Is a 'light deficiency' quietly ageing you faster? – with Professor Glen Jeffery

So if we think about light in terms of human health, it's been ignored but we now understand that large components of these wavelengths are regulatory when it comes to understanding your metabolism, understanding how you generate energy in your body, how you use energy in your body. And we now correlating that against disease, health and aging processes. Now Glenn Jeffrey is a professor of neuroscience at University College London. He's a leading expert in how different wavelengths of light impact our health. Welcome to age better with me Lizelle. Now it's my mission to change the conversation around aging. Through the conversations that we have on this podcast, I really want to share the latest knowledge and helpful tools that can enable us all to thrive in our later life by taking action today because well here's what I've learned to climb is not inevitable and when we understand what our bodies truly need, we really can age better. And one thing that I've become increasingly convinced about our body's absolutely needing more of the right type is light. Now it's something that I've been actively researching actually for the last three years or more now while writing my book called How to Age. That comes out in April and during that whole process, I really came to realise more than ever that when it comes to aging well, our relationship with light is fundamental. And this is why I am so very delighted/over-excited to be joined by our very good professor here today. Now Glenn Jeffrey's current research is examining patterns of aging and disease that are associated with declining mitochondrial function. Yeah mitochondria, I've talked about that here before and we're going to go into that deep this time. But this time we're going to look at the profound effect that light could have on mitochondrial function. So I do think that you're going to want to pause and rewind and listen to a lot of today's chat again because coming up we're going to be talking about everything from infrared to ultraviolet to artificial light, how that's impacting our metabolism, our organs, our eyesight, our brain health and potentially so much more. Well welcome Glenn, it's a real delight to have you here and you're a professor of neuroscience at the UCL Institute of Optalmology. Can I start actually by asking about your personal interest in studying light and you know particularly affecting human health because presumably you are an eye expert and yet a lot of your research is incredibly broad. Yeah one of my colleagues said I should have been put on Ritalin when I was a kid, focused me down a little bit more. My background originally was in experimental psychology and in vision. So Optalmology is about I think when something goes wrong with the eye. I'm really interested in vision and so you know spend a lot of time looking at bits of the brain that deal with vision but then became a little more interested as time went on about what was going into the system rather than what the system did. So what was it about light that was important for vision and vision, our visual world in terms of what we see ranges from sort of violet to deep red but in actual fact the light that we're exposed to solar light is incredibly wide. It goes into the deep into the ultraviolet and deep into the infrared. So I moved on as it were to look at light, how light's affecting the eye because vision was my background and then we drifted into perhaps bigger issues, wider issues such as lifespan, health, aging, what our environmental light is doing within that area. So that's kind of where I, I'm not say where I ended up because that implies that there isn't a future or going forward but that's currently where the lab is and it's currently where most of my research is. It's really fascinating and it's so forward thinking. In fact the only thing that I'm cross about with you being on this podcast is that Huberman got you first and I think that shows that the extent and the global interest, particularly in the biohacking community and people working in longevity space, that light is so fundamental. So can I ask you perhaps just to explain the basics of light and perhaps the different wavelengths, those that we can see with the human eye and also those that we can't see. Yeah certainly. So if we think about light in terms of human health, we're stuck in the middle of solar spectrum in this little area between sort of violet and deep red. If we go down into the violet, steep down into the violet to the ultraviolets, those are wavelengths of light that we don't see but they are wavelengths of light. They're absolutely critical for producing vitamin D. They're also the wavelengths of light that we respond to by getting sunburn. They carry a lot of energy. They don't penetrate very far into our bodies and that's why we get sunburn because all the energy is blocked in the skin. Very important for health in terms, particularly in terms of vitamin D, which most people walk around say we have a bit of a vitamin D crisis. That's partly because we spend so much time inside and we live in northern Europe, which is overcast and a bit grim for many months. So then we swing right over through the visual range, through the blues, the yellows, the reds and then we enter a region again, a much longer region that we don't see, which is the infrared range. And this is really an area which has been very much ignored. Infrared light, long wavelength light, it passes through your body. We can measure it coming out the other side. So if I stick you in sunlight on a sunny day and I put some instruments on your back and your face in the sun, I can measure that light coming through. Not a lot of it gets through but it does get through. It doesn't carry so much energy in terms of oomph. That's why you don't get sunburn from it. It's been ignored but we now understand that large components of these wavelengths are regulatory when it comes to understanding your metabolism, understanding how you generate energy in your body, how you use energy in your body. Throughout the whole of evolution we've generally been in solar light and the solar light has a balance between the red and the blue, the bits that we don't see at either end of the spectrum. And that's been great. We've evolved under that, all life for billions of years has evolved under this very stable solar light. And so the blues and the reds are in balance. I think the angle that we've come from is the surprise that when we move into the built environment, when we're in buildings, modern buildings, we're a long, long way from solar light, LED lighting which we currently have. We've got it because it's very energy efficient. It only produces light that we see. And you know, that makes sense. It makes sense as long as you've got a very, very limited view of vision and metabolism because all the blues, the deep ultraviolets and all the reds have gone. They've been taken out. And this is extremely alien for life forms. It's a very, very strange wealth. So you know, we started getting great results. I won't go into in detail. We could start getting great results using long wave length infrared light. I part from sort of polishing my ego on all these great results and publications. It wasn't until relatively recently, we realized that we're only getting these great results because you are living in an environment where there is no infrared light. And we call this infrared starvation. That is completely fascinating. And my regular listeners will know that we recently had Dr. Veronique Batai on the show recently. She's a consultant dermatologist alongside people like Professor Richard Weller, who are rethinking the skin's relationship with the sun. And their argument has been that all cause mortality is actually lower in people who get more sun. And I'm sure we'll come onto that. Obviously, when you talk about UV light, that's the one that people are taught to fear. And we cover ourselves in sunscreen and we avoid it. And you know, thinking about the days, hopefully getting warmer in the months to come. A lot of people are going to be thinking, well, where does that leave me? What do I need to do? Because we do live indoors. Don't we? And it's quite scary in a way to think that these lights that we're turning on inside the home could actually be damaging our health. I mean, do you think that is a reality? Yes. Yeah, I do. I've come around to that point of view in an evolutionary sense, very gradually. So a colleague of mine described it as modern day scurvy because it is a, we can, let's stretch our necks, let's call it a disease process. This disease process, this metabolic problem is occurring because you've taken something away. It's not that you've, you've suddenly hit with a toxin. It's that something important for Lyat has been taken away from you. As it did with scurvy, with sailors, I mean, they 18th century, who, you know, first of all, their teeth fell out and eventually they died because they had no vitamin C. It was an absence. So yes, I'm not going to stack my neck out too far, but I think there are many disease mechanisms that are aggravated because of our light environment. So, you know, the first one that we really kind of dragged ourselves into was diabetes. So, we can auto-metabolism with light and diabetes is a metabolic disease. And we can regulate your blood sugars to some extent by changing the light in your environment. So, if we give you a burst of infrared light, we improve your metabolism and to improve your metabolism, we consume more blood sugar. And that brings your blood sugars down. It's not the only answer to diabetes, but it's one to think about if you are in an environment with no infrared light, you're aggravating your blood sugar situation. So, could you then eat more cream cakes and stay outdoors? Is that the mid-million dollar question? I don't. Well, I tell you the experiment that we did is a glucose tolerance test. It's a horrible experiment. You really got to. You find out that your friends are when you need subjects. And you have to drink a very large glass of extremely unpleasant glucose, it tastes disgusting. And then your blood sugar peak about 40 minutes to 60 minutes afterwards. And we found that peak in blood sugars was significantly reduced with a burst of red light. So, I'm not saying you can eat more glucose. It's one of a number of things that we should be aware of. I mean, we can regulate our blood sugars also by exercise, but a lot of people are sedentary. And so, they're sedentary. They've got lighting which is challenging their metabolism. We need to put packages together, lifestyle packages together to deal with these problems that fundamentally are public health problems. You are so right. And yeah, I mean, I couldn't wave the flag more wildly for you. And let's talk about these longer wavelengths of light then. And the ones that we're talking about infrared light. Can we discuss how we can get more of these? Are we talking about things like the red light masks? We're talking about LED masks for skin, infrared soreners. What do we can buy gadgets that can help or do we literally have to go out and find some sunshine somewhere? Well, we've got to catch phrase in the lab now when people ask questions. Because the same questions come up, which is get a dog. If you've got a dog, you've got to go out twice a day. So outside is best because of the balance of light. The blues and the reds are in evolutionary harmony. If you can't do that, well, there's a number of ways forward. You can go and get an old incandescent light bulb. So which gives off loads of infrared that you can't see. I'm sitting under one at the moment. Nearly all of my colleagues have got incandescent light bulbs. Really good to have in the kitchen in the mornings when your metabolism is very, very sensitive to its light environment. There are a lot of devices on the market and there was a point where we started getting them and pulling them apart. And universally, we were very unhappy about them. First of all, we were we were we were shocked by the eye watering price of these things. Because when you pull them apart, there's almost nothing in them. So people sometimes send us devices. We were sent a panel from California, which I believe is about $5,000. When we pulled it apart, maybe it had $15 worth of equipment in it. You must be tempted to make your own surely. Well, yes. In the early days we were and I resisted that because I felt from from an academic point of view, as long as we were clean financially, we had no direct financial interest in these devices. We could be rude and we could get away with it. So we don't have financial interests. Face masks are a big thing. When we look at face masks, I mean, they have they have an initial appeal and there is an element of them that probably works. My main concern, not mine, our main concern, is the vast amount of energy they're putting into your body. And the same is true of the red light panels. It's enormous. You know, it is getting on for a thousand times more than I use in the lab on people. So if you buy a face mask, yeah, it will have some effect. What I'm concerned about is what's what's happening in 10 years time? You're putting all this energy into your body and you don't need it. You know, you take a face mask. Really, if you want to do that, I would be running them very, very low power. But as someone in the industry pointed out to me, you've got a bright red face mask and a dim red face mask. What are you going to buy? And yeah, I get it. I get it. But it is absolutely definitely the case that too much red light does not work. Okay, so it will work initially. But then what happens is that the metabolic system that absorbs that red light starts to get clogged. So what starts to happen is, first of all, there is a reduction in efficacy. We go a bit of efficacy initially, but you don't get it in the long run. Also, the wavelengths are very cramped. It's a very unusual form of light compared to say a incandescent light bulb, which produces the same spectrum of light as sunlight. Okay, so there's no balance in a face mask. A face mask is a very restricted series of wavelengths in the red, pumping lots of energy into a very small region of your body. And I think there are parts of metabolism that go into shock with it. And that's when things just stop happening. And we've tested this time after time. You know, if you put too much in, things stop happening. But I think there are a lot of people that are not going to pay too much attention to that. Really fascinating. What about something like an infrared sauna that has near infrared and medium and far infrared and is a much, you know, much bigger surrounding? You're not actually putting a device that's so strong and polarize perhaps on one small area of the body. Would that be a better option? I think I think that is a better option. But yet again, you're in an abnormal situation where the body is being bombarded within for red light. It, you know, we have evolved under sunlight in, you know, in central Africa, four, five million years ago, at least. And the vast majority of human existence was actually spent there. It's only really, so you've got four, five million years under natural sunlight. And then, you know, maybe 70,000 years ago, 50,000 years ago, we start migrating north. Now, the vast majority of our evolution has been under this natural sunlight. And we're already in the wrong place. We're in the wrong place living in Luton, Croydon, where we shouldn't be here. We should be, we should be where our immunity and our metabolism was established, which was on a 12, 12 light dark cycle that had very little variation over the year, lots of sunlight. But let's be pragmatic. We're here. So we have to deal with it. And that's the challenge that we face dealing with the problem. Putting on face masks, using red light, beds, doesn't help. Red light soreners, I've never had one. But I think we face a similar problem here. Okay, we're distributing the energy across the body. That's good. But at the same time, we are giving a very restricted series of wavelengths in isolation. And that's really something we should try and avoid. It's so fascinating, isn't it? And it's trying to come up with practical solutions. And we'll talk more about that, I think perhaps later, because it's just not practical for all of us to suddenly decamp and live in an open air setting and move our offices out doors. But I think there are steps that we can take, hopefully, to get more of this sunlight and not fear it. Let's just look at that cellular level, because I mentioned in the intro about mitochondria. And I know that this is a fascinating area, particularly for you coming from ophthalmology, because my understanding is that our eyes are incredibly rich in mitochondria. And presumably, that's got something to do with the way they're absorbing and responding to light. Well, they're incredibly rich in mitochondria because they're incredibly metabolically demanding. If you've got high metabolic demand, you also have a faster pace of aging. Okay, so metabolism and aging are inherently linked. A fly has got a very high metabolic rate and doesn't live very long. A whale has a very low metabolic rate and lives for a very long period of time. So these are all linked in with mitochondria because mitochondria regulate the vast majority of your metabolism. And the super interesting thing for me about mitochondria is they respond to light. I must confess, it's taken me about 15 years and you know, probably would have thought mitochondria was a pizza topping. It's not my background. Yeah, fundamentally I'm a vision person rather than the hardcore biologist. But you can watch mitochondria in real time. You can watch them change as they are exposed to different wavelengths of light. In fact, the great thing about mitochondria that only a few people really grab is the fact that they change colour depending on how hard they're working. And you can use that to ask yourself, how well are they responding? If you give them long wavelengths like they produce more energy fundamentally, the energy we use we call ATP, a denocene trifosphate. But I'd just regard it as the energy that comes from the cell, from the mitochondria. And there are thousands of mitochondria in each of your cells. They're all busy talking to one another. We've got absolutely no handle really on their communication. And from a point of view, practical application, they talk to one another across the body. So if I shine light in your eye, red light for instance, which is something we probably do most weeks, I can see an improvement in your say colour perception within a couple of hours. It's quite clear. But I can also shine long wavelength light on other parts of your body like your abdomen. I can get an improvement in your vision. What is it? It's 24 hours later. So they're talking to one another. Big question is, what are they saying? How are they saying this? What is the medium of communication that's going on in the serum in the blood? Something is. So for long wavelength light, they talk to one another. For short wavelength light, they talk to one another as well, but patch in a different way with a bigger delay on it. But we talk about mitochondria now as a community, as a metabolic community across the body. And that, if you look to the future about the big challenges in this area, big challenges are, what are they saying and how are they saying it? I'm not sure I've got enough heartbeat left to find that one out, but it's the big question. I do remember reading some research years ago about jet lag and somebody was saying that if you shone a torch on the back of your knees, when you reached a new time zone, then your effects of jet lag were mitigated. So maybe there was an early adopter of using light to regulate your circadian rhythm in some way, because that's what it's doing. That's the bottom line, isn't it? Getting up in the day and seeing that early morning daylight, that is just setting the whole body up and its body processes for the day ahead. Yeah, I'm not sure whether the back of the knee was something that was ever really replicated, but you're absolutely right about the importance of the early day. When you're in a stable condition, your mitochondria know when sun rises. So if you look at say animals like flies and everything I found in a fly, I find in a human and a mouse, it's highly conserved. If you look at mitochondria in a fly, they start to become active about half an hour before the lights go on in the lab. So they've got a clock, they know when the lights are coming on, and at that point onwards, they start producing a very large amount of energy, ATP, and that peaks around just before midday, and then afterwards, that big bowl of energy declines. So if you want to give red light therapeutically, best time to do it is when your metabolism is in flux when it's changing. So we improve people's vision with red light. It's a very, very standard thing to do, and we do it always in the morning, and we, you know, it's very, very rare for us not to get an effect. But if we give it in the afternoon, that doesn't happen. The increase is a minimal, if not at all. And that, I regard as being something that reflects what is your general state when you wake up. And when you, let's go back again, let me drag you back to Central Africa or an earlier stage in our evolution. You've been asleep all night. That's a very, very dangerous state to be in because predators may be looking at you, and you want to wake up and you really want to be aware and you want to be able to run if there's a problem. And it's not just your ATP that peaks, your mitochondria, working super hard, your hormonal situation is very, very different. Your blood glucose level is very, very high. So your blood glucose is high and is there to support you and support your mitochondria who will be demanding blood glucose because that's the petrol they need to generate the energy. So there's something about the morning. You can put it into an evolutionary context. I also read a piece of research recently looking at the effect of circadian rhythm on treatment, for example, radiotherapy or chemo, and it was assessing the successfulness of the outcome, depending on the time of day that the patient received the treatment. Would that be linked to this then? There is a link somewhere between circadian biology and mitochondrial function. I think for what we're trying to do is trying not to get the two mixed up. There is absolutely no question and I'm surprised that the NHS does not pay more attention to this. That outcomes from medical procedures have better times of the day. We're just not really aware of this. So maybe we should be doing, and I'm saying this off the top of my head, maybe we should be all doing kidney transplant at 11 o'clock in the morning. It's a big job to go back and look at success rates as a function of time of day, but it is absolutely definitely there. So different parts of your body have got different clocks. There's a master clock. Mitochondria have really got a very complex series of clocks. I've tended to avoid that in my research just because there's too many variables. I know I can kick it off in the morning, so that's where I've tended to stay. Brilliant. I'm going to pause when we come back. I'd like to talk more about how artificial light is affecting our health. And what we can do to optimise it going forward. Well Glenn, it's completely fascinating to look at the benefits that we can so easily get. I think the great thing is that the bottom line is that we can get them free. We can have a bit more sunshine. We can go out first thing in the day. Hopefully before the day crowds in, we can make a difference to our health overall. Let's look at the downside. We've looked at what red light can do for us, for example. What about the bad guys? Let's talk about how actually most of us live. We live indoors under artificial light, under those single spectrum LEDs. We're looking at screens and presumably screens are giving off light as well. I mean, how's that affecting our eyes and our overall health? I'm not a fan of screens. I didn't think you would be. You're talking to someone who's a fan of an abacus, quite honestly, when it comes to technology. The problem with the built environment is the short wavelength light, the excess light. We know where that little bit resides. It resides between what we call 420 and 450 nanometers. It's a very deep light, deep blue light. And there are bits of your mitochondria that are very sensitive to that wavelength range when it's not paired with red light. So when it's on its own. First thing you really notice is it slows mitochondria down very clear. There's also loads of evidence to show that if you slow your mitochondria down, mitochondria are not consuming the glucose in your blood. Therefore, you have less regulation of your blood glucose levels. So we're all sitting under LED lights, which some of them have got a spike, a big spike at 420 to 450. That's really bad news. But the big issue with them is there's just no long wavelength light to balance out the blue. There are loads of other issues that come up that are very, very clear with blue light. Screens, because I went straight for screens, I thought screens must be absolutely awful. And I was at one point having some very extensive conversations with a major computer company and their screen research department. Now luckily, the light that generally comes out from a blue screen saver is not within that dangerous range of 420 to 450 nanometers. It's a little further out. So your screens aren't as bad as you might think they are. This company however wanted to have a red screensaver. And for all the right reasons, the unfortunate thing was they put a proposal forward, but these proposals have to also go through the sales department. And the sales department said no because it would add 3 or 4% to the cost of the screen. So that fell rather flat. Blue screens though, there is evidence that blue screens increase cortisol. A cortisol is a marker of stress. And the other intro, I learnt so much from talking to this company, you don't want people sitting in front of red screens that are really going to relax them. You want people sitting in front of screens and just going to slightly stress them. Because you're slightly stressed and that is going to increase your attention. That was that was an eye opener. So, oh my goodness. Screens aren't great news. There's lots of other reasons why screens aren't on great news, apart from spectral component, but I think the key issue is it's not as bad as you think it could be. They're not producing light really right in that dangerous range. Most LEDs are and don't think when you go and buy a warm white LED, it's going to be any different. It's not. There is still going to be an absence of all that red light is not going to be there. So some of them are very spiky and difficult in what you could call the dangerous area, but none of them have got the red light that you need. But what it does mean is, you know, thinking about kind of Glenn 18 months ago, Glenn 18 months ago was going round as a profit of doom saying let's get rid of all LED. He's not so much a profit of doom now. More on the fact that we could get round this problem by just supplementing our light environment with long wavelengths, with with a few incandescent light bulbs to try and bring the balance back. We're not going to be, we're not going to get rid of LEDs. And when I stand and talk to architects, which is I spend a lot of time talking to architects now, they tell me no way can we get rid of LEDs. We need to compromise. And I'm more comfortable in the compromise zone than I was at one time. So yeah, we can get around it by engineering a compromise. And I think that's important for a step forward because we don't really want to we don't want to take on all the massive lighting companies. And everyone's going to say we bring incandescent back. You know, that's that's going to involve excess energy wastage. I listen to that and you can get around that by just taking an incandescent light and putting a dimmer switch on it, which is what we all do. Because as you dim the light down, dim the visible light down, the infrared remains rather high. And that's why even if you've got a dimmer switch on and you put your hand on that incandescent light bulb, it's still hot. So that's one compromise. We need to find compromises that we can get the architects and the lighting engineers to swallow on. And I think if I'm thinking about the places where I find light the brightest and since researching it, I'm so aware now and I go into environments that are this bright white and how it makes me feel. Unfortunately, I'm thinking about things like schools and hospitals and clinics. You know, places where you would really want good quality lighting for health and growth and attention and all of that. So, you know, it is kind of a public health message, isn't it, that you need to get out here, that we all need to be thinking about? You know, that's what I had started to sing about. So we've walked into some critical care units in major London hospitals and we've done lighting assessments for them and we've pointed out inadequacies. One of those critical care units has actually started to consider lighting in their stroke unit. So when you come out of the ambulance and you go into that stroke unit, you're in a very poor condition and in stroke, mitochondria suffer like crazy. So yes, we're talking to hospitals and hospitals are listening. Interestingly, you know, I'm sitting in part of UCL, research part of UCL that's right next to Moorfield's eye hospital and the lighting conditions in Moorfield's eye hospital are appalling. In fact, I walked in there with one of my architect colleagues who spent most of her life in Scandinavia and her comment was she couldn't put that lighting in a prison in Denmark. Wow, and it's an eye hospital. Yeah, but Moorfields are moving to a brand new eye hospital, which has just been finished and we will everybody moves in any year's time. And guess what? They've got horrible LED lighting and something we haven't discussed is that modern architecture uses infrared blocking glass and they do that so that they can control the temperature and the building. So all these modern buildings that you see that are constructed in glass will invariably be blocking at least 90% of the infrared. So even if you've got a window, the sunlight isn't coming in, the infrared isn't coming in and you've got pretty awful LEDs. If you put up a building, this is what the architects tell me, if you put up a building and you overspend on everything by three or four percent, the last thing you put in is the lighting and the lighting has to absorb that deficit. So you go for the cheapest possible lighting that you can get. And I look around outside my window at a whole series of new buildings around me. When I'm leaving at seven o'clock at night say this time of year, the light is a poor. I mean, it's harsh. Yes. Now schools, so we've got some hospitals to start paying attention. And we've got the architects partly on board because they're thinking, if I put up a building and the lights wrong, now that the story's out, could I be prosecuted by someone who becomes pre-diabetic? So they're nervous. Schools are a really great example of bad lighting modern schools. And here we face a very different problem because the lighting in schools, the absence of infrared light is associated now with the development of myopia. So myopia, the eye grows too long. So well, you know, people say we can correct that. We can give you glasses. Well, that's true. But when the eye grows too long, as you become an adult and you move into your 30s and 40s, the retina can start tearing and you can get a form of macular degeneration. But of course, that's not the problem for the politicians today. That's a problem for the politicians in the future. So ability to address that is very much limited by lack of political initiative. If you've got a patient in a bed and you know that you might be able to get that person out of the bed by changing the lighting, that's a problem for today. It's a problem for this week. The problem for the kids in the schools is a problem for 30 years in the future. And we're not addressing that. So you're absolutely right. It's about public health. It's not really about ophthalmology at all. It's dealing with the population as street lighting, hard-wired LEDs. They change my street lighting about two years ago. It's not comfortable. A few people in some London barriers have started to complain. I consider myself slowly no longer as a neurobiologist, but really is a sort of a mouth for public health. Well, I'm very glad we have you. Interestingly about the street lamps, I did read somewhere that they, in some councils, they were having to take them down, not because of the effect on public health and our poor children and elderly and all the rest of it, but because they were affecting birds. Yes. And the RSPB or whatever got involved and said, "Hey guys, we can't have these lights because our poor birds are suffering." So you know, never mind humankind that lives with it all around the clock. So maybe we need to find subversive ways to get things changed. Speaking as a parent with kids in school, obviously we can't get them to go in and change all the lighting. What about if we give our kids blue-blocking glasses? Would that be helpful? Now, isn't that such an obvious question? Just such an obvious question. And I was sitting here about four years ago thinking, "This is such an obvious question." So I gave everybody around me glasses that were blue-blocking. I chipped out and I just got some orange-masking sort of orange filters and stuck them over their glasses. But in terms of filters, they worked, they did what they should do. We got absolutely no effect. Why? Why is that? Well, three million dollar question. So then I started talking to my colleagues because you tend not to publish things that don't work. And then the stories were coming out, "Yeah, we tried that and it didn't work." So there's a variable here that we don't know about. It's just seen to make so much sense. And you know, interesting one evening, I got home and there was a radio program on about blue-blocking glasses. And the take home message from talking to all these people was, "Yeah, we don't think this works, but we don't know why." Now there's one way in which it works brilliantly because the optometrist can charge you for putting a filter in your lens. And so there's profits to be made in it. But in terms of the protective effect, I cannot find it. And you know, once every month we're sitting around having coffee and someone will say, what about trying this or what about trying that? You know, maybe it's something about your blue blocking glasses are only covering your central field of vision. I just don't know. And then how blue blocking are they? You know, if you make them really seriously blue blocking, you're not going to like it because the world will seem very odd to you. Having said that, though, Glenn, I've been wearing blue blocking glasses in the evening, and maybe it's to do with time of day more than anything and giving them to my kids. And we all say that we do genuinely sleep better and I track my sleep and I do get more deeper sleep if I'm for the last few hours before bed. If I'm, I do dim my lights as well, but obviously they're not all in kandessen. But if I do wear my blue block as these really strange, bright orange lens glasses, I do feel more rested and I do get a better quality sleep. Yeah, you are, you're right in that respect. So we know that blue light take, take you back to your television to your computer monitors. Blue light is stimulating, but that actually is a rather different issue. I'm trying to look at sort of long term damage, how mitochondria responding. That's separate from that circadian effect. I totally agree with you about the effect of blue blocking glasses late in the day. I've not done it myself, but it's widely reported from really reliable sources that it's associated with better sleep patterns, but it's not associated with anything that's going to protect your mitochondria, unfortunately. Oh yeah. Well coming back to protecting health and looking at infrared light, I've also read that infrared light could be part of a treatment for neurological issues. I mean, even things like Parkinson's, for example, and neurodegenerative diseases, is that a mechanism that's using mitochondria or how might that be working? Well, if we look at Parkinson's directly, Parkinson's is a mitochondrial disease. It's a disease of mitochondria in a very, very small nucleus in your brain to them. Now, Parkinson's disease can be induced overnight with a certain drug. Now, if you induce Parkinson's disease and then very shortly afterwards, you give red light, there is a highly protective effect. Very clear. Most of this work was done by one of my heroes, John Metrophannis from Australia. Did lots of work on this. The trouble is, say with Parkinson's, and this actually has a generality about it. Once that disease has dug in, it's very, very difficult to shift it. So we have used red light for macular degeneration. Our study didn't get a result, but others have learned from our failings, and they have got results. I didn't get a result because the patients I selected were too far down the road. So red light can help in many diseases if you catch it early, neurological diseases. Maybe that's why we get, that is a motivation for stroke treating it in stroke because someone's had a stroke there into hospital. They're fresh in their disease process. Parkinson's, I think it will work, but you've just got to get it really early, very early. Yeah, and that is one of the potential downsides for treating acute stage or even chronic disease. If you're too far down the road, it's not going to help. You're obviously based at Morefields, or spend a lot of time there working with the IEP people. A lot of what's going on there is looking at things like replacing cataracts and laser eye surgery. If we start doing things like that and interfering with the structure and the mechanisms of the eye, what effect is that? Is that going to damage our relationship with sunlight or help it? Well, if you're, if you've got very brown lenses and cataracts, you're you're you're you're going to want them out. You're going to want them changed. Our big problem is we're living too long. So we're confronting all these problems in normal life expectancy with no external support. Probably lifespan would be about 35 to 40 years, but we're hitting all these problems. Cataracts is a cataract is a classic one. Suddenly you you take a brown lens out that you know, you've had for 75 years and you put a clear one in everyone's response because it's generally done under local anesthetic is oh my god, the world is so clear, the world is so sharp. So people love doing it. You're not going to you know, you're going to have to interfere because if you don't interfere in some conditions, peoples, the quality of people's life goes downhill through aging, reaching a point where you know, a great great great grandfather's grandmothers didn't reach these points in aging. Yes. Because they're you know, they were all dead when they were in their early 50s. So we've got the shift in a population. It is certainly true. Let me drag you back to the big question. It is certainly the case that we do a lot of work on short-lived animals. So flies like this. Certainly the case if we change their lighting, they live longer. Absolutely definitely. The absolute lifespan doesn't change very much, but all those kind of problems that you get in midlife are far fewer. And you know, when you look at flies, you can actually do some really great things with flies. They're very, very cheap and the data you get from the flies very similar to the data you get from a human. Their mobility is better. They're more mobile. They've got more energy. So one of the things that we gave them red light, they live longer, they're more mobile. Their cognitive ability is improved as well. What we've got sitting in the lab down the corridor is a whole series of different flies under different light bulbs now. So you know, what can we can we translate sort of longevity in light bulbs by looking at what happens with a fly? I think we can. Absolutely fascinating. One last practical question before we go. And I think hopefully most people having listened to this will be inspired to get outside right now and get some daylight or at least open a window and look at the light sunglasses. You know, they've become such a fashion accessory. I'm always telling my kids to take them off unless they're suffering real glare. What's your view? Because every time I talk about this on social media, I get lots of rocks chucked at me by people saying, oh, you're going to damage everybody's eyesight. You know, what's the reality here? What should we be doing? Well, I think when light, I am slightly photophobic. So I don't like scorching bright daylight, particularly not facing into it. If that makes you feel uncomfortable, wear sunglasses. However, you didn't evolve. Keep saying the word evolve. You didn't evolve to wear sunglasses. What are they doing to you? Well, they're cutting out part of your visual spectrum. They're clipping down on the blues and they're reducing the amount of light that you get into the eye. I don't think they're a great idea. But when I look at the spectrum of problems that we've got with light in our environment, this one is nowhere near the top of my agenda. And you know, you do have mechanisms to deal with bright light. Like the size of your pupil, it becomes very, very, very small in bright light. I don't think it's really doing you any long term harm, but I don't really see it as being necessary for the vast majority of people. You sit on the tube and you find people wearing sunglasses. I mean, that's just hilarious. Absolutely hilarious. So last question then, if you were given a magic wand to do something magical for light within our community and our society, what would it be? I think because I want to happen this within the within the heartbeats that I have left, it would be trying to find a way of reintroducing a limited number of incandescence firstly in vulnerable situations which are hospitals, nursing homes and schools. They're absolutely, take an older doctor who spent some time in a hospital who's got a lot of experience. He'll always tell you you get your patient out of bed quicker if they're sitting by a window. It's about awareness and within the limited number of heartbeats I've got left, we can get there. In the long run, we need to think about it in a radically different way. But in the short run, I think we can make radical changes with limited amounts of incandescent light. And the other thing that is a key part of some of the research we're doing now is how many incandescent light bulbs do you need in a classroom? I think it's one or two, maximum, not change everything. So yeah, I creep around changing light bulbs in different parts of this building and seeing how many people I can influence. I would say that the lab has, I have said to the lab, we've got to cut back a bit on the research and we've got to turn the volume up on the communicating. We need to talk. And that's where it is. You're doing me a great favour because whatever podcast it is, it's about talking to people. If I can get someone who doesn't pick up on a lot of science stuff who's living in the back end of Huddersfield, If I can get them to become aware, someone who is aging, if I can get them to become aware that they can ameliorate some aspects of this with light, then that's a winner. That's how we make the world change Glenn, Jeffrey. Thank you so much for being with us. Thank you. Oh, Glenn, that was so brilliant. I can't tell you how excited I am to have recorded that. So many notes I was scribbling down and you know, just so practical. I love the way he said, get a dog, you know, it literally, it takes you outside outdoors twice a day at least, get some incandescent light bulbs, pop them in the kitchen. If that's the most important place to be in the evening, great. And wasn't that fascinating about stroke units and you know, having those conversations and he told me after the recording actually that it's not just stroke units, but once he was talking to the medics, they were saying, well, why don't we put incandescent lighting in ambulances, you know, so it's immediately there for people as soon as they are at point of need. Really incredible. And of course, altering metabolism with light. Isn't that fascinating too, diabetes? Perhaps we can actually sit on the beach in the sun and eat an ice cream. Maybe that's one cancelling out of the other. Oh my gosh, well, I really hope that this box, some conversation in your personal life at home, even if it's just as simple as changing a light bulb. Do let's chat on Instagram. You'll find us, of course, at Lizel Wellbeing. You can leave us a comment. And if you'd like to follow me personally, I am at Lizel Me. A lot of the resources and information that we talked about today, I will make sure we'll be in the show notes as well as a link to my new book, How to Age. And I have to say, the first section of the book is all about light. It's completely fascinating. It's very compelling and we really do need to get to grips with it if we are going to age well and improve our health span. Well, that is it from me until next time we chat. Go very well. Goodbye. Age better with Lizel is not medical advice. If you need help with a health concern, please speak to a doctor. This episode is presented by me, Lizel, and is produced by a new chateau for fresher production. With thanks to our Head of Brand, Ellie Smith, and social media manager, Naomi Van Guelen.