Undoctrinate Yourself - #25 - Dr. Martin Moore-Ede

Episode Date: March 12, 2025

Dr. Martin Moore-Ede is leading expert on circadian clocks and health problems related to aberrations in circadian biology including sleep disorders, fatigue, diabetes and cancer caused by light at night. As a professor at Harvard Medical School (1975 – 1998), he led the team that found the suprachiasmatic nucleus, or "master clock", in the human brain, pioneered research on how the human body can more safely adapt to working around the clock, and wrote the best-selling book “The Clocks That Time Us”. His new book ⁠"Light Doctor"⁠ is available now everywhere books are sold! You can also find it at www.thelightdoctor.comFind Dr. Moore-Ede on:Instagram ⁠@circadianlightdoctor⁠ https://www.instagram.com/circadianlightdoctor/⁠Substack⁠: https://lightdoctormartinmooreede.substack.com/⁠Twitter⁠: https://twitter.com/DrMooreEde⁠Google Scholar⁠: https://scholar.google.com/citations?user=lFyCIC0AAAAJ&hl=enFollow the podcast on Instagram ⁠⁠⁠⁠⁠⁠⁠⁠@undoctrinateyourselfpod⁠⁠⁠⁠⁠⁠⁠⁠Follow Dr. Alexis on Instagram ⁠⁠⁠⁠⁠⁠⁠⁠@dralexisjazmyn⁠

Hello, everyone and welcome back to Undoctrinate Yourself. Today, I have an incredible guest for you. This is Dr. Martin Mourid. For over 40 years, Dr. Moreed has been a leading expert on circadian clocks and the health problems caused by light at night, including sleep disorders, fatigue, diabetes, and cancer. As a professor at Harvard, Dr. Moreed led the team that discovered the master clock or the SCN, which you've all heard about if you've been listening to this podcast within the human brain. So he was really the one who set the stage. for the entire movement of circadian biology within humans, which is just absolutely huge. He's written two books, I believe, and you can tell me if you have more, but the clocks that time us, as well as a new book that's out now called The Light Doctor, as well as over 200 scientific articles. And with that, I'd just like to welcome you, Dr. Martin Moore, and so glad to have you on today. Well, Alexis is delightful to have a chance to chat with you and your beautiful surroundings there, which you tell me is real, which is great.

Yep, it's real. I'm trying to get my, you know, my light is really dialed in. I basically spend as much time as I can outside all day. I built like a little office space out here. So it's enjoyable. You're definitely following the rules. And that's so important that outside light. So critical. And so much of our time, over 90% most people are spending indoors and just not seeing that outdoor bright, rich, blue rich daylight. Yeah. And it's pretty crazy because it's unprecedented. for our species, right? And we'll get, of course, get into that. But the status quo state of most humans today is just, you know, working indoors all day and then just flip it on the light switches at night when it starts getting dark to continue being productive, let's say, not realizing that it's creating this incredible harm to health over time. And so maybe we can just start by getting into how you got interested in light in circadian biology to begin with. Well, that goes way back into the the old years way back when I was graduating out of medical school, I was heading towards a surgical residency and did my first year's surgical residency. And I found myself working those 36-hour shifts,

really non-stop 36 on my feet, under bright, blue-rich fluorescent lights, as I now realize. And then off for 12 hours, back in for 36, on for 12 hours, back for 13 hours, back to the 36, you know, 108 hours a week, and walking around pretty soon like a zombie. I mean, it was a bright, you know, energetic, enthusiastic young surgeon in training and finding myself just beaten down by the fatigue, by the disruption, by the malaise, and nodding off in the operating room at 3 o'clock in the morning, I mean, the surgeon in chief yell at me, writing the restrictions, I couldn't make sense of the next day. And it wasn't just me, of course, it was everyone under that.

And so that's the first thing that got me interested in circadian rhythms and in, and it's a very new feel at that time. Most of the work could be done in animals. And there was some human work coming out of Germany, but not much. When I started my medical training, only three papers on circadian rhythms and light were published the year I started medical school. So that just shows you how it's come. We're now in the multi-thousands of papers. So, and that then led me after that first year to sort of take a detour and I got an opportunity to do a PhD at Harvard Medical School, focusing on the physiology of circadian rhythms. And I was using monkeys, particularly with diurnal monkeys that were very similar circadian rhythms to humans. But I also had a position in the surgery department. so I could actually carry on research on humans at the same time at what's now the Brigham and Women's Hospital. So it was a great opportunity to do a postdoc

at the same time as my PhD, which is sort of an efficient way. Anyway, after all that, because no one else much was doing in that area, they invited me in the Harvard faculty, and I was a Harvard professor for about a 23-year period of time and had a chance to put together a lab and have some absolutely brilliant graduate students, postdocs, great team of people, and right at the start of sort of human circadian physiology, particularly its medical implications.

And so that led us to the identification of the – I mean, there were several things when I started. Number one, I was warned to stay out of the field by senior professors at Harvard and MIT. This is just an aberration. This is effects of the Earth's rotation on the humans. Nothing there, no clock. Then when circadian clocks were discovered, the SCN was discovered in rats and hamsters, 1972. The prevailing thought, including from those German scientists,

Ashoff and Waver and others who worked in studying people in bunkers underground and they could actually look at the circadian rhythms, they thought, number one, there wasn't a circadian clock in the human brain, like there wasn't animals, and number two, that light was not the main entrainer. And that seems so contrary to everything else. And since I was studying monkeys, I could see there was a circadian clock in the monkeys, an SCM. I could see that it was entrained by light, secondarily entrained by food, but certainly light was the most important Zaybber. And so that didn't make sense. So we were, went in and one of my postdocs, Ralph Lydick, who really made the breakthrough of realizing

that when you looked at atlases of the human brain, they were only showing you every 50th slice of the brain because there were very thin slices and throwing out the 49 slices in between. Now, when you do that, you obviously could miss some things, and one of the things that was being missed, what only randomly appeared was the super charismatic nucleus because it was small pinhead-sized cluster of 10,000 neurons or so. So it was missed. So he went back and looked all the other 49th slices and, of course, found it, and it was in the same position and the same morphology and structure as what we were seeing in the monkeys. And then the next major thing which to go on and realize, well, light, is it really true that light isn't a synchronizing

queue in humans? So together with Charles Seisler, who's now, of course, at Harvard, and Elliot We set up the first facility for studying people in the US 24-7 in totally time cube-controlled environments. And we're able to show very much so that light was indeed a strong circadian psychiever. So those are the two of the fundamental things that sort of got us going. And from there, you know, we had a great time because nothing is better when you're at the beginning of the scientific field. It's wide open territory and the fundamental assumptions are wrong. You know, that's fun science. And, you know, we cranked out, I know, in about eight years, 75 peer-reviewed articles and several books, including my book, The Clocks That Timus, which became

the textbook in the field that would publish back in back in 1982 at this point. Wow, yeah. So I mean that notion that like the technical error of throwing away the slices was what was what

manifested in missing that clock I think is just a really important like anecdote to share with a lot of scientists too because how much are we missing in science now because of also like technical error error, right? It's like so much of what...

Or shortcuts that people take, they don't work in between, right? Yeah, absolutely. It's one of those, you know, either the opinions of your scientific colleagues, every young scientist, of course, you know, realizes this, you know, there's all sorts of fossilized thought. And it's based on lots of great work, but assumptions have been made and shortcuts have been made and, you know, and the status quo has been adopted. and just go back and examine some of those fundamental assumptions. And, you know, you'll find some things that are really interesting.

Yeah, I mean, especially with the way that tech has developed, we have so many, like, new tools now with, through which to look at old questions that were just kind of assumed to know, we know the answer to. I'm curious from like, let's say like a policy standpoint or like a societal standpoint. I mean, you said you got some pushback from maybe other faculty members saying, like, this is a waste of time. Did you get a sense that it would be difficult to study this topic from like a funding standpoint or anything like that? Or was that something that you just, you know, weren't concerned with because you knew that this was the most interesting thing you could

study? Well, it was, of course, a developing field at that time. And funding is always challenging. But we were able to be quite fortunate in getting funding for a broad range of, you know, NASA funded us. And we ended up doing some. studies in space, both on the shuttle, on Soyuz and others. So we got some NASA funding. We got NIH funds, of course, National Science Foundation, Air Force funding. So we're able to actually, the field was catching on. So we're fortunate we were able to attract the funding.

And that's one of the things that brought me out from England. I couldn't get the funding to doing in England this research. that's why I came over to the US. And so we were able to get funding. Now, in terms of pushback in the field, we were, of course, there's always, you know, old views that you have to deal with. But, you know, it was the science of overwhelming. Great people were doing it.

And the world was spreading. And there were other teams. And of course, now we've got thousands of scientists. In fact, I was looking back at, you know, how many sciences. have contributed to this knowledge we now have today, the effects of light on circadian clocks, both the positive effects in terms of synchronization and the health damaging effects. Over 30,000 people have been authors of 24,000 scientific articles, you know, that form the core basis of this light in circadian rhythm.

So in the acknowledgement of my book, The Light Doctor, I acknowledge those 30,000 scientists. It's a huge body of people. And yet, this is a big problem, Alexis. We all speak to each other. The circadian scientists all speak to each other, but we don't speak to our neighbors. So the general public is quite unaware of the harmful effects of blue-rich light in the evenings and the night.

They're quite unaware of the big burden of obesity, diabetes, heart disease, breast cancer, prostate cancer, and many other things that are caused by this light pollution that our modern LED lights are producing. And so the big challenge today is to get the word out. And the lighting industry is rather resistant because they're really being focused on engineering the cheapest bright light they can make.

And it's all about cost and it's all about brightness and nothing to do with health. And that's been one of the big barriers and is today a big barrier. Even the regulators don't understand this and they're regulating, putting new rules in, which are making it hard to bring circadian lighting, which controls the spectrum across day and night, you know, creating challenges there. So a lot of challenges today, but it's another sort of challenges, you know,

just like the original challenges were getting the research done and getting the funding to do the research, and now the challenge is getting it adopted when it's such an important health, component. In other words, there are all sorts of pollution out there today. People worry about, they worry about the PFAS chemicals or forever chemicals. They worry about asbestos and things like that, of course. And they also worry about microplastics and all sorts of things. Those are very, very hard problems to get rid of or deal with. But light, my gosh, change the light bulb. It's so simple. You know, this is the easiest environment. or pollutant to deal with. But that's the message today, and that's one of the reasons that I say

my book is trying to be a guide to everybody who wants to get up to speed and know what the arguments are, and know what the science is, and know what the possibilities and what's available today. So that's what I really focused on. Yeah, that's incredible. And I was just, you know, thinking when you're describing how rich the science is and how many incredible scientists have contributed to this field. And yet it didn't have the effect you would have hoped on the regulation bodies on the development of like, you know, back when this research was initially happening, we didn't have our Apple iPhones and our computers and our tablets and our, you know, the LED backlit TVs. And then yet still, despite knowing this, the regulatory bodies gave the okay

to, you know, having LED lights everywhere and all of these back, blue lip back screens, which we'll talk about, like the importance of blue light in particular. And it just seems incredibly insane that despite the science being there, it's just disregarded in favor of, I mean, money and innovation, I guess, at a core level. But I mean, I don't know if you have any, do you have any insights on? And maybe we can wait until later in the conversation to talk about this, but why these LED, these highly blue enriched LEDs were chosen for common lighting as well as like all of our device screens. It's because the energy efficiency has been the key concern. Certainly, the environmental concerns, global warming, you know, we're all concerned about that.

We're all concerned about climate change. Not a little of us, but a lot of us are. And that's a big issue. And so when the industry was able, you know, there's a pressure on the industry, what could they would do to reduce, you know, energy use. The problem is that they've adopted a measure of light, which is not to do with the healthiness of the light at all. What they've adopted is something called lumens per watt. Now, lumens is the measure of what comes out of any light source, but it's only a measure actually, virtually all of it is to do with the green and yellow wavelengths in light.

it doesn't measure at all the blue, which is absolutely critical for circadian health, and it doesn't measure any red, which is also very important for healing. Because light, as we all know, is made of a more. You know, I think one of the things is for the layperson is a surprise. You look at a light bulb or look at a light source, you look at the sunlight, and you think, well, that's white or yellowish or whatever. But in reality, it's not white or yellow. It is comprised of all the colors of the rainbow.

that the violets, blues, greens, yellows, oranges, reds, that are fused together in our brains to be perceived as white or near-yellowish white. And yet those individual spectral components are so important. But the brightness measure that's used, the lumens, only looks, because it's looking at what the eye perceives is bright. It only looks at the yellow and green wavelengths, the small part of the spectrum. So it's not measuring the right, the whole benefit of light. And then it's per watt, which is amount of electricity. So now the regulators, the engineers and the regulators who are not biologists and not medical people, they've got some metric they can use now.

And now they can have this goal of cranking out. Now, last year the rule came out, you couldn't have anything less than about 50. lumens per watt. That got rid of all the incandescent bulbs. They were all banned. The halogens went. The fluorescence are going out for other reasons because of mercury and so forth. So they're all getting banned. And the only thing left on the shelves is these LED lights. Now, these LEDs is when they put the, now they've got new regulations aiming to get to about 122 lumens per watt by 2028. Wow. And the more they crank up the emphasis on cheap, bright light, in other words, how little electricity can be used to get the brightest light with no issue of quality, no issue of the health impact at all.

You know, we're just going down a terrible path here in terms of human health. We're exacerbating a problem. And, you know, the world's concerned with, you know, diabetes and obesity. Those are big issues. I'm concerned with heart disease, breast cancer, prostate cancer, all those are huge. issues, all largely hugely impacted by our misuse of light and the misuse of the wrong type of light. So that's the one side of it. So the regulators are doing that.

The lighting industry is, so there are three components, right? We talked about the regulators. Then the lighting industry. Well, the lighting industry, you know, does some innovations, but it will only build what people will buy. So now we've got the third part, which is the users. If the end user testament, that's you, me and all, everyone we know around the world, if we don't know about it or if our friends don't know about it and won't ask for it and won't willing to pay a little bit more for some health, then the lighting industry won't supply it. So now when you walk into the hardware stores and you see the rows and rows of light bulbs, they're all these blue rich LEDs, static, which means they don't change the amount of blue by time of day. And what's key here, and we can get into it more, is the amount of the particular type of sky blue light that you're seeing during the day as much as possible.

And as little as possible, none, if you can do it, that's dry blue light during the evening and night hours. That's the goal. But to get lights like that is now a problem because, you know, the industry says, well, I don't know if I spend money and put these things on the shelves or if people don't buy them, then they won't proceed. So it's a chicken egg, it's a supply demand problem. The big issue is education. That's again the reason for the book, the light doctor, to try to propagate that idea. And a lot of people are doing,

they're buying several books, and then sending it to their friends, their colleagues, their boss, or their whatever, to try to get the word out. And that's the purpose of it to do that. But that's the challenge. We're right at that critical phase, and we haven't met the tipping point yet.

I'm doing a lot of podcasts with people like you, but the mainstream media has not really got it yet. What they report on is how wonderful it is that we're reducing electricity use and lighting. But we are so harming human health right now. So this is, you know, my personal mission and mission of many others is to try to get this word out. It's so critical. Yeah, and especially because, I mean, there's a major focus at the society. level on nutrition and on exercise, not realizing that light is even perhaps a more important input because it's regulating the quality of your movement and actually what food you're craving

as well and then how many carbohydrates you're craving and your capacity to overeat as well. So maybe let's start diving into the science. So what's the deal with blue light? Why is blue light so important from a circadian health standpoint and also from a disease standpoint? Well, first of all, you know, when we first discovered back in the 1980s, that the light was the key synchronizing cue. We didn't have a clue that it was some part of the spectrum.

We thought any white light would do it. And that's what we, you know, just were thinking about. About 2000, some major breakthroughs occurred. One was the discovery of a photopigment in the eye, melanopsin, which is in the cells, the record gangman cells, intrinsically photosensitive. retinal gangan cells, IPRGCs. Those cells in the back of the retina

are light illumination detectors, but they're actually detecting, because of this melanopsy, because of this pigment that is detecting blue, particularly a sky blue color, which is around 480 nanometers in the blue in the spectrum. It's detecting that particular wavelength. That is the wavelength of the key signal

that tells the, The human body as well as animal species is all the way through the animal kingdom. That blue is what tells our bodies that it is daytime. And the absence of that blue tells our bodies that it's nighttime and we can go into restorative mode and so forth. That is detected, of course, by the IPRGCs or the melanopic receptors, trigger a pathway from the eyes from the retina, retinal hypothermic tract, to the supra-chaosomatic nucleus, the SCN,

that's in the hypothalamus, the brain. And that in turn synchronizes that clock. It runs free running, of course, in the absence of cues, but synchronize that clock today and night. In turn, that generates a whole set of signals, including various hormonal pathways, melatonin being won by the pineal, which is the signal that it's dark outside to the body,

cortisol being a key part of synchronizing that comes to peaks around dawn. That's the message that daytime is arriving. So all that timing cues, all that timing apparatus of the body. And of course, now we know there are millions of clocks in every cell, tissue of the body, skating clocks that need to be kept in sync with each other for robust health. and if we have discordant or confusing cues coming out of the SCN, coming from the light environment we're in, then in fact we get into this state of so-called circadian rhythm disruption,

circadian disruption, and that is the big element behind a lot of ill health. Now, when you're in that state of circadian disruption, all sorts of things go awry. You tend to eat more obese, You are diabetic. Your insulin resistance goes up and you show the signs of pre-diabetes and you develop diabetes at twice the rate. You increase the because the melatonin is suppressed by light at night.

Reparative tissue, reparative effects of melatonin are lost and breast cancer cells grow much more rapidly, prostate cancer and so forth. So all these effects are because we, if we, if we're living in the environment without that. An interesting thing, Alexis, which is really intriguing as sort of going down this path, was to realize that when the first life forms formed in the ocean a long, long time ago, they were deep in the ocean,

and those life forms were exposed, of course, to light that was filtered by the seawater. But seawater turns out to filter out all the colors of the rainbow, except for this sky blue, around 475, 480 nanometer light. So just give people who are not fully acquainted with light spectra, visible light runs from about 380, that's in the deep violet, up to 780, which is deep red, before we go into the infrared or down into the ultraviolet. And so blues are typically between violets, between 380 and 420,

There's a violet light. Blues go from 420, which is the violet blue to indigo in the 430s, royal blue in the 440s, and then up sky blue in the 480s, and then into aqua, we get into the 490 range. So lots of different types of blue that are there, and it matters which blue.

So one of the things that we were more recently have discovered in being able to identify and confirm is that sky blue color is the key. I can tell you, so I don't know how far you want to get into it, but there was a major, again, one of those major discoveries of misassumptions made that led us to that, just like not looking at those slices of the brain, the 49 slices, or just assuming that humans were synchronized

by social cues and it wasn't to do with light. A big discovery realization was that all the studies that looked at the effect of light on humans were done for the first 15 years of work in this field in people who were fully dark adapted. Now, that's a standard process if you're studying photobiology, you know, because that fully dark adapted diet, that means someone who's been sitting in the dark for at least two hours. It's got blindfold on typically, and then you dilate the pupils so they won't constrict and so forth, making them maximally sensitive to light. And that's a sort of, you know, experimental paradigm, which produces very beautiful, elegant results. The problem is that dark adapted eye, when they

looked at the effect of different colors, they found a broad range of effects. They found violet was doing it, blue, greens, wide range of colors was having this effect. on the circadian clock. And we said, wait a second, most of the day, 95%, we are fully light adapted. You know, once we've left our darkened bedrooms and switched on the lights or run outside, we're fully light adapted. And we stay in that state for 16 hours and warm before we go to bed. What, in fact, is the story in a light adaptive person? And so for the first time, we kept the like people in, they didn't dark adapt them. We put them in, kept them in fully light, lit environments during the day. We kept them in light all the way through the night. And we

tested which wavelengths worked. And what we found, it turned out to be a very narrow band of wavelengths that was close to 480. It made perfect sense because it was exactly what that melanopsin photopigment maximum sensitivity was. And that it was, in fact, no real effect of violent, no effect of green, and it's a much narrow pattern. So that actually turned out to be a very helpful discovery because it enabled us now to design and build lights that are either blue rich or blue depleted without having to mess too much of the light spectrum. In other words, we can produce reasonably good quality of light without and get rid of the blue or provide the blue in a rather narrow band. Again, that's one of those things. It was just looking at,

at what the classical paradigms had been and realizing they were great for studying rigorous science and beautiful, elegant work done, photobiology. But it wasn't actually representing what was working in the real world and how we normally see light and process light. And that proved to be the breakthrough where we could actually generate and create spectrally engineered LEDs that so essentially solved the problem. Yeah. And I mean, That just also points to the deeper issue of across science, at least translational science, we don't have light controls in our experiments. So how do we know that the effects of a treatment or the pathology of specific diseases

isn't being driven by the light that's being used, even among animal models? I mean, maybe we can talk about the difference between nocturnal and diurnal, but presumably small mammals like mice and rats also have melanopsin, and they're probably also entrained by blue light. and yet, you know, we're using LEDs or fluorescent lights within mouse rooms, and, you know, there's not much red light in there, if any, at all to kind of balance out those effects maybe on things like mitochondrial health. And so it's just really curious and interesting. And actually, I'm in the process of hopefully building out my own light research lab here at Princeton.

We'll see how it goes over the next year or so. But I really just want to revisit a lot of the questions that have been asked in the context of sunlight and full spectrum light. Now, one of the other interesting things, just that we talk about, there's an interesting conversation here about, you know, science and when there are roadblocks that people get into a particular paradigm, there's a whole lot sorts of work done on the effects of sleep deprivation. And all these diseases, quote unquote, caused by sleep deprivation. But if you look at most of that literature,

how they kept people awake was to put the bright lights in the room, right? they did not separate out. So you can't say it was sleep deprivation. In fact, a lot of the effects when you control them now and you keep people awake in the dark, you know, it's a radically different effect from keeping people awake using light. So again, there's another whole area of research that needs some really elegant dissection of which effects are truly sleep deprivation per se and which effects are actually triggered directly by the light exposure when you're keeping people away. Very important point. And you're also triggering me to mention just a brief anecdote about an experience that I had many times.

At Princeton, I was working with animals, mice in particular. And if I wanted to do some circadian studies on those mice, I would have to go visit them at nighttime. And when I go into the mouse room, I can only put on red lights because there's an understanding that, you know, if we put on the bright white lights in the middle of the night, that's going to be. to be disruptive and potentially skew our data, right? Because it was a metabolism research lab. It's very sensitive subject of study. And then, you know, I would go in and check on my mice and then I would go back to my lab, blasting myself with fluorescent lights, completely just the hypocrisy and understanding that these lights will impact the rodents, but then not having the same

regard for ourselves. Yeah, absolutely. You know, we always make, I mean, the whole element of science and how you get something reproducible is you have to control things really tightly. But you're making all sorts of judgment calls when you do control things. You have to do it in order to get reproducible results. You can't sort out things if everything is changing. But that's always, you've got to ask the question of what am I actually doing by this paradigm. And so, and, you know, how are we living our lives? And yeah, it's sort of light is take for granted. Oh, it's so easy, isn't it? Ever since Thomas Edison, there's a flick of a light switch and we get what we want. We want to look at our computer screens. We're not thinking

about what's coming out of those computer screens. And yet they're really, most of them are LED-based these days. Again, the blue pump. And when I say blue pump LEDs, by the way, that's how you get these highly energy efficient LEDs. You are converting electricity into blue light. That's the really efficient way to get electricity into light. And then you'll put something over the top of the LED, over the top of the chip, which is called phosphor mixes, which take light and convert it to different wavelengths. So basically, that's how you get the greens and reds and everything else. But the blue light pump is always there if you've got a blue pump, because it's such a strong, potent signal. So that's what's coming out of our screens. And we're looking

for elegance. We're looking for sharp, bright, crisp-looking screens. You know, the sharper, brighter, crisper, white looking it is, it may be aesthetically attractive, but it's certain to be pretty rich in blue to get that type of color. So yes, now we're betting ourselves in that, and yet, you know, 99.8% of light sold today are these bright blue pump LEDs and are static, which means they don't change. It means fine during the day to have the blue light. But, you know, it is, you know, once the size is set, you really shouldn't be seeing it. Yeah. And on the topic of blue light, it seems like every year there's new papers coming out showing melanopsin is expressed in a different tissue, whether it was subcutaneous fat or the blood vessels

and the skin. And do you have any thoughts on that? Like, is there a role for circadian entrainment through the periphery or is it, I mean, I would assume that the strongest input is through the eyes, but how do you parse together the peripheral expression of melanopsin as well? Well, I'm not so many, the research, there were some odd scientific findings of people shining light on skin and claiming they were getting some results, but that's been pretty not really reproducible, clearly by far the strongest effect in the eye. And this gets into this whole issue of sunlight and health, which is a whole fascinating. topic. Again, a wonderful scientific story is Professor Lindquist and his team in Sweden

are concerned about melanomas and the Swedish getting, and they said, well, how much effect is people who spend a lot of time outside versus people who spend a little bit of time outside versus people who are always indoors? And, you know, how much worse is the melanoma risk you know, in those people who spend time outdoors. And they put together this very large perspective study from many years, went on 10, 15 years, I think. And what they did is they tracked 29,000 Swedish women. Now, Sweden is a great country because they collect so much health data essentially, so they can track people individually. What they found is, yes, they had more melanomas and more skin cancers. But they lived much longer, these women. In fact, the effect of the people were outside.

The effect was as large as smoking versus non-smoking. It was a huge effect on lifespan. And that dates back to then they realized that there were previous studies done in the US Navy unexplained. Sailors were getting eight times more melanoma than regular people onshore because they're exposed to so much sunlight, daylight. But they were living longer than people unsure. Again, fascinating study. And the question is, that then gets this question when I thought of it, is because of your mention

about skin and other tissues. If you, the main benefit from light seems to be through the eyes, and therefore, you do not need to be in a bathing trunks or a swimsuit or on the beach. to be exposed to light. In other words, people get the melanomas because the skin surface is exposed. You actually don't need much more than the eyes to be exposed to get a lot of the health benefits and longevity benefits of sunlight. But the effect is massive and it's huge and it's,

you know, and it's been of course tracked now and multiple other studies, including the Biobank study in England. Great study of 88,000 people average age 60, tracked for multiple years, And look, how much light do they get during the day and how much light do they get at night? The effects are vast compared to the people who see the most light during the day, get much, far less psychiatric disease, less diabetes, less heart disease. People who see light at night, even small amounts of light, even one to six lucks of light in the bedroom while they sleep, you know, are showing increased risk of a variety of things. So it's really teaching us how critical it is to get outdoors and exposed to light like you are right now.

And at the same time, in the evenings, make sure you sleep in pitch dark bedroom at night. And so many people sleep with the lights on. It's staggering. I mean, I couldn't believe when I started to see the statistics. 40% of the general population, probably about 50, 55% of the elderly population is sleeping with. some lights on TV or the lights in the bedroom, typically anxiety or other things, the reason they do it. And so, you know, talking about bringing it home, I was talking about this, my wife, and only finally did she admit that every time I was out of town, you know,

on a conference or a trip or a business meeting or something, and she was at home, she slept with the lights on. I said, oh my gosh. I didn't know it because I wasn't there. my goodness. That's too funny. Also, because, I mean, you could imagine that that blue light and that bright light can also contribute to anxiety and, like, nervous system upregulation when it should be kind of winding down and going to sleep. So it seems kind of like a feed forward cycle. I'm also thinking with regards to like peripheral sun exposure in particular, I guess one exception could be like the vitamin D story because we obviously need some skin exposed to make that vitamin D and that vitamin D seems to really just be emerging as this biomarker. for time spent outdoors versus this thing that you can optimize via supplementation. I mean, the vitamin D supplementation studies have been very lackluster showing almost no benefit in the vast majority of population studied, maybe Ricketts being the exception. So I think it's, I mean, interesting. And also if we think about the more evolutionary perspective, flows were a somewhat modern

occurrence, right? So like we were likely in nature. We probably had our bare feet on the ground. We're probably having quite a bit of skin exposed. but that light input from a circadian standpoint, from a metabolic health standpoint, into the eye is just absolutely crucial and something that's so easy for people to change in their lives to get really big outcomes and benefits. Yeah. Yeah. Actually, before we continue down the topic of maybe some of the health implications of inappropriate light and what people can do about it,

do you have any thoughts on like the role of neropsin and UVA light in regulating the circadian mechanism because I know that's expressed in like the cornea and also in the retinas and the skin as well. But is there a role of UVA light in regulating the circadian mechanism? I don't know much about that. I mean, there are new areas, you know, I think we're learning a whole lot more about broad area of the spectrum. I think we're learning a lot about infrared light and impact of that. And in terms of generation and melatonone effects and all sorts of photobiomodulation effects. So I think those are the, I think those are some exciting areas.

I haven't tracked, you know, I mean, generally aware of them, but there is a lot of work to be done in this because I think what we have just assumed is that we can bottle light, in other words, we can bring in doors and create artificial lights that no longer have any UV in them, no longer have any infrared in them, actually have a rather distorted spectrum because all we're trying to do is simulate white light without realizing the effects of all the different parts of the spectrum. So, you know, for example, you know, we know violet light is antibacterial. You can kill bacteria on surfaces. Some of the blue light that we talked about, you know, the use of blue to cure the problems of jaundice in newborn babies. That was a very, very

exciting discovery. Again, one of those serendipus moments, a nurse in England who took the premature babies outside because she thought sunlight would be good for their health. And lo and behold, the jaundice babies cleared up all the jaundice. And then that led to the physician in charge doing the key experiments and deciding that it was actually 460 nanometer blue, a royal blue part of the spectrum that was, you know, getting rid of the bilirubin, called in the jaw, this. We know that green light, new research going on in green light in terms of being potent a way of reducing migraines of dealing with chronic pain. And so there's some exciting work going on on the use of green light. We know, as I say, with red light, we know about hair growth,

We know the scars heal much more rapidly. So all the different components of the spectrum, all which are found outdoors, as you're sitting outside there, you're getting those full spectrum and everything from the UV all the way through the infrared. And you're benefiting from that, whether it's a cloudy or sunny day,

and we haven't yet dissected out all the critical parts and which ones we need to see. Because one of the biggest challenges when we move outdoors, as you're sitting in, you know, it's a fairly cloudy day, just looking at the sky behind you. So you go about 10, 15,000 lux probably of light there. At a sunny day, you might get 50,000, 100,000 lux. You walk indoors, and we're living in 300 lux, typically, of light.

And so if they've got much less brightness to light, and therefore you have to be, you can't crank up the light to outdoors, levels, you blind yourself if you did. The glare would be horrendous. So you cannot reproduce the brightness or the energy level of light indoors. So therefore, you're going to be very selective of which wavelengths am I going to emphasize in order to get health benefits. And that's why, as I say, control in the blue is one of the critical ones for health. But we've got to figure out what else should be in the spectral mix, not just for pure aesthetics, which is the theme of today's lighting, because it's largely driven by lighting designers and aesthetic designers, but what, in fact,

should be in light for health? What's the right mixture that we should be providing? Which spectral elements do we need? And we may not need all of them at every time a day. And in fact, we certainly need different ones at different times a day. So, Another fascinating, on that theme, another fascinating finding to me is the psychiatric hospitals, that has been repeated now, where patients are admitted with various depression and PTSD and severe anxiety and other psychiatric issues, they're hospitalized, and they're hospitals with bedrooms that are facing south and east, and they're on the other side of the corridor, the bedroom, all facing north and west. Now these patients have got the same doctors, the same therapy sessions,

the same pharmaceutical treatments, identical. I think lo and behold, the ones that get the morning sunlight in windows facing facing east and south, get out of hospital at the Asakia hospital at half the time, half the time. I mean, it's staggering. And that's one of the reasons we know that in fact it's you need to see this blue rich light in the morning. The time to do this, you're doing this interview at the, you know, at the, at the right time here. You're doing it a morning hour, so you're getting morning light. That's what you need to see the light for the circadian benefits. So time of day is critical even within the day. Yeah, that's, that's so powerful and just really points again to like the ignorance of the mainstream about the

relevance and importance of light and health. And it's just, you know, when we think about the FDA and like the regulation of drug products and how rigorous the testing is, the same type of rigorous testing should be undergoing for light too. And filtering out what kind of light sources can reach the public because we're now realizing these completely significant effects on biology at a very high level and a very like all encompassing level. It's influencing all systems of our bodies through that circadian mechanism. I want to make sure that before you have to hop off that we cover shift work because it's a question I get a lot. What if I engage in shift work? And I mean, typically I say, you know, you can give specific actionable steps, but I did shift work back,

you know, 10, 12 years ago. And I developed IBS during that time. And it was a really, really bad time for me health-wise. And so, I mean, I'm always like, if you can strategize to get off shift work, that's probably your best bet. But while you're there, what can people do to offset some of the negative effects of working in that way? Well, the shift work is really key to so many industries. So many things that we take for granted run 24-7. So all the operations of oil refineries, nuclear power plants, all those things, of course,

but also a lot of manufacturing. you know, cars are built around the clock, computer chips are made around the clock, all sorts of things are done. Dog foods made around the clock. You know, everything's made around the clock. There's the sheer efficiency of doing it. And then, of course, we've got 24-7 transportation

and everything else. We want our parcels to get around the world on time. So that's good. We can't get away from shift work. And I think the lesson we've learned, and I formed a company called circadian 40 years ago, to really address the application of shift work, is to stabilize. Stability is really important. So as much as possible to produce a stable routine.

Also, we want to not have you flip back and forth between day and nighttime in your body. And so what we've found that works is to make sure keep yourself in terms of the lightings. the workplace, keep the blue rich light during the day and the blue depleted light at night, because then we're not resetting the clock. And you might say, well, there's a group of people that are arguing today that we should be using blue rich light because guess people are alert, and maybe they're more productive, and then we can really stimulate them. But you were really causing major circadian disruption when you leave blue rich LED lights on at night. So we've done a number of studies in major factories and chemical plants and all sorts of things. In fact,

we've put our light systems into 65 Fortune 500 companies now. And we found that when you have blue rich light during the day and blue depleted zero blue light during the nighttime hours, then this actually improves their sleep, both before and after shift, it improves their health, their appetite. Fassely, we really talked about some of the direct effects of blue light, but Blue light at night makes people hungry, and they eat more snacks. So guess what? When you have zero blue light at night, same in light intensity, but it's zero blue. They eat half the snacks, half the number of snacks.

We repeated that several times over now. We've also in the lab showed that we can measure appetite in people and how they're feeling, and when you've got blue rich light, they don't really get hungry. Take away the blue rich light. They don't. which, of course, then that leads to obesity in a weight gain, if you're snacking all the time. And we've also found that gastrointestinal disorders are reduced if we put people on the schedule. So the first thing is keep yourself fixed on that regular daytime night routine,

your family's on that routine, it makes it easier for your social life and so forth. You are going to have to sleep during the day when you're working night shifts, but do that in a really darkened room. And provided that your light signals you're seeing are not screwing up in circadian clock and disrupting circadian rhythms, then in fact you're going to be so much healthy. So I think that's what we're really learning.

And as I say, we've got experience now, 65 major companies doing this now, some hospitals and a variety of other, many different other major companies doing it. and really good results. So I think that's the lesson for us. Don't try to be cute and shift people around the clock because you're just going to strand them in the wrong time zone

and they're back at home and they can't do anything about it. And now you've really got them promptly jetlight. Yeah. I mean, when I was working shift work, I would work from 10 p.m. to 6 a.m. for like five days. And then I would get like a day and a half off. And then I would go on to morning shift, which was 6 a.m. to 2 p.m.

And then after a week of that, 2 p.m. to 10 p.m. So it's just like a disaster, right? Yeah, that was actually one of the very first studies we did back in the 1980s. We just sort of published the first work on how sleep was controlled by circadian clocks and so forth. And we got that published. And we got this call from a mining company actually was harvesting potash out of the Great Salt Lake in Utah and then evaporating it over the summer. and then digging it out and sticking in trucks and taking off to make garden fertilizer. So they had this chronic problem. They called us up and said, look, we've got these problem with all these workers. They can't sleep. We've got health problems. They're really having a hard time. Can you help us? And, you know, being a sort of enthusiastic young scientists, myself and my colleagues

went out and visited them in Utah. And we saw what was going on. We said, oh, my gosh, I think we could, first of all, revise the way you're rotating the shifts. We could give people breaks. We'd give them training or managing sleep. And I still remember the plant manager to this day, looking at me and he said, have you ever done it before? And we said, no, no, this is going to be great. This is going to be a scientific breakthrough. And his jaw dropped, because no plant manager, no one in the industry wants to be the first guinea pig to try and use scientific theory from Harvard. So, but essentially, he was brave enough or desperate enough to try. And when we put that into place, actually making it more circadian compatible the rotation of shifts

and with the training on how to sleep and eat and everything around, their health went up, improved with gastrointestinal disorders, their absenteers and went down, sick leave absenteers and went way down. And what impressed them most was the productivity went up by 30% and stayed there. In other words, the tons of potash leaving that facility went up by 30%. Wow. People were no longer making errors as they were loading up the trucks of potash and dumping it in the wrong place and all sorts of things. So really interesting. It was so science meets productivity.

And that's what, in fact, started my consulting firm because we lucky enough to get that published in Science magazine, which you know is a really top-ranked journal. And we just hit lucky. You could never do it again, you know, however hard you try. that week was a slow news week, science released, to press release and events. Dan Rather at that time picked it up on the CBS Evening News, went to the Wall Street Journal in New York Times. It went everywhere.

And we had 300 major companies from around the world calling us within the next month. And that's what we realized. Yeah, it was an interesting start. Now as a Harvard professor, I was only about to consult one day a week, which presented an issue. And that's when we formed our consulting company called circadian, which now is offices all around the world and works with over half of Fortune 500 on a regular

basis. But that was again another major thing there, understanding that these Sikinian, understanding of Siketian principles enormously important to health and well-being, and especially for shift workers, because the natural life is so disruptive of our natural patterns. What an incredible story. And I mean, I think from a mainstream perspective, it could be really easy to focus on the inconvenience of needing to think about this stuff. But when you frame it in the context of productivity, it's like when you're healthier, when your biology is working in a more synchronous fashion,

you're able to work more and be more productive and contribute more to your family, to your job, to society. And I think that's really the lens that we need to view this topic through because, I mean, at this point, like you said, it's kind of a race to the bottom with the light industry. And it's just setting us up for more disease and illness and drops in productivity and ability to actually do good quality work. So I think it's just so important. One last question on kind of on the topic of shift work before I let you go.

Would you recommend that people use like blue blocking glasses if they aren't able to change the lights in their environment when they're on a shift? Yes, I think blue blocking glasses can work. The real key is making sure it's blocking the right blue. A large number of blue blocking glasses are blocking quite different. I talked about all the different colors of the spectrum, right? Many of them are just blocking 420 violet blue. They're not blocking the sky blue at all. And aesthetically, when you go and get blue blocking,

you go and get the coating to your lens of your eye glasses and you get this slight, you know, elegant little blue tint, but there's clear glasses. That's doing no good at all. You're spending $200 on nothing that's going to help. your circadian health. What you need is glasses that block, especially around the 480, where you really need to block around the 460 to 490 range. And when you do that, you're going to get a yellowish-orange-type tint to the glass. So if the glasses don't have an orange-yellow tint, then they're really useless.

And so I think there is a wild west of blue blocking glasses out there. Many of them are quite ineffective. key is trying to balance the biological effectiveness with the visual, you know, effect and ability to see clearly. But yes, it is a solution and it is effective and you can help, you know, a little tip bit of fascinating study just done by McLean Hospital, the Harvard Psychiatric Hospital here recently was working with teenage children ensuring that if you give them blue blocking glasses in the evening and you gave them a light book in the morning, which provided blue. As you blocked the blue at night and in the morning, you gave them that, their math scores went up in school significantly. And a whole lot of their interesting brain connectivity

changes they could find by MRI and so forth as well. But it was fascinating, just simple intervention. Wow, that's so powerful. I mean, I think we provide a lot of actionable takeaways for people here. This was a really valuable conversation. I think we could probably go for another hour, so I'd love to have you back on. I've got more questions we didn't get to, but I want to respect your time today. And so thankful that you could share some of it with me as well. And I'm sure my audience is going to love this episode too. So where can people find you and your new book? Well, the new book is a bestseller on Amazon. So you just look on the Light Doctor on Amazon. And the subtitle is using Light to boost your health, improve sleep,

and live longer, which is a really interesting thing, but it's the Light Doctor, and it's on Amazon. And yeah, please look at it and give me a review. I'd like to get reviews on Amazon too, just to help broaden out the awareness of people. But yes, I'd really look forward to seeing people read the book and discuss it and share it with their friends. And then I have a website called circadianlight.org, which can give you some ideas of where you can find light bulbs and light fixtures and blue blocking glasses and other things, just as a general information. Incredible. And I'll link to all this in the show notes too so people can easily find it all. And I just want to thank you so much again for spending time with me today. And I hope you

have a great day. Well, fun conversation, Alex. I enjoyed it. Me too, me too. Hopefully we'll talk again soon. All right. Have a good one.