Dr. Glen Jeffery: Using Red Light to Improve Your Health & the Harmful Effects of LEDs

Let's talk about indoor lighting because I am very concerned about the amount of short wavelength light that people are exposed to nowadays, especially kids. This is an issue on the same level as asbestos. This is a public health issue and it's big. And I think it's one of the reasons why I'm really happy to come here and talk because it's time to talk. When we use LEDs, the light found in LEDs, when we use them, certainly when we use them on the retiny looking at mice, we can watch the mitochondria gently go downhill. They're far less responsive. They their membrane potentials are coming down. The mitochondria are not breathing very well. Can watch that in real time. Welcome to the Huberman Lab podcast, where we discuss science and science-based tools [music] for everyday life. I'm Andrew Huberman and I'm a professor of neurobiology and opthalmology at Stanford School of Medicine. My guest today is Dr. Glenn Jeffrey, a professor of neuroscience at University College London. In today's episode, we discuss how you can use light, in particular red, near infrared, and infrared light to improve your health. And no, not just by getting sunlight, although we do talk about sunlight. Dr. Dr. Jeffrey's lab has discovered that certain wavelengths or colors of light can be used to improve your skin, your eyesight, even your blood sugar regulation and metabolism. Dr. Jeffrey explains how light is absorbed by the water in your mitochondria, the energy producing organels within your cells to allow them to function better by producing more ATP. He also explains how longwavelength light, things like red light, can be protective against mitochondrial damage caused by excessive exposure to things like LED bulbs and screens, which of course we are all exposed to pretty much all day long nowadays. And simple, inexpensive, and even zerocost ways that you can get longwavelength light exposure. And again, not just by getting more sunlight. He explains that longwavelength light can actually pass into and through your entire body and that it scatters when inside you. Now, that might sound scary, but it's actually a great thing for your health because that's how long wavelength light can improve the health of all your organs by entering your body and supporting your mitochondria. Believe it or not, certain wavelengths of light can actually pass through your skull into your brain and help promote brain health. During today's episode, we also discuss new findings that correlate the amount of sunlight you're exposed to with longevity. Those are very surprising findings, but they're important. Also, why everyone needs some UV light exposure. And we discuss whether it's important to close your eyes when using red light devices or in red light saunas and how best to apply red light and things like infrared light in order to drive maximum health benefits. Today you're going to learn from one of the greats in neuroscience as to how to use light to improve the health and longevity of any and every tissue in your body and the mechanisms for how that works. Before we begin, I'd like to emphasize that this podcast is separate from my teaching and research roles at Stanford. It is however part of my desire and effort to bring zero cost to consumer information about science and science related tools to the general public. In keeping with that theme, today's episode does include sponsors. And now for my discussion with Dr. Glenn Jeffrey. Dr. Glenn Jeffrey, welcome. Thank you. Thank you very much. We go way back. Later I'll tell a little bit of the story and why it is truly unforeseen that we'd be sitting here talking about what we're talking about. But it's great to see you again and I'm super excited about the work you've been doing over the last few years because it's completely transformed the way that I think about light and health, light and mitochondria. And frankly, every environment I go into now, indoor or outdoor, I think about how that lighting environment is impacting my cellular health, maybe even my longevity. So, if you would be willing, could you explain for people a little bit about light as, let's say, the visible spectrum, the stuff that we can see and the stuff that's kind of outside what we can see as a framework for how that stuff impacts our cells. Because I think without that understanding, it's going to be a little bit mysterious how it is that lights of particular colors, wavelengths as we call them, could impact our mitochondria the way they do. But with just a little bit of understanding about light, I think uh people will get a lot more out of our conversation. Yeah, sure. We think about light purely in terms of the light we see and that's that's perfectly natural. And the light we see runs from deep blue, violet out to pretty deep red, deep bicycle light. Um, and that's what we see. That's what we're aware of. The trouble is that actually there's a lot more of it than that. The sun kicks out a vast amount of light that we don't see. So, let's say the visual range is just grab the numbers, which is say 400 to 700. That's that's our spectrum. Nanometers. Yeah. Nanometers. And there we're talking about the wavelength, how bumpy those wavelengths of light are. Sunlight extends out almost to 3,000 nanometers. Just think about it. Big big range. And then that's in the infrared. And on the other end, the bits that we don't see, the deep deep blues and the violets, that goes down deeply to about 300 nmters. Now, this is a continuum. We parcel it up because there's bits we see and there's bits we don't see. You can think about it as a continuous wavelength. And the wavelength gets longer and longer and longer as we go out into the deep red. So short wavelength lights, the ones just below blue, they're very very high frequency. They carry quite a kick. And that's why when you're sitting in the sun and you get sunburnt, it's mainly because of those ultraviolet short wavelengths that are present and then you go beyond our visual range beyond 700 and the wavelengths become very very long and they carry a certain kind of energy but they don't carry the kick. So the important point to think of is when you go out in sunlight, you see all these colors, blues, greens, reds, but there's so much out there that you don't see. And we thought probably you didn't need to be aware of, but nearly all animals basically see this visual range that we have. Red, orange, yellow, green, blue, indigo, violet, right? We can separate those out by shining light through a prism. I think the cover of the Pink Floyd Pink Side of the Moon album. Um, and that's separating out the different wavelengths. Um, you say that the short wavelengths have a kick. Uh, I want to talk a little bit about what that kick is. Uh, we distinguish between ionizing and nonionizing radiation. And I think for a lot of people, they hear the word radiation and they think radioactive and they think that all radiation is bad or dangerous. But in fact, light energy is radiating, right? So, it's radiation energy. But at the short wavelengths below UV, they are ionizing radiation. And maybe we could just explain what that means, how that actually changes our cells because if we get too much of that, it indeed can alter our DNA. I think the important point to think about is not only what the wavelengths are, but also how body responds to those wavelengths. So let let's bounce back a little bit to for instance the sunburn. Um we're getting sunburnt because the body is blocking those wavelengths. those wavelengths cannot penetrate very far. So when you're out on the on a hot sunny day and part of your body goes pink, it's going pink because it's blocking those wavelengths. So the energy is not being distributed throughout the body. The energy is hitting the skin and you're getting an inflammatory response to it. Now, interestingly, we block those from our eye because our lens and our cornea also blocks those short wavelengths. So that's part of the reason why we don't see them. Um but it's also the reason why for instance people get snow blindness because it's just sunburn on the cornea and the lens. It's recoverable from but it's very painful and with age some people who get a lot of sun exposure will get cataract. Yes. Yeah. Which is a kind of a um the lens becomes more opaque. It does. And I've heard that described as being the lens being cooked. Um, but in actual fact, you know, I used to run uh the eye bank at Morfield's Eye Hospital, Eyes for Research, and you can actually open a patient's eyes up when they're dead. And you can look at the color of the lens, and you can get a rough idea of how old that person was. So, one of the one of the surgical procedures that, you know, medics love is um to replace a cataract. take an older person um they've got this thick brownish lens and pop it out and put a clear lens in and the instant response in 90% of them is wow in the patients. Yeah. These are live patients. They're live patients. It's done under a local anesthetic in in older patients. They just go wow isn't that amazing? Suddenly they're getting a lot more light in their eye. Because the lens was brown it blocked a lot of the blu wavelengths and so they go everything is very bright. everything's very sparkly. Um, and it it was it was quite a dramatic response. But the interesting thing is two days later they said, "Yeah, it's gone." And and the brain kind of reapts that visual input from from the retina. Um, but going back over the literature of replacing cataracts, it's quite interesting. It tells you actually, you know, quite a lot. Now when we put those plastic lenses in, we have UV blockers in them so that the amount of so you don't actually get a lot of short wavelengths coming through. Um but there was certainly the response in the earlier days when we didn't have UV blockers of people saying, "God, that's sparkly. That's really sparkly." Yeah. The the sparkliness being those short wavelengths um like think of off the top of water on a really sunny day. So, I think the takeaway for me is that we should all be protecting our skin against too much UV and other short wavelengths and we should probably protect our eyes against too much ultraviolet exposure over time. We know that you don't want the mutations of the skin that um or the the uh clouding of the of the lens. I mean, you pointed out you can replace the lens, but um you know, I think at the same time, we need UV, right? I mean, vitamin D production is uh requires UV exposure. Um, do we know how what that how that works, what that pathway is? Yeah, we've got a fairly good idea, but I want to just take you back a step if I may. There's some really fantastic work coming out at the moment where a few dermatologists are re-evaluating the issue of sunlight on the human body. And the leader of that is um is a character called Richard Weller um from Edinburgh. and he's going back over all the data and Richard's coming out and saying, you know, um all cause mortality is lower in people that get a lot of sunlight and his argument is that the only thing you've got to avoid is sun burn. You know, the mutations of DNA are occurring really when you've got very very high levels, not when you've got relatively low levels. And Richard's work has been terribly interesting because he's dug out all the little corners, all the little things that you think about three days later. He's dug out all those little corners. And you know, things like uh aboriges in Australia don't get skin cancer. You know, um white people there probably are in the wrong place given their evolutionary stage. But yeah, high levels of skin cancer in Australia, in the Caucasian population, but maybe they're getting too much sun exposure too fast. The UV index is very high down there. I will say you can I mean you got you feel it quote unquote. That's interesting. I hosted a uh a derm oncologist on this podcast Teao Dr. Teao Solommani. So he's a dermatologist who's also an on dermcology. So skin cancer is his one of his specialties. And he um surprised me when he told us that um indeed sunburn can lead to skin cancers. Too many sunburns can lead to skin cancers. But that the most deadly skin cancers, the most deadly melanomas are not associated with sun exposure. Those can occur independent of sun exposure and they often occur on parts of the body that get very little sun exposure. Like the melanomas will show up. I think Bob Marley died from uh eventually from one that that started on his between his toes or something or on the bottom of the foot. There's a lot to unpack about the relationship between light and skin cancers. And I'm I'm going to chase down the literature trail of this uh Weller guy. Oh, Richard Weller is a Richard Weller is very interesting. He's he says I think he said he hasn't got any dermatological friends anymore. Probably not. But he also pointed out that um if skin cancer was directly related with sunlight, then we should find in skin cancer patients, you know, very high levels of vitamin D. In actual fact, they've got relatively low levels of vitamin D. So, as you say, that story needs to be unpacked. And what's happened, I think, in the dermatological literature is that we've followed a pattern. Yeah. We've followed an assumption and it's gone a very long way down the line and then it's taken a little bit of a rogue to come out and say, "Hang on, we need to take a step back here." And I think Richard Weller is leading that. And um um we we obviously both have an interest in daylight uh but his interest in daylight tends to be focused a little bit more on those blue short wavelengths whereas I'm at the other end of the spectrum but uh I think he's a mover and a shaker. Great. Well, I'm excited to see where that literature leads and I I'm glad that somebody's, you know, parsing, as you said, all the corners of it because I think we've been fed um a story that, you know, excessive sunlight leads to skin cancer. And the data on all reduced all cause mortality um in people that get a lot of sunlight. I I saw a study out of Sweden looks very very solid, but more data is needed clearly. Yeah. So, I think that that story um there was a story out of Sweden. There was also a story out of the University of East Anglia and um we're talking big numbers, you know, we're talking very big numbers on that. So it could have a lot of points that we don't quite understand yet, but I think the solid thrust of it and the interesting thrust of it for me is that that all caused mortality flagships up on that are cardiovascular disease and cancers. It's not the obvious ones that we'd be thinking about. So yeah, let's use the term unpacking. That one definitely needs unpacking. But from a public health perspective, that's an important area. Well, I'm certainly a fan of people getting sunlight both in their eyes and on their skin. Although not to the point of burning, obviously. Yeah. In today's financial landscape of constant market shifts and chaotic news, it's easy to feel uncertain about where to keep your money. However, saving and investing does not have to be complicated. There's a solution that can help you take control of your finances while still managing risk, and that's Wealthfront. I've trusted Wealthfront with my finances for nearly a decade. With the Wealthfront cash account, I can earn 3.5% annual percentage yield, or APY, on my cash from program banks, and I know my money is growing until I'm ready to spend it or invest it. One of the features I love about Wealthfront is that I have access to instant no fee withdrawals to eligible accounts 24/7. That means I can move my money where I need it without waiting. 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JWV makes medical grade red light and infrared light therapy devices. Now, if there's one thing that I've consistently emphasized on this podcast, it is the incredible impact that light can have on our biology and our health. In fact, that's the topic of today's discussion with Dr. Glenn Jeffrey, the world's most accomplished biologist, on the power of red light for promoting different aspects of your health. Red light and infrared light have been shown to have remarkable effects on cellular and organ health, including improved mitochondrial function, improved skin health and appearance, reduced pain and inflammation, and even for improving vision itself. Recent [snorts] research shows that even relatively brief exposure to red and infrared light can meaningfully improve your metabolism and blood sugar regulation. Now, there are a lot of different red light therapy devices out there, but what sets Juv lights apart and why they're my preferred red light therapy device is that they use clinically proven wavelengths, meaning specific wavelengths of red light, near infrared, and infrared light in exactly the right ratios to trigger the cellular adaptations for health. Personally, I use the JWV whole body panel about 3 to four times per week for about 5 to 10 minutes per session. And I use the JV handheld light both at home and when I travel. If you'd like to try JWV, you can go to JWV, spelled Jovv.com/huberman. Right now, JWV is offering a special holiday discount of up to $600 off select JWV products. Again, that's JWV. jov.com/huberman to get up to $600 off. So, let's talk about um how light impacts mitochondria and other aspects of cellular function and maybe use that as a segue into the longer wavelengths. Yeah, sure. that area is expanding enormously. Um, and it's expanding enormously in lots of little pockets and the pockets aren't weren't always talking to one another very well. Um, the first person that came along and said, "Look, longer wavelengths are really positively affecting mitochondrial function um was a lady called Tina Karu in Russia and who was very largely ignored. Um, I don't I think she's still alive. I would love to buy her a glass of champagne if only because she started it off. She kick kickstarted it off. But she was very much of the opinion that mitochondria absorb long waves of light. Parts of the mitochondria absorb it. And one of my studies um to try and pin this down was to take a whole load of mitochondria, put them in a test tube, put a spectrometer on them and a light and say, "What are these guys absorbing?" Well, I found the point where they were absorbing the damaging blue light, but I could not find the red. I could not find it. There was a lot of stomping around in the lab. You know, who's made a mistake? You know, everyone parceling the brain blame on. But it changed. It changed because what absorbs long wavelength light? Well, a most obvious one is water. The sea is blue because the long wavelengths are absorbed. So someone came along and said is it about water? Is it about water in mitochondria that's doing this? Now when we make mitochondria make energy they make energy called ATP and you make your body weight in that every day. It's a vast process and you make it as a wheel turns round. Mitochondria have these little wheels these pumps that spin around but they spin around in water. Nano water. And apparently I'm not a physicist. Nano water is viscous. So one idea I think which we have to take quite seriously is that the viscosity of water is changing as a consequence of long wavelength light that penetrates deeply in the body. There is an increase in the spin rate of the motor that produces ATP and it gains momentum. Now that is absolutely fine. I can I can stick with that one. I think that one makes considerable degree of sense and it gets us over a problem. Mitochondria themselves are not absorbing long wavelength light. It's the water that they're surrounded by. It's it's their environment. Okay. So I think in the end when you talk about the function of anything we tend to focus on that thing and we don't talk too much about where is it, what is it, what's it surrounded by and how does it influence it. So the first reaction I think is that the motor starts to go around a little faster. But then something else happens which is really interesting which is we start to make more of these chains that make energy. So let's say mitochondria has got a is a chain. It's a series of things and electrons are passed along that chain um to produce energy. Well when we give long wavelength light we find the proteins in those chains we find a lot more of them. So my analogy is that giving red light gets the train to run down the track faster. That's true, but then something detects the speed of that train and says, "Lay down more tracks. We need more tracks." So we're finding a lot more protein there um that is associated with passing that electron down the pathway to make energy. Interesting. So it sounds as if longwavelength light via water is actually changing the structure of mitochondria and its function as well. Yeah, I I think I I think I would say it's it's improving the function and it's influencing the the mito more mitochondrial proteins to be synthesized. So we've got an immediate effect and we've got a longer term effect as well. Well, one thing we know about mitochondria is that they started off as independent bits of biology and then the ukareotic cells which we have, you know, essentially took those in and they became fundamentally part of the the cell and it's passed on through the genome. So, the idea was that mitochondria were separate from our cells at one point or from cells and were were essentially um co-opted by our cells or hijacked our cells, we don't know which. And then now they be because they share a genome, mitochondrial DNA and and genomic DNA, um they're passed along. And it makes perfect sense to me as to why that if they're really of bacterial origin, which we think they are, that they would be absorbing or through the water, they would be absorbing long wavelength light because they evolved in water. I think it's worth us just uh mentioning uh this business of absorption versus reflection in terms of colors. I think people might find this interesting that uh you said you know the ocean appears blue because it's absorbing all the red all the long wavelength light and it's reflecting back the short wavelength blue light. Yeah. Yeah. Red stuff does the exact opposite. Like when we see a red apple it's doing the exact opposite. It's reflecting the red light back towards us. The long wavelength light. I think most people probably don't realize that. And then we talk about you know white containing all the wavelengths and black absorbing all the wavelengths right? That's that's the the notion. So it's it's it's interesting um to think about light as either being absorbed or reflected back and makes perfect sense to me why the mitochondria would absorb the red light. But of course I'm saying that under already hearing the the just so story. So it makes sense once you hear it. It makes sense when once you hear it and and why the hell did we not think about that five years ago? We know we were scientists make really big mistakes in the pathways that they follow and you know they don't talk about their mistakes but their mistakes are every bit as important as their their great results. Why didn't we think about water? Because our minds were trapped in a certain pathway going down a certain alleyway. And so whatever you think about the water hypothesis, the key point is that improvements in function as a consequence of exposure to longer wavelengths light correlate tightly with what water absorbs. Right? So okay, that's a big one. That that's a big one that is there. We know that's true. You can pull it apart and find there things called water holes where there are places where water absorbs a bit more than it does in other places. But fundamentally the absorption of long wavelength light fits water. So much of your work focuses on how long wavelength light can enhance the function of cells that are not on the surface of the body. They're not on the skin. They're in the eyes. And um and now we'll get to these data soon, but uh you publish data that longwavelength light can penetrate very deeply and even through the body. Mhm. Even when people are wearing a t-shirt, like all the way through the body and impact mitochondria all along the way. So maybe we should just talk about longwavelength light and how it can penetrate through the skin. You mentioned that UV is is essentially blocked by the skin. So if I step outside for instance on a nice sunny morning or even a partially overcast morning but some long wavelength light is coming through is it passing all the way through my body and impacting the water and mitochondria of every cell along the way? How is it scattering? I mean how how deep does this stuff go? Okay, so let's stand you out. Let's let's let's let's strip you off and stand you out in sunlight, you know, 12:00 in July. The vast majority of longwavelength light is being absorbed in the body. So what we assume is that it has a very very high scattering ratio. So the vast majority of that long wavelength light is going to hit inside your it's going to get through into your body and it's going to bounce around. So it's going to literally go through the skin. It goes through the skin. And let's let's take the simple experiment. The simple experiment was you strip people off and you stand them in front of sunlight and you put a radiometer on their back. Tell us what a radiometer radiometer measures the amount of energy coming through. Okay. And then we put a radiometer on we put a a spectrometer on your back as well which tells us the wavelength. So what we get from that the reading we get from that is that a few% a few% is coming out the back. Now, we shouldn't concentrate on that. What we should concentrate on is what happens to the rest because it's not bouncing back from the surface of the skin. Very little bounces back. It's being absorbed. Amazing. Which is amazing. Well, it's very interesting. It makes sense based on the physics of it, but but it's amazing, right? That the long wavelength light is actually penetrating our skin, bouncing around in our internal organs, and some's getting out the other side. I think that's going to surprise a number of people. [laughter] In any conversation like this, we need to talk about silos, people coming from different angles [clears throat] at a problem. And I have the advantage of uh Bob Fosbury working with me. Bob was um lead for analyzing atmospheres on exoplanets with the European Space Agency. He had a lot to do with the European use of Hubble and a lot of his spectrometers are up on the James Webb telescope. Now, there are super advantages for having someone from another silo to come in, but there also really annoying issues as well. So, I said, "Bob, I really want to measure whether light goes through the body." And he said, "We all know that. Forget it. It's a waste of time, you know." And I said, "You think you know it based on principles of physics. I don't know it." And actually, I don't think you know something until it's published and everybody knows it and can talk about it. So, yeah, Bob came along and said, "Yeah, it has to long wavelength." has to go through. Um and um but it needed demonstrating. Now the other thing that I Bob did pick up on this and did start to get a lot more interested in it because then he went through his wardrobe and he took different layers of clothing from his wardrobe and put long wavelength lights behind them. So what goes through clothing? And the amazing thing is long wavelength light goes through clothing. It goes through clothing. It goes through any clothing. Well, if you want to wear rubber, I think not. But if you want to wear um your standard t-shirt, I think I think he used six layers t-shirt. And does color matter? Like I'm wearing a black shirt right now. Makes no difference whatsoever. And the other thing we do not know, and this is terribly important, there's lots of we don't knows here, is this long wavelength light bounces around all over the place. So we have got some long wavelength light sources. And I think I'm shining this long wavelength light there, right? And then when I put my instrumentation up, it's all over the place inside the body. Inside the body, inside the room, it's going every I can't control it. Not unless I start putting materials like aluminium foil to block it. So when we think about long wavelength, its advantages, you know, we talk about, you know, using this device or that device. What we also need to think about is uh okay, you've got a small device with a small beam of light going here. It's bouncing all around the room. It's coming in from a different angle in different parts of your body, but certainly most concentrated in terms of energy at at the at the point source, but you cannot assume that the point source is the only source of that long wavelength light if you're in a confined confined space. Well, let's um use that as an opportunity to talk about a related study and then we'll circle back to the the uh let's call it the the light passing through the body study. Um because the study I'm about to mention I think is going to be so interesting to people um and a little bit shocking and very very cool because it's actionable. uh which is you did a study showing that even if you illuminate just a small portion of the skin with long wavelength light, it changes the blood glucose response, literally blood sugar response is altered by shining red light on the skin. And for years there were these, let's call them um uh corners of the internet that would say things like, "Oh, you know, when you eat out of it, it has a different effect on your body than when [clears throat] you eat indoors." But there are too many variables there, right? Because when you eat out ofdoors, typically it's at a picnic and then you have greenery and there's socializing and no one's going to fund a proper study to look at, you know, to parse every variable in a picnic versus an indoor cafeteria and and it's not worth the taxpayer dollars, frankly. You did the right study, which was to shine light on what was it, the back. It was on a small area of the back. Yeah. And and I must make it very clear first of all, the person whose idea this was was my my colleague Mike Pner. And um and Mike's thought processes were very very clear. We were on a long drive to do some research well out of London and that's a great time for cuz it's the the journey starts at 5 in the morning that it's a great time for gossip. It's a great time for wild ideas for streams of consciousness which sometimes are very important in science. And it was Mike who said to me, you know, if we make mitochondria work harder, then they need glucose and they need oxygen. So, pause while Glenn, who's driving, kind of has to catch up on this idea. I'm generally about a mile behind him intellectually. And I went, "Yeah, yeah." So, he said, "Well, let's not make idiots with ourselves. Let's do it with bumblebees." Right? So our first experiment was to to increase of course why not the the why first experiment was on bumblebees because it didn't involve people. Um it was simple to do and all we did was we starve bumblebees overnight. Gave them a standard blood glucose test. So you know lot sounds a lot harder than working on humans. No it's not. You just give them a little bit of glucose cuz they haven't and they go and their blood glucose goes up. you've gave them red light or blue light. We give them red light and their blood glucose does not go up as much. We give them blue light and their blood glucose goes very high. So, they're using more of the energy. Yeah. So, in the red light condition, in the red light condition, in the blue light condition, we're slowing their mitochondria down and so the uh there is more glucose flowing around. I should say that sampling the blood in a bee is a little bit difficult, but um you basically pull off one of the antenna and you squeeze a bee and you get a little piece of Well, the bee lover, but you know, we went to the chemist and we bought just the standard blood glucose test that you can get for a few dollars. We got a result. Therefore, it's worth moving forward. Therefore, we got the ethical permission. Therefore, we did the exper I can't do the experiment on blue light. I regard that as unethical. But really, yeah, we're under blue light all day. I'm absolutely convinced that being under blue light or short wavelength shifted light all day is altering blood glucose in ways that are detrimental. But in any case, before I rant about that, what what happened in humans? So, in the humans, we did a standard blood glucose tolerance test, which is horrible. So, you get people to starve overnight. They come in, they drink this big sort of cup of vile glucose. So, we really pump up the glucose in their body and then we prick their fingers at regular intervals and sample their blood and see how their blood glucose level changes. And your blood glucose level will peak in about 40 to 60 minutes. It's hard getting subjects for this one. Um, we also put a tube up their nose so we could detect how much oxygen they were consuming. You're calling on friends. I mean, I even dragged my son in as a as a subject for that one. The result when we gave people a burst of red light beforehand to stimulate their mitochondria was super clear. It wasn't ambiguous. The blood glucose levels went up, but they didn't peak anywhere near as seriously as they did without the red light. Now, I'm told that the level of your blood glucose is not necessarily a massive issue for concern. What is an issue for concern is it spiking how much it spikes and the reduction in the spike was of the order of it was just over 20% if I remember correctly. Where was the light shown on the body? It was shown on the back and it covered I forget what the percentage of the body area was. I did this calculation four or five times because it was ridiculously small. So we were stimulating a very limited area of the body but we got a systemic response. There was no way that the mitochondria in that little patch of skin was having that effect. But it fits into a wider notion that all these act as a community. Now we now know that that's coming all from different corners. They act they do things together. It takes them a little time to have a conversation about it, but they act together. And if we're doing something which was over one to two hours, that's that's long enough for them to hold that conversation. I'd love to know more about that. Do you recall whether the subjects could feel heat from the infrared light? Okay. So, they're not they're not feeling heat. So, that removes also a potential placebo effect of some sort. Do you recall just roughly uh what the area of illumination was? Was it you it's in the publication. Let's go like this. Okay. So, for those just listening, maybe like a 4x6 rectangle. Four 4x6 rectangle makes sense. 4x6 in. Yeah. For the all those metric system folks out there, we're on common ground here given you're from the UK. We're not unique in finding this. It's just that other people are finding things with red light that are sitting behind different walls. So John Metrofanes in you did most of his research in in Australia, he induces Parkinson's disease in primates, which you can do pretty much overnight with a drug and and then he was giving red light to different parts of the body. Now Parkinson's disease originates from a very small nucleus deep in the brain stem. Um but he was reducing the symptoms of Parkinson's disease in these primates very significantly with lights that were being shown on the abdomen. So any one of these you take in insul insul isolation and there are many of these studies and you go yeah maybe yeah what does he think it was doing? I mean it's clearly it's not rescuing the dopamine neurons that degenerate in Parkinson's but maybe it's rescuing components of the pathway. it could be rescuing components of the pathway. Um, I think that we know that red light and we we we're using that term very loosely. Perhaps we shouldn't. We know that long wavelength light reduces the magnitude of cell death in the body. Cell death is very often initiated apoptosis by mitochondria. When mitochondria get fed up and that I see them as batteries when the charge on the battery goes down low enough they put their hand up and they say time to die and I think they actually present a molecular eat me signal. Yes. Which is interesting like you know when we talk about cells dying that we think about it as a um you know sort of they they go from a shout to a whimper and then they get cleaned up like they they just they die but they actually um they solicit for their own death with this eat me signal. Yeah. they'll get optionized you know for the people that you know think about the immune system optinization there similar things so if I understand correctly he induced an insult to these dopamine neurons and then he used red light shined on the abdomen to offset some of the degeneration that would have occurred yeah okay now that that again fits into the wider spectrum of other research that's not put together so that was John and John has been a big leader in uh red light dementia and Parkinson's disease. Um, and a lot of it in primate models, which is which means it's it's got some it's got a lot of validity to it. Yeah, they're similar to us to them. Yeah. Another experiment we did was over life you will lose a third of your rod photo receptors in your retina. Maybe just explain for people what the rod system is. Okay. The rod system is the majority of your photo receptors are rods. They tend they're the receptors that you use when you're dark adapted. Um, which a lot of us aren't really much these days. So, we've got our cones which deal with color and deal with bright light. Then, as we turn the lights down, we start to use our rods. So, loads and loads of rods, relatively few cones. What I usually tell students is this is like you in the old days when everyone didn't have a smartphone near their bed. You wake up in the middle of the night and you need to use the restroom. You you can navigate to the restroom. You might flick the light on in the restroom. I don't recommend doing that. It'll quash your melatonin unless it's a red light. Or you go out on a hike and you don't bring what we call a flashlight, Glenn. You guys call a torch. But as you come back, your your eyes start to adapt. It's it's getting dark. You can still see the outline of the trail. There's not starlight yet, but you you're able to, as you say, dark adapt and you can see enough of what you need to see. You're using your rod system. Yeah. The key thing here is rods are me very very numerous. Cones are not. So, so what what happens then for instance if we take a aging animals and we just expose them to red light every day we give them a burst of red light and then we count the number of rods they've got when they reach old age and the result is super clear. We have reduced the pace of cell death in the retina. Okay. So red light is affecting mitochondria. Mitochondria have the ability to signal cell death. And we're drawing back the probability of that cell dying. Now, we did that mice. We did it on a lot of mice. It was a killer of an experiment to keep animals going forever. And then I forced one of my graduate students basically to go 1 2 3 4 and count photo receptor out the segments. She was a hero. Um so we can use red light to reduce the pace of cell death. So I am not too surprised that John Metrofanis would have reduced the pace of cell death in the substantia Niagara that nucleus that gives rise to uh Parkinson's disease. Um I'm seeing that coming out of loads of different labs things that are all consistent with that kind of story. The other thing that I think you can you can start to address is if you've got bad mitochondria say very loose term if you've got bad mitochondria as you do have in uh Parkinson's disease you know they're bad they're not functioning very well on their way to death are [snorts] they influencing other parts of your body you know Parkinson's patients you think well okay they're all going to have movement disorders but actually a lot of Parkinson's patients have a lot of other things that are going on in them And we're minded to think that as good information can be passed to mitochondria and can be shared in that community, so can bad information. You know, if you really upset mitochondria in one place, then other things are changing in different places. So the big takeaway here, and it's not controversial to say, I've heard lots of people saying it, and I didn't say it originally, is that they're a community. You can't deal with them in isolation. Even across cells in different areas of the body, they're a community. They are a community. Probably by secretreting certain things that support each other. Um maybe I've heard some evidence that mitochondria can actually be released from cells. Oh yeah. Um different although not entirely different than neurotransmitters are released between cells and communi communicate between cells. very interesting when one thinks about mitochondria of uh having maybe bacterial origin again that our cells co-opted or they co-opted us. We don't know the again the direction there. Um I have a question about how far long wavelength light can penetrate and through what tissues. I realized that in the studies we've been talking about it's long wavelength light exposure to the back lowering the blood glucose response or to the abdomen offsetting some of the degeneration uh as it relates to this Parkinson's model. If I were to take a long wavelength light and put it close to my head would it penetrate the skull? Oh definitely. If you look at um if you if you look at a longwave light source and again this is published Bob Fosbury did this he put his hand on one come straight through his hand but the interesting thing is you can't see the bones it's passing through the bone so that led me to go into grabbing a few skulls and yeah it's it's really not affected that much by bone and I was talking to some aiology guys at uh in Cambridge who wanted to use red light and they were they were taking I think heads or something and and looking at them and they were shining red light in the eye and they say we can see it in the ear that's not I can see it and vice versa. So there are things that red light does not will not doesn't go through. So it is absorbed by deoxxygenated blood. So you get fantastic pictures of your veins in your hand um or in your head. But the most obvious thing that you think is that long wavelength light would be blocked by something thick like a skull. The answer is no. So going back to our example of the ocean appearing blue because of blue light getting reflected back and red light getting absorbed. I think this is very important to kind double click on in people's minds because people will see an image for instance and I'll put a link to it in the from this recent publication of yours of red light and and other excuse me long wavelength light not just red light um being shown on a hand and indeed you don't see the bones and you see the vasculature this deoxxygenated blood when people see a structure under a particular wavelength of light the kind of reflex is to assume assume that those structures are the ones that are um uh using the the the light, but in fact it's just the ex exact it's the stuff you don't see right that it's passing through. And I think I think for a lot of people that's just kind of counterintuitive. So they'll see an image of of the the veins during that deoxxygenated blood and they'll say, "Oh, you know, red light is is impacting the veins, right?" But but the interesting thing is that it's passing through all that is interesting on in itself but it's passing through all these other structures and to me the idea that when I go out on a sunny day because the sun includes long wavelength light or were I to be near a long wavelength light emmitting device that it's actually getting into the deep brain tissue through the skull for I think for most people it's just not intuitive to think about light passing through things that are solid in that way. Yes. And and I have exa I had exactly the same problem. I had exactly the same problem. Um if you you put a radiometer and a spectrometer to measure the energy and the wavelength on one side of someone's head and a light source on the other side of someone's head, you you get a clear result. Now, interestingly, as a it's not a sideline, it's actually a very important issue. Um a a biomedical engineer Ilas Takanides at UCL has used this because he works on some of his work is on neonates that have had stroke and he takes the neonate and actually does exactly that experiment. He passes red light wavelengths of light through the side of the neonate's head and records them coming out the other side. and he can use that as a metric of how well the mitochondria are functioning in that damaged brain. And the readouts that he gets are readouts that are indicative of the potential survival of that neonate. Wow. Now, I think there are lots of wows here. First of all, he's got his work into a major London teaching and research hospital. He's got it into kids. And we've acknowledged that this is not dangerous, right? He's gone through loads of ethics committees. The long wavelength light red and out towards infrared and near infrared is nonionizing. Yeah. Right. It's not altering the DNA of the cells. It's it's contributing to the healthy function of the mitochondria. Forgive me for interrupting. No, I think because when people hear about light passing through a baby's head, in order to make that kid healthier, I mean it's spectacular. I love that this is being done at at such a fine institution and so carefully. But the reason it's safe is because that's long wavelength light. Were this to be short wavelength light, we have no idea what it would be doing. I mean, babies have very thin skulls. UV would be who knows. X-ray certainly you would never ever ever want to do this. So, yeah, I think it's important that people really remember what we're talking about passing through. Okay. And and I think that it's a very important point because I have gone through so many ethics committees to shine long wavelength light to do various things including on people that are they've got problems. So they've got they've got sight problems, their patients. We've actually also done it with children. Um, and we've got through ethics committees really with very very little comment because on many of the ethics committees there are physicists and they understand the issue. By now I'm sure that many of you have heard me say that I've been taking AG1 for more than a decade and indeed that's true. The reason I started taking AG1 way back in 2012 and the reason why I still continue to take it every single day is because AG1 is, to my knowledge, the highest quality and most comprehensive of the foundational nutritional supplements on the market. 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I've been using the Aurora countertop system for almost a year now. Aurora's filtration technology removes harmful substances, including endocrine disruptors and disinfection byproducts, while preserving beneficial minerals like magnesium and calcium. It requires no installation or plumbing. It's built from medical grade stainless steel and its sleek design fits beautifully on your countertop. In fact, I consider it a welcome addition to my kitchen. It looks great and the water is delicious. If you'd like to try Rora, you can go to roora.com/huberman and get an exclusive discount. Again, that's r o r a.com/huberman. Let's talk about the two uh sort of bookends of uh age. You just mentioned uh babies and we'll return to uh babies, children, and youth. Uh let's talk about some of the work you've done on retinal aging and using longwavelength light. I'm being very careful with my language here because if I say red, people think you have to see it, but there's red, near infrared, nir it's typically shown as IR, infrared light. And I think we we batch those when we say long wavelength light. It's going what 650 nmters would be red out to I guess is as far as 900 nmters or so. And and yeah, and then beyond 900 is infrared. So we've got we've got the near infrared and we've got the infrared. Now you're right, we've got to start kind of we've got to start defining these terms a little bit more clearly. But I think for nearly all of the research we're talking about, we're talking about where vision stops, which is around 700, and we're talking about the near infrared, which is for practical purposes is going up to around 900. Um, but you know, I I I remember doing an experiment with um with UV once, and it was an experiment, bizarre experiment, trying to work out if a reindeer could see UV light. Do they? Uh yeah, they do actually. But then, you know, while we were doing the experiment, I I was beginning to say, look, I I'm not believing any of this data because I can see this flashing now. And as was pointed out to me, you will see wavelengths of light, you know, that you shouldn't see if you just turn the energy up, right? So, if I put you in a room with UV and I pump loads of energy into that UV, you'll see things that you shouldn't. And likewise with uh the reds, you shouldn't really see much above 700. I can get you to see at 150 if I just turn turn the energy up a bit. And you see these little red glows. Yeah, this explains a lot of people's ideas about whether or not they've seen ghosts, but that's a different that's a different podcast, ghosts in UFOs. But an interesting discussion for another time. But um and I can't help but mention that, okay, maybe we'll return to this later, but Glenn has worked on a variety of species uh as have I over the years. So maybe at the end we'll do a quick catalog of uh the species that we've worked on over the years. So I'm not surprised to learn that you worked on rain reindeers given the other species you've worked on. But returning to um the human you published some papers over the last uh you know five six years or so looking at how when the eyes specifically are exposed to long wavelength light it can do excellent things for preserving vision or offsetting some uh loss of visual function. Could you detail those experiments for us? So let's take two pieces of information first. So one of the main theories of aging is the mitochondrial theory of aging. Mitochondria regulate the pace of aging. So if you can regulate mitochondrial health, you can regulate aging. That's relatively clear. So that's that's the first thing. And then the second thing to remember is that there's more mitochondria in your retina than there is in any other part of your body. Your retina has got the highest metabolic rate in the body, ages fast, and my argument always is it's the sports car. Bangs out of the garage, you know, but after after so many thousand miles, you got to service it otherwise it falls apart. So, there was a very strong argument for trying to manipulate mitochondria in the retina, which is great for me because I'm a retinal person. I'm a visual person, so I had the tools to do it. So the first experiment we did which was I very [clears throat] gratifying was to actually measure people's ability to see colors. Now, we used a rather sophisticated test first of all, and that was we'd put on a a very high resol resolution monitor, say the letter T in blue, and then we'd add loads and loads of visual noise to it in the background or or we'd have a an F in red, visual noise, and then we found the threshold at which they could see that letter and happily identify it. So, we found out what their visual ability was for colors. We then gave them a burst of red light to improve their mitochondria in cells that are very mitochondrial dependent. And we then brought them back and we found the threshold had changed. The threshold had improved in every one of those subjects by one. They could see something they couldn't see before. See before by one. I think it's hard. Uh what what scale is it on? Like some of these tests like this is like the Triton test. Well, so we tested Tritan and Proan. So, this is nerd speak for the different visual tests. Um, most people are familiar with the Snellen chart. When you go to get your driver's license, you have to read the letters of different sizes. Very different. This is measuring the just noticeable difference between you can see something, you can't see something. When you say there was an improvement of but one, could you frame that in real world context for for people who are not thinking about visual psychophysics? Okay. It's very simple. Of all the people we've tested, we've got an improvement and there's very large numbers of them except one subject. Ah, you're saying but one. I thought you meant that was the numerical size of the the effect. If you look over the population, the size of the effect is around 20%. It's very substantial. Okay. But the our ability to improve visual function varies enormously between individuals. You said but one. This is a UK uh US [laughter] uh moment. No, but don't apologize. I should apologize. Um okay. An improvement of 20% improvement in threshold. So people are seeing better than they did prior. Could you explain what they did for them for the intervention? How how many times a week, a day? How long are they shining red light in their eyes? What's the excuse me, long wavelength light? What what's the nature of that light? Maybe even tell us how far away from it they are. Okay. So in our first experiments we used 670 nanometers right which is a deepish red light. The only reason we used that is because all the studies before us doing different things had used 670. Consequently there was a database. So that's why we did it [snorts] and we did it with a little torch that we put in front of somebody flashlight. That's trans I'll translate for the flashlight. Not a torch with fire near the eye. [laughter] No definitely not. Um and um we did that for 3 minutes and originally we did that every day for an hour. I open not not very little difference because the long wavelength light passes through the lid without it being affected very much. So I said to people, whatever you're comfortable with, you're doing me a favor. You're being a subject in my experiment. I'm not paying you for it. You want to keep your eyes closed, you keep your eyes closed. And those people all had an improvement in their color vision. Now we then titrated that down. So instead of doing it every day for so many days, we just did it for one day and 3 minutes of that light one day and we brought them back. I think it was an hour later that it all improved. How stable was the effect? I mean, did they have to only do one treatment ever? No. Oh, I wish that was the case. In all of those people, and I'd have to say we did it, we we've done similar experiments on flies, on mice, on humans. It's 5 days. It lasts 5 days. 5 days. It's a solid 5day effect. So, something very fundamental that is conserved across evolution is playing a role here. Five. And I have to say that to a first approximation, anything I find in a fly, I find in a mouse. Anything I find in a mouse, I find in a human. I can't find a a big disjuncture between those those things. So, it lasted it lasted five days. And the real big point to take on board is it's a switch. There's not a dose response curve here. It is a you put enough energy in at a certain wavelength of light and it goes bang and click and then 5 days later goes chunk and stops. I have a lot of questions about these studies. So, um I'm going to try and be as precise about them. I know what's on people's minds. If people are going to get in front of a long wavelength light emmitting device, do you think it's critical that it be 670 nmters or could it be 650 out to 800? I mean, how how narrow band does the does the light actually have to be in terms of wavelength? pretty much anything works to a rather similar extent at 670 going upwards. When you go below 670 towards 650 the effects tend to be somewhat reduced. If this is happening uh very quickly you said an hour later the vision is better thresholds have changed and it lasts 5 days. Do you think we can get this same effect from sunlight given that sunlight contains these long wavelengths of light or is it that the the sunlight isn't of sufficient energy for most people? I mean with this what you call torch I call flashlight light source you know you the way you described it and showed it with your hand for those listening is you know fairly close to the eye maybe you know eyelids closed or maybe open if people can tolerate that and you're shining that light in their eyes for a couple of minutes. How different is it than stepping outside on a really bright day closing my eyes if I look in the direction of the sun because that's pleasant or just walking in the sunlight and getting long wavelength exposure. I'm a big big fan of natural sunlight because you've evolved life's evolved for billions of years under sunlight, right? It's only recently changed. I don't know that cut off point, but there's an enormous difference between the light produced by a flashlight and sunlight. Sunlight is an enormous broad spectrum and that flashlight is just a little window of light that happens also to be present in sunlight. Now, I think the two situations are probably incomparable, right? And and I'm not going to spend whatever is left of my career hunting that down. We know and I I think this is the global concept I've got, which is that we can do much with single wavelengths of long wavelength light, right? Like a a flashlight which is 850 or 610. We can do a lot, but we can never do the same as you can get from sunlight. But you can't do those tight controlled experiments with sunlight that I can do much more easily with specific wavelengths. Yeah. And you're in the UK, so you'd have a lot of days to do experiments at all. I'm just kidding. Well, I must say, you know, often times when I tell people to get sunlight in their eyes in the morning to set their circadian rhythm. I'm like a, you know, I'm like a repeating record with that and I will be till the day day I die. People will say there's no sunlight where I live. And I remind them that even on a very overcast day, there's a lot of photon energy coming through, but the long wavelength light is cut is cut off. Um, so they're still getting a lot of photons. I mean, compare how bright it is at 9:00 a.m. uh versus midnight the night before their sun is that they can't see the outline of the sun as an object is what they're referring to. I I think the important point there is that long wavelength light gets scattered by water. It gets absorbed and scattered by water. So on a winter's day we've got a cloud and that cloud has got contains water. There will be an attenuation of the longer wavelength light. It won't be vast but there will be an attenuation but more it will start coming at you in different angles. So when you when you're walking on a sunny day and you're walking down the road, sun's in front of you, you feel warm in your chest when you've got clothes on and it's a longer wavelength light doing it because it's relatively focused. on that winter's day, you're still getting a lot of long wavelength light, but it's coming at you in a lot of different angles and it's slightly attenuated. So, my argument, which is the new mantra of the of the lab to some extent, is get a dog, right? Get a dog because you'll have to go out in you'll have to go out in daylight two or three times a day. You'll get no argument from me. You [laughter] you're uh you're making me very happy. Uh Glenn, uh I I love dogs. listeners of this podcast will know I absolutely love dogs and my last dog it was an English bulldog half English bulldog half mastiff. So the next one will also be an English bulldog. Uh couple more questions because I know people are curious about longwavelength light emmitting devices for their eyes and and other tissues. Um you mentioned that one subject did not respond and if I'm not mistaken these effects at least on the eyes I don't know about the other effects on blood sugar etc but on the eyes and visual function seem to be gated by age right if I recall people younger than 40 um you you saw less of a of an effect overall statistically we saw less of an effect you know some people. My youngest son responded very very strongly and at the time I think he was about I think he was about 25. So you have to look at a population level to get that but okay look this all makes sense. Mitochondrial theory of aging means that if we imp we we should have more room to improve mitochondria in the elderly than the young. But we all age at different rates. One of the biggest problems about doing experiments on humans as opposed to mice is we all do radically different things. Some take exercise, some have very good diets, some have poor diets. And mice sitting in our animal house eating the same food. They're very, very similar to one another. Everything is the same. So, we have to accept that noise. But generally when your mitochondria are in a poor state which is consistent with aging, yes, we've got more room to lift them up and improve their function. What was the time of day so-called circadian effect uh of this? Very clear. Again, same in flies, mice, and humans. Your biggest effect is always in the morning and it's always generally just before perceived sunrise up until about 11:00. So, and it's very very clear, but let's look at the backdrop to this. Your mitochondria, they're not doing the same thing all the time. So, if we we we did this experiment 24 hours looking at mitochondria. And if you look at what mitochondria are doing over 24 hours, it's shifting sh. not the same even over a 3-hour period. It's shifting and so the the proteins that we have in different parts of mitochondria are changing in concentration radically. It's it's a very very active area. So if you're doing area if you're doing research on mitochondria and you're not taking account of time a day, you may have a problem. So but the mornings are very very special. Um in the morning there are lots of things changing in your body. Your hormone levels are very, very different. Your blood sugars tend to be picking up. You've been asleep. A predator may have been watching you. You need to wake up and you need to be ready on the road. You can't be like a lizard that's got to wait for the sun to rise and to get themselves into into a position where you can get your body temperature up. So, the morning is very important. You're making more ATP, this this petrol that mitochondria make in the morning than at any other time. Now I can improve function across a wide range of issues in the morning. I can't do it very easily in the afternoon. And I think this comes from a very myopic point of view which is we think about mitochondria as purely as things that make energy. They do lots of other things and and my interpretation is that in the afternoon well the standard lab joke is they're doing the ironing. They're doing other things that as organels they need to do. They are over a period of a day they're making contact with other organels in the cell particularly something called the endopplasmic reticulum. They're junctioning with that. We've got such a limited view of what they do. I was surprised to find that a mitochondria at 9:00 in the morning was not a mitochondria at 4:00 in the afternoon. that poses some very serious problems about the interpretation of our data if people are doing things at different times of day. So if somebody wants to improve their vision with long wavelength light exposure um maybe we can just give them a a rough contour of what this would look like uh long wavelength of 670 and greater um emitting flashlight torch um at a comfortable distance from the eye. So it could be, you know, 3 in, 6 in, a foot, depending on how bright it is. But if I were going to run the experiment, I'd probably want to bring it about as close as people felt like they wanted to close their eyes, but then move it back just a little bit, just below the threshold of kind of I don't want to say discomfort, but where it's just too bright. And then you're saying it doesn't matter if their eyelids are closed or open. You give it 3 minutes, 5 minutes of exposure once every 5 days or so. And is that going to be sufficient? There is the difference between something that has an effect and then the efficiency of that effect. So if you take a 670 nanometer light source and you do exactly that, you will have an effect. Mhm. Now, as we're going forward, we're finding certainly we're finding the energy at which you give that wavelength is dropping and dropping and dropping and still effective. So, you don't need a very bright light. No, no, you don't. So, we were the original uh experiments they used watts. They measured it in watts, not lux. flux is not very meaningful to this situation because it's it that's adjusted for the human eye. We want to know what was the energy that the cell experienced. So people started off at say 40 mwatts per cime squared and I looked at that I thought criy that's bright that's very bright big after effect. Yeah that's going to make someone wse it is. So then we got ourselves down to what we do in the lab now generally which is around eight which is very comfortable has the same effect. But then we had someone in the lab do an experiment um and we had the flashlights that had batteries in them. She got a lovely effect and we found out the batteries have been run down and she was getting an effect close at 1 mill per cm squared. That is low. That's dim red light. That is low. Okay. So, sounds like one can use dim to moderately bright red light that's comfortable. Um, I say red, but I mean long wavelength light that's comfortable and likely get the effect. Um, sounds like the effect can occur at any age, but it's going to be more pronounced in people that have experienced some loss of vision because of age, which everybody does. Yes. You've also looked at this in the context of macular degeneration which is a very common form of blinding and especially in people as they get older. Uh what were the results in terms of rescuing vision in people with macular degeneration? Okay. So macular degeneration is when you could put it crudely that the center of your retina that you you're using for reading um degenerates and it's part of an you could say it's part of an aging process. If I get you all to live to 50, uh say if I get you all to live to 100 years, probably 20% of you will have macular degeneration. It remember the retina as a sports car. It burns out. So um I had a I had a very significant failure in a clinical trial because we took a whole group of patients um who had macular degeneration. We treated them with red light and we treated their part more women have macular degeneration than men. We took their husbands as the control subjects. Um and to a first approximation we got absolutely no effect whatsoever. Uh this is kind of a point where you know people people working with Glenn are getting getting losing enthusiasm. Um but lo and behold their husbands their vision they didn't have macular degeneration but their vision was improving enormously particularly the way in which they could deal with darkness. So we we we stomped around over this something was wrong and we found that when we looked back at it we found that the subjects that we were dealing with the patients their disease had reached a certain point. It had gone beyond a certain point. Now when that study was replicated by someone who thought about it a bit more than me, an opthalmologist called Ben Burton in the UK, he got a great result. He started to get a really good result. And when you talk to people about red light and I talk to people, I talk to Parkinson societies, I talk to various groups and I talk to the researchers and it there is one thing that's very clear is that red light can impact on aging. It can impact on disease. But it can't do it if that disease has really got its teeth into you. Right? So where we need to get into situations is early on in disease. So we we thought very much about one point about rheumatism um you know rheumatoid arthritis. Yeah. Very common autoimmune condition. Yeah. And um we had absolutely zero effect. But all of the all the subjects we dealt with already had hands that were quite twisted. It wasn't people coming in saying I've got this ache in my hand which is where we should have intervened. So early intervention is absolutely critical. We don't have to give high energies. We don't have to give long exposures. We can improve situations but where we need to put our effort is the efficacy of how we improve things. If I can improve something 20% well that's great for that person but can we improve it 80%. And that's all about wavelengths. It's all about energies. It's all about us thinking a little bit more carefully before we set up the experiment. It also makes me think that even though long wavelength light can penetrate the body and it scatters like for instance the shining of light on a 4x6 in rectangle on the back impact blood glucose regulation everywhere. shining long wavelength light into the eyes improved presumably mitochondrial function in order to increase uh the visual detection ability um and on and on. Presumably the tissue that you focus the light on if it's a focused light is going to derive the greatest benefit right or at least the most opportunity for mitochondrial change. Then there will there will be these systemic effects. Those mitochondria are talking other mitochondria. I mean, I'm fascinated [snorts] by how mitochondria are perhaps transported between cells and around the body. There's there's a not even a cottage industry anymore. I think a lot of biologists are thinking about this seriously. But let's say I want to improve the fun the mitochondrial function in in my gallbladder. Um, should I shine the red light on my gallbladder? It seems to stands to reason that that the answer would be yes. I think the answer is yes. The issue is how quickly the effect takes place in distal and proximal tissues. So if you shine the light on your kneecap, something will probably happen within 1 to two hours at the kneecap. At the kneecap, but then if you're examining the response of that um on your hand, it's 24 hours later, right? So the message has to get out and things have to the story has to spread and the spreading of the story the spreading that's an intense kind of area of of activity. What is the signal? Where's it coming from? What is the signal? And I think we we poked our finger at that slightly because we found that cytoine expression in the serum changed a lot. Inflammatory cytoines are going down. No. um increase in cytoine expression at low levels is protective. Okay. So what what it's saying to the body is brace yourself something's coming. Immune system is getting mobilized. Yeah. So um that was very very clear. So animals that had improvements in physiology also had changes in cytoine expression. I looked at that and I thought is that the real reason or is this a secondary, third or fourth level effect? Now, um there's a there's some stunning stuff that I'm waiting to come out from, uh Westminster University in the UK, um being done, uh by uh a great scientist, uh Ify, uh there. And what she's showing is a means of communication that we are very really rather unaware of, which is these micro vesicles that go around the body, go around the serum. These microvesicles carry cargos. Now they carry all different sorts of caros and people have played with them a little bit in terms of changes in the gut microbiome. How does that affect the whole body? Um they've been talking about microvesicles and she's shown that microvesicle concentration is changing quite significantly with in fact what we did with her was we didn't give her a red light we gave her an LED light where we change the LEDs in there to put some longwavelength elements in it. So the communication around the body what is doing we've got to break that one what is it it's probably not one thing you know again scientists always think about one thing um it's a complex pattern when I looked at the changes in cytoine expression my first reaction was I need a mathematician sitting next to me all these things are changing in a complex manner and I'm only looking at 50 of them and there's probably over 300 so I could be missing the point but communication and you're right you know Um, you can see cells come along to a sick cell and they join together and the mitochondria is pushed in to the sick cell. How amazing. We'd have never thought about that. Your mitochondria are ill. I'm going to come along and I'm going to give you some fresh mitochondria. It's amaz they they the mitochondria are amazing and it's amazing how um little we really understand about how they work and yet what we do understand points to how spectacularly important they are for energy longevity and as you pointed out how malleable they are. Yeah. Um and it all makes sense in the evolutionary context of water and the absorption of red light. Another way that's kind of fun to illustrate this red light absorption by water thing is if uh anyone ever goes snorkeling what on a tropical reef, you'll notice that in the first, you know, uh 10 ft of water from the surface down, you can see beautiful oranges and reds and um and then if you go deeper, those seem to disappear. They haven't disappeared. It's just that the red light isn't penetrating that far, right? It gets absorbed. Yeah. uh if you bring a flashlight down with you as night divers do or even day divers will do that sometimes in order to see those those red fish are still there deeper um but uh it disappears to you so it's very very interesting I'd like to take a quick break and acknowledge one of our sponsors function last year I became a function member after searching for the most comprehensive approach to lab testing function provides over 100 advanced lab tests that give you a key snapshot of your entire higher bodily health. This snapshot offers you with insights on your heart health, hormone health, immune functioning, nutrient levels, and much more. They've also recently added tests for toxins such as BPA exposure from harmful plastics, and tests for PASES or forever chemicals. Function not only provides testing of over 100 biomarkers key to your physical and mental health, but it also analyzes these results and provides insights from top doctors who are expert in the relevant areas. 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As a consequence, I decided to join their scientific advisory board and I'm thrilled that they're sponsoring the podcast. If you'd like to try Function, you can go to functionhealth.com/huberman. Function currently has a wait list of over 250,000 people, but they're offering early access to Hubberman podcast listeners. Again, that's functionhealth.com/huberman to get early access to function. I'd like to um talk a little bit about the other end of the wavelength spectrum, shortwavelength light. And here I'd like to move to artificial lighting um and point to what I think is a very serious concern. I I know it might seem a little bit uh extreme, but I am very concerned about the fact that people are exposed to so much short wavelength, what's commonly referred to as blue light, but I don't think that really captures it because people hear the words blue light and they think, oh, if a if a light source looks appears blue, then that might be messing with my melatonin at night and might be messing with my mitochondria even. It's the white light coming from LED sources, which are basically what we use as lighting sources nowadays, that yes, they contain blue light, but they also contain, you know, violet light and stuff that doesn't appear blue because you've got the other wavelengths in there. In other words, white light coming from LEDs is very short wavelength enriched. To me, that's a problem. if short wavelength light is causing dysfunction of mitochondria and I do believe that's the case unless it's balanced by the longer wavelengths and at the same time like anything it can be remedied if we do the right thing. So could you illustrate for us what what happened over the last you know 30 years or so in most every country as we moved from in uh well actually let's take it further back. Let's go from fire candle light and fire light to incandescent bulbs. Let's also talk about hallogen bulbs and now LED bulbs. I know people like to focus on screens, but we'll set aside screens for the moment. Let's talk about indoor lighting amount of shortwavelength light that especially kids, especially given what you told us about blood glucose regulation. What's known about this? Okay, this is this there's a group of us shuffling around corridors all mumbling to one another saying, "How big a stink is this?" And some people are I I reviewed a document that was sent to the European Commission last week just before I came over here from a very balanced uh Dutch lighting engineer when he wrote to the European Commission saying, "We've got to rethink this." And so [gasps] the group of us that are shuffling around, some of them are saying this is an issue on the same level as asbestos. talk because it's time to talk, right? We we've got enough data. So LEDs came in and people won the Nobel Prize for this very rightly at the time because they save a lot of energy. They are very energyefficient because they do not produce on the whole light that we do not see. So the effort is all in what we see. Now, as you pointed out, the LED has got a big blue spike in it, although we tend not to see that. And that is even true of warm LEDs, and there is no red. Remember? So, we're talking about billions of years of evolution under broadspectctrum sunlight. When we had fires, that was pretty…

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