Scientist WARNS: You're Being LIED To About Sunlight

0:00 The next thing, and this is really key, it could have gone first, but you want to view sunlight or 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 that activates these melanopsin intrinsically photosensitive ganglion cells, you know, 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 superchiasmatic 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 Mhm. Compared to the overhead sky.

0:46 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." Okay. 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, which there are two 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 is sort of hangs outside the brain, and then adrenals. You release adrenaline. There's a unique window that passes

1:33 after about an hour following waking, where your superchiasmatic 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. Here's what it would look like if you didn't view bright light in the first hour of your day. It would be here, 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, they'll say, "There's no sun where I live." Okay, this could easily see it say daylight. Why? Because there's always daylight out. If you look at how bright it is on an

2:18 overcast day in the middle of December, even in the UK, at 8:00 a.m. versus midnight the night before, it's different. >> Mhm. >> You know, it's obvious. When there's overcast skies, less of the long wavelength lights, 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, let's call them, at night, which is great. Buffers stress. And, moreover, kick-starts 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

3:04 the book, I explain a number of different ways how this peak relates to this trough, if people are interested, but if you don't have access to sunlight or daylight, having it 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, etc. 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. So, having bright days is great for your mental health and physical health along a huge number of parameters. Significantly improves them. But, having dark, even if you were in dim light all day, making it dark at night, people are healthier. The risk of dying early, if you have bright nights,

3:50 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. >> And when last time we spoke, you took me outside after the conversation and you had an app on your phone. >> Right, light meter. Now, I have no relationship to the app, but I use it. >> And that is able to tell you how much lux of light you're getting at the moment. >> 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 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

4:35 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 it's not completely scattered, but not as much of that is 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 kick-start this increase in cortisol in the morning, but they are very capable of increasing your cortisol levels at night because the this low level of cortisol makes you vulnerable to big increases in cortisol.

5:21 It's a little bit of a detail that I 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 to be exposed to it? >> 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. Uh beautiful work from Glenn Jeffries lab at University College London. You know, I can't believe this. They do a glucose tolerance test. So, they fast people, they have them drink a glucose drink, they measure how fast a blood sugar rises. And if they shine red light, so long wavelength is red is long wavelength light. >> Like that, like that. >> Yeah, like this would be medium wavelength cuz it's yellow. A red would be um so this is probably I'm guessing somewhere between 500 and 600 nanometers of light, and red would be probably somewhere between 580 and 700, and then

6:08 infrared goes out further, you know, into the 800s and thousand. The sun emits all of those. Okay, so this is long wavelength light. Okay. So, they shine the long wavelength light on people's backs, and they do the glucose tolerance test, and 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. >> Just to summarize, they shine red light on someone's back while they have a glucose shot, and their glucose spike is lower. >> 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 can It gets absorbed, and it can go about 8 cm into the body, red light.

6:55 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 This is so amazing. It actually allows your mitochondria to 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

7:40 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 cuz 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 from Glen Jeffery's lab and others that it actually may damage the mitochondria. We talked about melatonin coming from 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 protects you against the oxidative stress and damage to cells. And this has many many positive effects. So

8:26 Glen's lab has done experiments where they literally taken a light like this and they have people look at it like this 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, right? He's not he's not a biohacker. He's not he's has no interest in commercial products actually. 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 they go, "No, your your

9:12 everyone makes a claim on this." 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 us in this. So 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. What? Yes, your eyes and your body and brain are not the same at 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

10:00 increases. Not immediately, but it increases gradually. Your need for bright light in your eyes in the early part of the of the day is immense. You need this. You 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 two to three times per week when the UV index is low. You can just look on your phone, what's the UV index? And in general, be the earlier that or the later half of your day when the UV index is lower. And to get out 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, Glenn Jeffery and Robert and Roger Swartz, he's a physician who talks about the immense benefits of getting sunlight onto the

10:47 skin for getting over disease, for enhancing immune system function, and on and on. >> Can you cuz there's going to be little people right now that are going to go buy red light lamp? >> Not necessary. >> No, sunlight. Pink Floyd. Pink Floyd Apple 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 UV B 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, etc. Strong effects. So, sunlight has it all. What you don't want is to go outside when there's so much UV that you

11:33 get a sunburn. And you don't want to think that, you know, red light's the only light you need. You want that warmth from from the sun. And it gets better because And notice I'm I'm sort of like it gets better like a salesman. I'm selling nature. Okay, I'm telling you 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 look and they 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 Rod 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

12:19 around, and it goes through you. So, get out into nature. Walk outside. If you work in a work and live in a city, get outside. Take off a brimmed hat because you do want that the sun getting down onto your 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 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 um but we have to admit it's there, lived longer than non-smokers who didn't get enough sunlight. There And there are other things, too, like exercise, etc. But don't smoke, but get sunlight. There'll be a lot of night shift >> workers listening. >> I have a section specifically for night shift workers because

13:05 here are the two 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 nightshift work, barring some of the more extreme ones, was most of them were on how many people after 6:00 p.m., right, 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 nightshift worker. You don't have to work all night to be a nightshift worker. So, we have a

13:51 generation of kids that are metabolically sick. And I don't like to be one of these like fearmonger people, but here's the cool thing. I'm going to skip, cuz we're on to this, I'm going to skip to number six. Okay. >> Okay. >> Okay? As the sun is going down, you don't have to watch the sunset. That would be cool to watch the sun 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 like 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, cuz we all get up and go to sleep at different times, you buffer you those cells in your eye

14:38 against the negative effects of artificial light at night. This is your Netflix inoculation, as I call it. Like you can be on your computer at 9:00 or 10:00 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

15:23 problem. Remember I said high cortisol sets you up for low cortisol? >> Yeah. >> Low cortisol sets you up for high cortisol. So, you've got a population of people, kids, who have their 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. >> Mhm. >> You know, 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, you know, like my new bulldog, Strummer, clings to a chew toy, you know, it's like you take it away from them, but like they hate you for it. So, I said view daylight cuz 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. >> Mhm. >> I feel like I'm giving a lecture in class. >> That's amazing. That's what I wanted to >> we said hydrate, sunlight, and then number three, I know everyone's heard

16:10 it, but if you can exercise in the first three to four 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 three hours of your day. >> Cardiovascular or resistance training? >> Yeah. And in the book I devoted an entire chapter, chapter two, 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. And it's basically structured you either lift or do cardio on alternating days. Three days total of lifting. Warm-up, reasonably low volume of work sets, two

16:55 to three work sets per exercise, emphasizing compound movements. So, not a like 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 muscles at once. >> Multiple joints moving at once is compound ex- um some hip hinge movement, so could could squat, hack squat, some deadlifts, and then I talk about how to get specific aesthetic effects in there, too. I mean, I'm by no means an exercise physiologist, but I've been resistance training since I was 16. I'm I'm now 50. I'll be 51 in a month. So, I feel great. >> Cardio at the start if you're doing resistance training or not at all? >> 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. One day of cardio is long and slow for about an hour. One is about 30 minutes at moderate intensity. One is a

17:42 short one like I did this morning I'm I'm 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. >> Mhm. >> And the day after leg day, if you do your legs right, take a rest day. >> Yeah. >> Yeah. But the here's the interesting thing about exercise. You notice I didn't say deliberate cold exposure. You want [clears throat] 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 cuz a lot of people said, "Is your book going to be for women and

18:27 men?" I distinguish between data when there are data showing that it's different for women and men. I acknowledge when there's no data in women. 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 that 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. >> Mhm. >> 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.

19:13 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 going to 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, "Oh, the surface of my body is warm. I should probably cool my core body temperature down." And you fall asleep better. You know, this is like the the putting socks on effect or the hot bath effect, right? >> I assume a massage or something like that also. >> Great. You have access to that in the last hour of your day like we need to learn more about your life. >> [laughter] >> My fiance used to be a masseuse for many

19:58 years, so she >> Awesome. So, when you exercise for a few days early in the first 3 hours of your day, let's say you do that two 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 change. Your superchiasmatic nucleus all day is clocking what you're doing. Let's say you eat like 9:00, 12:00, snack at 3:00, and 6:30. You have a food anticipatory signal. You have 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,

20:44 but a lot of it actually is your brain is anticipating exercise is coming. Oh, cool. That's I use I teach neuroanatomy, so this is fun. >> I have a 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. Yeah. You reminded me of something that I saw you talk about, which was the anterior mid-cingulate cortex. And I think you described this as being one of the most interesting >> Yeah, yeah. >> discoveries of neuroscience. >> 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, right? I mean, just to remind people, like when we feel some sort of pressure, social pressure, physical pressure,

21:30 traffic that we hate, and we decide I'm going to lean into this, like I'm going to compete or 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, etc. 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,

22:16 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, cuz I've got a little stiff over the years, I know. So, 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. >> If you love the Diary of a CEO brand and you watch this channel, please do me a huge favor, become part of the 15% of the viewers on this channel that have hit the subscribe button. It helps us tremendously and the bigger the channel gets, the bigger the guests.