How LED Lighting Is Harming Humans With Professor Glen Jeffery

In this insightful podcast discussion, friend of the podcast, Professor Glen Jeffery, sheds light on his recent study published in Nature (https://www.nature.com/articles/s41598-026-35389-6)

Introduction
In a world dominated by LED lighting, we often overlook its potential health consequences. Professor Glen Jeffery's groundbreaking study highlights the significant effects of artificial lighting on our vision and overall metabolic health.

The Research Background
Professor Jeffery begins by addressing growing concerns about how artificial lighting affects our health, particularly in environments with scarce natural light. The study was conducted in a building at University College London. The hypothesis was that the lack of natural light and the prevalence of LED lighting could be detrimental to overall health, particularly in terms of colour perception and metabolic functions.

The Experiment
The unique aspect of this study was its real-world setting. Instead of a controlled laboratory, the researchers chose an office environment where participants would typically work. Participants were given old incandescent light bulbs, which emit a broader spectrum of light, including infrared, crucial for metabolic health.

Surprising Results
The results were striking: participants showed a highly significant improvement in their vision after only a short exposure to incandescent lighting. This improvement persisted for months after the bulbs were removed, suggesting that exposure to a broader spectrum of light is vital for visual and metabolic health. Professor Jeffery emphasised that this study is a wake-up call about the damaging effects of LED lights, which may suppress our physiological functions, including colour vision.

The Importance of a Balanced Light Spectrum
Professor Jeffery highlighted that while LED lighting is often considered energy-efficient, it poses risks to human health by limiting the spectrum of light we are exposed to. He discussed the need for architects and lighting engineers to rethink building design, emphasising the importance of incorporating a wider spectrum of light for optimal health. The study also raised concerns about the glass materials used in buildings, which block essential infrared light.

Moving Forward: Practical Solutions
To address these challenges, Professor Jeffery suggests we don’t need to eliminate LEDs entirely. Instead, he advocates a balanced approach to lighting by integrating incandescent bulbs into our environments. Simple measures, such as using incandescent bulbs with dimmer switches, can mitigate the negative effects of LED lighting. He also urges policymakers to rethink regulations surrounding incandescent bulbs to ensure a healthier future.

Key Takeaways

1. LED lighting may impair our vision and metabolic health.
2. Exposure to incandescent bulbs can significantly improve colour perception and overall well-being.
3. A balanced approach to lighting, incorporating a variety of light sources, is essential for our health.
4. Policymakers must prioritise health implications when designing lighting regulations.

The paper is available for download here: https://www.nature.com/articles/s41598-026-35389-6

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Transcript

Introduction to the Study

Dave Wallace 0:00

You've just published a paper in Nature, and it really caught my eye. Could you just start by briefly introducing what the paper was about?

Speaker 0:10

There has been concern for quite a while now that the lighting that we experience in the built environment at home and at work is affecting our health. And I think a lot of that concern has been around light emitting diodes, LEDs. LEDs now take over our world. So what we did in a study was we went to University College London to a horrible building that had no windows that let in normal daylight. Incredibly harsh LEDs and people working there eight hours a day. And we tested their colour vision and then we walked back into that environment and we gave them old incandescent light bulbs that we left sitting around on their desks. Now, old incandescent light bulbs are like sunlight, vast amount of infrared. But we came back and we tested their vision, and there was a highly significant improvement in their vision. Um, it really surprised us. I mean, we were very surprised by the magnitude of the effect. There's a package for health that is very obvious. And it is public health, and it's small modifications that lead to improvements in public health improvements in health span. I want to be 80 and still knocking around and having. I'm not sure I care that much when I die, but I want to make sure that at least until that last five minutes before they put me in the coffin, I have a high quality of life. That is, you know, that's paramount. Welcome to Sunlight Matters, the podcast that reconnects us with the sun. Join us as we explore the power and influence of our star, the force at the heart of everything. Each episode, we speak with leading experts to uncover the ways sunlight shapes our world.

Dave Wallace 2:02

So, welcome back to the podcast, Glenn. Thank you so much. Uh, very short notice for coming on. Uh, you've just published a paper in Nature, and it really caught my eye, and I thought actually, it might be a great opportunity to kind of grab you while the ink is still fresh on the paper, so to speak, uh, and get you to just talk about the the the study that it talks about and some of the conclusions that that you reach from it. So I wonder, could you just start by briefly um introducing what the the the paper was about and and and the sort of headlines on the study, and and I guess what the hypothesis was that you were were trying to prove through through the work that you did.

Impact of LED Lighting on Health

Glen Jeffery 2:51

Sure. Thanks, Dave. And and it's always a pleasure to come back to this site. Um there has been concern for um quite a while now that the lighting that we experience um in the built environment at home and at work um is affecting our health. And and it's been something that people have been very susceptible to and talked about, but not much has gone on about it. And I think a lot of that concern has been around light-emitting diodes, LEDs. LEDs now take over our world. Um, and they're peculiar because they only give off light that we can see. Yet there are other parts of light that we don't see, particularly towards the infrared, that have a profound role in health, including our blood sugars, our life expectancy, a whole range of things. So, what we did in a study was we went to part of UCL, University College London, to a horrible building that had no windows that let in normal daylight. In fact, we went to deep in the building and all they had was incredibly harsh LEDs and people working there, you know, eight hours a day, very often in winter, not going out for lunch. And we tested their colour vision and looked fine. And then we walked back into that environment and we gave them old incandescent light bulbs that we left sitting around on their desks. Now, old incandescent light bulbs are like sunlight, they've got a vast amount of light in them that we don't see, a vast amount of infrared, and they are very much like daylight. So we left these there and we said to people, you don't have to look at them, just move around them, go do what you want to do, go to the loo, have your lunch, just leave them as part of your world. And we came back and we tested their vision, and there was a highly significant improvement in their vision. Um, it really surprised us. I mean, we were, I mean, we walked into that environment, we all agreed the environment, the light environment, was awful. It looked awful. Um, but we were very surprised by the magnitude of the effects. And then what we did, we took the light bulbs away and we went back and tested them subsequently. And the improvements that we got lasted much longer than we thought that they should do. In fact, they lasted for getting on for a couple of months. And the study stopped and came to an end because we hit Christmas and everybody went, everybody left, everybody went home, everybody had then had a very different light experience, everybody had too much to eat and too much to drink, so we stopped the study there. So the key implication of this study is what we thought, perhaps going back previously, which is LED lighting is suppressing your metabolism, it is suppressing your physiology. We chose the retina or visual system because it's easy to assess. We can say, we can say, can you see this now? Can you see this tomorrow? Could you see this in the past? We get hard numbers out of it. But the same metrics we have there, other people have used with these lightings and said, Well, actually, look, this this lighting is shifting your blood sugars. So it is a pretty hardcore, I think, well-controlled study that shows that LED lighting is having a damaging effect in suppressing, in this case specifically, suppressing your colour vision. How many people have we got in the world where their ability to perceive colours correctly is critical to the functions that they perform in life? Um, people who sit in worlds with no natural daylight. I mean, the great thing about this building, uh, which I'll go on about because it's a most horrible building I've been in for ages, is the limited amount of glass it had, which was not in the environment where we worked, blocked all light that you couldn't see. So the glass, it's not only the lighting that is our problem, it is the glass in buildings, because glass now blocks that infrared light that is critical for metabolic health. If we take animals that have short lifespans, and we take them from an environment where they've got LEDs, because nearly all animals are in LED light environments as well, in animal houses, and we give them long-wave light, they live longer. Their blood sugars are better, they have health, they're much greater health span. So it's really important for the built environment that we have a wider spectrum of light. And I must say, the people have really picked this up and are concerned are the architects and the lighting engineers. They are sitting there thinking, are we going to get prosecuted for putting up a building which has been unhealthy and made you pre-diabetic? That's a realistic question. And it's interesting, they responded much faster than the medical profession. Medical profession still has not really responded. New Moorefield's Eye Hospital, you would think a great centre for light and looking after people's eyes. All harsh white LEDs going in and all infrared blocking glass in the building. So we're still not there yet.

Dave Wallace 8:34

No, I mean, and and can I just quickly going back to I guess the the the um research itself, you were trying to make it much like a kind of working environment. Now, obviously, it was in in a basement, but it wasn't dressed up like a it was where people went to work, wasn't it?

Glen Jeffery 8:54

It was the real world. It was the real world. So you could argue that the problem with this experiment was that um it wasn't super tightly controlled, but I don't want to do super tightly controlled experiments anymore. I want to do experiments in the real world, real life experience. And yeah, you're right. We didn't say you've got to sit down in front of this light bulb for your working day. It was just part of your world. The LEDs were still there, but what we'd done was we'd put wavelengths of light in to counterbalance the negative effects of those LEDs. So, real world, that's important, real world experience.

Dave Wallace 9:32

So, and I mean, again, just uh, because I I noticed in the paper you mentioned that people's sort of access to sunlight was pretty limited as well, because you know, they were inside, like if they could go out, it was like for 15 minutes at lunchtime and things like that. So you kind of there was a degree of control around what you uh in terms of what you were sort of seeing from the participants as well.

Glen Jeffery 10:00

Yeah, it was uh you could say it was a worst case scenario. Um, it was an environment where, and we did this in in in early winter months, so the daylight was fairly restricted, but then it was a real-world experience. So I said to them, how'd you get to work? Well, you know, we get public transport. Check the public transport, it's all LED lit. Um they weren't getting a break from this, and I was then saying to them, what time are you leaving? Oh, about 5.30. And we checked all the weather reports. They were leaving actually when it was dark. So they got a bit of light in the mornings, um, but and I I actually I actually quantified the cloud cover. Um they they were getting a little bit of light in the mornings, but it wasn't great. But how many of us are like that? In in winter months in the northern hemisphere, that's our life. You know, the building yeah, the building I am in, okay, my office I've got, I don't have dominant LED lighting, but the majority of the building I am in is lit with harsh LED lighting because it's economic.

Dave Wallace 11:09

Well, I I I think, I mean, what what the importance of of the reason, I mean, the result is is is I mean, in a way, when you talk about things being significant, it really makes me think, well, this is you know, you demonstrating in a kind of controlled way that this is very problematic. But I like the fact that you did it in kind of people's working days as well. Because as you say, like the majority of the working world uh across the world now sits in like poorly lit offices, and you know, we're I'm here at home, and actually I I've got a shouldn't say to you, but I've got a hue system here with so I'm under LED light behind uh IR blocking glass in front of me, and um, you know, I'll be going off for uh incandescent my incandescent sort of hit in the bit. You've got incandescent bulbs in the house. But the major this is the majority of people's lives now, isn't it?

Rethinking Lighting Policies

Glen Jeffery 12:14

Definitely, definitely. Try and find uh try and you know, when you go to the shopping, uh, you know, when you when you go to shopping somewhere in the house, in your work environment, it is all LED lit. And what I think we need to move towards ultimately is uh determining how much LED light you should be exposed to. Now, this is not an insurmountable problem because looking at that study, what we did show was we showed that the LED was damaging your visual health, but at the same time, we brought something in to counterbalance it. So that doesn't mean necessarily that we've got to go into an environment and strip out all the LEDs. We don't have to do that. We have to be very careful in how many LEDs we use, and then we have to introduce other lighting systems that balance it. So we are not talking about rewiring buildings, but we're talking about very careful consideration of the quality of light that we have in there. And maybe we can bring that in by just having just what I have got, an angle poise lamp with an old incandescent light bulb in it. That's good enough.

Dave Wallace 13:32

But I I mean, at the same token, you've got incandescents, you know, we can still buy them. There's places around the world where you can't buy them. And I think in some countries they're even illegal to own incandescent bulbs. So, um, but but there is you, you know, here in the UK, we're kind of like using up reserves. There isn't people manufacturing incandescent bulbs, and that feels like that might be something that has to be rethought, you know, because um, like you say, the the maybe what you go for is a kind of mixture of lighting between LED and incandescence. But but it just requires a wholesale rethinking of lighting, doesn't it, from a kind of policy level, I guess.

Glen Jeffery 14:16

Absolutely. And, you know, we do have a few meetings coming up with policy makers in this field. Um and then, you know, there are ways around this if you think about things. So everyone goes, the first reaction is we can't go back to incandescent, it uses too much energy. Well, actually, if you take an old incandescent light bulb and you take a dimmer switch, which costs $9.95 off Amazon, um, if you turn the light down, you're turning the visual light down, but you're not turning the infrared light down anywhere near as much. So you can just turn it down and you're not going to increase your electricity bills that much. There are intelligent, intelligent ways around this. So we mustn't take polar views about it. We mustn't say strip it all out. Um there's an intelligent approach that we can get. Now, we also got positive effects by taking old old LED light bulbs, pulling them apart, and putting an infrared um LED into it. Right. Now, that produced an improvement, but the improvement was nowhere near as good as the improvement with a full spectrum incandescent light bulb. And I think people should also be very aware because there is a lot of adverts out there for full spectrum lighting, and I've yet to test one that is full spectrum lighting. Um, it depends how you define it, but it's not sunlight. So just an incandescent light bulb. We can still buy them, as you say. Um, we're not allowed to put them in new builds. Um they're still they're still out there um under the name of either incandescent or halogen bulbs. Right. Um, but America is banning them. And there is a campaign now in America to try and try and change that. I'm not sure it's got a lot of traction at the moment. I hope our research can contribute towards that, but we're lucky here. European legislation is definitely moving towards a complete ban. So it's a fight that it's a fight I think we'll win. It's just going to take a bit of energy to get there.

The Cost of Poor Lighting on Health

Dave Wallace 16:36

But I but I think, you know, the I mean, just not to sort of I guess skate over the consequences of this. So, you know, to in my head, actually spending a bit of money on an incandescent bulb and the energy used for it is a fraction of the healthcare costs of looking for someone with after someone with diabetes or you know, some other metabolic disease or you you know macular degeneration or whatever it is, you know. So the preventative side of all of this stuff is I I think far outweighs the costs of um of the damage that could be done. If you're enjoying Sunlight Matters, make sure to subscribe and leave us a review on your favourite podcast platform. You can also search Sunlight Matters on Google to find more episodes, guest information, and further insights about sunlight analysis, solar exposure, and the way light shapes our spaces.

Glen Jeffery 17:38

Completely, totally agree with you, but you need a politician to sit back and grab the big picture. These problems are not the problems for today's politicians, they're the problems that will be generated for tomorrow's politicians. And you know, most politicians just care about what's going to be on the front page of the Daily Mail tomorrow. They don't see the long the longer run. But you know, the one I really love and I go back to a lot, which is go back to your older hospital that didn't have infrared blocking glass. Everybody knew that you got patients out of bed earlier if their bed was by a window. That's telling you something about daylight. Now think about bed blocking. I mean, we're talking to critical care units. How much does it cost to keep someone in a critical care unit for 24 hours? It's thousands. So that it's costing the taxpayer thousands. And at the same time, the person, the person, we could get that person out of that bed earlier. Do we really care about the price of a light bulb? You know, let's get let's get the big picture here. Um and you know, I think people have people have started to listen, but they need direction from those that establish standards. They need direction. So, you know, I raised this point where I work partly at Moorefield's Eye Hospital, and they're saying, well, the um the system doesn't allow this. You know, that the standards state A, B, and C. They do not state D. So we have to influence policymakers. That's that's a real big issue.

Dave Wallace 19:25

I mean, uh you we've talked about this before, like scurvy, I guess you've got smoking. You recently mentioned asbestos as well. And I think, you know, what do they all have in common is it took a long time for you know, the the science was there and obvious. It just took a long time for policymakers to kind of catch up with all of this stuff. I I think in in this instance, what I just sort of beggars belief, why can't the why can't people learn from these mistakes? You know, I mean I mentioned to you that I unfortunately I had personal experience. Experience of asbestos because my mum died of mesothelioma. I mean, she lived the healthiest life ever, but somewhere along the line, she got a small particle of asbestos in her lungs, and that caused cancer. And um, you know, so I I know from personal that if you get this stuff wrong, it ends up with ill and frankly dead people. And you know, as a society, like I think you mention it specifically in your paper about care homes and people at the you know who need kind of looking after, like giving them sort of light as a nutrition, like with incandescence will probably improve their sort of health and you know, probably improve their well-being as well, won't it?

Light as Nutrition in Care Homes

Glen Jeffery 20:51

Yeah. I have, and I'm not the only one, I have been banging my head against the wall regarding care homes. Really banging my head against the wall. We can all the animal studies show us that older debilitated animals, we can get them moving much more efficiently if we give them the right spectra of light. So we've got these people who, you know, when they're in a care home, they have limited mobility, which means they have a chance that they might fall and break their hip, which in many cases that becomes fatal because they're put flat in a bed and they get pneumonia and they die. Their quality of life is absolutely rock bottom and they lose control of their blood sugars. What is it all about? Well, a big fraction of this is about light. We can walk into environments, all the science is there, we can put a light bulb in, and we can improve the quality of people's lives. It is, as I say, I'm I am not the only one. Many of us are banging our heads against a wall. You know, if my if my mother were in a nursing home, I would be, I would be in there. So, you know, I do with an angle poise lamp and an incandescent bar. Yeah, well, actually, you don't even have to have an angle poise. You can go to IKEA and buy one of these cheap little bendy things, right? Just, you know, something's like 10 10 pounds and put an incandescent, which is what I've done with my aging aunts and my aging uncles.

The Role of Sunlight and Metabolism

Dave Wallace 22:30

That's amazing. Well, I I I did it for my son. I sent him off to university with an incandescent bulb. And I am pleased to report, like, his health seems to be like he's not a sports person, he's not outside, but he seems to be on a level. So, you know, I'm I'm seeing the positive results of just like, you know, we've replaced a lot of our bulbs with incandescence. The amount of illness in the family uh has kind of dropped off. So there's something going on, which I think is really interesting. Yeah. I have to ask a question like you, because you talk about LED suppressing metabolic health. If I did I did I get that right, or is that sort of No, no, that that that that is right.

Glen Jeffery 23:15

So if we if we take the wavelengths of light in LEDs and we put animals under those wavelengths, they become pre-diabetic. That's a metabolic thing. So that is that is clear. And if you dig through the evidence, it is clear that you get a similar pattern in humans. All right? Now, what's that costing the NHS? It's costing us fortune. Absolute fortune. This time of year, people are spending more time inside, they become relatively sedentary. Um, you know, over the Christmas period, they've consumed too much. This is just this is just ridiculous. You know, I it is it seems to me to be ridiculous that we we're not getting traction on it.

Dave Wallace 24:04

So I mean, I think it's all up to all of us to kind of do what we can in terms of sort of banging the drum around this thing.

Glen Jeffery 24:11

Yeah. Yeah, definitely. Definitely.

Dave Wallace 24:14

I and I I sort of puzzle over it because I like we do I I think we we sort of talked briefly, and I know on the Huberman podcast you talked about the the the people getting dogs. I mean, I think like getting outside, like walking, all of this other stuff, but yeah, yeah, you know, is kind of super critical as well. Because I I guess the thing with incandescence, and I get going back to LED being narrow spectrum, that incandescents create light from heat. So what you then end up with broad spectrum. And I what one of the questions is is do you understand is it wavelengths in the incandescent, or is it the because you got and you've kind of mentioned this because of the uh infrared LEDs, but is it do you understand the sort of what's going on from a broad spectrum perspective in terms of the impact it might be having?

Glen Jeffery 25:07

I I think from the science perspective, we're we're we're pretty much there now. Sort of, you know, we're we're dealing with we're dealing with entities called mitochondria that generate energy, and the right kind of light improves the energy you produce, wrong kind of light reduces the energy. I think we're pretty much there now. So when we talk, and and I know you've spoken to Bob Fosbury, who's a big pusher in the physics of this, um, when we talk, we're all sitting there saying, okay, we know enough. We know enough to feel that we're not idiots. We know enough to say, now's the time to talk. Now's the time. So I'm hoping that somewhere out in the world there is some senior civil servant in the Department of Health who's who's watching this, who will then stroll into work and say, how many millions can we save by changing lighting? He can think about money. I'm thinking about quality of life. Um, that is the kind of person we need to get hold of. The science is there, and it's been driven by Bob Fosbury, an atmospheric physicist. Um, so why are we waiting?

Dave Wallace 26:23

Yeah, I mean, I think you're absolutely I mean, you know, if any MPs end up listening to this, I mean, you could you could make a name for yourself by actually taking up this taking up this cause. Because I mean, what better thing is there to sort of actually change the health of a nation by Yeah, yeah.

Glen Jeffery 26:43

I I don't want to make a name for myself. I quite like to drift to the back. Um, but I do I must end up.

Dave Wallace 26:49

Sorry, you shouldn't then be appearing on Huberman's podcast.

Glen Jeffery 26:54

Fortunately, I'm not recognized walking down the street. Um, but I do have a meeting with an MP next week.

Dave Wallace 27:01

Great, great, great, great.

Glen Jeffery 27:02

Um, so so just crawl up that wall. Just crawl up that wall until someone notices you. That's what that's the philosophy.

Dave Wallace 27:12

So, I mean, one question on like I think you again you mentioned about the industry, and there's lots of people with IR panels and IR light. And have you got any thoughts on dosage at all?

Concerns About Overexposure to Light

Glen Jeffery 27:28

Like well, dosage, dosage was a conversation with Bob Fosbury at about nine o'clock this morning because we're talking about it all the time. Uh, these panels are producing far too much light, far too much light. And we're sitting here thinking this is going to cause a problem in the end. Why is it with all these panels that, okay, you sit there, let's just say, for argument's sake, the first 10 minutes is okay. But we know from the research that if you sit in front of that panel too much, the effect goes. Right? It just it just goes. And what we know is got pretty sure is going on is that the metabolic system is getting clogged up with too much energy. So, particularly these face masks and these big whole body panels, um, of which we pulled apart a few. First of all, they're unbelievably overpriced for what they are. Uh, you know, a a thousand pounds worth of panel has probably gotten 15 pounds worth of product in it. Um, but they're producing too much energy. Your body is not used to getting a vast wall of energy, that deep red energy. The the first the first couple of minutes may be really good, um, but after that, no, you are challenging your metabolism um by overloading it.

Dave Wallace 28:56

That's really interesting because again, this was why I wanted to talk to you about the research that you've done, because it's proper science. And I sort of feel like when you look at a lot of what's out there, people are not being led by science, they're being led by commercial opportunities.

Glen Jeffery 29:17

Definitely, definitely. I I deal with I I had said we'll I'll answer emails. I deal with walls of emails from people who say, I've got this device, is it gonna work? Well, I can't answer. Um, because unless I have that device in the lab and we pull it apart and spend a day looking at it, um, I can't really answer. But the vast majority of devices that we have looked at are of extremely poor quality and very high price. Um, and you know, and the you say to people, well, actually, it's kicking out too much energy. And then a manufacturer will say, Well, if I've got a device with a dim red light and a device with a bright red light, everybody's gonna buy the bright red light. No one's gonna buy the dim. And I get that, I understand that, I understand the sales pitch. But the point is they're producing too much energy. What happens to, and I don't know the answer to this, what happens to the lady who buys a face mask, uses it quite heavily? What happens in five years' time? I don't know. I just don't know. But I am cautious enough to say, I know you're jet that's generating too much energy, and I know that your metabolism is going to struggle to cope with that. I do not know what the consequences are.

Future Research Directions

Dave Wallace 30:40

It's again, I mean, great. I mean, it's great to what I love about you, Glenn, is you're uh you speak the truth as you as you see it, you know, and I think uh you know it's in it's great to kind of have that, and I'll be telling my wife to take that face mask off later because uh she got one for Christmas. So um, no, it's it's it's it's really, really interesting. I I mean one thing that I wanted to ask you was about sunlight. Um and you know, one of the things I did last year was to try and get out a bit more in the mornings, and you know, and I I really do feel it kind of made a difference to me. So decided to try and go a bit more hardcore this year and and follow the sun's pattern if I can, just to you know, and I need to kind of think about what could I measure in order to sort of see what impact that would have. So, you know, I'm talking about like four, four in the morning, I could I guess in the middle of summer getting up and getting the dogs out. Um for for me, just as a sort of citizen scientist, is there anything that I could do just to kind of measure um simply like the impact that might have on me?

Glen Jeffery 32:05

No, and but it's a really important question. So people will say, How do I know? How do I know? And I'm struggling to find a metric that you yourself have access to. So I can I can improve all your blood sugars, right, with light, but you're unaware of it. You know, you don't, okay, when you're when your blood sugars crash, you're aware of that, but you're not aware of when your blood sugars reach dangerous levels. Much of what I think we do has a prophylactic angle. It's preventing things happening that's negative in the future. Um I know that there are some people, um, I mean some people at Westminster University who are looking at a whole load of markers in the blood. Um will there be a time when, for instance, you can prick your finger and go, oh look, something's a hell of a lot better here? Um that will come, but I don't know what the I don't know what it is. So with the with the red light or the incandescent light and improving vision. Most people come away from that and they can't really tell the difference. When when I'm when I test them, I can see the difference. Right. A few people come along and say, oh, you know, the curtain's moving in a slightly different way. I think Bob Fosbury did that. Um, but it's there when you test it. It's there when you test it. And I've got big advantages of working with vision, but I've also got big negatives. So you can lose vast amounts of your vision, say, for instance, in glaucoma, where you lose your peripheral vision, you don't even know it's gone. You start to register you've got a problem when you bump into the coffee table when you walk past it. And that's because whatever is happening in your eye, your brain is constantly recorrecting it to take things back to where they were before. You can test it and you say, I know, I know that's better, I know that's worse. But for the person, very often they're largely unaware. If I can find that, if I can find that thing that says, you now tie up your shoelaces three seconds faster, I'll find it and and and I'll tell people about it.

Dave Wallace 34:20

No, it's it's it's really interesting. I mean, I I think one of the things is just to kind of check inside yourself and say, like, do I feel better? Like, I think feeling better is a it's quite a difficult thing though to measure, isn't it?

Glen Jeffery 34:36

Exactly. And we and and the the the reason why I did the study that we did in changing the light bulbs is it's hard science.

Dave Wallace 34:47

Yes.

Glen Jeffery 34:47

You know, it's a number. Here is a number, and it's different on this day after this experience than it was before. And if we're going to get people to believe hard-nosed civil servants, people in charge, they've got to they can't have the I feel better phenomena. Whether that's true or not true, they can't have it.

Dave Wallace 35:08

Yeah, I I I totally, totally agree. I think it's really, it's really interesting. So, so what's next? I mean, you you've this is a kind of I feel a groundbreaking piece of research, which I think proves a lot of what you've been thinking and hypothesizing, and you know, you and Bob sort of chatting about. So uh have you got anything that you're kind of lining up for future research as well?

Glen Jeffery 35:33

Well, we you know, the the the the the kettle is still the kettle's still on. Um, so we've got a whole load of stuff looking at, for instance, how long does it take for that incandescent light bulb to improve your vision? Uh, what's the time course? And actually, I have to say, it's shockingly brief. We put light bulbs in for a couple of weeks. We're now seeing changes in people um uh within an hour of introducing different lighting into the room.

Dave Wallace 36:06

Wow.

Glen Jeffery 36:06

And I've gone out and I've gone out and said to uh uh this is this is a guy called Mark Mark Robinson, who's a graduate student in the lab. And I said, Mark, can you do all this again, please? Um let's let's let's make sure we get this one right. But it is it is clear the effect can be corrected relatively easily, and the effect can be corrected relatively quickly. Okay, so what about that person when that person comes out of the operating theater after a big operation? Could it be the case that they only need an hour of an incandescent light bulb to support their metabolism, right? One of the worst light environments on the planet is an operating theatre, right? Very rarely have they got windows, they've all got harsh LED lighting. You walk in there and you think, oh God, it's like being on a stage in a plant. Where did all this come from? And those people in that environment are there, you know, they can be there for hours and hours and hours. And you know, the great thing about our NHS NHS is it's fantastic. People are dedicated to it. And I know of some surgeons that sit in that environment a hell of a lot longer than eight hours a day. Um, so yeah, maybe just an incandescent light bulb in the recovery room might be enough. You know, as as as I say, as I say all the time, if this is a load of rubbish, okay, I'm an idiot, but it hasn't cost you any money. You know? Um I like.

Dave Wallace 37:44

But I I think what you're proving is that there is uh this isn't a load of rubbish. And I I mean when you actually I I guess what I've sort of done is I've sort of sat back and thought about it and you go, well, it's obvious, isn't it? Of course we've kind of got a connection to to light and sunlight and broad spectrum light because we've lived most of our histories outside, haven't we? So um you know, it would be almost surprising that we have. I guess the big surprise is we haven't really thought about this until fairly recently.

Glen Jeffery 38:18

No, I you know, this is the thing that is really striking and is a problem about resistance. People are saying, well, hang on, we've we've we've we've had these uh LEDs, you know, since 2000, 2005. We're not dropping dead. What's the problem? Yeah, and and and and and and then where are you coming from with these odd comments about LEDs? You know, we're all we're all happy. Um that's quite something to try and overcome, you know, um resistance. And that's not only resistance from the industry, it's resistance from public perception. The public aren't really aware. Um, the consequences are not here yet.

Dave Wallace 39:01

I'm uh actually chatting to Anne Levine, who wrote a book Incandescent next week. And you know, she's fascinating because she kind of lays out what happened in the lighting industry um and that move to sort of LED LEDs and away from incandescence. And at no point did anyone think about the kind of health consequences of all of this stuff. It wasn't even factored in.

Glen Jeffery 39:26

No. No. And superficially, why should it be? Yes, superficially, you know, it you know, it do even, you know, vast majority of the scientists. Why should it be? We've got more light and it's cheaper. It's not costing us anything when we move to an LED. But we just didn't understand the light we don't see, but our bodies in different ways perceive. My uh my mitochondria in my body are aware of of. Long wavelength, deep infrared light. That light goes through your body. I can measure it coming out the other side. And it influences them even at very, very low concentrations. So yeah. How do we get across public perception?

Dave Wallace 40:17

No, I well, I look, I think it's like one of those problems you go back to asbestos and scurvy and smoking is because the problems don't come for a little while. So you know, the problem with the LED thing is it's sort of, you know, we're we're only a decade into the journey, really, or a couple of decades into the journey. What are we seeing is where we're seeing metabolic diseases increasing, you know, and certain cancers increasing. And I I mean, like we talk places like the Middle East, they have diabetes rates which are absolutely astronomical. Yeah, yeah. You know, and what's the common, what's the common kind of denominator across all of this? Inside time, behind glass, under LED light. Yeah. Eating probably ultra pro you know, so yeah. I mean, all of this stuff must be kind of work. I mean, you you I I do wonder if you could ask a mitochondria what's going on, they'd go, none of it's good, is it?

Glen Jeffery 41:21

There's um there's a great study uh undertaken in Papua New Guinea where um the diets of the people are almost pure carbohydrate. Um, you know, so you look at them and you think, well, you know, diabetes should be rampant. These people live fundamentally outside.

Dave Wallace 41:40

Yeah.

Glen Jeffery 41:40

There is no significant history of diabetes in that population. You know, they they they have firelight, they live outside. Um it's telling you something. I mean, you can argue, well, maybe they're all genetically different. Well, that's possible, but then let's stack up the evidence. Where's all this different evidence coming from? And that is great. And then on the on the alternative side, you look at the Gulf, you look at Saudi Arabia, highest incidence of diabetes. They never go out in sunlight. They have got artificial lighting, they've got infrared blocking glass to keep their wind to keep their environment cool. Uh, let's look at those two extremes. There's something going on there. Um, and the whole of the Gulf has got that problem. Kuwait's got that problem. We've been out there talking to them about it. Uh, all of the Gulf.

Dave Wallace 42:30

Isn't it 40% or something like the rate of diabetes in Kuwait?

Glen Jeffery 42:34

I mean, it's yeah, it's something like that. Pre-diabetes isn't, they've got this massive, massive diabetes research institute. There's not a lot going on in it yet, but the government acknowledge that they've got a ticking time bomb with diabetes, and they are not sure what to grab hold of. There's one or two very smart scientists there that are actually raising the flag about light. Um, and I know, I know one of them is in the medical school, and she's got one, uh she's got one lecture theatre for one group of students with incandescent light bulbs in it, and another lecture theatre with the LEDs. And I'm looking forward to seeing the results.

Dave Wallace 43:15

Amazing. No, that sounds great. I mean, and I think, you know, obviously your focus is on, you know, eyes because of your background, but I guess anyone from the scientific community who's listening to this who I mean, to me it would make sense to like take the work you've done and then maybe look at Dart. So do you sort of feed people Big Macs for uh as part of the process? I mean, and I know that's not eyes, you're probably looking at blood blood glucose levels and things like that, but you you know, there's obvious things that you could do to build on this, to kind of basically look at the real relationship between light, food, and all of these other bits and pieces, isn't there? Yeah, yeah, and and yes, I completely agree.

Glen Jeffery 44:03

There's a package for health that is very obvious, and it is public health. And it's small modifications that lead to improvements in public health improvements in health span. I I want, you know, I want to be 80 and still knocking around and having, I'm not sure I care that much when I die, but I want to make sure that at least until that last five minutes before they put me in the coffin, I have a high quality of life. That is, you know, that that's paramount.

Dave Wallace 44:35

Well, and I think you so, you know, was it Alistair Nunn talking about morbidity, compression, and all that whole notion of okay, we're living longer, but we're not living healthier lives.

Glen Jeffery 44:45

We're not. We are not.

Dave Wallace 44:47

That thought makes me very depressed, you know. So um, I mean, so anyway, well, listen, thank you so much because I think we've covered a lot of ground. I feel like you've completely demystified the research paper. I mean, I would encourage people to actually read it. Um, you know, now they could probably start with listening to the podcast, then have a look at the paper because I think it kind of really brings it to life. But it's a very impressive piece of work.

Glen Jeffery 45:15

I want, I wrote certainly the abstract and the introduction of that paper with the idea in mind, could my mum get it?

Dave Wallace 45:25

Yeah.

Glen Jeffery 45:25

Right? My mum's my mum's just a housewife. Could my mum get it? Because as I've said before, it's all about communication now. Everything is about communication. Um, hopefully they'll get the abstract, hopefully they'll get the introduction. That's good enough.

Dave Wallace 45:45

I think they will. I think they will. But it's I love the protocol, I love the descriptions of how you went about it. There's some very interesting photos as well. So, you know, I think it's brilliant. So thank you so much, and uh look forward to seeing what your next project is as well. Thank you, Dave.

Glen Jeffery 46:03

Thank you for helping to publicise it.

Dave Wallace 46:08

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