The Science of Sleep

Summary

Podcast Summary: "The Science of Sleep" – All Of It with Alison Stewart

Introduction

In the March 10, 2025 episode of All Of It, host Alison Stewart delves into the intricate world of sleep, exploring how our sleep patterns are influenced by both biological factors and modern-day societal changes. This episode features science journalist Lynn Peoples, author of The Inner Living With Our Circadian Rhythms, who provides expert insights into the science behind sleep, the impact of circadian rhythms, and practical hacks to enhance sleep quality.

Understanding Circadian Rhythms

Alison Stewart opens the discussion by highlighting the disruption caused by Daylight Saving Time (DST), prompting the episode's focus on sleep. She introduces Lynn Peoples, who begins by explaining how DST affects our internal clocks.

Lynn Peoples [03:19]: "When we switch to daylight saving time, we are essentially stealing an hour and tacking that on to the night. Our circadian rhythms evolved with bright days and dark nights, which our bodies rely on to keep our clocks ticking."

Peoples elaborates on circadian rhythms, emphasizing their pervasive influence on various bodily functions beyond sleep, including the immune system and muscle strength.

Lynn Peoples [03:57]: "Circadian rhythms are trillions of clocks ticking in nearly every cell of your body, helping your body anticipate environmental changes and set you up to do the right things at the right times."

Impact of Daylight Saving Time and Modern Lifestyles

The conversation shifts to the effects of DST and modern lifestyles on sleep quality. Peoples explains how the shift in light exposure can disrupt sleep patterns by altering the natural cues our bodies depend on.

Lynn Peoples [03:53]: "Losing that morning light and gaining more light at night can impact our sleep, making us stay up later or disrupting our ability to fall asleep."

Chronotypes: Early Birds vs. Night Owls

A significant portion of the episode discusses chronotypes—a person's natural inclination toward being an early riser or a night owl. Peoples highlights the genetic basis of chronotypes and how behaviors and environments can exacerbate or mitigate these natural tendencies.

Lynn Peoples [06:07]: "We are born ticking a little differently, you and I. There's a very strong genetic component to being an early bird versus a night owl."

Listener Participation and Sleep Hacks

Alison encourages listener interaction, inviting them to share their sleep challenges and solutions. Several listener tips are shared, such as using audiobooks to fall asleep and white noise apps to mask urban sounds.

Listener [09:14]: "I listen to an audiobook with earbuds. I find that if I get out of my own head and to-do lists, I will go to sleep within half an hour."

Peoples responds by discussing the effectiveness of white noise in urban environments, noting that our ancestors did not evolve with the constant background noise of modern cities.

Lynn Peoples [09:33]: "People in New York City are living with a lot of background noise. Trying to mute that out with natural sounds makes sense."

Long-term Effects of Sleep Disruption

The discussion then turns to the mental and physical consequences of disrupted circadian rhythms. Peoples explains how misaligned sleep schedules can impair cognitive functions, mood, and overall health.

Lynn Peoples [09:48]: "Throwing your circadian rhythm off can shift the timing of when you're at your best, dampen your rhythms, and reduce the quality of your sleep, affecting both your performance and happiness."

Historical Perspective: Biphasic Sleep

A listener named Nicole raises an interesting point about historical sleep patterns, referencing the novel Harlem Shuffle, which suggests that ancestors practiced biphasic sleep—sleeping in two phases with a wakeful period in between. Peoples acknowledges the historical context but notes that modern science generally supports consolidated sleep.

Lynn Peoples [11:31]: "The majority of the science now suggests consolidating our sleep to those seven to nine hours is best for our physiology."

The Role of Light in Sleep Regulation

Peoples underscores the importance of natural light exposure in maintaining healthy sleep schedules. She advises getting at least 20 minutes of morning sunlight and minimizing blue light exposure in the evenings to support the body's natural rhythms.

Lynn Peoples [12:23]: "Morning light is really key to helping recalibrate our clocks. Daylight is what we evolved with; it's brighter and has more blue wavelengths, which our indoor lighting doesn't compare to."

Handling External Sleep Disruptions

When Andrew from Ridgewood, Queens, shares his struggle with noisy neighbors disrupting his sleep, Peoples empathizes and offers practical advice, though she acknowledges the difficulty in finding easy solutions beyond earplugs and white noise machines.

Lynn Peoples [14:00]: "Beyond earplugs and white noise machines, it's tough. I wish I had an easy answer other than talking to your neighbor and asking them to reconsider their noise."

Technology and Sleep

The impact of modern technology, particularly blue light from smartphones and TVs, on sleep is explored. Peoples explains how blue light interferes with melatonin production, making it harder to fall asleep.

Lynn Peoples [14:43]: "Blue light from devices tells our bodies it's daytime, delaying the rise of melatonin that helps us fall asleep."

She recommends using apps that dim screens or blue light-blocking glasses to mitigate these effects.

Diet and Circadian Rhythms

Listener Pam expresses concern about shifting work hours and the potential clash with her natural circadian rhythm. Peoples discusses the emerging research on time-restricted eating, suggesting that eating meals earlier in the day can support circadian alignment.

Lynn Peoples [18:01]: "Time-restricted eating, similar to intermittent fasting, involves consolidating your eating hours during daylight and stopping calorie intake a few hours before bedtime to enhance sleep quality."

Additional Sleep Tips

Annette from Brooklyn shares her use of weighted eye masks to improve sleep consistency, prompting a brief discussion on their effectiveness. While Peoples hasn't researched this specific tool, she does endorse weighted blankets as beneficial.

Lynn Peoples [21:54]: "I use a weighted blanket. For the record, I find that helpful."

Conclusion and Final Tips

As the episode wraps up, Peoples reiterates the importance of aligning daily behaviors with natural light cycles—"brightening your days, darkening your nights." She emphasizes that even with societal constraints like DST, intentional efforts can significantly improve sleep quality.

Lynn Peoples [21:54]: "Brightening your days, darkening your nights, and making a little extra effort can help your sleep."

Key Takeaways

• Circadian Rhythms: Our internal clocks regulate not just sleep but various bodily functions. Disruptions, such as DST, can have significant impacts.

• Chronotypes: Genetic predispositions influence whether we're natural "early birds" or "night owls," but environmental factors can modify these tendencies.

• Sleep Hacks: Exposure to morning light, minimizing evening blue light, using white noise, and adjusting meal times are effective strategies to enhance sleep quality.

• Modern Challenges: Urban noise and technology pose unique challenges to maintaining healthy sleep patterns, requiring targeted solutions like sound masking and blue light filters.

• Historical Sleep Patterns: While historical biphasic sleep existed, modern science supports consolidated sleep for optimal health.

This episode of All Of It provides a comprehensive exploration of the science of sleep, offering listeners actionable advice to improve their sleep hygiene amidst the complexities of modern life.

Transcript

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[WNYC Studios]

Listener Supported WNYC Studios.

[Alison Stewart]

This is all of it. I'm Alison Stewart live from the WNYC studios in soho. Thank you for spending part of your day with us. Coming up on the show today, it has been five years since the COVID pandemic hit New York City and our area, and all week long we'll be taking a look at how it has changed the way we work. Later in the show today, we'll be kicking it off with you. We want to know where you were both physically and mentally five years ago. This week we'll also continue our conversation with women who work behind the scenes in music. Producer Lauren Christie joins us to talk about her experiences. And we'll speak with Joshua Mealy. He is a MacArthur Genius Fellow and an inventor. And his new memoir is titled Connecting Dots. A Blind Man's Life. That's the plan. So let's get this started with a conversation about how to get a good night's sleep. Daylight savings is here. Did your body feel the effects of springing ahead an hour? Was getting up this morning a little tough? Well, for today's installment of our series what the Hack, we're focusing on getting good sleep. Our next guest, science journalist Lynn Peoples, has a lot of experience in that area. In fact, she even conducted an experiment to better understand her internal clock by depriving herself of light in a Cold war error bunker 50ft below ground. She also explored emerging science about chronotypes. That's a person's natural tendency to wake and sleep, about the outcomes of sleep deprivation on our physical and mental health and the differences in circadian rhythms for people of different ages and gender. The book is titled the Inner Living With Our Circadian Rhythm. Science journalist Lynn Peoples joins me now for our what the Hack Sleep Edition. Hi, Lynn.

[Lynn Peoples]

Hi.

[Alison Stewart]

Good morning, listeners. We'd like for you to participate in this conversation. Are you finding it tough to sleep at night? What have you done? Have you turned off your phone? Do you use a weighted blanket? Give us a call or text. 2124-3396-9221-2433-WNYC or hit us up on social media. We want to know your sleeping hacks. Do you find yourself taking naps during the day or do you work the late shift? How are you able to keep your sleep schedule intact? 212-433. WNYC 212-433-9692. Lynn, how do man made adjustments such as daylight savings? How does it affect our inner clock?

[Lynn Peoples]

Right, so when we switch to daylight saving time, we are essentially stealing an hour and tacking that on to the night. Whereas our circadian rhythms we evolved with bright days and dark nights. That is what our body is counting on for those cues to keep our clocks ticking. Right. So that can throw us off as we can lose that morning light we need and gain more light at night, which can impact our sleep and help or make us stay up essentially later.

[Alison Stewart]

Yeah. Just so we understand, could you give us just a clear definition of circadian rhythm?

[Lynn Peoples]

Right, so it's really plural. We've got clocks ticking in nearly every cell of your body. So that's trillions of clocks. And these are helping our body anticipate changes in the environment and setting us up to do the right things at the right times. And that goes beyond sleep. That includes our immune system, that includes our muscles. There's certain times a day that you're stronger, that affects your cognition. There's certain times a day that you're more alert. So all these things ebb and flow throughout the day in a rhythm.

[Listener]

A lot of people have heard that.

[Alison Stewart]

You need somewhere between eight and nine hours to feel well rested. Eight or nine hours of sleep, I.

[Listener]

Should say, to feel well rested.

[Alison Stewart]

Where does this idea of a full.

[Listener]

Night'S rest come from?

[Lynn Peoples]

Yeah, so this is, it's really personal. So there's a lot of nuance here. So, yeah, you know, we hear maybe seven to nine hours is what we need. That amount of sleep changes a little bit throughout our light, our life, as far as how much we need. But it's also very personal. Some people get by on a little less sleep or a little more sleep. And it also has a lot to do with the timing of that sleep. So it's not just how much sleep you get, but it's when you get those hours of sleep that can have at least as much impact on the quality of that sleep.

[Listener]

So when is the impact the best?

[Lynn Peoples]

Good question. So again, that's personal. So as you alluded to earlier, we all have a different chronotype, and that's essentially how our clocks are ticking and how we orient with the light dark cycle on our planet. So for some people, those optimal hours of sleep are a little earlier in the night. For other people, they're a little later. And this is where it really, you know, this daylight saving time and these other things that modern society does to impact when we're able to sleep, including no early start times for schools or workplaces, that can throw us off from sleeping at the optimal times, which is going to reduce the quality of your sleep, even if you attempt to get just, you know, the optimal number of hours.

[Listener]

So that example of someone saying, oh, I'm a night owl or I'm an early bird, that is individual. That is about each of us having our own chronotype.

[Lynn Peoples]

Exactly. So we are born ticking a little differently, you and I. So there's a very strong genetic component to that. Early bird versus night owl versus anything in between. There is also our behavior in our environment can impact that. So for a night owl, they can exacerbate their night owl nests, for example, by staying up later and seeing more light late at night, which is, you know, what daylight saving time does. It can, you know, add a little more challenge to a night owl who is forced to get up early, intends to stay up later. That light later in the day is going to potentially keep them up even later and potentially help them or force them to miss morning light, which is, which is necessary to kind of rein in their clocks a little closer to the 24 hour day.

[Listener]

I'm curious if our sleep patterns can be altered. Like I usually get up at 5am that was when I get up, I like it. I'm the morning person. But you know, I wanted to get up a little closer to 6am this morning according to the clock. So do our bodies change according to the culture?

[Lynn Peoples]

I guess so. We have, we have wiggle room in our clocks. So, you know, this the power of our behavior in our environment to tweak how we tick and how we coordinate with the, the sun cycles. We have a little power in that regard. However, you know, we do. We are programmed in a certain way that there's kind of only so much give that they have to keep us ticking. Right. So yeah, I think there is. By getting more light in the morning, for example. And other things I talk about in the book, such as when you eat, those things have power to help you kind of pull a little closer to maybe the schedule that you're forced to live by.

[Alison Stewart]

We're discussing a few hacks for getting a good night's sleep with science journalist Lynn Peoples, who recently published the book the Inner Living in Sync with Our Circadian Rhythms. We love your particip. This conversation Are you finding it tough to sleep at night? What have you tried that worked for you? 2124-3396-9221-2433 wnyc or hit us up on social media. LLNYC. Do you find yourself taking naps during the day? Do you work the late shift? How do you keep your sleep schedule intact? Call in and share your thoughts. Give us a call. 212-433-9692. We got a text here that says, I listen to an audiobook with earbuds. I find that if get out of my own head and to do lists, I will go to sleep within a half an hour. Also, I look forward to my bedtime story. Thanks for that text. Another one says I use a white noise app and play rain sounds. I can't sleep without it. I'm curious about that. What is it about the white noise?

[Lynn Peoples]

That's a good question. I'll be honest, it's not something I looked into for the book, but absolutely. I mean, most of us, or a good number of us, especially there in New York City are living with a lot of background noise. You know, we just didn't evolve with sirens going down the street.

[Alison Stewart]

Right.

[Lynn Peoples]

And honks. So trying to, trying to mute that out and cover it up with some much more natural sounds. It makes sense.

[Alison Stewart]

How could throwing your circadian rhythm off potentially affect your mental and your physical.

[Listener]

Health short term and long term?

[Lynn Peoples]

Yeah, acutely. Like I noted earlier, we, we evolved with these kind of ebbs and flows in various aspects of our physiology. And that includes our brains, and that includes our cognition, our focus. Those things change throughout the day. So if your circadian rhythms are thrown off, that can do a couple things that can shift the timing of when you're at your best. And it could also dampen those rhythms when our clocks fall out of sync with each other and with the sun, that can just dampen our rhythm. And then you're, you know, your peak slower, essentially you're not able to get that optimal, you know, mental clarity or functioning. So, and that goes, you know, that mood is the same thing here we got. There's threats to both our ability to perform produce and also our happiness is at risk if we throw off our rhythms.

[Listener]

Let's take a call. This is Nicole, who's calling in from Pelham. Hi, Nicole, thank you so much for calling all of it.

[Nicole]

Hi, I have a question. I read a book recently called Harlem Shuffle. I don't know if anybody read it. It's a novel. And he, like, he the main character in the book would go to sleep and then wake up at like 10 or 11 and like, you know, kind of plot and do whatever his crimes were going to be. And the book talked about how historically our ancestors would go to sleep and then wake up for a few hours and then go back to sleep.

[Lynn Peoples]

Sleep.

[Nicole]

So I'm wondering if there's any truth to that and if so, how. When did we change from that to, you know, just going to bed and staying asleep for seven or eight hours?

[Listener]

Thanks so much for calling, Nicole. Had you heard of that, Lynn?

[Lynn Peoples]

Yes, it's really fascinating history. So that's this biphasic sleep idea. And there's been some scientists who've looked into that. It seems from, you know, the majority of scientists I talked to that that was sort of culturally based and potentially fit the times. Maybe there were more risks the middle of the night that you had to prepare for. Maybe things weren't as comfortable. But the majority of the science now suggests consolidating our sleep to those seven to nine hours is best for our physiology. Again, that doesn't mean that everybody fits that pattern. Right. There might be variations on that norm.

[Alison Stewart]

Let's talk about some sleep hacks you've researched. The importance of light in helping you sleep. What role does. Let's talk about natural light help us in maintaining our sleep schedule?

[Lynn Peoples]

Yeah, that is so crucial. So again, we evolved with these bright days and dark nights. And morning light in particular is really key to helping recalibrate our clocks that want to naturally drift a little bit. Depending on your chronotype, they might drift a little later throughout the day. But if you can get morning light, it kind of pulls them back. And that's going to help you fall asleep earlier at night. And daylight is the best. It's what we evolved with. It's natural, it's brighter, it's got more of those blue wavelengths. Our indoor lighting just doesn't compare. So this is why it's really key to get outside, get at least, you know, maybe 20 minutes of daylight in the morning. And if you can, supplement your indoor lighting with as much bright blue wavelength light as you possibly can. Better yet, get by a window as much as you can during the day.

[Alison Stewart]

Let's take a call from Andrew in Ridgewood, Queens. Hi, Andrew, thank you so much for calling, all of it. You are on the air.

[Andrew]

Hi. Yes, thank you. So I live on a pretty quiet street, but we had a downstairs neighbor for some time who would use power tools all hours of the night, generally very loud and disruptive always pushing furniture around and you know, while we normally have no problem going back to sleep, this kind of has disrupted our behavior. She's now gone, but now the landlords are there making the same amount of noise. What can we do to help sleep with an external factor like that?

[Alison Stewart]

Thanks for the call. Yeah. When external factors rear their ugly heads, Lynch.

[Lynn Peoples]

Oh, I am sorry to hear about that. I will say if you find a solution, please let me know. I mean beyond earplugs, that can only go so far and white noise machines which can only go so far. I'm sure you've tried both of those. It's tough. I really wish I had an easy answer for that. Other than talking to your neighbor and, and begging them to reconsider when they make that noise.

[Alison Stewart]

Could you tell us a little bit about how technology like smartphones and TV screens affect our ability to fall and stay asleep?

[Lynn Peoples]

That goes back to that blue light that I mentioned. We really want that during the day that tells our bodies it's daytime. But when we shine blue light on our faces at night with a screen or LED lights overhead and again it's telling us it's daytime. So that is throwing off our rhythms, that's delaying the timing of that melatonin rise that we need to trigger that whole cascade of things that helps us fall asleep. So it's, you know, it's definitely contributing to the problem. I think it's part of a bigger, the bigger picture of all these other things we're doing to affect our rhythms. Again, the LED lights in our homes have a, you know, are brighter and bluer these days. So that can impede our sleep. We also have tools like there's a lot of apps that dim your screen and pull out some of that blue light. Those can be useful as well as blue light blocking glasses. Those may also have a place. But everything you can do to dim your nights and try to pull out that blue light, make it a warmer, oranger hue, that is going to help.

[Listener]

So what do the blue light glasses do?

[Lynn Peoples]

They literally filter out the blue wavelengths of light that are coming out of your device or out of a light fixture. It's cutting down on those messages that are going to your clocks that it's daytime, hopefully then lessening the impact there and helping you go to bed or fall asleep easier that night.

[Listener]

This is our what the Hack Sleep edition. Our guest is science journalist Lynn Peoples. She recently published the book the Inner Living in sync with your circadian rhythms listeners. What have you tried that has worked for you? To get a good night's sleep, give us a call. 2124-3396-9221-2433. WNYC this text says I'm a big believer of no devices in the bedroom. I think of it as a sanctuary. When my husband and I got engaged, I had a quote condition, no TV in bedroom. And we've been married 43 years. Sounds a little wonky, but we've been faithful to this. Let's talk to Pam. Hi, Pam, thanks for calling all of it.

[WNYC Studios]

Hi, good afternoon. I work in news and I've always worked in morning news and I'm a morning person, so it has served me well. But I'm going to be shifted to a later shift and I'm terrified because I think I'm just going to be constantly fighting my natural circadian rhythm. Or is it just because I've worked in morning news for so long that I'm used to it?

[Listener]

What do you think, Lynn, Is a good question.

[Lynn Peoples]

I think it's probably a combination, but you are probably programmed to be a morning person if you feel like that, if that's something you've been living your whole life, I don't know, you know, growing up, if you felt that way too. So, yeah, I think it could be a challenge. But again, within that wiggle room that we have in our rhythms, there are things you can do, the ways you kind of manipulate light, your light exposure throughout the day and your meal times that hopefully can make that transition a little less painful. There is, you know, our bodies do have some adaptability, so it's not hopeless.

[Listener]

Well, let's talk about food. Tell us how someone's diet might affect their circadian rhythm. This might help out. Pam.

[Lynn Peoples]

Yeah, absolutely. So there's really interesting new research coming out talking about what scientists call time restricted eating, very much like various other diets that like intermittent fasting. But this is really trying to consolidate the hours that you eat during the day and that's any calories coming in, including a single chip or a sip of wine at night. So you really want to kind of try to eat during ideally daylight hours, depending on the season, and you want to concentrate your calories earlier. So the bottom line here really is trying to stop taking in any calories maybe two, three hours before you want to go to be that is really the key. And especially any heavy calories you want, try to try to aim for those earlier in the day, a bigger lunch, for example, and a lighter dinner.

[Listener]

Let's talk to Ed from North Arlington, New Jersey. Hey, Ed, you're on the air.

[WNYC Studios]

Thank you. Love your show. I'm wondering how you count the seven hours. Everybody says seven to nine hours. Seven or eight hours. Nine. And I have. I struggle to get to seven, but I'm an older person and my bladder forces me to wake up in the middle of the night. And sometimes I go right back to sleep, but sometimes I don't. And I lay there for half an hour or 40 minutes and then I get to sleep. Do I count those 40 minutes laying quietly in bed as part of my seven hours, or do I have to add another 40 minutes at the end?

[Listener]

Very interesting question. Thanks for asking, Ed. What do you think, Lynn?

[Lynn Peoples]

Yeah, that's interesting. I think technically speaking, it is the hours you are asleep, unfortunately. I think there are things you can do to try to help yourself fall asleep faster after you get up. One thing that I certainly have learned in all my research is the importance of not exposing yourself to light when you get up in the middle of the night to go to the bathroom. Instead of flipping on the switch in the bathroom, try, like a worm, nightlight, if you don't already in the bathroom. Because just a little bit of light in the middle of the night can really throw off your inner clocks and your ability to fall back asleep because your. Your body's not primed to see light. It's going to be a shock to the system and it's going to confuse the clocks, thinking it might be daytime.

[Alison Stewart]

Let's talk to Annette, who's calling in from Brooklyn. Hey, Annette.

[Annette]

Hi. How's everyone doing?

[Alison Stewart]

Well, what's going on with you?

[Annette]

So it's so interesting that the conversation is about sleep right now because I'm visiting my mom in Texas and I had the worst sleep last night. And in Brooklyn, I live right next to a fire station and I sleep phenomenally. I wanted to add that one thing that I. That I have incorporated maybe a few years ago is weighted eye covers. And I have learned that if I don't sleep with it, I automatically wake up numerous times at night. So that has been a big help. I have regular eye covers, but I also have the weighted ones, and I tend to combine both. But my question. I have a question as well and something that I read a long time ago. And I don't know whether it's valid or not, but I do remember reading that based on the time that we were born, is our natural circadian rhythm. Is there any validity to that?

[Alison Stewart]

Is that true or not? Well, first of all, good luck in Texas, and come home to Brooklyn. What do you think, Lynn? Is that a true story?

[Lynn Peoples]

I have not heard that, but I am now going to look it up. As well as these weighted eye masks. I also haven't heard about that.

[Alison Stewart]

Oh yeah.

[Lynn Peoples]

But I do use a weighted blanket. For the record, I find that helpful.

[Alison Stewart]

Yeah, we've got somebody else who said they use the weighted eye mask too. Well, we got some good tips today.

[Progressive Insurance Ad]

Yeah.

[Alison Stewart]

Any last thoughts you want to give our listeners before we go?

[Lynn Peoples]

I just thank you for the, thank you for the new tips that I hadn't even been aware of. No, I think, yeah, really the biggest bottom line is brightening your days, darkening your nights. And it's a little extra challenging during daylight saving time. So just takes a little extra effort. Make sure you, you do that should help your sleep.

[Alison Stewart]

Lynn Peoples is the author of the Inner Clock Living with Our Circadian Rhythms. She's been with it with us for what the heck? Sleep Edition. Nice talking to you, Lynn.

[Lynn Peoples]

Yeah, thank you. For 140 years MultiCare has been in.

[Listener]

Washington prioritizing long term solutions, partnering with.

[Lynn Peoples]

Local communities and expanding access to care.

[Listener]

Together, we're building a healthier future.

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