The science of sleep (re-broadcast)

Dan Schwartz (00:00):

Hi, everyone, it's Dan Schwartz. We're away this week getting the new Stanford Graduate School of Education buildings open. This is an exciting milestone for the school community. So as summer winds down and the new academic year ramps up, we wanted to bring back one of our favorite conversations from the archive. Of course, all the episodes are my favorite, but this one's particularly relevant to the start of the school year where people have to wake up early, pack lunches, pack schedules, try not to go to sleep late. [00:00:30] It's from April 2019 with Dr. Rafael Pelayo. He's an expert in sleep. We dig into what sleep really does for our brains, why it matters for learning, and how school start times may be setting everyone up to fail. Enjoy the episode.

Denise Pope (00:51):

Welcome to School's In, your go-to podcast for cutting edge insights in learning. From early education to lifelong development, we [00:01:00] dive into trends, innovations, and challenges facing learners of all ages. I'm Denise Pope, Senior Lecturer at Stanford's Graduate School of Education and co-founder of Challenge Success.

Dan Schwartz (01:14):

And I'm Dan Schwartz. I'm the Dean of the Graduate School of Education and the Faculty Director of the Stanford Accelerator for Learning.

Denise Pope (01:24):

Together, we bring you expert perspectives and conversations to help you stay curious, inspired, [00:01:30] and informed.

Dan Schwartz (01:31):

So my son's superpower is sleep.

Denise Pope (01:36):

Ah.

Dan Schwartz (01:37):

You know, it, it's, like, it's a third of your life, it's sort of, you don't have direct control over it. He does.

Denise Pope (01:43):

Well, okay, explain.

Dan Schwartz (01:44):

It's a... He can go to sleep at any time, in any situation. Uh, he could do that as a baby. What a, a-

Denise Pope (01:50):

Nice.

Dan Schwartz (01:50):

you know, talk about a gift of a child.

Denise Pope (01:53):

Ohh, your gift to the dad.

Dan Schwartz (01:54):

Ah, so he had to ta... But, but he doesn't, you know, fall asleep when he shouldn't.

Denise Pope (01:58):

Right.

Dan Schwartz (01:58):

He's really got control over it. So he [00:02:00] had to take this flight to do a job interview across the country. He took this crazy flight that, you know, saved money. It was, like, three legs. I'm like, "What are you doing?" and he said, "I'll just sleep the whole flight." And I'm like, "Sorry, it's 12 hours in the air-

Denise Pope (02:12):

(laughs)

Dan Schwartz (02:13):

... and it leaves at 11. He says, "No, I got it. I got it."

Denise Pope (02:15):

Right.

Dan Schwartz (02:15):

So this is, this is a superpower.

Denise Pope (02:17):

He doesn't have to take drugs. He just literally does-

Dan Schwartz (02:18):

No, no. It's just he get-

Denise Pope (02:19):

No, that's amazing.

Dan Schwartz (02:21):

As a baby, oh, my God, it was so easy.

Denise Pope (02:23):

Oh, it's a dream.

Dan Schwartz (02:23):

It's not like I'd snap my fingers and he'd fall asleep, but...

Denise Pope (02:26):

But he, he was a good, solid sleeper.

Dan Schwartz (02:28):

Always has been. I, I, and it, [00:02:30] it didn't come from my side.

Denise Pope (02:32):

Yeah.

Dan Schwartz (02:32):

Uh, my brother's an insomniac.

Denise Pope (02:34):

Oh.

Dan Schwartz (02:35):

I'm, I'm, I'm an okay sleeper, you know, uh-

Denise Pope (02:37):

Do you try to get, I mean, 'cause I know you stay up late.

Dan Schwartz (02:40):

I do.

Denise Pope (02:42):

So, and I, you know, sometimes I get emails from you, I've already gone to bed, so-

Dan Schwartz (02:45):

Right. That way you can't respond.

Denise Pope (02:46):

(laughs) I know.

Dan Schwartz (02:46):

It's a perfect strategy (laughs).

Denise Pope (02:48):

It's a little scary for me. But what, so how... You stay up late, but then do you sleep in, like, are you-

Dan Schwartz (02:53):

No.

Denise Pope (02:53):

How do you, so you write-

Dan Schwartz (02:54):

Yeah, I'm, I'm-

Denise Pope (02:54):

You make sure.

Dan Schwartz (02:58):

I'm one of those people where, if it was left to me every night, I'd sleep an hour later and wake [00:03:00] up an hour later and just go around the clock.

Denise Pope (03:01):

(laughs) Oh, my...

Dan Schwartz (03:03):

It's just, it, it's sorta...

Denise Pope (03:04):

I don't think that's good.

Dan Schwartz (03:05):

No, I think it's, I think this is what ha- they put, like, people in caves or something-

Denise Pope (03:08):

(laughs)

Dan Schwartz (03:09):

... and they found this, they, they would, like, go an hour later. Uh, whether that's bad for me, I don't know. Uh, I, I know sleep's important.

Denise Pope (03:17):

Sleep is extremely important.

Dan Schwartz (03:18):

Yeah. Well, it's, it's a third of your life. My God. That's re-

Denise Pope (03:19):

Doesn't that freak... That freaks me out a little bit. It's a third of your life.

Dan Schwartz (03:20):

(laughs)

Denise Pope (03:25):

Well, that's a lot!

Dan Schwartz (03:26):

So, so do you wish you lived a third longer, so you could just not lose all [00:03:30] that time?

Denise Pope (03:31):

It, I, it, there are people who would say, "I wish there was, you know, a way for me to not have to sleep as much." There's people who say, "I can get by on five hours," and, and maybe our guest is-

Dan Schwartz (03:41):

Yeah.

Denise Pope (03:41):

... gonna dispute that, but they, they tell you how much they get done before you're even up and-

Dan Schwartz (03:47):

Oh, yeah. I've always wished-

Denise Pope (03:48):

(laughs)

Dan Schwartz (03:48):

... I could be a morning person. It just, it's not gonna happen.

Denise Pope (03:52):

It's just not (laughs) gonna happen.

Dan Schwartz (03:52):

(laughs) It's just not gonna happen.

Denise Pope (03:52):

It's... (laughs)

Dan Schwartz (03:52):

And I like, I like falling asleep. I don't like waking up.

Denise Pope (03:55):

Yeah.

Dan Schwartz (03:55):

Yeah.

Denise Pope (03:56):

I hear you. I hear you.

Dan Schwartz (03:57):

So, so anyway, uh, we're gonna learn about [00:04:00] why sleep's important.

Denise Pope (04:01):

Yes, and particularly why sleep's important vis-a-vis learning.

Dan Schwartz (04:04):

Eh, yes.

Denise Pope (04:06):

So we are really excited to have Dr. Rafael Pelayo here with us. He is a clinical professor of Psychiatry and Behavioral Sciences at Stanford Medicine. He studies the science of sleep and he does research on narcolepsy, sleepwalking, dreams, and treatment of sleep disorders. So a real sleep expert, isn't it?

Dan Schwartz (04:24):

Yeah, yeah. Yeah. So, so I was gonna tell stories about this and then I realized they're probably not true.

Denise Pope (04:30):

[00:04:30] (laughs)

Dan Schwartz (04:30):

So we're (laughs) gonna, we're gonna let the expert take us forward.

Denise Pope (04:33):

We're gonna leave it, leave it to the expert. Welcome. Welcome.

Dan Schwartz (04:34):

Welcome, Dr. Pelayo.

Rafael Pelayo (04:35):

Thank you for having me, guys. Thank you.

Denise Pope (04:36):

So first of all, you've heard a little bit of, (laughs) of our first co-

Rafael Pelayo (04:40):

I actually enjoyed the conversation a lot.

Denise Pope (04:41):

Did you?

Rafael Pelayo (04:41):

You guys hit a lot of things.

Dan Schwartz (04:42):

Yeah.

Denise Pope (04:42):

(laughs)

Rafael Pelayo (04:42):

Several things, actually.

Denise Pope (04:43):

Okay, so tell, take it where you wanna go. Why is sleep so important? I, I feel like we know so much more now. Why is it so important?

Rafael Pelayo (04:50):

I like when he was talking about his baby. You just spontaneously said it's like a dream. And I don't think you, you did that pun intentional.

Dan Schwartz (04:53):

(laughing)

Denise Pope (04:53):

Oh, I didn't even know I said that.

Rafael Pelayo (04:53):

Yeah, I was listening.

Denise Pope (04:53):

Ah!

Rafael Pelayo (04:53):

But you said, you said it was like a dream. [00:05:00] You just said it was such, like, "Oh, my God. It's such a fantasy thing." I, I would think of it. And our dreams aren't always pleasant, but you made it sound like it's a pleasant thing, a dream.

Denise Pope (05:08):

Yes.

Dan Schwartz (05:08):

Mm-hmm.

Rafael Pelayo (05:09):

Right? Do we really want our dreams to come true? We bear some pretty scary dreams.

Denise Pope (05:11):

Yeah.

Rafael Pelayo (05:12):

And what you were saying is very true about shifting over time, because it ties into this, uh, the work why, why we're here today-

Dan Schwartz (05:19):

Yeah.

Rafael Pelayo (05:19):

... was that work in the caves. That was at Mammoth Cave where they did that early research-

Dan Schwartz (05:22):

Oh, yeah.

Rafael Pelayo (05:22):

... where they isolated people and they found out you could become free running. And they knew that the biological clock-

Dan Schwartz (05:26):

Free running.

Rafael Pelayo (05:26):

Free running is a term that you described.

Dan Schwartz (05:28):

Great term.

Rafael Pelayo (05:29):

Free running actually [00:05:30] is considered a problem for people who are blind.

Denise Pope (05:32):

Ah.

Dan Schwartz (05:32):

Yeah, I've heard-

Rafael Pelayo (05:32):

But we see a lot-

Dan Schwartz (05:33):

I've heard about this, too.

Rafael Pelayo (05:33):

We see it a lot in Silicon Valley, and a lot of our graduate students will often will do this when they finish with all their coursework, just need to get their thesis done and they're done, their lives become, "I'm, I'm, I've been working on this around the clock pretty much-

Dan Schwartz (05:45):

Mm-hmm.

Rafael Pelayo (05:45):

... so I eat whenever, sleep whenever," and they become completely desynchronized from the outside world, and they become free running themselves.

Dan Schwartz (05:51):

Yeah.

Rafael Pelayo (05:52):

And then they find themselves staying up, uh, later and later and then sleeping during the day.

Dan Schwartz (05:55):

I stopped it because I realized I was, like, waking up at 8pm [00:06:00] and I would never see the sun. And it was just sort of like, nuh-uh-uh-uh, I gotta have day, daylight.

Rafael Pelayo (06:04):

Yeah. So it's free, so that term free running is a real term, and it's actually now in the news if you watch TV, because for the first time, the FDA approved the medication specifically for that situation. And you'll see commercials on TV, I'm not plugging any products, guys, I don't have any-

Denise Pope (06:18):

(laughs)

Rafael Pelayo (06:18):

... conflicts on this-

Dan Schwartz (06:18):

No, I've seen this. It's, uh, it's online.

Rafael Pelayo (06:19):

... but, but it's called-

Dan Schwartz (06:19):

Yeah.

Rafael Pelayo (06:20):

... but it's called non-24.

Dan Schwartz (06:22):

Huh.

Rafael Pelayo (06:22):

That's the phrase they're using, non-24.

Denise Pope (06:23):

Oh, I've seen that.

Dan Schwartz (06:23):

Yeah.

Denise Pope (06:23):

I've seen that.

Rafael Pelayo (06:25):

That's, and that all comes directly from the research on these caves. And the reason I wanna tell you this, just briefly, [00:06:30] I'll get to your answer in a moment, I don't wanna hijack this, but, um, the reason that the, Stanford is the world's oldest sleep program was because Dr. Dement, coming outta World War II, wanted to visit and, and learn about this. And the guy who did that work was in University of Chicago, Nathaniel Kleitman. So that work on the kids was done. In Chicago, Dement learned about it, and then came to Stanford and set up our sleep program.

Dan Schwartz (06:49):

Hm.

Rafael Pelayo (06:49):

So our entire program at Stanford on sleep, and we're the main center in the world for sleep work, is from, um, that work that you-

Dan Schwartz (06:56):

Oh.

Rafael Pelayo (06:56):

... you happened to touch-

Dan Schwartz (06:56):

Yeah.

Rafael Pelayo (06:56):

... on the caves.

Denise Pope (06:56):

Wow, Dan.

Rafael Pelayo (06:56):

You didn't name it, but I named that.

Dan Schwartz (06:56):

Okay.

Rafael Pelayo (06:56):

You said that.

Denise Pope (06:56):

You knew that.

Rafael Pelayo (07:00):

[00:07:00] For that work in the caves. Anyway, why is sleep important?

Denise Pope (07:03):

All right, so why is sleep important?

Rafael Pelayo (07:04):

I think a- anything that has a brain has to sleep, and, and sleep is a basic, uh, biological function. There should not need to be any convincing of anybody that sleeping is good for us. Sleeping is something the brain has to do. It's not the kidneys or the lungs that have to really sleep. It's the brain that has to do this. And if you think about it, it's a really crazy thing that it's doing because the most vulnerable thing you can do as an animal is sleep.

Denise Pope (07:21):

Yeah.

Rafael Pelayo (07:22):

So all animals protect themselves while they're sleeping. And one of the earliest sleep scientists said, "If sleep has no function, it's the biggest mistake evolution ever made," because [00:07:30] it's a really weird thing that we do. And all these different animals, as they specialize and adapt to their environments, they retain their need for sleep. One crazy maybe exception to all this, there's, there's debate whether the, whether bullfrogs sleep, but, but that's a separate issue.

Dan Schwartz (07:44):

I thought it was sharks. I thought sharks had to-

Rafael Pelayo (07:46):

No.

Dan Schwartz (07:46):

... like, keep moving.

Rafael Pelayo (07:47):

Yeah, no, but, but you can move and sleep at the same time.

Dan Schwartz (07:48):

(laughs)

Rafael Pelayo (07:48):

It all says to how you define sleep.

Dan Schwartz (07:49):

Ah.

Denise Pope (07:50):

Ah-hah.

Rafael Pelayo (07:50):

But the example that's often used is how dolphins sleep. Dolphins, uh, very specialized animals, need to breathe, swim fast, avoid, avoid sharks, make, make more dolphins. They [00:08:00] can swim and sleep at the same time. One half of the brain sleeps, the other half of the brain, um, uh, stays awake, and they switch from si- side to side. And birds that migrate do the same thing. They can actually fly and sleep at the same time. And in California, we know that the seals, when they're in the water, they sleep like the, like the dolphins do, half the brain at a time. When, when they're on the beach, both heights, both sides sleep. So in the end, sleep is a restorative process to the brain. It makes you feel good. We have to do it.

Denise Pope (08:24):

This is School's In with Dan Schwartz and Denise Pope. We are talking with Dr. Rafael Pelayo about sleep and the importance [00:08:30] of sleep. And let's turn this now to why it's important for learning. What happens?

Rafael Pelayo (08:36):

Right.

Denise Pope (08:37):

So it's restorative-

Rafael Pelayo (08:38):

Mm-hmm.

Denise Pope (08:38):

... but I also know there's some connection between sleep and learning.

Rafael Pelayo (08:41):

There has to be. I mean, pretty every, an- anybody who's ever studied or had to learn something has had the experience of working, staying up, doing some homework, working on, on something you have to get done. And at some point, the pages, the lines get blurry. You can't concentrate anymore. You're like, "I can't do this anymore. I don't care." I remember doing this in college. Like, I have to stay up and do this work. [00:09:00] I'm like, "I just, it just, I can't stay awake anymore. It's not sinking in." You just close it and you fall asleep. I fall asleep on my books many times-

Denise Pope (09:07):

Oh. (laughs)

Rafael Pelayo (09:07):

... just crash, go to sleep. And then after a few hours you pop awake and all of a sudden something that seems impossible to understand a little while ago now becomes clear to you.

(09:14):

So, this, the brain needs to sleep, and in part, one of the current thinking about sleep is that sleep is related to one of the, one of the functions, with an S, functions of sleep, will be this idea of how the brain forms memory, how does it learn? And it's actually been studied where they do experiments, where they, [00:09:30] uh, teach people some, they give them some tasks to learn-

Dan Schwartz (09:33):

Like, like typing.

Rafael Pelayo (09:33):

... like-

Dan Schwartz (09:34):

You learn to type.

Rafael Pelayo (09:35):

Typing with, with, with, with the non-dominant hand, for example.

Dan Schwartz (09:39):

A jo... Yeah.

Denise Pope (09:39):

Oh.

Rafael Pelayo (09:39):

Or, or memorize a list of words.

Dan Schwartz (09:42):

Right.

Rafael Pelayo (09:42):

And they do this, and then they have, uh, they do the experiment where you have to learn this. They let the person sleep and then they repeat the testing of it, and the person's scores always jump after you let them sleep. Not just the passage of time 'cause they'll, they control for time by, by flipping the order of how the experiment is done to manipulate it, so they isolate just the sleep component. And whenever the person is allowed to sleep, their scores improve. [00:10:00] Anything that has to do with memory or memorization and learning-

Dan Schwartz (10:03):

Yeah.

Rafael Pelayo (10:03):

... you'll do better if you learn. And not just memorization, also what they call procedural memory. Like a play or something you have to do a sequence like, like typing, play-

Denise Pope (10:10):

Yeah.

Rafael Pelayo (10:10):

... playing a musical instrument - you need to sleep.

Denise Pope (10:12):

So that old adage that I say to my kids like, "Don't stay up and cram all night," um, to study for a test, you're actually gonna do better if you go to sleep and let it sink in.

Dan Schwartz (10:23):

Yeah. Let it sink in.

Denise Pope (10:25):

So, let it sink in.

Dan Schwartz (10:26):

So, so, uh, allow i- so there's different stages of, or phases of sleep. [00:10:30] Uh-

Rafael Pelayo (10:30):

Mm-hmm.

Dan Schwartz (10:31):

Do we know, like, which one - so, like, if I get that 20-minute nap and, and I'm gonna hit a particular stage of sleep, is that the one that's gonna help me consolidate that memory and? Or-

Rafael Pelayo (10:41):

It's cu- it's a common question.

Dan Schwartz (10:42):

Yeah.

Rafael Pelayo (10:43):

Um, like, people say, "Whi- which, which part of sleep is more important?"

Dan Schwartz (10:45):

Yes.

Rafael Pelayo (10:46):

And I always say it's kinda like asking which gear in your transmission is the most important one. Is it, you know, do you, if your car can't make it to fourth gear, you can get from here to wherever you're going in third gear-

Dan Schwartz (10:54):

Yeah.

Rafael Pelayo (10:54):

... but it's inefficient. You're putting wear and tear on it.

Dan Schwartz (10:56):

Great analogy.

Rafael Pelayo (10:56):

It's, it's the con- it's the continuity-

Denise Pope (10:57):

(laughs)

Rafael Pelayo (10:57):

... that really matters-

Dan Schwartz (10:58):

Yeah.

Rafael Pelayo (10:59):

... to it. It, it's, [00:11:00] it's overall flow, how smooth it goes.

Dan Schwartz (11:01):

Yeah.

Rafael Pelayo (11:01):

You can get by with less sleep. We're not fragile creatures. You can skip lunch without going into hypoglycemic shock. You can, you know, go without water for a while. You can go longer without food or water than you can without sleep, by the way. Sleep is more important than, than, than both-

Dan Schwartz (11:14):

Yeah.

Rafael Pelayo (11:14):

... of those things.

Dan Schwartz (11:14):

Do they, the-

Denise Pope (11:15):

Oh, I love that, sleep is more important than food or water.

Rafael Pelayo (11:18):

As far as how-

Dan Schwartz (11:18):

Didn't, didn't-

Rafael Pelayo (11:18):

... how well you can do, you can go longer without eating than you can without sleep.

Denise Pope (11:21):

Wow.

Dan Schwartz (11:22):

Didn't, didn't they do studies with puppies where they, like, kept them up and-

Denise Pope (11:25):

Oh.

Dan Schwartz (11:25):

... they, like, died?

Denise Pope (11:25):

Shh... oh, no!

Rafael Pelayo (11:25):

So-

Dan Schwartz (11:27):

It was, like, the darkest, darkest study ever.

Denise Pope (11:28):

That's so horrible!

Rafael Pelayo (11:30):

[00:11:30] So actually, yes, the original sleep deprivation research was with puppies and they, and they died.

Dan Schwartz (11:34):

Yeah.

Denise Pope (11:34):

Oh, my gosh.

Rafael Pelayo (11:34):

They were sleep-deprived to the point of death, and they died of sepsis, of infections. But the problem with those early research, and I don't do any animal research. But, um, the problem with that - not that I'm opposed to, it's just, I just, I, I'm just, don't have the skills to do it - the, um, the thing with the animal research, those early days of sleep deprivation, the only way you could sleep-deprive an animal was by torturing it.

Dan Schwartz (11:53):

Oh.

Rafael Pelayo (11:54):

Because how could you keep it awake? If you let, leave the animal alone, they would sleep.

Dan Schwartz (11:57):

Ah.

Denise Pope (11:57):

Right.

Rafael Pelayo (11:57):

So they were never able to separate the effects of lack [00:12:00] of sleep from the stress-induced-

Dan Schwartz (12:01):

Mm-hmm.

Rafael Pelayo (12:01):

... by making you stay awake.

Denise Pope (12:02):

Ah.

Rafael Pelayo (12:02):

'Cause if you leave the animal alone, they'll just sleep.

Denise Pope (12:04):

A- all right, so-

Rafael Pelayo (12:05):

So anyway, t- as far as, as, as the sleep, it's, there i- different parts of memory seem to have different parts to sleep, it seems-

Dan Schwartz (12:11):

Mm-hmm.

Rafael Pelayo (12:11):

... so that some of the emotional stuff needs to be related to, uh, to dreaming-

Dan Schwartz (12:15):

Mm-hmm.

Rafael Pelayo (12:16):

... but stage two sleep is, uh, thought to be more at the spindles like a complex of, of do, more memory consolidation, and then slow wave sleep, which is this different kind of sleep, also has a separate role. So memory is so, so complex that different parts of sleep have different roles in it.

Dan Schwartz (12:29):

Interesting.

Rafael Pelayo (12:30):

[00:12:30] And interesting how we all, this all played out because, um, at Stanford, Dr. Dement is still here, anybody who wants to meet Dr. Dement, he's around, you can meet him, he thought dreaming was it. Coming out of World War II and Freud, it was all about dreaming.

Denise Pope (12:41):

Yeah.

Rafael Pelayo (12:41):

And he just found the link. He helped find the link between rapid eye movement, sleep, and dreaming. And because he was a two-finger typist, he didn't wanna keep writing rapid eye movement sleep, he called it R-E-M, REM. And then everything else was non-REM, because it was not important.

Dan Schwartz (12:54):

Ah, that's right. Right, right.

Rafael Pelayo (12:55):

So it's very disrespectful to the rest of sleep.

Dan Schwartz (12:56):

(laughing)

Denise Pope (12:57):

Oh, Dr. Dement-

Rafael Pelayo (12:58):

And that's how it all played out... Yes.

Denise Pope (12:59):

... you gotta be more [00:13:00] respectful.

Rafael Pelayo (13:00):

No, he knows it now.

Dan Schwartz (13:00):

(laughs)

Denise Pope (13:01):

No, he's, he's a legend. He's-

Rafael Pelayo (13:03):

Actually-

Denise Pope (13:03):

... incredible. This is School's In with Dan Schwartz and Denise Pope. We are speaking with Dr. Pelayo, a sleep expert here from Stanford. And, and I know that adolescents have a whole different way of sleeping. This is very important when we're talking about schools, and schools start so early and kids are exhausted and they're... I- in our study, in the Challenge Success study of 100,000 kids, the average of these adolescents [00:13:30] is about six hours a night. That's the average. So that's, that can't-

Dan Schwartz (13:34):

So, so they, are-

Denise Pope (13:34):

... that can't be good.

Dan Schwartz (13:35):

Are they all walking around with headaches all the time?

Denise Pope (13:37):

They're, yes. They have headaches, they're exhausted, they have trouble staying up. They have a whole bunch of sleep issues. So, talk to us about what we should do for these adolescents.

Rafael Pelayo (13:46):

You wanna make sleep a priority in their lives. And this is something that adults are, are, are putting on their kids. You talk about sleep deprivation as a, as a form of torture. We are torturing these kids. Now, it's, how many times in your professional careers have you ever said at a lecture or heard somebody say to you, "I want [00:14:00] you to follow your dreams. Follow your dreams"? Well-

Dan Schwartz (14:02):

(laughing) I know where this is going.

Rafael Pelayo (14:05):

Well, well, uh, you may know this, dreaming dominates the last third of the night. Dreams are-

Dan Schwartz (14:09):

Ah.

Rafael Pelayo (14:09):

... not evenly distributed. Dreams are the last third of the night. So when you wake up early, what you're cutting off is the dreaming sleep specifically.

Dan Schwartz (14:15):

Yeah.

Rafael Pelayo (14:15):

We want these kids to dream. You're cutting off the chance to dream for them. In fact, when I look at a sleep study, when I evaluate it, if I wanna know whether the study is done properly or not, I look at how much time they spend dreaming.

Dan Schwartz (14:24):

Mm-hmm.

Rafael Pelayo (14:25):

And with, and oftentimes they get, the kids get kicked out too early from the sleep lab and they cut off their dreaming time.

Denise Pope (14:29):

Wow.

Rafael Pelayo (14:30):

[00:14:30] When you don't get enough sleep, the first sign of getting inadequate sleep is being inattentive and a little bit grumpy, little trouble with memory or word-finding stuff. But usually inattentive. Just know whenever you interact with any teenager, odds are that person is sleep-deprived. And girls seem to be even more sleep-deprived than boys. So, you know, you're dealing with somebody who's inattentive. It's not uncommon for kids to fall asleep in class in high school.

Denise Pope (14:52):

Right.

Rafael Pelayo (14:52):

It's very rare for this to happen in, in elementary school.

Denise Pope (14:56):

Right.

Rafael Pelayo (14:56):

If a third grader or second grader falls asleep in class, the parents would be notified because [00:15:00] the assumption is, well, they're asleep because they're bored.

Denise Pope (15:02):

Mmm.

Rafael Pelayo (15:02):

But was high school more boring than second grade? I don't think so.

Dan Schwartz (15:05):

Yes.

Denise Pope (15:08):

(laughing)

Dan Schwartz (15:08):

I'm sorry.

Rafael Pelayo (15:09):

In some ways, right?

Denise Pope (15:09):

For Dan. For Dan.

Rafael Pelayo (15:09):

But, but, but how people now evaluate the quality of a teacher, a teacher's considered a good teacher if they, if they are entertaining.

Dan Schwartz (15:14):

Yeah.

Rafael Pelayo (15:14):

Because you have to entertain the, entertain the kids to keep them awake-

Dan Schwartz (15:16):

Yeah.

Rafael Pelayo (15:16):

... 'cause they're, you know, a sleep-deprived audience.

Denise Pope (15:18):

Right.

Rafael Pelayo (15:18):

That's what's happening with them.

Denise Pope (15:19):

Right.

Rafael Pelayo (15:19):

Not getting enough sleep. And it's not just whether they are, have headaches or not, but lack of sleep is an independent risk factor for suicide and for car accidents. The two most common causes of death in these teenagers is car accidents [00:15:30] and suicide-

Dan Schwartz (15:30):

Mm-hmm.

Rafael Pelayo (15:31):

... and sleep is directly linked to both of them. This has been shown now by, by... there's data now showing that if the kids get more time to sleep, these things improve. Mental health improves-

Dan Schwartz (15:39):

Was that, like-

Rafael Pelayo (15:39):

... and car accidents decrease.

Dan Schwartz (15:39):

... the, the cor-

Rafael Pelayo (15:39):

The RAND Corporation, this has been, been now demonstrated.

Dan Schwartz (15:41):

It's, it's correlational study? Are they RC or-

Rafael Pelayo (15:44):

It's, it's always gonna be correlational or, or public health t- type studies because-

Dan Schwartz (15:47):

Oh.

Rafael Pelayo (15:47):

... you can't really do the interventional type study-

Dan Schwartz (15:49):

Yeah, well, that's what I was wondering.

Rafael Pelayo (15:50):

... because the ethics of it.

Dan Schwartz (15:50):

Yeah.

Denise Pope (15:51):

But we know, we absolutely know that there's a correlation and, and the, the horrible suicide clusters that we've been seeing across the US-

Rafael Pelayo (15:59):

Mm-hmm.

Denise Pope (15:59):

... in teens, [00:16:00] many, many, many of them, the parents will have said, "You know what, I have no idea when he was going to sleep. I think he was sleeping three or four hours a night." Um, and that was causing the suicide, I don't, I shouldn't say causing. Tha- that was related to suicide ideation, death by suicide, et cetera. So depression, anxiety, we always know that when you're depressed or anxious, it's harder to fall asleep. Like, your mind is spinning. But I think we're-

Dan Schwartz (16:22):

Yeah, so-

Denise Pope (16:22):

... just finding out now that it actually, sleep deprivation, I think it can lead to a depressive episode, yes?

Rafael Pelayo (16:28):

Yeah, no, it is not only that. It's, it's a bidirectional, [00:16:30] but the, but the science has been worked out even, even better than that. There's something called the fMRI, functional, uh, magnetic imaging. And fMRI data shows that when somebody is sleep-deprived, the brain goes into a mode that's different than when the brain is sleep-satiated. Because, we said earlier, animals do not voluntarily sleep-deprive themselves. If everything is okay, they'll sleep when they need to, eat and do what they have to do.

(16:52):

So to the brain, if you're not getting enough sleep, it means something is wrong. And what happens is when you don't get enough sleep, the brain switches into a mode that something [00:17:00] is wrong, and therefore the, the brain takes bigger gambles. And the brain now, will now, uh, undervalue the, the, um-

Dan Schwartz (17:08):

Risk.

Rafael Pelayo (17:08):

... the, the punishment, the risk-

Dan Schwartz (17:10):

Yeah.

Rafael Pelayo (17:10):

... thank you, and overvalue the reward.

Denise Pope (17:11):

Mmm.

Rafael Pelayo (17:11):

So people become impulsive. This is now like gamblers. The longer they, they stay awake, the more they like to do it, but it's been seen with teenagers, and also, uh, sleep-deprived teenagers, 'cause you can do driver simulator experiments with them.

Denise Pope (17:21):

Yeah.

Dan Schwartz (17:21):

Mm-hmm.

Rafael Pelayo (17:22):

And that's in a safe environment. And they find-

Dan Schwartz (17:23):

Yeah.

Rafael Pelayo (17:24):

... that as they sleep-deprive the teenager, the, when you sleep-deprive yourself, cortisol se- secretions surge. Cortisol makes us feel good. [00:17:30] So all of a sudden you're feeling euphoric and people start getting, don't, don't get enough sleep a little bit, they actually have a, a good feeling about it. Sleep deprivation has antidepressant properties at a mild, at a certain level.

Dan Schwartz (17:39):

Mm-hmm.

Rafael Pelayo (17:39):

So they feel good about themselves. And the, and the scary part is the teenagers, when they were, when they sleep-deprived them when they're driving simulators, they thought they were driving better than when they were fully sleep shaping-

Dan Schwartz (17:46):

Yeah.

Denise Pope (17:46):

Ahh.

Rafael Pelayo (17:47):

... but they were making more mistakes.

Dan Schwartz (17:48):

Yeah.

Rafael Pelayo (17:48):

The worst combination of all.

Dan Schwartz (17:50):

Yeah, yeah.

Rafael Pelayo (17:50):

You think you're sleeping well and you're making more mistakes.

Denise Pope (17:52):

I wanna move us to a topic that is somewhat controversial in my work, which is this idea around later start times, [00:18:00] particularly for middle schools and high schools, so particularly for adolescents. And to explain what that means to folks who don't know is, right now, many, many, many schools across the country start at 7:30, 7:40, 7:50. And what we know from adolescents is that they are not fully awake at this time, or at least that's what I'm hearing. You'll, you can back that up.

(18:20):

And there's a bunch of people out there who are trying to get schools to start later. Ideally, I think the American, um, uh, Pediatric Association said 8:30 should be the earliest. And, [00:18:30] um, it's hard to get all these people to agree. We've got bus schedules, we've got... you know, this affects when the school day ends. We've got... well, then there's no lights on the field for, for athletics if that's gonna go later. Everybody has an excuse for why these late starts are so difficult. So what's, what's your opinion?

Rafael Pelayo (18:52):

Well, the science is that as people go, as we shift into puberty, the way that we sleep is differently. Um, primates do this and rodents do this also. Um, when [00:19:00] you, uh, go through adolescence, you actually, there's a biological shifting towards a tendency to go to bed later at night. This is balanced by a tendency for older folks to go to bed earlier. In the tribal people, it makes sense that somebody should be watching the fire at night.

Denise Pope (19:13):

Mm-hmm.

Rafael Pelayo (19:14):

Who's gonna watch the fire? People, (laughs) you make the young people do it.

Denise Pope (19:17):

(laughs)

Rafael Pelayo (19:17):

Also, some people have also argued, explained that. See, in science, we know what we can measure, but we try to find the whys of speculation.

Denise Pope (19:24):

Mm-hmm.

Rafael Pelayo (19:24):

So the, it's the biological fact that a population of teenagers, when they go through puberty, will shift [00:19:30] to a later bedtime. It's not the TV, it's not the technology, because again, other animals do this, too, when they go through puberty.

Dan Schwartz (19:37):

So let, let me-

Rafael Pelayo (19:38):

Go ahead.

Dan Schwartz (19:38):

'Cause I always get confused on this. Uh, we do have seasons and there's longer light.

Rafael Pelayo (19:44):

Hm.

Dan Schwartz (19:44):

So, right now, as we're getting to a longer light period, will the teenagers go to bed even later? Is it, is it-

Rafael Pelayo (19:50):

To some degree.

Dan Schwartz (19:50):

... locked to sunlight or is it locked at 24 hours?

Rafael Pelayo (19:52):

I think there's no doubt. Well, we can speculate this a little bit, but human sleep is probably seasonal. If I ask any of you, any listener [00:20:00] about your sleep needs or sleep desires, you're gonna gimme two numbers, and you'll say things like, "I like to get seven, but I can get by with five." "I love nine, but as long as I get six." And you always have these numbers in your head. That's probably the seasonality of this. And-

Dan Schwartz (20:11):

Hm.

Rafael Pelayo (20:11):

Listeners in Alaska will tell you they sleep more in the winter, less in the summer.

Denise Pope (20:15):

Mm-hmm.

Rafael Pelayo (20:15):

We're diurnal creatures. We're social creatures. We've got excellent color vision. We should take advantage of the long days.

Dan Schwartz (20:20):

Mm-hmm.

Rafael Pelayo (20:20):

Daylight savings is all about swapping morning light for afternoon light. That's all it is.

Dan Schwartz (20:24):

Mm-hmm.

Rafael Pelayo (20:25):

So there is this idea that there is some seasonality to this. At the [00:20:30] same time, people often ask about hibernation 'cause that's not sleep. It's a different thing that'll do. That's, there's, there's less food available and you save energy that way. But the teenagers have this biological shifting that goes on. And also what happens is growth hormone secretion peaks in the first third of the night. You're not really growing all the time. The lengthening of the bones occurs in sleep.

Dan Schwartz (20:49):

Okay.

Rafael Pelayo (20:49):

Underwriter Laboratories has actually measured this.

Denise Pope (20:51):

Yeah.

Dan Schwartz (20:51):

Wow.

Denise Pope (20:51):

I knew that.

Rafael Pelayo (20:51):

Smoke alarms, smoke alarms will not wake up a sleeping teenager in, when they're in their slow wave sleep. You can't count on a smoke alarm to wake up a sleeping teenager in the first third of [00:21:00] the night. You have a very deep sleep. Or deepest sleep as far as the level of sleep, as far how much noise to wake somebody up or how much stimulation to wake somebody up, the depth of sleep is greatest at that, the beginning of the night, right then and there.

(21:11):

It used to be in California, school started at 9:00 in the morning, a long, long time ago. And what happened is the population grew in this, in, in this, uh, throughout the country, transportation was underfunded. So instead of adding buses, they said, "Let's just stagger them." And the idea was, well, the high school kids can get to school earlier on their own, so even the high school kids start earlier. [00:21:30] In the middle school, in the middle, and the little kids go a different time.

(21:33):

So we end up in a situation now where the kids are sleep-deprived. A lot of kids are starting at 7:00 in the morning. And there's always been this push because if you try to change the school's start time, well, all the schools have to be coordinated. And, and it's very cynical, and I remember learning about this when it first came out, their thinking was, well if we just delay the school start time, the kids are just gonna stay up later.

Denise Pope (21:52):

Yeah, that's what they always say.

Rafael Pelayo (21:54):

Right, and they can say whatever they wanna say, but we have, we, but we, we can measure these things. You can do the experiment. And the data [00:22:00] was, over 20 years ago, they did it in Minnesota, it was the first place that did it, was when they changed the school's start time by an hour, the kids got about 40 more minutes of sleep per night. Yeah, they stayed up a little bit longer, but they got 40 more minutes of sleep every single night. But more importantly, grades went up and things improved. And now this has been replicated over and over again.

Dan Schwartz (22:15):

Wow.

Rafael Pelayo (22:15):

In some school districts, when they changed it by 15 minutes, the kids ended up with 21 minutes of sleep-

Denise Pope (22:19):

Right.

Rafael Pelayo (22:19):

... because the kids now are learning the importance of sleeping and then they feel better. The teachers can tell this. In schools around here that have block schedules, they'll notice that in the days the kids get more sleep, the kids, it's a different environment, different, different [00:22:30] feeling of this. So we gotta put this, the cynicism aside.

Denise Pope (22:33):

This is School's In with Dan Schwartz and Denise Pope and we're speaking with Dr. Pelayo about all things related to sleep and teenagers. We're just talking about late starts and it sounds like you have studies that show that they're not gonna just stay up later, that it actually does help them get-

Rafael Pelayo (22:47):

Mm-hmm.

Denise Pope (22:47):

... more sleep. And even 15, 20 minutes will make a difference?

Rafael Pelayo (22:50):

Yeah, of course it will. I mean the, the idea that some, if you let them s- uh, if school starts later, they're just gonna stay up later, it's like saying to somebody, "I know you're starving, but I'm not gonna feed you 'cause you're gonna waste the food."

Denise Pope (23:00):

[00:23:00] Mm-hmm.

Rafael Pelayo (23:00):

And that's not what people do. They will eat 'cause they're hungry. This sleep-

Denise Pope (23:01):

I am gonna use that.

Dan Schwartz (23:01):

(laughing)

Denise Pope (23:01):

I love that.

Rafael Pelayo (23:01):

Please do. Please tell everybody.

Denise Pope (23:01):

(laughs)

Rafael Pelayo (23:06):

This is a biological thing. We don't do this. See, one thing happens with teenagers, the first evidence you see somebody's not getting enough sleep is the sleeping in on weekends. That's not a biological thing to do. Parents wish the second graders would sleep in. Eight or nine-year-olds don't sleep in.

Denise Pope (23:18):

Right.

Rafael Pelayo (23:19):

They pop away like it's a regular day 'cause they're sleep-saturated, sleep-satiated. The kids are getting, uh, are not getting enough sleep, um, during the school week, they try to sleep in. Imagine we did this with food. We say to kids, "Hey, Monday through Friday, [00:23:30] I'm not, I'm gonna starve you. Saturday and Sunday, eat all you like, and then sat- Monday I'm gonna start starving you again." We think that's insane, but that's exactly what we're doing with their sleep right now.

Denise Pope (23:37):

So should we allow our teenagers to sleep in on the weekends?

Rafael Pelayo (23:41):

We want them to have healthier sleep throughout the 24-hour cycle all the time, make sleep a priority to their health. Kids these days, they know the dangers of smoking. It's been drilled into their head about drugs and alcohol since the very beginning when they first step foot on, on the schools. But sleep is just an afterthought. It's not really talked about too much.

(23:58):

And the first thing we wanna do is get, provide [00:24:00] this education. That's why I'm happy to do shows like this because people need to understand the, that's, that it's not natural to fall asleep just because you're bored. Boredom does not make anybody sleepy. If somebody's falling asleep to my voice right now, it's not my fault. Not that I'm boring you, it's that you're sleep-deprived to begin with, and you should pull over if you're in a car.

Denise Pope (24:16):

(laughs) Yes.

Rafael Pelayo (24:16):

Okay? Um, because monotony unmasks sleepiness, 'cause monotony to the brain is equated as safety.

Denise Pope (24:23):

Mmm.

Rafael Pelayo (24:23):

You don't feel, uh, bored when you're in danger. You feel bored when you feel safe. Monotony. Right? And [00:24:30] if you are safe, then the brain says, well, what should I do now? Let's catch up on this thing that I'm missing, which is sleep. It's safe to sleep 'cause sleeping is dangerous. If I'm bored, it's mean it's a safe time to catch a nap and sleep. That's why we like routines for sleep. Okay.

Dan Schwartz (24:41):

So, so uh, really quickly, naps in middle school, naps in high school, we set aside 20 minutes, everybody lays down and...

Rafael Pelayo (24:49):

I'm wondering maybe you, you, you needed less naps yourself and that's why they made you the monitor 'cause-

Dan Schwartz (24:52):

Could be.

Denise Pope (24:52):

(laughs)

Rafael Pelayo (24:53):

'Cause that's why they did it. You were awake, anyway. Might as well make-

Dan Schwartz (24:54):

(laughs)

Rafael Pelayo (24:55):

... make this kid do something. Put, put him to use.

Dan Schwartz (24:57):

Yeah.

Rafael Pelayo (24:58):

Yeah, there's a natural tendency to nap [00:25:00] and, um, that'll tend to go away between the ages of three to six. And I remember me being in kindergarten and you would have, like, a towel on the floor-

Dan Schwartz (25:07):

Right.

Rafael Pelayo (25:07):

... all, all they gave us.

Dan Schwartz (25:08):

Yeah.

Rafael Pelayo (25:08):

And, um, having, like, laying there bored and you hated it because it's, you don't wanna do this.

Denise Pope (25:12):

So in the very last minute, I wanna know what you think then of sleep pods, because that's, like, the hot new thing in high schools is to allow... and only one person can fit in there.

Dan Schwartz (25:22):

This is like a telephone booth on its side?

Denise Pope (25:23):

Yeah, and, and it's to get kids to, like, to really take some naps. What do you think?

Rafael Pelayo (25:29):

It's, um, in [00:25:30] each... Yeah, there, there, there are sleeping clubs and, and, and napping clubs in different schools, a lot of technology. And there's all this tech. I just came from a, a conference just on mattresses and, and all this technology, and you think about this, and I'm looking at this tech and I'm thinking to myself, we, we took naps in kindergarten on, on a towel.

Denise Pope (25:47):

(laughing) Yeah. On a hard floor.

Rafael Pelayo (25:47):

And in high school, in high school you'd fall asleep in somebody's couch in college and now they have these thousand-dollar devices. Um, anything that's gonna make people respect their sleep is important. So I'm, I'm okay with the technology, but the key thing is somebody say, if somebody says, "I can't sleep without [00:26:00] it," that's an issue.

Denise Pope (26:01):

Mmm.

Rafael Pelayo (26:01):

You should be able to sleep normally. You should be able to go to f- go to bed feeling safe, comfortable, and loved. You want serenity, and that's what you really want in your, in your s- uh, in a good, a good night of sleep.

Denise Pope (26:08):

Thank you so much for being here-

Rafael Pelayo (26:09):

Thank you.

Denise Pope (26:09):

... Dr. Pelayo, and thank all of you for listening to School's In with Dan Schwartz and Denise Pope.