARTLETT: (02:02:29 – 02:02:29) What’s that?

ANDREW HUBERMAN: (02:02:30 – 02:02:32) It increases choline, which increases acetylcholine.

STEVEN BARTLETT: (02:02:32 – 02:02:34) Oh, I’ve got acetylcholine in the cupboard.

ANDREW HUBERMAN: (02:02:34 – 02:03:12) Yeah, which can increase your ability to focus. I’m a big believer in this. It’s not for everyone, but rather than going straight to a prescription stimulant — and I’ll tell you why — there are very, very few things that can increase focus and energy that don’t damage your sleep. But even better, alpha-GPC gives you more REM sleep. Nobody wants to hear this, but it’s absolutely true. The important caveat is that it can increase something called TMAO, which can increase cardiovascular risk. A simple way to mitigate that is you take 600 milligrams of a garlic capsule, and it doesn’t smell like garlic, so I kind of tuck that in with it. You can take it anytime, same day.

STEVEN BARTLETT: (02:03:13 – 02:03:14) Is that 5?

ANDREW HUBERMAN: (02:03:14 – 02:04:22) That’s 5 because I threw garlic in there. No — because we said magnesium bisglycinate or threonate, we said omega-3, we said vitamin D, and then we said alpha-GPC would be my preferable thing to nicotine or prescription stimulants. But caffeine is great — great data on caffeine. In fact, 200 to 400 milligrams of caffeine per day has been shown to offset dementia in meaningful ways. It’s not causal, it’s correlative, but those data are covered in the book as well. So I’m going to continue drinking my yerba mate and my coffee.

I suppose the last one is kind of like creatine — dealer’s choice. But creatine seems to work best for cognitive enhancement when you’re a bit sleep deprived or stressed, this kind of thing. I’ve been taking creatine since I was 17 or 18, somewhere in there, 5 to 10 grams per day. I like it because I’m trying to maintain or build strength, and it puts water in your muscles and makes you stronger, and it feels good to be strong, and you’ve got to train, but that’s why I take it.

Walking After Meals and Blood Glucose

STEVEN BARTLETT: (02:04:22 – 02:04:33) The last thing I wanted to ask you about — I saw a clip, I think it was one of your most viral clips of all time, where you talked about how going for a walk after you eat can have a really big impact on your body.

ANDREW HUBERMAN: (02:04:34 – 02:04:34) Yes.

STEVEN BARTLETT: (02:04:35 – 02:04:35) That most people don’t realize.

ANDREW HUBERMAN: (02:04:36 – 02:06:29) Most people don’t realize. There’s a section — I think walking is necessary but not sufficient for health. I don’t think you need to count 10,000 steps per day, but I think 7,000 to 8,000 steps per day should be the goal. You can do it. I’ll pace while I’m on calls. Every time I finish a podcast with my team, we take a walk. I’m always trying to take stairs when I travel — I take stairs, not the escalator. You arrive a little sweatier to your plane, but you’re also rucking your bags, this kind of thing.

So walking is incredible because those low-level repeated muscle contractions really help buffer blood glucose, especially after a meal. There’s this wild study on the soleus muscle — the one that gives the calf width, you know, when you do seated calf raises, it’s this muscle underneath the gastrocnemius. That muscle is about 1% of your total musculature, but it has an outsized and significant glucose utilization. In this study, which is not practical, they had people do what they called soleus push-ups — basically non-weighted seated calf raises while sitting, done repeatedly — and they looked at blood glucose regulation, and it powerfully regulated blood glucose, it buffered the peaks.

And it turns out this is related to walking. So unless perhaps you’re stuck on a plane or in an office, I’m not suggesting you should do this all day — some people probably would accuse us of that. No, what I’m saying is walk, because when you walk, you’re getting that low-level repeated muscle contraction. It’s a slow-twitch muscle, and it seems to be — I don’t want to call it a sink, but it seems to be an unsuspected furnace for glucose utilization.

STEVEN BARTLETT: (02:06:29 – 02:06:30) And why does that matter?

ANDREW HUBERMAN: (02:06:31 – 02:11:10) You don’t want big peaks in glucose. You can manage them — more insulin will be secreted if you have a big peak in glucose, that’s why insulin’s there, to make sure glucose is managed. You don’t want it too high, you don’t want to be hyperglycemic — in fact, that can be deadly. You don’t want to be hypoglycemic either.

But when people eat, they experience an increase in blood glucose, and while the peaks are manageable if you’re buffering them — so you’re sort of flattening out those peaks with 5 to 10 minutes of walking after a meal — you will have fewer energy crashes. In theory, over time, your metabolic health can be better, or at least cannot get worse. Dr. Rhonda Patrick has pointed out there’s a comparison study where people either walked after meals for 30 minutes or so per day, or did 10 air squats every 45 minutes or so — just stand up and do air squats — and it looks like they were comparable, maybe the air squats were even better. I don’t know about you, but I’m not going to stand up and do air squats in a restaurant, or when I get out onto the street of New York — if I have the great experience of having dinner with you and James Sexton again, like last time — I’m not going to do air squats, we’re going to walk. So I’m not being disparaging of Rhonda, I think she was pointing out a mechanistic feature, not a protocol necessarily. But if you’re stuck on a plane, you could do some air squats, you could bounce your knee — non-exercise-induced thermogenesis is a massive calorie burn.

People who move a lot tend to be rather thin, they tend to be lean. I go back to my undergraduate days when we worked on metabolism and physiology, scientists like Rothwell and Stock and some other folks who figured out that there were people who could eat a lot more than you would think they needed, but they always stayed lean. Turns out they’re moving a lot during the day, burning up to 1,800 calories a day. Now, that’s extreme, but some people who just move a bit more, about 1,000 calories per day.

There’s this paper published in the journal Science — great journal, not as great as Nature, the Brits get the cake there, people will argue, but it’s true — that the decline in metabolism that we all associate with aging, “oh, metabolism slows as you age,” turns out that’s not true. Turns out that if people maintain muscle mass, that doesn’t happen. So you say, okay, well then aging is muscle mass loss, is reduction in metabolism. Actually, no — people are moving less.

I’ve been, as everyone else has been, absorbed with this longevity thing, and I look at older people, in particular people in their 80s, and you know what I see a lot of? A lot less spontaneous movement, and a lot of mouth breathing, which at rest is not good — we know this, it deprives the brain of oxygen, it’s not good. You can mouth breathe during exercise, physiological sighs, et cetera, but you don’t want to be a mouth breather in sleep or in wakefulness.

And then you host people like James Hollis, or Twyla Tharp, who’s — I don’t know her exact age, I think she’s in her early 80s — choreographer, world-class dancer, who deadlifts a lot and works out for 2 hours a day at 5 in the morning, who boxes, who choreographs. They’re so mentally sharp, they’re physically lean. There are other examples I could rattle off. What is happening? Mike Snyder, my colleague at Stanford, who’s not that old, but he’s in his 70s — you look at him and go, what’s going on? And they’re moving all the time, they’re mentally active. They have posture like you, they’re exercising sure, but they are moving, moving, moving. The spontaneous movement is burning calories, that’s one piece, but it’s also the glucose regulation, it’s the fact that they’re not sitting stagnant.

Blaine Norton has pointed out quite beautifully, actually, that what’s the problem with caloric excess? There’s the fat, aesthetic piece, right, body fat aesthetic piece, but that aside, it’s that you have a toxicity of energy. The world’s expert in mitochondria came on my podcast recently, Jared Rutter — he’s a phenom in the biochemistry and genetics of mitochondria. And he’ll tell you, when you overload a system, and therefore a cell, with calories, the mitochondria, the whole system gets sick — the energy management system of a cell gets sick. And your metabolism, this thing that you call your metabolism, is the collective makeup of all these trillions of cells. So you jam too much fuel in there, and they don’t work as well. Caloric restriction at times might be beneficial, caloric maintenance maybe a little bit more at times, a little bit less. So movement, movement, movement, because it’s obviously calories in, calories out.

STEVEN BARTLETT: (02:11:10 – 02:11:11) You know what this is, right?

ANDREW HUBERMAN: (02:11:11 – 02:11:13) You’re telling me I need to stop?

STEVEN BARTLETT: (02:11:13 – 02:11:19) No, no, no, no, no. This is not a clock. This is a CO2 monitor.

ANDREW HUBERMAN: (02:11:19 – 02:11:22) I thought it was a lux meter. Okay, okay. How hard — oh, we have a lot of CO2 in here.

STEVEN BARTLETT: (02:11:22 – 02:11:35) Yeah, it’s something we always have in the studio, because I think I learned over time that the higher this got, the more tired I felt. Obviously because there’s not great ventilation in this studio here, we started at 600 and we’re now at 1,700, and we’re under short-wavelength light.

ANDREW HUBERMAN: (02:11:35 – 02:11:41) Light. But before we came in here, what did we do? We went outside and got a blast of full spectrum sunlight.

STEVEN BARTLETT: (02:11:42 – 02:11:51) Sunlight. Yeah, I think about this a lot now when I’m trying to do good cognitive work, because I’ve read some studies that if this gets above 1,000 parts per million, cognitive performance starts to go down.

ANDREW HUBERMAN: (02:11:51 – 02:11:56) Well, if your cognitive performance gets any better, we’re all in trouble, because you’re very kind.

Closing

STEVEN BARTLETT: (02:11:56 – 02:12:36) Andrew, thank you so much for so many reasons. It’s such an honor to get to learn from you. There’s no books that I’ve been waiting for — is there any book in my life that I’ve been waiting for? No, there’s not. This is the only book in my life that I’ve been waiting for, for years now. And I say that because I believe in your approach, your scientific rigor, the nuance you apply, the stories that you tell, the experiences you’ve had, the unbelievable, almost mesmerizing ability you have to remember things, remember names. You didn’t reference one study without referencing the author of the study. I’ve never seen that — I was thinking, how the f* has he done that? How do you know all the names of all these people?

ANDREW HUBERMAN: (02:12:36 – 02:12:42) Years of training, and advisors who drilled into me that attribution is important.

STEVEN BARTLETT: (02:12:42 – 02:12:51) It’s remarkable. There’s so much information out there around health and all the things we’ve discussed today, but I was waiting for your book because I’m not very good at reading books.

ANDREW HUBERMAN: (02:12:52 – 02:12:55) Well, there’s an audio version too, if you prefer. It’ll be a long run.

STEVEN BARTLETT: (02:12:56 – 02:13:08) No, I’m trying to build the anterior midcingulate cortex, Andrew. I always said to myself, whenever he publishes that book, I will read the whole thing from cover to cover. And this is the first copy in the world, I believe, that’s been printed.

ANDREW HUBERMAN: (02:13:08 – 02:14:21) Yeah. This is an opportunity to say what I’ve been waiting this entire podcast to say. The copy you’re holding in your hand is the first, the very first, and the only hardcover copy that I have, or have touched, or have seen, and I’m gifting it to you. I want you to have the book. Seriously, I want you to have it. And I’ll sign it if you want, or not sign it if you don’t. But it would be an honor for me to be able to do that, because I’ve learned so much from you. You’ve been an amazing colleague and friend and supporter, but also just really, you’re an amazing human being. You’re a truly good human being. I’ve spent time with you on and off mic, and the number one thing you need to know about Steven is he is who he appears to be. He’s a super kind, curious, loving person, flawed like the rest of us, albeit less flawed than me — that’s clear. But you really are a great human being, and you’re trying to do great things in the world for everyone around you, and for the world. So it’s a vastly lesser token of my gratitude to you for all those things than it could be or should be, but I’d like to gift it to you.

STEVEN BARTLETT: (02:14:22 – 02:14:25) No, it’s such an honor. I was thinking of ways to steal it, so go ahead.

ANDREW HUBERMAN: (02:14:25 – 02:14:32) I’m gifting it to you. And now I’m going to go read your book, and I look forward to your next book.

STEVEN BARTLETT: (02:14:32 – 02:15:08) Yeah, me too, thank you so much. It’s such a beautiful book. I’m really glad that it netted out at the size that it did as well, it’s I think the perfect size. And I think you’ve done a wonderful job throughout — as I was flicking through as you were speaking and jumping to different sections, I think you’ve done a wonderful job of making it really accessible. Because I’m not the smartest cookie as it relates to science, but I was able to understand everything, and I think that’s a really remarkable thing. It’s also gorgeous — dare I say, and I’ll probably get f*ed up for this, but I think sometimes the British version of books are good-looking, and then the American versions, I always wonder why they’re a little bit uglier.

ANDREW HUBERMAN: (02:15:08 – 02:15:28) The aesthetics in Britain — people dress really well in Britain, they take care, they pay attention to these little details, like in their shoes and things. What do you call it, smart. They dress really smart. I’m a big fan of Ben Sherman and Fred Perry clothes and things like that. I like — the details are what make those look so cool.

STEVEN BARTLETT: (02:15:29 – 02:16:03) Well, this felt like a very European design, beautiful book. And also your podcast is incredible, I have to say — so many of the guests that I’ve had on here are because I listened to your show and got mind-blown by the guests that you have on your show, and I’m like to my team, “oh my God, this person is unbelievable, he said this,” and I’m sending your podcast all around. Whenever someone in my life is really struggling with something, I go out and search usually on YouTube and then I stumble across your channel and find an episode that you’ve done about that particular thing, and I’m always sending them around. So I highly recommend anyone that subscribes to this channel go and subscribe over on your show as well. I’ll link it below so everyone can get it.

ANDREW HUBERMAN: (02:16:03 – 02:16:09) So it turns out Huberman Lab is a sort of gateway drug to Diary of a CEO for science and health content. Literally.

STEVEN BARTLETT: (02:16:10 – 02:16:25) It’s worth being honest about it. And you’ve got to get the book, it’s finally here. Comes out September, so this episode will air in September, so it should be out now for preorder or order. You’ve got to go get it. For me, it’s the definitive book on this subject. Thank you so much, Andy.

ANDREW HUBERMAN: (02:16:25 – 02:16:26) Thank you, Steven.

STEVEN BARTLETT: (02:16:26 – 02:16:29) I appreciate it. Loved this conversation. I hope to have another conversation sometime soon.

ANDREW HUBERMAN: (02:16:29 – 02:16:29) Yes.

Related Posts

• Mel Robbins Podcast: w/ Gut Specialist Dr. Rajsree Nambudripad (Transcript)
• Transcript of FO556 Raj Shamani Interview: w/ Andrew Huberman
• Transcript of Tukaram Mundhe Interview: Nation Wants To Know With Arnab Goswami
• Transcript: Dr Andy Galpin Interview on The Diary Of A CEO
• Transcript of David Sinclair Interview: Joe Rogan Experience #2537