How To Take The Ideal Nap And Avoid Bad Sleep

Sleep expert Matthew Walker explains how naps can negatively impact your body.

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Following is the transcript of the video:

Matthew Walker: My name is Matthew Walker. I am a professor of neuroscience and psychology at the University of California Berkeley and I am the author of the book, "Why We Sleep."

Should we actually be taking naps during the day? Well, we certainly know from evidence in my own sleep center and that of many other scientists that naps can give you benefits for both your brain and your body. But naps can actually be a double-edged sword because whilst we're awake during the day, we're building up sleepiness or sleep pressure. So that when you try to fall asleep at night, you'll fall asleep quickly and then you'll stay asleep. And when we sleep, we actually release that sleepiness, almost like a valve on a pressure cooker, so that we wake up the next morning feeling refreshed.

So if you take a nap during the day, especially if you take it too late in the afternoon, you will actually release some of that sleepiness and it will make it that much more difficult to fall asleep and stay asleep soundly throughout the night. So the advice would be if you don't struggle with your sleep and you can nap regularly, then naps are just fine.

But if you do find it difficult to fall asleep or stay asleep at night, then you should avoid naps and try and build up that healthy sleepiness in the evening.

The ideal nap depends on what you want from that nap. Different stages of sleep actually give you different types of brain and body benefits.

But if you want to avoid that grogginess that you can often have after a long sleep, then you should perhaps avoid naps that are longer than maybe 40 or 50 minutes in length.

You should also try to avoid naps late in the afternoon so that you wake up at least after you finish the nap and still have enough time to build up that sleepiness, that sleep pressure so you can get to sleep in the evening.

Can naps help with sleep debt?

Walker: And the answer, unfortunately, is no. Sleep is actually not like the bank. You can't accumulate a debt and then hope to pay it off at some later point in time. So sleep is an all-or-nothing event in that sense. So you can't short sleep during the week and then try to binge and oversleep at the weekend.

So if I were to take a human being and deprive them of sleep for one night, so that they've lost eight hours of sleep and then I give them all of the recovery sleep that they want on a second, a third, even a fourth night, they do sleep longer but they never get back that full eight hours that they've lost.

And we can ask then, "Why isn't there some kind of a credit system in the brain? Why don't we have a cell that can actually store up that sleep?"

Because there is precedent for this. We actually have a storage system for calories within in the body and they're called, "fat cells." Because there was a time during the evolutionary process where we had feast and where we had famine. And when we had feast, we would store that caloric energy and fat cells that when we went into a debt during that caloric famine, we could actually survive.

Human beings are the only species that deliberately deprive themselves of sleep for no apparent reason. And that means that Mother Nature has never had to face the challenge of sleep deprivation during the course of evolution and therefore, she's never had to come up with a safety net mechanism that overcomes a sleep debt.

[jennyoyster]

A 15 minute nap feels so amazing, you guys. I always feel so refreshed and relaxed when I wake up. Once you go past 30 minutes, in my opinion, you’re heading towards sleep. That’s not a nap.

[harinath]

He simultaneously looks 46 and 19 at the same time.

[iiNeedSkins]

I slept for 19 hours yesterday, was glorious.

[tavovv]

0:55 buddy jumped in his bed with his shoes on. Wtf.

[maltezz]

i once slept 20 hours, was awake small peroids but for some reason i were just tired as hell, i remember it as epic i kept going in and out of the same dream almot like being in a movie.

[glenaldsouza]

Well nothing can stop me from sleeping after lunch in my college.
XD

[RedGamingChair]

So from what I understand, nap is sleep during day. And sleep is... sleep. Also I have had a 15 minutes nap. During this pandemic, online class is all there is. For me, there is 15 minutes gap between every subject. Theres this one time where I took a nap and woke up 15 minutes later and it feels so good and refreshing! I was so ready to get in class! I want to do that more!!!

[u.s.a]

to all impatient people:
if you nap and find difficulties sleeping at night don't nap if you don't have difficulties sleeping after then it's ok to nap and the nap should be around 40 to 50 minutes not more
there I just save you 3 minutes

[LeviAckerman-lnkt]

I usually use "Naps" to catch up on missed night sleep. Longest "nap" I've ever taken was 4h. But I only got 3h of sleep during night and I REALLY needed it. Usually my naps are like 60-120min. I know that feeling of "UGGGHH" but the tiredness is gone and that's what I want.

[timclarinlazaro]

How about college students when it comes to taking a nap? Every time after school, I always feel tired!!!!

[mbogdanov]

2:16 actually that's exactly what has been happening to me for many years now - 6-7 hours every week night and then on saturday normally I sleep 10-11h (sometime on sunday too, but mostly saturday)

[shh]

Upcoming next: breathing could be dangerous

[glorysky]

I can never sleep well because my legs are crushed by my huge dog, also gaming online and watching these videos keep me up.

[OnlySatire]

Me at 2pm: okay 10 minute nap
Me wakes up at 1:07 am : dammit

[syameful]

i get sleep paralysis almost everytime i take a nap

[loctruong]

I am reading 40% of his book:"Why we sleep". I found the consequences when we don't have enough sleep. Use youtube to find some tips for a good nap, I see him, introduce himself the author of the great book. It is miraculously coincidental. 😅😅😅

[icatputla]

What if I only sleep 4 hours at night and then I take a nap and sleep for like 3 hours to fullfil my 7 hours of sleep, then I sleep normally in the next day, how about that?

[gioch]

Ok so I wake up @ 5:45 AM Mon-Fri for college. When I get home from school @ 4:30 PM I sleep for 3+ hours, wake up around 8:00 PM (which causes grogginess due to sleep inertia), and I end up going back to sleep @ around 2:00 AM the next day. Repeat.

[ashknoecklein]

What about marine mammals that sleep one hemisphere at a time? That sounds like an evolutionary answer to sleep debt to me. From my understanding of elephants, they only sleep about 2 or 3 hours a night, and when they have to forego even that small amount of sleep it appears to have no negative effect on them. And prey animals that live on open plains in groups barely sleep as well. I'm not saying humans should forego sleep, but I don't think that sleep is the same for all living creatures.

[hxsmvwy]

Thanks alot, I was having a lot prob with it. I used to sleep 1.5 hrs at afternoon and thought why I'm not feeling fresh at morning..