Tag: sleep

You read that right. I mean: it’s really good news about teens and sleep.

We all want adolescents to sleep more. Better said, we know that they need to sleep more.

More sleep should benefit, say, their mental health, their physical health, and their academic performance.

Heck, they should just feel better.

One Obvious Solution

If teens’ biology prompts them to stay awake later and wake up later (it does), then we could help adolescents sleep more by starting high school later.

Although obvious, that solution has two important flaws:

First: we haven’t tested its efficacy.

Second: teens might just stay up later, and thereby rob themselves of the extra sleep we’re trying to provide. We just don’t know. (See previous paragraph.)

Here’s the first part of unambiguously good news: researchers have now tested the solution.

The city of Seattle, Washington delayed high school start times from 7:50 am to 8:45 am. Researchers measured lots of student behaviors both before and after that change. What did they find?

Teens and Sleep: Obvious Solutions Work!

First: students slept more. They got, on average, 34 minutes of extra sleep: from 6 hours 50 minutes to 7 hours and 24 minutes.

Second: they got higher grades. The average among measured students rose from 77.5% to 82%.

(The researchers hesitate to make strong causal claims; something else might account for the better grades. But, it’s a highly plausible hypothesis that extra sleep helped them learn more.)

Third: at one of the two high schools, first-period absences fell. (At the second, the absence rate remained constant.)

The researchers don’t make a strong argument about the reason for this difference. They do note, however, that the improving school has a higher percentage of economically disadvantaged students. Perhaps the combination of early start times and low SES made on-time arrival especially challenging.

Methodology

Part of the unambiguously good news: this study boasts particularly strong methodology.

In particular, it doesn’t rely on student self-reports — as so many sleep studies do. Instead, it asked students to wear a wrist monitor that tracked their activity levels.

Also, it took both pre- and post-change measurements. That is: they didn’t wait until after the change and then start measuring. Instead, they got a solid baseline, and then compared the after-effects to that baseline.

A final note: this article says that other school districts — and even states — are contemplating similar changes. Here’s hoping they follow through. And, here’s hoping that parents support these changes.

Do naps improve learning?

If you teach teenagers, you almost certainly want to know the answer to that question. Whenever I talk with adolescents about brains, it’s one of the first questions I get.

Alas: an important muddle makes that question noticeably hard to answer.

The Nap Research Problem Explained

On the one hand, we’ve got plenty of research showing that naps boost learning.

If I give you a list of words to study, you’ll remember more of them after a nap than you would if you hadn’t taken that nap.

In one study, for example, Olaf Lahl found that

“An ultra short period of only 6 min of napping is already sufficient to significantly boost declarative memory performance beyond waking control levels.”

You read that right. Even a SIX MINUTE nap helped participants recall more words.

But wait: there’s a problem.

We know that good night-time sleep is essential for consolidation of long-term memories. (Here’s a great article on the subject.)

It seems plausible to me that an afternoon nap might feel good at the time, but might make it harder to sleep at night.

If that’s true, then the short-term benefit of the nap will be more than offset by the long-term detriment of a bad night’s sleep.

In other words: I might remember that list of words better after the nap, but I might be likelier to forget everything else.

This uncertainty has always held me back from recommending naps.

The Nap Research Problem, Solved

Researches in Jintan, China looked at the cognitive results of napping — and their method fixes this research problem.

They gathered nap and night-time sleep data from 363 6th graders. And, they tested them on a variety of cognitive functions: executive control, spatial memory, and complex cognition among them.

What did they find?

First: frequent nappers get better nighttime sleep than infrequent nappers.

Yup: naps didn’t make it harder for these 6th graders to sleep. In fact, they slept better.

Second: frequent nappers did better on a variety of the cognitive tests. For instance, they did better on tests of sustained attention. (In schools, we require A LOT of sustained attention).

They also did better on tests of non-verbal reasoning.

In brief: frequent naps don’t make it harder to sleep at night, and they do improve some cognitive functions. Win win!

Nap Research in Context

This study’s authors wisely note two key limitations.

First, the data on sleep come from self-reports. This method, alas, allows for participants’ faulty memory to skew the results.

Second, the study took place within a particular cultural context. Naps are a cultural norm in China. That norm just might have an influence on the relationship between napping and cognition.

We just don’t know.

(To think more about the important of context, consider the perils of WEIRD neuroscience.)

For me, this study’s specific findings about cognitive capabilities are interesting. However, its general finding that naps don’t interfere with nighttime sleep means that the other studies about naps’ benefits can be taken at face value.

So: you’d like to take a 6 minute nap? GO FOR IT!

If you’ve ever met a teenager, you might be skeptical about the idea of starting high-school classes later. After all, you might worry that they’ll just stay up later. They are, after all, teenagers…

What does research on high school start time say?

According to a recent study done by Penn State researchers, you needn’t worry. Later high-school start times do in fact translate into more sleep.

Specifically: students whose first class started later than 8:30 got between 27 and 57 (!) more minutes of sleep. Imagine just how much more learning might happen if a teen regularly got an extra hour of sleep.

The researchers based these conclusions on sleep diaries that lasted only a week; I’d be more persuaded if they had data from a longer period of time.

However, this finding does echo a conclusion that I reported on back in April. Given these converging data–and, frankly, common sense–I’m inclined to believe that later start times really do help students get more sleep.

Research findings that support later high-school start times have been more and more common in recent years. (See also here.) And teachers I know are increasingly vocal about letting teens sleep later.

And yet, when I talk with high school leaders, they ruefully cite sports schedules to explain the impossibility of making serious changes.

(I’ve also read that bus schedules get in the way.)

Here’s another–quite surprising–reason that this change might be hard to accomplish: parental uncertainty. According to this recent study, published in the Journal of Clinical Sleep Medicine, half of parents whose teens start school before 8:30 don’t support a later start time.

The study concludes that we need to do a better job educating parents about the biological changes in adolescent sleep patterns.

The more that parents understand how melatonin onset–and, hence, sleepiness–changes with adolescence, the more they might understand that their awake-at-midnight teens aren’t simply being willful. They are instead responding to powerful chemical signals.

Given all we know about adolescent sleep, and the effect of sleep on learning, teachers and parents should be champions of reasonable high school start times.