Today is the first class of your new four class set (4 of 6). J is a full 4 classes ahead. We will begin class with a causal conversation. We have one piece of material today, an audio story with a transcript. I want you to take the time to listen. You can listen with or without the transcript. Listen to as much as you can.
This is FRESH AIR. I'm Tonya Mosley. If you need an alarm clock to wake up each morning, which most of us do, you are likely suffering from social jet lag. That's a mismatch between your biological clock and your daily schedule. And according to a new book by science journalist Lynne Peeples, drinking coffee or sleeping in on the weekends won't help you get back on track. In her new book, "The Inner Clock: Living In Sync With Our Circadian Rhythms," Peeples gets into the latest science around our circadian rhythms and their importance in our overall health, even beyond the hours of sleep we get each night.
Peeples conducted her own experiment, first by living for 10 days in an underground bunker, 50 feet below ground with no sunlight, watches or clocks, to better understand the rhythms that guide her from day to day. In her book, Peeples digs into the latest research about how our internal clocks impact every facet of our lives - how well we do in school, our performance at work, how we interact with people and even how long we live. There are even studies that link circadian disruption to cancer, depression, dementia and Alzheimer's. Lynne Peeples is an MIT night science journalism fellow. She's also a biostatistician and has conducted HIV clinical trials and environmental health studies. Her writing has appeared in the Guardian, Scientific American and Nature.
Lynne Peeples, welcome to FRESH AIR.
LYNNE PEEPLES: Thanks so much for having me on.
MOSLEY: Let's just start with this experiment that you did. So this self-imposed hideout that you went on, it didn't just shield you from the sunlight. You were without any emitted light, right? That even means your cellphones and your computer. None of those things were available to you to see light and also to see the time.
PEEPLES: Well, to some extent. I did have LED lights in this bunker. So kind of an untraditional, a nontraditional bunker. This was a souped-up former Cold War-era bunker that somebody had purchased and set up as an Airbnb. And so he had LED lights throughout the bunker, which I could tune. And because I had learned that red light is the color that's least likely to affect our circadian rhythms, I set the entire bunker to a dim red light. So I could see. I had some light, but it was nothing like what we experience indoors or especially outdoors. So absolutely no daylight, and then none of those blue wavelengths of light that are known to particularly affect our circadian rhythms.
MOSLEY: What is it that you wanted to understand about your body's rhythm by undergoing this experiment?
PEEPLES: Yeah, I wanted to get a sense of my personal rhythm. So we all tick a little differently, and so I wasn't totally clear on just how my inner clocks ticked. You know, where was I on that spectrum of night owl to early bird? And then just what happens when we throw our clocks out of sync? I knew that, from my research up to that point, that cutting myself off from daylight and from any other cue as to the time on the Earth's 24-hour clock could throw those clocks out of sync with each other and out of sync with the sun. And we all experience that, you know, at least acutely when we travel internationally. We get jet lag, right?
And so I wanted to get a sense both qualitatively, with how I felt, as well as quantitatively what that kind of looked like and how those paired up. So I decked myself out with a whole bunch of different sensors. So I was measuring my temperature of various body parts. I was measuring my heart rate. I had a glucose monitor. You know, I was checking my light exposure as well. And all that data, I had uploaded. But I wasn't looking at it until after the experiment when I had scientists help me kind of tease apart, how were these various clocks in my bodies ticking throughout those 10 days? How did they change? How did they drift both apart from the sun and apart from each other?
MOSLEY: I want to know a little bit more about how you felt over the days when you were down there because there wasn't just a lack of awareness of the time and no sunlight. Some of the stuff in your body started to go haywire, like your ability to regulate your temperature.
PEEPLES: (Laughter) Oh, yeah. About halfway through is when I really started to feel it. And, you know, halfway is very subjective, right? I had no sense of time. I had no clock, access to clocks. But about halfway through, yeah, during the day, I could feel my, you know, temperature rise and fall, like, in seemingly unnatural ways. You know, I was - middle of the day, I'd be, you know, kind of hot and sweaty, and then I'd get cold. I'd feel kind of this brain fog. At certain times, I found myself really clumsy. While I was down there, I was teaching myself to juggle and play harmonica. And this particular day, about, I think, Day 7 or 8, I was just dropping everything and super uncoordinated. And then, yeah, feeling hungry and tired at all hours of the day. So it was pretty clear, based on how I felt, that my clocks weren't quite ticking right.
MOSLEY: Something really interesting in the data that you were able to collect with the researchers is that for a period of time, though, you were pretty close to your schedule above ground. So I'm thinking about, like, when you were eating meals. But there came a time when then things started to almost flip, like, completely upside down.
PEEPLES: Yeah. Yeah, right. I was, well, kind of proud of myself, looking at the data, like, about a day in. I was consistently making guesses of the time into a voice recorder, which I could then, you know, check back later with the actual time. And a day or so in, I was really close. I was living about 24-hour days. But over time, that drift accumulated and jumped a bit. So it was a couple days before the end of the experiment when the data showed that I had completely flipped. I was kind of being silly one night and decided to have breakfast for dinner. I was making blueberry pancakes. And it turns out that while I was eating them at what I thought was, you know, evening time, it was actually the morning. I had completely flipped my clocks at that point (laughter).
MOSLEY: You all assess this data, and what conclusion did you come to?
PEEPLES: Yeah, so the scientists helped me see that these various inner clocks in my body had fallen out of coordination about midway through. So about that same time that I was feeling just really out of whack - you know, uncoordinated and a little loopy and, you know, mood swings - that was when the data showed that my heart rate rhythm and my temperature rhythms were no longer coordinated, and also when I was, yeah, becoming more and more uncoordinated with the sun. So it was fascinating to know that, again, my kind of qualitative or how I was feeling, those notes that I had made could really be linked pretty directly to that data of what was happening inside my body.
MOSLEY: This, of course, was an extreme experiment. I mean, most of us are not going to lock ourselves in a bunker. But I think there is also this thought that circadian rhythms primarily have to do with sleep, so I think maybe it would be a good idea to have you explain just how expansive our circadian rhythms are and how important they are to our overall health.
PEEPLES: Right. For a long time, I too thought - every time I heard circadian rhythms, I just thought sleep-wake, sleep-wake cycle. But in fact, we have trillions of tiny clocks in our bodies, really, when you think about it. Nearly every cell in your body has a clock. And these clocks evolved to coordinate with each other and with the sun to help our bodies be primed to do the right things at the right time. And, sure, one of those things is to go to bed and sleep at the right time and wake at an optimal time, based on our pirouetting planet and the light and dark cycle and what - you know, the times we evolved to be most alert and awake and take advantage of the light of the day. And the circa in circadian means about or around. So that really tells us - so our inner clocks did evolve to be - to tick at around 24 hours, but they are not precise timekeepers. So we need that regular calibration from the environment, from the Earth's 24-hour cycle, to keep them coordinated with each other and with the sun so that they are prime to do those right things at the right times.
And that is - again, so that's sleep-wake, that's also digest food and metabolize food. It's perhaps the time that we're, you know, strongest and fastest to perhaps sprint away from a predator for thinking evolutionarily, or the time that we should be - set up our defenses stronger against invading pathogens. So our body can do all these things at all times across the entire day. So we've sort of evolved with an allocation of resources across the clock.
MOSLEY: You live in Washington State, and in reading about how crucial sunlight is to our health and well-being, I just had to think about - what came to mind for me rather is just the high percentage of seasonal affective disorders and suicides that happen in that state. And it's always been attributed to the lack of sun at certain times of the year. Can you just delve a little bit deeper into how crucial sunlight is to staying in rhythm?
PEEPLES: Yeah, I can speak from experience. I mean, I think a good part of the motivation for me to write this book, I mean, somewhat subconsciously, is having grown up in Washington, growing up with really what I felt was sort of this almost bipolar feeling throughout the year. You know, summer, it's so much light, so long throughout the day. In the wintertime, I mean, your - the hours of daylight are really shrunk down. And I felt that effect. I felt, you know, in the wintertime, just more depressed and down and less alert. And especially going to school. In high school it was before 7:30 that the first bell rang, and so I wouldn't see daylight before I got to school.
And then after school, you know, maybe I'd be a basketball practice and come out in the dark as well. So absolutely, we need daylight. Our clocks and this coordination of our entire physiology really counts on those inputs of light and dark to tell the body that it's day and night and coordinate those activities. And when we don't get daylight, when we don't get those photons to help calibrate those clocks, then things go awry. And that affects your - our mental health and our physical health.
MOSLEY: What I'm also hearing from you is that the time of day that we experience that light is also just as important. So you mentioned going to basketball practice and leaving when it's dark or not getting sunlight until the middle of the day, and that might be too late.
PEEPLES: The science suggests that light across the whole day is crucial, but in particular, morning light. Again, the science is evolving. There's always new data points here that maybe slightly tweak the picture. But it's pretty clear that during the daytime, especially in the early hours, getting daylight will help recalibrate our rhythms. And then throughout the day, the accumulation of that - getting those photons from the full spectrum that the sun offers, in particular, those blue wavelengths of light that we get from the sun will help align our rhythms as well as help making them more robust.
So we create really this kind of stronger amplitude of our rhythms throughout the day, which is also crucial. So yes. And then at night, again, to keep that contrast, to make the body understand that this was day and this is night when we're supposed to wind down for sleep, that's when we need the lights down and, you know, not blasting our overhead lights in our homes, for example, or putting our face in front of screens. So, yeah, it's all about that contrast.
MOSLEY: I'm going to get into that with you because I think so many of us - well, like, I mean, the majority of people nowadays, are so tied to their phones and looking at screens and looking at screens before bed. I mean, how bad is that for us?
PEEPLES: Yeah, it depends who you ask. In general, screens do emit light and a lot of blue light. But it's - sometimes, when we talk about screens, I think we overlook the bigger picture. I mean, if we're sitting in a living room that has super bright LED, overhead lights blasting and, you know, maybe, you know, a floor lamp beaming it down on you too, that is at least equally as important as the screen in front of you. And there's also tools now with our iPhones and our computer screens to kind of suck out some of that blue light so that it's not quite as - doesn't have quite the same effect on our circadian rhythms, as well as to dim it. So I think there are tools to use.
You know, I think, in general, there's probably a good rule of thumb to try to tone down our use of screens at night, but there's a balance to be had as well. I think it's not necessarily that we need to completely cut them out, but then a few hours of bed, trying to trim down how much of those photons, particularly blue ones that are making their way into our eyes.
MOSLEY: So I guess it's really bad if you're waking up in the middle of the night for you to grab your phone to help you go back to sleep. Like, that's probably doing the opposite.
PEEPLES: Yes. Or walking...
MOSLEY: Asking for a friend.
PEEPLES: (Laughter) Or walking to the bathroom and flipping on the lights. That's another huge one...
MOSLEY: Yeah.
PEEPLES: ...'Cause our body is not anticipating that light at night, so it has a super-powerful effect on our circadian rhythms and our alertness. So it makes it a lot harder to go back to sleep. So I have now - I put a night light in my bathroom that is dimmable and very warm colored, so I will not be flipping on that light at night anymore. Yeah.
MOSLEY: If you're just joining us, my guest is scientific journalist and author Lynne Peeples. We're talking about her new book, "The Inner Clock: Living In Sync With Our Circadian Rhythms." We'll continue our conversation after a short break. This is FRESH AIR.
(SOUNDBITE OF THE MOUNTAIN GOATS SONG, "PEACOCKS")
MOSLEY: This is FRESH AIR. And today we're talking with author and scientific journalist Lynne Peeples about her new book, "The Inner Clock," about living in sync with our circadian rhythms, the internal clock in our bodies that control our behavior and mental and physical states. As part of her research for her book, Peeples spent 10 days in an underground bunker without access to natural light or time cues. Her internal clock became desynchronized during isolation.
You conducted another experiment that was kind of the opposite of the light deprivation where you soaked up the summer sun in Alaska. What are some of the things you found from other researchers about the impacts of a place like Alaska, where people experience those heavy differences and swings in light during the summer and darkness during the winter?
PEEPLES: Yeah. On my way, actually, to Denali for this trip, I stopped in Fairbanks to meet with a sleep doctor there. I mean, he was telling me stories about his patients and how he'd have an increase in patients during certain times of year, particularly during these transition times, 'cause as the days rapidly shorten or rapidly lengthen, he was finding a lot of patients coming in with physical and mental issues and lots of struggles with sleep, obviously. And he thinks that's - you know, it's really confusing our clocks.
As those days shorten a lot more rapidly than, say, where we evolved at the equator, where we had 12 hours of light and 12 hours of dark. That just throws the body off. And there's been research that shows that in some of these high northern latitudes, there are certain populations of people who maybe migrated there at earlier points in history. And so their genetics may have evolved a bit more to compensate and to adapt to that changing light environment. And they might be less prone to things like SAD during the winter, for example.
But in Alaska, you know, we have this diverse population, and, you know, he's finding that definitely, overall, we've got increased rates of these things. Also, you know, schools there - the kids supremely affected by those short days in the winter where they're going to school in the dark and leaving in the dark. And that might be one of the links between lower graduation rates in Alaska.
MOSLEY: You know, to a lesser extent, this is reminding me of daylight saving time...
PEEPLES: Yeah.
MOSLEY: ...And the difference - the changes to our bodies when it happens. What is the impact of daylight saving time? We've been seeing more research about it, and we know - 'cause we can feel it. You know, so many of us feel the differences when we have to move our clocks backward or forward.
PEEPLES: Yeah. It's twofold. So when we spring forward or fall back, we are giving ourselves a dose of jet leg. But we're also - you, know, we're keeping -we're locking the clock there. So when we spring forward, we're essentially stealing an hour of light from the morning, which is when we really want the light, right? And we're tagging that on to the end of the day when we - our bodies really are looking for the dark. And it's throwing us out of alignment from the sun.
So the sun - I mean, before we had any kind of standard time around the world, locally, the sun was generally at the highest point of overhead at noon, right? If we shift that with daylight saving time, we're throwing that off. Yeah. We're throwing our bodies out of alignment from the sun and those cues that, again, were kind telling our bodies what to do when - those messages are getting mixed up.
And so there's some pretty creative research out there that has taken data from opposite sides of a time zone. So if you look at the U.S. and can kind of take folks that live on the western edge of a time zone and compare them to people who live on the eastern edge of a time zone and control for various factors, socioeconomic factors, for example - and scientists have found that as you move from east to west - east being where the sun comes up earlier, west being where it comes up later - there are increasing rates of things like cancer, car accidents. Wages decrease as you move from east to west. So really fascinating - it's kind of this natural experiment - right? - that we're constantly living based on our time zones. And so that's one way we might look at how daylight saving time could be affecting us overall.
So again, we need light in the morning. We need darkness at night. And the popularity of daylight saving time is making it difficult to kind of - to get that message out. The scientists are really pushing policy towards considering permanent standard time, which, again, will keep us more in alignment with the sun. But most people - I'm guilty of this too - have equated daylight saving time with those long days of summer. But there's really no way we can - we can't affect how many hours of daylight we have - right? - whether that's summer or winter. So it's just that allocation of the hour that we're really talking about.
MOSLEY: Our guest today is author and science journalist Lynne Peeples. We'll be right back after a short break. I'm Tonya Mosley, and this is FRESH AIR.
(SOUNDBITE OF SONG, "YOU ARE MY SUNSHINE")
RAY CHARLES: (Singing) Whoa, you are my sunshine, oh, my only sunshine. Oh, look how you make me happy sometimes when my skies are gray. You'll never, never, never, never know, dear, how much I love you. Whoa, I don't want you to take my sunshine away.
MOSLEY: This is FRESH AIR. I'm Tonya Mosley, and my guest is scientific journalist and author Lynne Peeples. We're talking about her new book, "The Inner Clock," which is about living in sync with our circadian rhythms, which is the pattern your body follows based on a 24-hour day cycle. Peeples is an MIT night science journalism fellow and biostatistician. As part of her research for the book, Peeples spent 10 days in an underground bunker without access to natural light or time cues, and her internal clock became desynchronized during isolation.
Can you explain more of how chronotypes - what they are and how they work in conjunction with circadian rhythms?
PEEPLES: As I've mentioned, we all tick a little differently. Those inner clocks in our bodies that tick at around 24 hours, for some of us, that means that they take a little longer than 24 hours, and for some, they're faster, and it's a little under 24 hours to do its full circuit, so to speak. So because of that, there's times a day that we have a greater predilection for certain things. And if we think about sleep-wake, that's where I think most of us experience these differences.
So there's some of us that if we have a shorter circadian rhythm, we might more likely be early birds. It's easier for us to go to sleep early at night and we might wake early. And on the other end of the spectrum, there's the extreme night owls, where they may be at their peak late and be awake and alert into the night and then wanting to sleep in late in the morning. So it's both the speed at which our clocks tick as well as this alignment with light. So scientists are trying to understand that more now, but how our body responds to light is also affecting how these clocks align with a 24-hour day. But there's not just early birds and night owls - there's a full spectrum that goes to pretty great extremes. Different genetics can predispose some people to truly function better overnight than during the day.
MOSLEY: Right. You talked to several people. I mean, there are actually seven chronotypes, right? There's several.
PEEPLES: Right. There's a normal curve, a continuous distribution, really, of chronotypes. Really, we're all a little differently - just like the size of our feet, for example, or our height. There's a full spectrum. But we can kind of put people in buckets, as some scientists have done, to try to look at the differences.
MOSLEY: I'm thinking about how it evolves with age. Teenagers need more sleep. They typically sleep later in the day. But then, you know, I have seen senior citizens who then, it seems like their clock is completely turned upside-down with age.
PEEPLES: Yeah. So our circadian rhythms do differ. Chronotypes do differ across our lifespan. So when we're first born, as parents can attest, we don't really have a lot of rhythm. We're kind of eating and sleeping throughout the day and night. And then as we get a little older, young kids tend to be early risers. And that quickly changes when we reach adolescence. So at that point, early teen years, our rhythms start to drift later. So it can be as much as two or three hours. Now, you know, a kid that used to rise and be alert and ready to go at 6 a.m. Now it might be more like 9 a.m. And, of course, that means it's harder for these kids to go to sleep at night.
And then as we get older, it kind of balances out a little bit. And then in our older years, on average, we tend to be maybe slightly early risers. But even perhaps more important as the scientists are finding, as we get older, our circadan rhythms get blunted. They get weaker. So we do not have as profound of, like, a rise and fall in our rhythms, and that manifests in a weaker sleep-wake cycle. So we might be more prone to napping during the day.
You know, you think about the grandparent sitting in the chair and a falling asleep during the day, and then maybe struggling to sleep at night. That is always partially due to the circadian rhythm being weakened as we get older. But because we're understanding that, we're also understanding how to potentially strengthen those rhythms in part through things like getting that extra contrast of light and dark throughout the day.
MOSLEY: The time we eat seems to be so important. I mean, I think we've all heard that eating late at night is bad, but something that shocked me in your book is that scientists are finding that saving your heaviest meal for the evening like dinnertime is actually really bad for your circadian rhythms.
PEEPLES: Yeah. We're doing it backwards in the Western world. Yeah. The science suggests that it's late morning early afternoon when our bodies tend to be most ready to handle those incoming calories. And late at night, things start shutting down. Our insulin levels drop. Our other hormones that our bodies release to help handle incoming calories and metabolize and break down fat - those things - those are weaker.
And this is why scientists are suggesting we really should be eating in a narrower window of time and earlier in the day. One scientist talked about a sweet spot of, like, 10 hours during the day. If we can do that, if you can eat from say, you know, 10 a.m. or 9 a.m. to 7 p.m., that is really ideal to help strengthen your circadian rhythms and potentially, based on some research that's coming out, that may improve your long-term health, your longevity, decrease your risks of developing chronic disease.
MOSLEY: There's so much research that shows working overnight can lessen your life expectancy, and it seems to impact women more than men. Why is that?
PEEPLES: Right. For the majority of us that are not extreme night owls, working at night is going contrary to what our body is primed to do. We're telling our body we need to be alert and awake and probably, you know, digesting food and doing all these things throughout the night when those parts of our physiology are essentially shut down. They're not ready for that. So it's perhaps not a surprise - and scientists now have data to back this up, but that is throwing off our metabolism, which then drives up rates of obesity and diabetes. And having that - those cues chronically coming in at the wrong times of day, at night versus daytime for most of us, just over the long term, it's the subtle kind of constant destruction that it's doing to our rhythms and our physiology that's counting on those rhythms to do it's job.
MOSLEY: Can we hack our bodies in some way? Can we - I'm just thinking about those fake sunlight lamps. I think they're called sad lights. Many people who work overnight use them to mimic the sun. If they're able to mimic the sun during their night hours and then have blackout lights during the day and sleep all day, I mean, does that work? What has the science found?
PEEPLES: Yeah. As we're understanding the impacts, we are understanding better what kinds of strategies shift workers could use to mitigate the impacts. And indeed, I mean, a lot depends on what kind of shift the worker is doing and if they're trying to, you know, flip-flop - let's say they're doing a night shift for three days and then they want to live on the same hours that their family does, for example, and so they flip to daytime. That's going to be a little different than somebody who's able to, say, shift their schedule seven days a week to night hours. And in that case, a strategy for, say, submariners or people who are working in isolation where that's possible is to do, as you said, you know, try to trick your body into thinking nighttime is daytime and that daytime is nighttime. And you could do that with some lights now that have the potential to be really bright and really blue, a little more closer to mimicking the sun. And then, yeah, use blackout blinds while you're sleeping to create the illusion that it's nighttime.
Really, new research is pointing to the idea that even if you're working at night, you could try to consolidate the hours you're eating still to daylight hours because, again, I think a lot of the science is suggesting the consequences of shift work is due to that effect on our metabolism. So if you can eliminate that factor, if you can still try to eat - you know, maybe it's right before you go into work, it's, like, maybe still light out in the evening, you eat your meal, go to work and then try to hold off on eating again till you get out of work next day.
MOSLEY: Are our bodies resilient? Meaning that if you've worked for years and years on a night shift, and then - you've done all of this damage. Your circadian rhythm is out of whack, and then now you're back with the living, can you get that time back on the damage that you've done to your body?
PEEPLES: I mean, I think - I don't know that there's any answers on that yet. I think for everybody, it absolutely makes sense to do the best you can in your current situation. So by working to keep robust circadian rhythms when you're back among the living, as you said, it certainly helps trying to get things back in alignment and keep it that way for the long term. 'Cause I did talk to one submariner who had a lot of trouble after doing some crazy shifts on a submarine underwater for years. You know, he continued to have struggles with sleep. But he was trying to implement some more of these ideas of accessing those circadian cues to get his rhythms back in alignment. And that is definitely possible.
MOSLEY: Our guest today is author and science journalist Lynne Peeples. We'll be right back after a short break. This is FRESH AIR.
(SOUNDBITE OF MUSIC)
MOSLEY: This is FRESH AIR. And today we're talking with author and scientific journalist Lynne Peeples about her new book, "The Inner Clock," about living in sync with our circadian rhythms, the internal clock in our bodies that control our behavior and mental and physical states.
You write about how hormones impact so much of our circadian rhythms. So what do we see in men versus women?
PEEPLES: Right. So men on average, until about midlife, lean a little later. There's going to be a higher percentage of night owls among men than women. But as women's levels of estrogen drop, as they near menopause, for example, then their rhythms are shifting. The estrogen actually helps keep rhythms more robust and perhaps lean a little earlier. But as that estrogen is lost, their rhythms become a little closer to men's rhythms. So there is that kind of shift over the course of our lives where there is a bit of a split, but perhaps we come together, maybe go to bed at closer to the same times at night.
MOSLEY: I mean, any woman who has gone through menopause knows that for so many, there's this bewitching hour when sleep eludes. I think I've been reading research about how 3 to 5 a.m. is, like, a really important time for REM sleep, but it's also where it's the biggest disruption for menopausal women in their sleep cycle. Is that something that humans - just women have to live with, or is there a way through our understanding of our circadian rhythms that we can get that REM sleep that we need during that time period in our lives?
PEEPLES: Yeah. It's a really interesting question. And I did talk to one researcher who was really keyed in on the impacts of estrogen, menopause, and how things like the time-restricted eating could help. So we know that once a woman reaches menopause, those estrogen levels drop. We find that that's when chronic diseases start to rise. So she's wondering if one of the mechanisms by which that's happening is through this dampening of her circadian rhythms.
So if that's the case, then if we're able to have that woman, you know, eating in a constricted period of time, getting light early in the day, darkness at night, feeding her those cues to help try to make up a little bit further lost estrogen and try to help strengthen her rhythms, could that potentially improve her health long term and reduce the risks of these chronic diseases? I mean, it's an open question. The science gives pretty good rationale for that potentially being true, but the data will be forthcoming, probably in the next few years, to see how that actually plays out.
MOSLEY: Lynne, you write about scientists at the University of Pittsburgh who found many of the rhythms that are dominant in most humans were missing or altered in the brains of patients with schizophrenia. And that just made me wonder. It's so fascinating, that research. Is there a correlation between some mental health disorders and the differences in rhythms?
PEEPLES: Yeah. There's really fascinating research coming out suggesting that very well might be the case. In fact, it might be the case that certain drugs that are used for mental health disorders, like schizophrenia and depression, might actually work by affecting the circadian clock. And scientists are finding that night owls and patients with weak circadian rhythms tend to actually respond poorly to, for example, lithium.
And he's also finding - or he's thinking one reason for that is that lithium lengthens and strengthens circadian rhythms. For those that respond well, that's what's happening, and that could potentially explain the benefit for lithium to some patients and the fact that it really doesn't work for other patients. And so this kind of line of research, thinking about this for various treatments, as well as the idea that focusing directly on helping a patient's circadian rhythms, again, through these techniques, we're talking about, you know, getting more light during the day, darkness at night, eating patterns and such. That could potentially be a strong treatment itself.
And then the idea comes up that, you know, this vicious spiral that happens with a lot of mental health disorders where, you know, somebody is depressed, for example, and they're indoors during the day. Well, on average, we all spend a majority of our days indoors, at least 90%. But being indoors and missing that morning light then sets them up to more likely stay awake later at night. And then that's going to, you know, set them up to sleep in the next day, and overall, that's going to weaken their rhythms. And if there's a link between that and the disorder itself, you know, it creates this snowball effect that some of the science is pointing to potentially a way out.
MOSLEY: What is the connection between circadian rhythms and things like cancer and Alzheimer's?
PEEPLES: Right. So there is mounting data that is finding correlations between circadian disruption, as well as exposure to light at night, and cancer. The jury is still out on really, you know, directly linking the two. But the science is pretty clear that as we disrupt our rhythms and we disrupt our immune system and, again, our ability to metabolize food at the right times of day and all these things, it's not a shock to scientists that there could be ramifications for how that could propel the development of cancer and heart disease, other cardiometabolic disorders and then, in the long-term, potentially dementia. The hypothesis at this point is it's probably bidirectional when we think about that, because we know that a patient with dementia, the part of the brain that's affected by that is also affecting the circadian clock.
But we also have evidence to suggest that a disrupted circadian clock potentially could lead to an increased rate of development of neurodegeneration. So they think it could be going in both directions and leading to this spiral that, unfortunately, some people reach in those latter decades of life. But again, it's also pointing to if we understand that, maybe that could help us find new treatments or, again, help certain people, you know, as we get older try to access more of those cues, more of that circadian hygiene that helps their rhythms stay robust. And could that, again, delay the onset of these diseases? Or if somebody has that disease, could having those stronger rhythms alleviate some of the symptoms and slow down the progression of that disease? These are open questions, but a lot of promising research that's suggesting that there is a lot of potential here.
MOSLEY: Lynne Peeples, this was such a fascinating conversation. Thank you so much.
PEEPLES: Thank you so much.
MOSLEY: Lynne Peeples' new book is "The Inner Clock: Living In Sync With Our Circadian Rhythms." Coming up, TV critic David Bianculli reviews two new comedy series, one about a woman whose ex-boyfriends begin dying off and another about a military colonel who's forced to take command from his estranged daughter. This is FRESH AIR.