68. Importance of Circadian Rhythms for Obesity & Cancer | Martin Moore-Ede MD, PhD

Dr. Martin Moore-Ede aka the Light Doctor, is a world leading circadian biologist and researcher, having led the team that located the suprachiasmatic nucleus, or circadian master clock, in humans.

In this interview we discuss role of light in health, why life evolved circadian rhythms, the health consequences of artificial light at night on diseases including cancer, obesity, diabetes, solutions to this light apocalypse and more.

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TIMESTAMPS
00:00:01 Circadian Biology and Health Impacts
00:09:54 Impact of Light on Circadian Rhythms
00:16:27 Blue Light's Effect on Circadian Rhythms
00:22:58 Circadian Rhythms and Light Synchronization
00:30:33 The Importance of Circadian Rhythms
00:46:45 Impact of Artificial Light on Cancer
00:54:56 Impact of Light on Health
01:01:44 Impact of Blue Light on Health
01:11:57 Improving Health and Performance With Light
01:18:00 The Light Doctor Book Release

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Website: https://circadianlight.org/
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DISCLAIMER: The content in this podcast is purely for informational purposes and is not a substitute for professional medical advice, diagnosis, or treatment. Never disregard professional medical advice or delay in seeking it because of something you have heard on this podcast or YouTube channel. Do not make medication changes without first consulting your treating clinician.

#light #circadian rhythms

Transcript

Speaker 1: 0:01

Dr Martin Moore-Ede is a medical doctor and world-leading researcher on circadian biology, having led the team that located the suprachiasmatic nucleus, or circadian master clock, in the human brain. In this interview, we discuss the role of light in health, why life evolved, circadian rhythms, the consequences of artificial light at night on human diseases, including cancer, obesity, diabetes, as well as solutions to this light apocalypse. Dr Martin Morgan, thank you for coming on to the Regenerative Health Podcast. Pleased to be here. So you're the director of the Circadian Light Research Centre in Boston. You are an expert in circadian rhythms and the physiology of circadian effects on health, so maybe we could start by giving the listeners an idea about how you got into this very interesting but still quite niche area of science and health.

Speaker 2: 1:09

Well, I graduated in medical school Guy's Hospital, medical School in London and then went over to actually to Toronto to do my surgical internship and first-year residency and along the way, you know, I found myself, of course, working those classic 36-hour shifts on your feet, on stop, and then 12 hours off, back in 36, 12 hours off, and so on. And that was all done, of course, thinking back, under bright fluorescent lighting at that time, and I experienced the classic symptoms of jet lag, without the joy of travel, right, in other words, the fatigue, the sleep issues very clear, but there's a general sense of malaise and also cognitive things. In other words, I couldn't remember a prescription, I couldn't figure out why I'd written a particular prescription and more than once I nodded off in the operating room and had the chief surgeon yell at me All the symptoms of what's called circadian disruption, when our circadian rhythms, our 24-hour rhythms, are disrupted by our natural light-dark cycles. And that's got me really interested in taking a detour out of surgery, out of doing a surgical career. Came down to Harvard, I was fortunate enough to get a joint position in the Department of Surgery. I managed to do a postdoc in the Department of Surgery at the same time as doing a PhD in the physiology department and as a result, my research was focusing on, you know, what's causing the circadian rhythms, how they generate.

Speaker 2: 2:49

Now, when I started and this was back, you know, in the 1970 type of period very little written at all about some things on circadian rhythms, very little on circadian rhythms and light. The year before I entered medical school only three papers were published about circadian and light, for example. I was warned off this subject. I was told this wasn't a good topic for a young man to put his career on, let alone do a PhD thesis on. Phd thesis on. Because, you know, at that time the circadian clocks had not been identified in any animals. It would be a year later before they were found in rats and hamsters. It certainly wasn't known in man. But I went ahead anyway because I was really interested in the topic and, of course, had a chance to be at a front row seat in this very rapidly developing research area and it was an exciting experience.

Speaker 2: 3:49

You know we were able to show that light in fact does synchronize the circadian clock of humans. We did that in isolation facilities where we could control light and dark, and precisely the general theory at that time was it was social interactions that were synchronizing human circadian rhythms. We were able to show that it was indeed light and then we were able to show that the humans actually have a suprachiasmatic nucleus that's the circadian master clock in the brain, just like other species do. It had been missed and, quite frankly, being missed was interesting because the brain atlases of the human brain only publish or print every 50th slice. They throw away the 49 slices in between, so you've got something small. It doesn't show up, but only occasionally shows up in these atlases and we're able to show that by looking at all the slices in between, we can show that the master clock of the circadian system was in humans too. So that told us that this was part of the same system that animals have and it's really a fundamental system throughout nature, as you know.

Speaker 2: 5:03

And that led at Harvard. I was on the faculty there as a professor for 23 years, able to get a great group, brilliant group of graduate students and postdocs, and we had a lot of fun in those days, really, brand-new field mapping it out, defined the circadian timing system as a new system, just like the cardiovascular system or the respiratory system. Circadian timing system as a new system, just like the cardiovascular system or the respiratory system circadian timing system, and also showed some of the really disruptive effects it had in health and disease and how it was linked to various disease conditions. So that was an exciting time and that was my academic career at Harvard through about 1998. Academic career at Harvard through about 1998.

Speaker 2: 5:48

During that time we started getting a lot of requests from industry for help with people who work around the clock and so I formed a consulting company called Circadian. Not much imagination there in the name, pretty straightforward. But that consulting company has now grown. We work with almost all around the globe. We have offices in Brisbane, australia, in Amsterdam, in London, obviously, in Boston, and we literally are all over the world. I do work in Chile even, for example. You're down there in Chile right now, since you're down there in Chile right now. So we are. And that was to really apply circadian rhythm science to the science of how you work shifts around the clock. These are companies that are working 24-7. They're the big oil companies, the airlines, the manufacturing plants, the utilities, nuclear power, you name it. And that's what our client base has been, and that's now 40 years along the way, anyway. So that took me away into, you know, really applying.

Speaker 2: 6:55

But then a problem came up and that was the science around the year 2000 started to show some very important things about what light was doing to people. The first evidence came out solid studies showing 50% or more increase in breast cancer risk in women who work night shifts Big studies done by three separate groups it showed. Then there was more evidence showing that in animals you could replicate this the melatonin suppression, which is the hormone from the pineal. When it's suppressed by light at night that melatonin is lost or its effectiveness is lost in suppressing cancer cells. You could show that if you in fact had blood rich in melatonin, cancer cells didn't grow fast. If you have blood that was depleted in melatonin at night, cancer cells grew much, much faster.

Speaker 2: 7:52

So now we've got a situation where we found these clients of mine and this is half the Fortune 500, all these big companies said Martin, you know, world Health Organization has just come out with a finding that light at night is carcinogenic. What do you do about it? We can't switch off the lights. We can't turn off our businesses. Our businesses have to be 24-7. We can't get away from it. What do we do. And that led me back into developing the Circadian Light Research Center to really study this problem, and we got funding from the National Institutes of Health here and from various other sources and we're able to then really focus on how do we solve the problem.

Speaker 2: 8:34

The key was interesting because along the same time the research was coming out showing that there was blue light, blue part of the spectrum. Now I'm sure you've educated most of your audience about light that you look at a white light or sunlight or whatever. It looks white, it looks yellowish white. In fact it's made of all the colors of the rainbow fused together in our brains. It looks white, but what you're actually receiving is violet, blue, green, yellow, orange, red, et cetera, plus some ultraviolet at one end and some infrared at the other. So that's what light really is, and it turns out that what the circadian clock, the circadian system, is sensitive to is blue clock the circadian system is sensitive to is blue. It's sensitive to a particular sky blue color around 480, which is detected in the intrinsically photosensitive retinal ganglion cells, the so-called IPRGCs in the retina, in the retina of the eye that detect this blue signal. The retina in the retina of the eye that detect this blue signal and that's what the brain is told as to whether it's day or night If you see blue, it's day, if you don't see blue, it's nighttime.

Speaker 2: 9:54

And that worked really well in the natural world when we had sunlight during the day. All our 10,000 generations of humans, before we invented the electric light bulb, only saw sunshine, daylight during the day and saw darkness at night. They used, you know, candlelight and fires, of course, but they have very little blue in them. So as far as everybody's concerned, that's the issue. So now we've got a situation now where we are sitting indoors 90% of the time.

Speaker 2: 10:24

So now we've got a situation now where we are sitting indoors 90% of the time, way less blue than we normally would see during the daytime, and during the nighttime hours we see way too much blue, particularly since we're using more and more LEDs, and the LEDs are a problem because they are based on a blue pump technology and so, anyway, that is the problem and we said, okay, if we could solve this problem, could we develop lights that look white but don't have any blue in them, and could we enhance the blue during the daytime. Other lights, also looking white but have enhanced at the 480 key signal, enhanced at the 480 key signal. And you know, if we could, we could provide some protective function. So we spent a few years doing that, raised money, got some venture money and all the rest of it to do this, develop patented technology, and you know that's how we got to circadian lights. But I'll stop now and let you, you know, tell me where you want to go with it all.

Speaker 1: 11:25

Yeah, no, thank you. That's a very good overview of every topic that I really want to get into in depth in this podcast. There's a passage of a paper that you've written and it was called Lights Should Support Circadian Rhythms Evidence-Based Scientific Consensus, and this was published last year, and I'll quote a passage because I think it really sums up the problem that we're facing from a health point of view in terms of this light environment and the light diet that most people are consuming. So what you've written is the timing, duration, intensity and spectral composition of ocular light exposure have a profound effect on circadian clocks and rhythmic physiological processes.

Speaker 1: 12:04

For the first 10,000 generations of Homo sapiens, the contrast between bright daylight between 10,000 and 100,000 lux and nocturnal darkness 0.0001 and 0.1 lux robustly entrained the human circadian timing system to the Earth's 24-hour rotation. However, for the less than four generations over the past century, the natural 24-hour cycle of daylight and darkness at night has been replaced in the developed world by electric light. Approximately 90% of our time is now spent indoors under electric light that is typically 100 times dimmer during the day than natural daylight and 1,000 times brighter after dusk than even the brightest moonlight. So that is another way of very eloquently describing the problem that we're all faced with. Can you quickly describe to us this measurement of lux Because and I think it's very, very relevant, especially talking about the magnitude of light that we're getting and expecting between daylight and nighttime- yeah, there is this measure of lux.

Speaker 2: 13:06

In the old days, when people were thinking about how to measure light, they were concerned, thinking really, the mindset was light is for vision, light is for being able to see your environment around you, and it so happens that the green and yellow wavelengths in that spectrum of light are the ones that we're most sensitive to, and so the lux and lumens and those types of measurements are measurements of how bright light appears, but it's not a measure of what light you're receiving.

Speaker 2: 13:42

It actually doesn't really measure at all the red parts of the spectrum, all the blue parts, all the violet parts of the spectrum. Virtually all is the yellow and orange, yellow and green parts of the spectrum that it's measuring. So it's a useful measure of brightness, but it's a terrible measure of the health effects of light, and that's turned out to be a big problem because regulations on LEDs are all based on lumens and the number of lumens of light produced per watt of electricity. That's turned into a big problem which is starting to really have a negative impact on the science of healthy lighting and limits what sort of white bulbs and fixtures can be built that provide healthy components of light, not just the brightness components of light.

Speaker 1: 14:37

Yes, and it's an example of extreme reductionist thinking and reductionism in terms of an endpoint or a goal that perhaps organizations and governments are trying to strive towards, but it misses out so much nuance about the essentially evolved requirements that we have in terms of our light environment. I want to go into the mechanisms of circadian entrainment and you've mentioned these special, intrinsically photosensitive retinal ganglion cells, which I've talked about a lot myself, so maybe go in depth in terms of how the body recognizes these light wavelengths and maybe, as you've done, really briefly contrasting this camera function and vision function compared to the light sensing function of the circadian system.

Speaker 2: 15:30

Well, these retinal ganglion cells in the eye that we're talking about have got a peak sensitivity of around 480 nanometers and that turns out to be sky blue light. And when they were first studied, you know, 20 years ago, the first studies defining, you know, the human response to different colors of light and basically you put people in a room and you shine lights of every color in their eye and then see what effect it has on a physiological endpoint such as the melatonin suppression as an example. When you do that, they showed a rather broad effect. They show violet light had effect and blue and green certainly had an effect. So it was a rather broad range of violet, blue, green light that was causing the problem violet, blue, green light that was causing the problem. When we looked at that, we realized that all those studies were done in people who were dark adapted. Now, dark adapted means they put them in a totally dark room. They put a blindfold on them to make sure there's no light whatsoever going in their eyes. They have to sit like that for two hours. Whatever's going on in their eyes, they have to sit like that for two hours and now they're in that state that you're in, which enables you to walk around in the dark Well, because you know or to see stars in the sky is what astronomers do before they use their telescopes. They get fully dark adapted, but it's a very different state from how we are during the day, because during the day we become light adapted and we said let's look at this in the light adapted eye, not the dark adapted eye. And that's when we found there's a far narrower band which is between about 440 and 495. It's it's all in the blue, and that that was actually very interesting finding because it meant that we now had a rather narrow band of the color spectrum that we needed to control. We didn't have to deal with all sorts of different colors which could really distort how the light looked.

Speaker 2: 17:38

So how does it work? The human eye and eyes of animals detect the blue and the intensity of this blue light, these blue wavelengths coming in. That in turn signal is sent back through a tract called the retinal hypothalamic tract to the suprachiasmatic nucleus, which is really the central pacemaker. Now it's not the only body clock. There are body clocks in virtually every cell of the body, so there are probably trillions of body clocks in our bodies and that's pretty important. But essentially the master clock receives the signal and then disseminates that timing information to the rest of the systems of the body. It disseminates it through control of hormones melatonin is a key one, cortisol is another key one those the systems of the body. It disseminates it through control of hormones Melatonin is a key one, cortisol is another key one.

Speaker 2: 18:28

Those are some of the mechanisms, but essentially that blue light falling on the clock can shift it. At certain times of day, in the evening, blue light will shift the clock to later hours. It will shift it westward, as it were. Light will shift the clock to later hours. It will shift it westward, as it were. At certain times in the morning, early morning, it will shift it the opposite direction, eastward, and that turns out to be the so-called phase response curve to light, which is the description of how light adjusts us to the time zone. So we fly across, you know, from England to Australia, and it takes a while to adjust, but when we do it, and that adjustment is happening by nudging this biological clock over and shifting it to a particular point.

Speaker 2: 19:13

So normally what is happening if you're living in sunlight and sleeping in the dark is you're well synchronized to your local term zone and that light is nudging your clock and just keeping it established.

Speaker 2: 19:25

Now the clock naturally drifts If you don't have any light-dark cycles. If you're in a room with constant dim illumination, for example, it tends to drift Most people rather longer than 24 hours has its own frequency. That's one of the so-called free-running circadian rhythms and that's seen across the animal species. But it's the light in the morning and the light in the evening that is keeping us tightly synchronized to the circadian world and circadian clock. And it turns out that the vast effect of that light is in the blue. And it's a very nice experiment done. You can shift. You can actually derive how much shifts occur with general white light. Take fluorescent light or LED light or a single dose of very sharp, pure blue light, and that's at least 20 times more effective than the broad spectrum. In other words, you can use very low amounts of blue light to get the same effect as much brighter amounts of white light containing all the color spectrum. Again, now more evidence that the key signal is sitting there in the blue.

Speaker 1: 20:36

Yes, and what you're describing is this idea of zeitgeiber and light being the primary zeitgeiber, or influence on our circadian rhythm. That is not quite 24 hours, but really needs synchronization to external environmental signals, of which light is the most important. There's obviously processes and you've mentioned these clocks in not only in the brain, but in all our tissues and cells and this was the subject of the 2017 Nobel Prize and to really delineate the mechanism by which the circadian clocks were operating, do you mind explaining about these clock genes and how, on a cellular level, these timekeeping is happening?

Speaker 2: 21:22

Well, I think the Nobel Prize was done by a work from scientists. Three scientists in particular, who were defined, got the credit for defining these clockwork mechanisms. And I'm not the molecular biologist. But essentially there are a sequence of genetic products which together conspire to create a very robust circadian rhythm synthesis, destruction of elements and so forth, and those together. It's a complex system, but it describes how each cell or organism can actually. But it describes how each cell or organism can actually derive a circadian rhythm on its own, robust periodicity through molecular mechanisms. So it's really describing the molecular biology of the circadian clock as an entity which has ability to maintain time and to regulate the timing of the organism through a robust, self-sufficient system within each cell which then needs to be fine-tuned and synchronized by hormonal signals so all the cells in the body are aligned. If they're not aligned, we get what we call circadian disruption.

Speaker 1: 22:43

And in terms of the other entrainer or zeitgeibers that influence this system, other than light, what are other entraining signals that are important or relevant?

Speaker 2: 22:58

Well, food appears to play a role and certainly in the animal kingdom and we can. A lot of studies showing various animal studies showing that food at a particular time of day can entrain. One of the most fascinating studies early on was done way back in, I think, probably in the 1920s, 1930s, with this family who was eating breakfast outside every day and, being a Germanic, they were so precise in their timing of breakfast, it was always, you know, exactly at 9 o'clock, right and so, and they ate outside and bees would arrive and the bees, the asylum noticed that the bees would arrive just before breakfast, just before the marmalade was put on the table and, you know, and they thought that was pretty interesting. Until one day they didn't have breakfast and the bees still arrived exactly on cue. And a whole lot of studies have actually gone to elaborate lengths of flying beehives across to the other side of the Atlantic and to New York and seeing that they maintain German, they come out and look for food in German time.

Speaker 2: 24:06

So animals have this intrinsic nature. It is one of the cues and it is and I'm not certain certainly people do restricted feeding here. That may be part of the effects of restricted feeding times. We humans tend to not have all our food at one time a day, which would be the most robust signal, but certainly food is one of the signals. Meal timing is a signal.

Speaker 1: 24:32

Yes, and that's something that I've discussed as well, which is the importance of I favor breakfast and basically coupling that with early morning sun exposure to entrain the liver, the gut clocks and all these metabolic clocks, and there is good evidence from a metabolic and insulin resistance point of view that circadian dysfunction fundamentally alters those mechanisms. From your perspective, what is the unique value of morning sunlight versus circadian signaling later in the day? Because obviously we have a unique spectral composition of morning sunlight, but we also have evening sunlight and a sunset that is quite similar in terms of its enrichment in infrared and red and obviously absent in ultraviolet. So how do you see morning sun compared to sunlight later in the day? Why is that particularly important?

Speaker 2: 25:31

Well, I think the interesting finding is well, first of all, the biology.

Speaker 2: 25:38

The human skin system tends to drift longer than 24 in most people.

Speaker 2: 25:43

So therefore, the nudge you need, the key nudge you need, is the morning nudge, right, in other words, just to make sure you don't drift, sleep in later and later, as it were, and that morning light is a key, one of those key synchronizing things. Secondly, there is evidence now, which is really interesting in the real world, that if you admit psychiatric patients to hospitals and so what happens is that a hospital has rooms on one side that are facing east and south, so they're catching the morning sun, and the other side of the hall, the rooms are facing north and west. Lo and behold, the psychiatric patients same doctors, same psychiatric conditions, depression, so forth, same medications get out in half the time when they get in the morning sunlight, which is really fascinating, and that's been shown by at least a couple of people. Which is really fascinating, and that's been shown by at least a couple of people. So there's something pretty significant about morning light in terms of synchronizing and keeping our circadian systems robust and preventing circadian disruption. That perhaps is less critical for evening light.

Speaker 1: 27:00

That's a fascinating finding and I imagine that those windows would still be filtering light. That's sort of fascinating finding and I imagine that those windows would still be filtering light. They would still be filtering out a lot of the infrared and the UV.

Speaker 2: 27:14

The UV doesn't come through glass, right. But it's just fascinating because this is indoors, right. These patients are indoors and there's all sorts of evidence showing that people who are in rooms near a window have much better, robust sleep. They're comfortably performed better than the poor guy who's stuck back in the cubicle away from the windows. Because that's what we did when we started, when we invented fluorescent lighting and air conditioning. Lo and behold, buildings became a much bigger platform floor level, floor size between the walls. You can build much more efficient space that way. The old buildings always were very narrow, so that daylight would penetrate them. In fact, you look at buildings up to 1900, it was very narrow. The early skyscrapers in New York were extremely narrow buildings because they wanted to make sure that they couldn't rent the space that was more than about 20 feet away from a window.

Speaker 1: 28:17

Yeah, and look, there's a reason why the CEO of the corporation gets the full-length floor-to sorry floor to ceiling window looking out at, you know, prime real estate and all the minions have to sit in the middle of the building under pure artificial light.

Speaker 1: 28:34

So you know, there's many reasons for this. But what talk to us about and I'll only make the point now briefly that light and psychiatric disease is so intimately linked and I truly believe that so much depression, anxiety and other forms of even more serious psychiatric disorders, neurodevelopmental behavioral issues in children, pediatric populations, could all be improved dramatically if not resolved with tight circadian regulation. But we'll talk about that when we go into the specific diseases be improved dramatically if not resolved with tight circadian regulation. But we'll talk about that when we go into the specific diseases. Martin, I'd like to ask you about the evolutionary role of circadian rhythms and I've at alternative times posed or talked about the adaption of circadian rhythms as one is cellular and organism efficiency, and how do you perceive is the reason why circadian rhythms as one is cellular and organism efficiency, and how do you perceive is the reason why circadian rhythms arose?

Speaker 2: 29:31

Well, I think what's fascinating is, you know, early life developed, as far as we understand, deep in the oceans, and one of the most phenomenal insights is that if you look at the spectrum of sunlight as it penetrates into the ocean deeper and deeper, all the colors of the rainbow are absorbed by seawater, except for, finally, just blue right. And this same blue is detected by the back of our eyes. So basically, it is blue down there, detected by the back of our eyes. So basically, it is blue down there. And so in the early evolutionary world, blue meant day. No, blue meant night. They didn't see the other unless you rose up to the surface, where there was too much bombardment from all sorts of ionizing radiation in those early days. That, basically, that was the signal. And so why? So, basically, and so night follows day. So why would you care? Well, if you're prey, if you're in the food chain, if you've got predators after you, you want to be hidden away during the time when you're most vulnerable, to be hidden away during the time when you're most vulnerable. And you need to make a choose Are you a night species, a day species, and adapt it accordingly. And you adapt that way, if you know, and if day and night are different, having a clock that keeps you in sync is good. If you can detect the blue, you know, that's the first thing. If you can have a circadian clock that only detects the blue but enables you to predict when blue is occurring, in other words, when night's occurring, you can make that move to safety. Or if you're a predator, you can make the move to where your feeding grounds are timed by your own internal clock. And I think it's a very fundamental part of biology. And what's fascinating to me is that even single-celled organisms in the sea, like gonialyx, the red tide algae, they have in their single cells a blue detector. They can detect this blue color, they've got a circadian clock and they even produce melatonin. And that's amazing because, it said, melatonin goes way back. So those compounds, that's the fundamental ingredients, three fundamental ingredients of this clockwork system the detection of the anite outside, the internal measurement of time and the signal to the rest of the organism. And of course, it becomes even more important in full-scale organisms, multi-celled organisms like us, through using substances like melatonin to send the signal as to whether it's nighttime. It's a nighttime hormone. It tells us it's nighttime. So I think that's really being conserved. So I think that's really being conserved, and so it's very interesting that something that worked well in the oceans still works here.

Speaker 2: 32:31

And in fact, you know there are some very interesting phenomena, like the Chappius effect. I don't know if you know about that one. There is something called the blue hour. It's actually less than an hour, but in the evening, just at sunset, the sky suddenly becomes much richer in blue, about 20 minutes after the sunset. And similarly in the morning, before the sun rises, the sky becomes much richer in blue. And why is that?

Speaker 2: 33:03

Because ozone is a light filter. It absorbs all the other colors, but it lets blue through. So at the certain angle of the sun, the ozone layer, 15 miles above the earth, is absorbing all the colors and making it predominantly blue that we see. So there's now a signal that occurs 20 minutes before dawn. That's blue, which is fascinating. So, in other words, there's much and this is obviously of evolutionary import. So and blue is something that you know it's the color of blue skies, so it's probably the strongest part of the natural spectrum as well, although that's much fuller. So it's fascinating. Basically, you know, blue was conserved as the signal and we have it still today.

Speaker 1: 33:51

It is incredibly fascinating and I've spoken to Scott Zimmerman, who's doing very interesting research on melatonin and the extra pineal production of melatonin particularly. But he's pointed to in a couple of very good review papers how conserved melatonin molecule and its actual role of an antioxidant and even preceding its indicator or role as a day-night indicator. So it's a very old circuit and the other point to make about that is how old this melanopsin and non-visual photoreceptor protein is and we didn't mention it. But that's actually the mechanism by which this 480 nanometer blue light is being detected and that is something that is conserved. I believe it was originally discovered in an amphibian, xenopus livus. I believe was skin is how they first discovered it. But all that background is to say how critical the reception and perception of daylight is to the organism's fitness.

Speaker 2: 35:02

No, absolutely. It's a fundamental old system, a core system that you know equips us to deal with night and day. And why do we need it? Well, you know I did a run out of it quite some years ago about intellectual lectureship, the American Physiological Society, where I talked about homeostasis, and the classic homeostasis is how the mechanism of the body keeps stable. It gets cold outside, your body keeps warm. It gets hot outside, your body keeps the same temperature. That's homeostasis and that's classic physiology. Walter B Cannon whose desk, by the way, I inherited at Harvard, and so it was fun to write on the desk with the guy who invented homeostasis. But what I realized was that that is reactive homeostasis, that is, temperature changes you adjust.

Speaker 2: 35:57

Predictive homeostasis is what the circadian system is doing. It is now getting the body to start doing things that take time, synthesizing proteins in preparation for daytime that you need for the day, changing systems that take time. You can't just switch them on and off so you can get the body ready for a particular state with processes that take time if you have a clock that can start that process, and so that's one of the really key parts of this, that it's a predictive adaption. There's an advantage to knowing in advance when something's going to happen. That gives you an advantage. Otherwise, life will be full of surprises. You're surprised that dawn occurs, surprised that night comes on and you could be in a very you know, at this age it's place for your survival if you didn't have some predictive capability of when dawn and dusk are going to occur.

Speaker 1: 36:58

That's a very interesting way of thinking about it. Thank you for that insight. I hadn't thought about it that way, but that makes complete sense to me and I think it is so relevant to the discussions about the hierarchy of health inputs. And in holistic health circles, diet is prized very highly. But if we're thinking about the ancient pathways that we've just discussed, I think, the primacy of light signals in terms of programming biology, and then we add in the fact that 70% of our genome is regulated by circadian signals, that we've got these circadian clocks in all of our cells, then I really think that that's a good reason to reorder this list to put light at the top of the list. Are you aware at all, or do you have any commentary on the so-called nocturnal bottleneck hypothesis, which was to do with mammalian evolution and this idea that we were small furry mammals during the time of the dinosaurs, that that had specific adaptations to nocturnal light?

Speaker 1: 38:07

no, I don't know that one, that's okay. No, I was just just wondering. It's uh. Uh, there is good. There was some good evidence that that was the real one of the inflection points, or turning points for mammalian evolution. And after the dinosaurs disappeared, then we were able to re-acclimatize to daylight conditions. But did you have any more that you wanted to say about the evolution of this circadian system before we get into clinical implications?

Speaker 2: 38:38

Let's move on to the clinical side of it. As I say, I think the fundamental importance of the system is clear for physiology, survival and so forth, but the clinical implications is something we're really starting to understand much more about.

Speaker 1: 38:54

Yeah, and look, it's an interest of mine, particularly diabetes, obesity, insulin resistance, leptin resistance, and it's unequivocal at this point, although clinical practice hasn't incorporated these scientific realities, of how critical circadian signaling is to our metabolic health. So maybe describe for us the mechanisms by which circadian dysfunction is linking to metabolic disease, cardiovascular disease particularly.

Speaker 2: 39:25

Well, there are a number of sides of this.

Speaker 2: 39:28

I can take some examples, but, for example, how glucose is metabolized is radically different depending on the light you're seeing at night.

Speaker 2: 39:42

So if you're seeing light and we've got, our studies are being focused on you know, this is part of us trying to figure out a solution focused on lights that are the standard lights, which are fluorescent, or LEDs rich in blue, and if you have someone to keep them up overnight with those lights on, as I did when I was a junior surgeon, with so many people 20 million people in America, 60 million worldwide who are working night shifts do, what happens is several interesting things. Number one they get actually much more appetite goes up. It has an appetite inducing effect and they eat way more snacks on the night shift under blue rich light than they do. You know same people. But now, with the light that's got none of this blue in it, it's quite a dramatic effect. They don't feel hungry, they don't snack when they're under zero blue light. When they've got blue rich light, they feel hungry and they snack, and that, of course, has impact on metabolism and obesity. And so forth.

Speaker 2: 40:47

The other side of it is the way that the glucose metabolism is regulated, that people under blue rich light show increased insulin resistance, which means the insulin is less effective. Blood glucose climbs more. They become less glucose tolerant. And so if you just study again people overnight under zero blue light or blue rich light and then you do a glucose tolerance test as a classic test, where you give a drink of sugar water to gain glucose typically and you then watch or take blood samples as the insulin and glucose levels rise and then in a normal person return to baseline within about a couple of hours. In a diabetic they rise and they rise further and they stay there. With blue rich light they become pre-diabetic. In other words, the insulin is less effective, the glucose climbs further and if you go to now using zero blue light, you reverse that effect. So again, that's the direct effect of that light. So that's the sort of work we've done as an interesting end marker there.

Speaker 2: 42:08

And it's clearly that you know increased risk of obesity, of diabetes and so forth is inherent in people who are look at the light, who sleep with the lights on at night, you know, in their homes or work at night. Nice thing about those studies. Now I'm showing that people who sleep with the lights on are much the same state as those who work at night are work at night. It's not a shift work thing related to some part of their job or environmental exposure. It also happens when people use lights at night in their bed. Much the same sort of things happen in terms of health, and in terms of not only diabetes but also prostate and breast cancer risk and so forth.

Speaker 1: 42:53

It's absolutely fascinating.

Speaker 1: 42:54

Thank you for bringing up that evidence For those listeners of my podcast who followed my Dr Jack Cruz series. He talks about the mechanisms of how blue light is affecting the cleavage of POMC, pro-opioid melanocortin, and really favoring this hyperglycemic, hyperinsulinemic situation where we're really becoming and putting on the path to metabolic dysfunction, without even eating anything. And having worked night shift myself in emergency departments, I can vouch that personally for the effect on appetite and satiety of of a night shift, and particularly before I put in some you know kind of mitigation method measures. Uh, for myself, you definitely are hungrier, um, after working a night shift or having a circadian disruption, and that is it's. It's unequivocally noticeable, and particularly for carbohydrate and other kinds of sweet, uh, sweet foods. And it's a note I I'm sure you would have noticed this, martin, in your consulting is that these workplaces so frequently have a bowl of sweets or other form of snacks in the nurse's station or you know somewhere else, and it's a really a recipe for turbocharging the development of metabolic disease and obesity and type 2 diabetes.

Speaker 2: 44:20

Absolutely no. It's a real issue. We've seen it both in the lab and in the real world. It just is quite traumatic.

Speaker 1: 44:27

The other point I'm making about the oral glucose tolerance test, which is the shape of that curve, is as you've described. Test which is the shape of that curve, is as you've described, is enlarged or made larger and longer by this blue light exposure. The other fascinating implication, which was work of Glenn Jeffrey early this year, was he actually shone six, seven nanometer red light. I don't know if you're familiar with this study, martin. He shone 670 meter red light onto patients. This was a randomized control trial and actually saw a significant decrease in blood glucose levels between the control and the intervention group. So that's suggesting that not only is blue light elevating or causing hyperglycemia, but red light which we would get at sunrise and sunset, is actually putting it down. So it goes to show and illustrate the profound effect on metabolic health of our light environment.

Speaker 2: 45:25

And, of course, what we're doing with these. Coming back to these light bulbs and the light bulb rules, the LEDs, there's no benefit to putting red, much red, in the spectrum, because it doesn't add to the lumens that they measure for so-called energy efficiency.

Speaker 1: 45:43

Yes, that's a great point. Let's talk about prostate and breast cancer, because this is something that is becoming a bigger and bigger problem. I personally know friends of friends whose parents this close to me. They're two parents who've just been diagnosed with breast cancer. So so obviously there there's a multi-fact, multiple factorial process. But you have made a very good case that artificial light at night is responsible, uh, primarily for what we're observing in breast and prostate cancer.

Speaker 2: 46:18

Yeah, I think the real issue is that when you look at cancers, smoking is clearly a major contributor to lung cancer, human papillomavirus, to cervical cancer and so forth. So we've got some sense of some cancers, as to what the causes are, but breast cancer has been less clear in a lot of studies. Why has there been a big rise in breast cancer? And the evidence I think is compelling that it is related to light exposure. It used to be a really rare disease. It didn't rank high at all in cancers before Edison invented the light bulb, and we can see it ramping up as illumination occurred. More and more homes are illuminated, more and more businesses are illuminated, particularly with blue rich lights, and so the rate of breast cancer diagnosis went up fourfold between 1970 and 2010 as the fluorescent lights were taking over, and now, as LED lights are coming in and are coming into people's homes where they weren't before, because everyone was using incandescents and halogens and so forth, now we see this even faster rise. It's accelerated. So there was this increase in breast cancer rate. It's now accelerating right now at 4% a year, which is huge. These are 4% the rate of new diagnoses. It's going up. Gastrointestinal cancers like colorectal cancer, gain-related skin disruption is going up, and so I think we're seeing things going on that just are not being credence.

Speaker 2: 48:10

Now, why do I think it? Well, if you look at parts of the world, women who've never seen electric light don't get breast cancer, already get breast cancer. Well, who are those women? They're women before electric light was invented. They're women in parts of the world where there is no electrification. There's still millions of people who don't get electricity in sub-Saharan Africa and so forth, so there's no electric light. And in blind women, which is interesting because you could say well, those parts of the world maybe the healthcare is different and all the rest of it. But blind women in Westernized societies, you know, have less than 50% of the rate of breast cancer, and that's women who are blind before the age of 65. If you go to women who are blind since puberty a smaller group it's likely to be a much bigger effect.

Speaker 2: 49:01

So, basically, the absence of light exposure, electric light exposure in the evenings is highly correlated. And then, of course, we have all the mechanisms. We know that we can duplicate that light exposure suppresses melatonin, that melatonin levels are low. Breast cancer risk is highly correlated to the level of nocturnal melatonin. Total overnight melatonin is a very steep relationship between that and breast cancer risk and as well as diabetes and other things. We've got a whole mechanism there where, as I say, this whole mechanism studied I think the early studies.

Speaker 2: 49:42

What's also interesting is that what are the rates of breast cancer? Well, in the pre-electric era there were about 20 cases per 100,000 women per year. Now in electrified societies it's 110 or more cases and that now is really climbing up per 100,000 women. So that's a fivefold increase. So it's hard to see. You could say what else is going on. Maybe there's something else going on, maybe there's something else in our diets and all the rest of it. But there's a pretty big arrow pointing particularly as blind women say.

Speaker 2: 50:21

I like pointing to the issue that this is light at night is a real carcinogenic effect and it's now been recognized by the World Health Organization. It's recognized by a big study done by the National Toxicology Program of the National Institutes of Health. They did a big study on this, concluding the carcinogenic effects of light at night and breast cancer is well documented. Prostate cancer is also documented and it's related to light exposure, as I say, whether you're working at night or whether you're just sleeping in your bedroom with the lights on, which is an amazingly common occurrence. More than 50% of elderly people do, 30% 40% of younger people tend to sleep with some lights on in the bedroom, and so yeah, the story, I think, is pretty convincing and it's fixable, for heaven's sake, right. This is unlike a lot of environmental pollutants. Try to get rid of PFAS chemicals forever. Chemicals that's a nightmare. This one just changed the damn light bulb. It's pretty simple.

Speaker 1: 51:30

Yes, the piece of evidence with the blind women is particularly compelling because if we were arguing that it were dietary endocrine disrupting contamination, you'd expect in that population that they'd be equally consumed by the blind and the non-blind women. So it is an elegant line of evidence, specifically with regard to prostate cancer, and elegant line of evidence specifically with regard to prostate cancer. And are there any other unique mechanisms or reasons why that prostate cancer might be elevated with artificial light at night?

Speaker 2: 52:07

Well, again, these are hormone-sensitive cancers, you know, first of all. Secondly, by the way, there's a huge body of animal studies on this, in other words, for example, studies with prostate cancers, human prostate cancers implanted onto mice or rats, right. So now you've got the human cells cancer growing on another animal and you can now very systematically look at what the effects of light is. Light, you know, enhances. Light at night accelerates the rate of growth of those tumors. Darkness suppresses the rate of growth.

Speaker 2: 52:45

You can tie it to melatonin, those mechanisms. It's also tied to circadian disruption. It's more than just melatonin, it's the dissociation of the clots of the body and, interestingly, that key medications used to treat breast cancer become less effective when there's light at night. Again, looking at some of the fundamental mechanisms. So you know, the evidence is pretty strong. I think it's something that, however, is just not on the radar For some reason. The cancer epidemiologists, they haven't got that yet. You know, they've got all sorts of other things they look at, but it really needs to get up on the radar of causes of cancer.

Speaker 1: 53:35

Yes, and there's a whole bunch of things that cancer researchers and cancer patient advocacy groups are not focusing on. Artificial light at night obviously, like we've just discussed, is a major one. Processed food, very simple. But accelerating these processes and look, the artificial light at night also makes sense to me as having these carcinogenic effects through insulin resistance and through the metabolic pathways as well, and there's probably more than one mechanistic line of action. What is your perspective on chronic disease in general and artificial light at night? Because, again, if I, if I've, if we, there's a perspective that it's mainly the food that is responsible for what we've observed. But I think there's a very strong case to make that the the arrival of chronic disease in human populations, uh, in the industrialized world, really began with thomas edison in the late 1800s and that really preceded the widespread introduction of, you know, refined foods and seed oils and widespread sugar consumption. So do you have a particular opinion about that hierarchy or maybe artificial light and light being the chief driver of chronic disease?

Speaker 2: 54:50

Well, I think you know what's fascinating is the recent biobank studies. You know, in the UK this was the study, as you know, where 88,000 individuals had meters on them to determine how much light they saw during the daytime, how much sunshine they got. You know, were they outside, were they indoors and at night, were the lights on in the bedroom or not? Because they put light monitors on them. And those 88,000 people that then tracked over eight years, they were in this average age, in the 60s, and the death rates were 30% faster in the people who had lights on in the bedroom at night, for example, the ones who slept in, the people who had lights on in the bedroom at night, for example the ones who slept in the pitch darkness and those with the brightest light in the bedroom. And if you look at the daytime, those who are exposed to daylight and sunshine live longer. It's significantly longer. In fact, the effect for sunshine exposure to daylight is the same order of magnitude as smoking or not smoking in terms of scale Right Now. If that is true, all those people were exposed to the same processed foods. There was nothing to do. It would be nothing distinct about the people who were out and about in the daytime and slept in the dark versus those who were indoors, the food is unlikely to be very different. So I think that shows above everything else and these studies are quite dramatic. They show the rates of hypertension, deaths from heart disease, the rates of cancer, you know are all strongly influenced.

Speaker 2: 56:38

And in fact you know one of the studies on sunlight done by Lindqvist in Sweden, big study. It was a melanoma study. They were concerned getting study from 29,000 Swedish women about melanoma because they're concerned about, you know, that major. It's a fatal cancer of the skin. And they found in that study that, lo and behold, sunlight, the people who they thought were going to die sooner of skin cancers all lived longer overall because of the benefits of sun. And even the melanomas there's some evidence to show they don't go so far when they're exposed to sunlight as fast as when they go to sunlight when they're not. So it's a fascinating study. So yes, there is a concern about sunlight in places like Australia where you see a lot of sun and the incidence of cancer and the ultraviolet light affects on inducing certain types of skin cancers. But the overall effect on lifespan is huge, far outweighs that from all sorts of other disease causes. Types of diseases.

Speaker 1: 57:51

I'm very glad you brought up the UK Biobank, because that cohort has provided so many important insights into the role of light in health, and what comes to mind is Professor Richard Weller, one of your countrymen. He's a dermatologist and investigator of the systemic effects of sunlight on health, and his analysis unequivocally showed that greater UV light exposure and he ascertained that both via latitude and via sun-seeking behaviors and a questionnaire on sun-seeking behaviors was associated with lower all-cause mortality, lower cardiovascular mortality, lower cancer mortality and lower skin cancer mortality, which again is really hammering home the point that you just raised. The other analyses of the UK Biobank have also showed lower all-cause mortality as a function of vitamin D status, which is simply another indicator of light exposure. And now that the study you're referencing is a third way of demonstrating the importance of circadian rhythms and sunlight and natural light in influence on really hard endpoints of all-cause mortality and rate of death.

Speaker 1: 59:04

The Peli-Lincus study, which you mentioned, is one that I have talked about at length, and it is such a fantastic study because, as you say, these investigators were about to have the intention of proving how harmful sun-seeking behavior in UV light was in terms of melanoma death, and they essentially found the complete opposite and, as you've mentioned, it's a large study, very robust, over 20 years, and showed twice the mortality rate in those women who avoided the sunlight. So that's the other facet of this problem, this light story, which is natural sunlight is, and how that risk versus benefit equation for UV light exposure truly is in favor of more sun rather than less. For all these reasons, let's talk a little bit about artificial light, because we previewed it briefly or the problem with LED versus the standard, maybe thermal lighting that used to exist before this non-thermal LED lighting was invented.

Speaker 2: 1:00:17

Well, what matters is the ratio between the amount of blue it's got and the luminosity, in other words the brightness of the light. The standards for lighting are all set around, as we discussed around lux, particularly desktop lux, and so if you wanted standard office lighting, the recommendations is somewhere between 300 and 500 lux on the desktop, for example, is some of the standards that people who design lights use. But the question is to get there. It matters a lot what the spectrum of that light is. So the incandescent light bulb is very much lower in violet and blue than it is in the longer wavelengths. So it's got a lot of orange and red to it, a lot of infrared to it. In fact it's 88% infrared, about 12% visible light. That is what we had Edison's light bulb, and that was the predominant thing. Fluorescent lighting is a different matter. It has spikes at different frequencies and you can make, by the way, white light by different combinations and combinations of colors. You can even make white light using just two or three separate pure colors and put them together and you could create an artificial simulation of light. It's not quite different from natural light. But what we looked at is what percent of the light fell within this circadian critical band between 440 and 495 in the blue and the incandescent light. So candlelight and fire have less than 1% blue of that circadian active blue, minimal effects of the blue Plus. They're pretty dim as compared to electric light. Incandescent light had 4%, so it had more blue in it, but still not so much more. He was really aiming to replace candlelight and gaslight, so that's what he was trying to do get the same look, very little blue. But today's fluorescents and the LEDs have 15%, 20%, sometimes 25% of this circadian blue and so they are much more potent in the evenings of suppressing light, suppressing the circadian system, shifting the circadian system, causing circadian disruption. So one of the things we looked at is how could we create light that had less than 1% and less than 2% blue? Right, so we've brought it down to the amount of blue for firelight and what we realized is by balancing the spectrum. When you do that, when you take out all the violet and all the blue, you end up with a yellow-orange color which is sort of somewhat ugly. Now some people say, well, it's like firelight, but it's nothing you really want to work under. Most of the time it's okay, maybe just before bedtime, but if we add violet, because that was not triggering at all the circadian system, we add violet instead of the blue pump of the LED. And the LEDs are based on a primary color pump, which is a chip which converts electricity to light, and typically it's blue, typically around 450 blue. If we went down to 420 violet, that has very little effect on the circadian system, but we can whiten the light with it. So we could use the violet to bring the color of the light back to an acceptable level but create a dip, an absence of light in the blue part of the spectrum. That was key and we could then get down well below 2%, 1% blue. And so that's what we've been developed. We've got zero blue light bulbs, we've got fixtures now and so forth which do that at night.

Speaker 2: 1:04:15

But you do the converse. You need to do it during the day. You need to enhance that 480, that blue around 480 in particular to give the strongest circadian signal, because we just don't get enough of a strong circadian signal. Normally, living indoors, we're in twilight levels of light. Indoors, as we mentioned, it's 50,000 lux. Outside, 100,000 lux on a bright, sunny beach. Indoors we're living at between 50 and 500 lux, way less light. We're living at between 50 and 500 lux way less light, and you know and so you have to enhance the light, to give blue um, to add to the blue, to make sure you've got a reasonable circadian signal and, of course, much better, to get outside as well. Up a party with mornings um is really the key advice and not just rely on electric light yes, I think that that that needs to be definitely uh point emphasized.

Speaker 1: 1:05:14

And and what I like to tell people is uh, when the sun goes down, no light is the best light, but uh, if you have to work and if you're living, if you're working in a, you know, a coal mine or you're working in a nuclear power plant, then then there has to be workarounds, and what you're describing sounds like a workaround. So I mean, melanopsin has peak absorption. This blue light detector has a peak absorption of around 480 nanometers but can be activated up into the green up to 500. So, as far as I understand you correctly, you really engineered a bulb that prevents as much as possible activation of melanopsin in that peak. Is that correct Exactly?

Speaker 2: 1:05:58

Yeah, the whole idea. You want to activate the melanopsin during the daytime and you need to non-activate it, deactivate it, as it were, during the nighttime. In other words, you're trying to simulate night and dark, or the blue content of daytime versus nighttime.

Speaker 1: 1:06:16

Yeah, and the spectral composition of sunlight, from a photon point of view, is at least 50% infrared. So does your light contain any infrared photons, or is it only a visible-only emitter?

Speaker 2: 1:06:31

It's really a visible-only? I mean, that's an interesting question, because I think what we're really recognizing is that the infrared light and there's more and more evidence about the healing effects and photobiomodulation effects of near-IR, near-infrared light and infrared light, near IR, near infrared light and infrared light, and so we may have lost a lot with banning the electric classic incandescent light bulb, because that provided a lot of that infrared light as well. We couldn't see, we've not in the products that we've developed. Initially. We've not put that in, but I think there's a case to be looking about adding some of the infrared back in.

Speaker 2: 1:07:12

But the problem is, as I say, these regulations which we've just got, a final rule just came out last month in the US which said that every light bulb must have 125 lumens per watt. For a regular light bulb, 125 lumens a watt really is something that really blue pump LEDs are only really designed to do, and so I think that's something where a battle we're fighting over here to try to get the regulations to recognize that light is not just for vision, it's not just an aesthetic thing, and unfortunately the lighting industry for so long has considered light as really aesthetic, functional light for vision as their mission and not healthy light. So it's really changing the paradigm, changing the goal. And you know one of the interesting things, that the US Department of Energy has a definition of what energy efficiency is. They say it's providing the same function using less electricity. Well, that's great, but it's not the same function, right? If you provide light that has no infrared, it doesn't handle the blue content appropriately, and so forth, in order to provide health.

Speaker 1: 1:08:39

Yeah, it's really. We're having a multi-species level extinction event being engineered upon us with these lighting regulations that are so failing to recognise the fundamental lighting influence of light on human but not only human biology, but also on other animals. And it's sad that we're in this situation where the people making the rules and the regulations are so disconnected from the biologists who, like yourself, who are researching these topics. And the irony in my mind is that we're doing this to prevent death from climate change, and that is the stated goal, whereas there's a way, more proximate danger to human health, which is the breast cancer diagnoses, it's the cardiometabolic disease, it's the acute myocardial infarctions that I see when I'm working in the emergency department. I mean, it's really an uh performative example of the law of unintended consequences and how and wrong things can go when we've got such siloing and decision making being made by people who um, really have no idea about um, what is truly um going on here.

Speaker 1: 1:09:48

The infrared light is one very interesting point. I've interviewed Scott Zimmerman, who's an optics engineer. His solution is to run a filament, a tungsten filament, alongside the visible LED at a very low voltage, so that the light is still under any kind of regulation by these regulatory bureaucracies, but still providing some infrared in an optical to non-visible watt ratio. That is much more close to what we need. So it's interesting to see what kind of workarounds are going to be developed in this. But I think it's a it's a critical um nutrient deficiency, which is uh indoor infrared deficiency from from being inside. Do you mind sharing with us some of the effects that your lighting has had in these workplaces, because you've obviously had extensive experience in in in industry, and what has your response been? Or the effect of in removing the blue from the lighting with your products on productivity, on metabolic health, in all these working outcomes of companies that you've consulted for?

Speaker 2: 1:10:58

Yeah, when we first developed the lights and started installing them around 2017, so we've been going at this about seven years we were able then to put circadian lighting, which is blue rich during the day zero blue, effectively very low blue at night, automatically switching, with a control panel so that it would actually control board, with a clock so that it was tuned to the local time zone so as the sun set below the horizon, the clocks inside the building would change to the right, to the nighttime orientation, and vice versa with the sunrise. We installed those lights in 65 Fortune 500 companies, big companies like Dow, chemical, chevron, all sorts of places. We were able to do some studies in those. A very good response. People liked it all. That that was good. It felt better.

Speaker 2: 1:11:57

But we did some studies where we literally, you know, compared outcomes and what was very interesting is that we found and we compared people a year later. So we looked at people before they switched and then after they switched and they, of course, had no recollection what their answers were or their findings were or what they told us before the lights. You know later, with the same questions, we showed the amount of sleep. The duration of sleep was improved both before and after night shifts we found the quality of sleep, the duration of sleep, was improved. Both before and after night shifts we found the quality of sleep was improved. We found gastrointestinal symptoms were reduced, the GI-type symptoms. We found the use of over-the-counter prescriptions, pain medications, went way down.

Speaker 2: 1:12:46

Interestingly, people don't take them if they're feeling well. You know, in general Appetite. We found they were far fewer snacks Half the number of snacks they were eating on the night shift under our circadian items and we found several studies that the rates of errors they were making were reduced. Their performance in these times. These are critical, safety-sensitive places. They're controlling oil refineries, hydroelectric power generation you name it power plants and the rest. So we found their performance went up. Their sleepiness scale during the night shift was improved. So they felt more alert during the night and that's probably because the violet, by the way, is stimulatory in there. It's actually more stimulatory than blue and their sleep was when they went home and slept. Their sleep was longer and better quality. So it was pretty satisfying to see that and, as I say, we've done some significant studies in those populations of people.

Speaker 1: 1:14:00

That's very, very fascinating findings and it's great to hear because these people are performing critical functions that are essential for our society's. You know, ongoing, um, healthy, ongoing use, their critical use. So any and all measures to improve their health is is well, uh, is very well needed. I I am um personally of the opinion that isolated blue without infrared is not necessarily a healthy thing. So I'm a little bit concerned that without the infrared we could be maybe destroying or accelerating the destruction of melanopsin and perhaps also DHA, which is important for photoreception. Have you? I guess the main issue here is the potential of adding back more red and infrared to closely match what is a sunlight spectrum. Do you have any plans to engineer a bulb that more closely represents sunlight and not just that massive melanopic stimulation during the day?

Speaker 2: 1:15:13

Well, it's certainly one of the things on the list of things to think about. I mean, I think the issue really is we've got to do this on a scientific, evidence-based thing. Just replicating what we see in nature doesn't necessarily give us health right, because of course the intensities are way less when we're indoors and so it's not the same thing. You know you could say, well, full spectrum light, should you know, let's use full spectrum light, but if it's 100 or 1000 times less bright than daylight, it's not, it's actually not necessarily helping you. You need it enhanced in certain areas, like in the circadian blue area. So our process at the Scheme Night Research Center is to actually validate in the lab, with people working for a week at a time, controlled situations, and we can actually do really hard, measurable results in tangible measurements. So we measure polysomnography to measure sleep. So we measure polysomnography to measure sleep. We do glucose tolerance tests, we do all sorts of biomedical as well as performance tests in the real world. You've got to adapt to what you can measure realistically in the real world. But again, the whole principle is if you can show an effect, then I think it's valid. So we know that we're doing better than the standard significantly better than the standard conventional LED lights. So that's a step.

Speaker 2: 1:16:39

Can it be improved? Certainly, I think that's very real and that's part of the whole discussion here. I think we're learning a lot more about other parts of the spectrum, like green is actually something that we've involved in pain mitigation. Quite interesting Some evidence now that you can reverse migraines and the like using the green part of the spectrum. So I think we're going to learn more and more about which parts of the spectrum do we need to enhance. But the challenge indoors is you're really limited because you can't make the lights too bright, because you get glare reflections. So therefore you have to do it at a much lower intensity and hence you have to be highly selective as to which spots of the spectrum we're going to use. You can't have it all. Yes, if you want it all, go out and get sunlight.

Speaker 1: 1:17:28

Yes, that's great points. Thank you, martin. That's very interesting and relevant. And if you're operating the controls of a nuclear power plant yes, you can't have a massive glaring bulb in your face can you Do you test for and control for flicker in your lights?

Speaker 2: 1:17:47

Yes, flicker used to be a problem. Now it is really not a problem now. It's really. Most of the lights are really low in flicker. Leds are pretty good on that now, but in the early days it was an issue.

Speaker 1: 1:18:00

Okay, and maybe just to finish up, you can describe your latest book and the educational kind of attempts, the work that you're doing to help raise the profile of this problem.

Speaker 2: 1:18:11

Well, one of the things I realized is there is this big gap and you're really helping fill it with your podcast, but there's a big gap in understanding about this science, and it's not just the science of kini rhythms, it's also the technology of lighting, and it's also the practical advice of okay, where do I find lights?

Speaker 2: 1:18:35

And so I did a on Substack. I've got a blog, another one on psychology today which talks about these issues, but I think it's time to put together a book. So I now have a book which is just coming out within the next month, called the light doctor. It's a book that is really for it, designed for, you know, the average health conscious person, if someone wants to live a healthy life, make good choices. But it also explains the science, explains the sort of things we've been talking about, and also talks about the practical results and the practical advice of species in the outside world that are being affected by our choices of lighting and are being significantly harmed by it. So, anyway, it's the Light Doctor and, as I say, it will be on Amazon shortly.

Speaker 1: 1:19:42

Fantastic. Well, I will include that link in the show notes of the podcast so everyone can find a copy of that book. So thank you very much, Dr Maureen, for spreading this message and for sharing your knowledge with the audience.

Speaker 2: 1:20:00

Good Well, thank you, it's been a pleasure, great conversation. Thanks, Max. Thank you.