A daytime nap is good for the brain | Hacker News Reader

A daytime nap is good for the brain

bbc.com

433 pointsandsoitis217 comments

My napping routine is to lay down, tell Siri to set a timer for 25 minutes, tense all the muscles in my body for 10-15 seconds, the relax every muscle and imagine black nothingness, letting go of all other thoughts for just a few seconds. 9 out of 10 times, the next thing I hear is my alarm going off, and myself saying "fuuuuck!" because I feel like I had just drifted off and I want to keep sleeping. But I force myself to get up and go on with my day because if I nap longer I'll end up super groggy the rest of the day and have trouble sleeping at night. For me, 18-24 minutes napping is the sweet spot.

I thought I was alone doing this "body tensioning" technique.

That sounds a bit similar to progressive muscle relaxation[1], where one goes through different muscle groups and tenses, then relaxes them one after the other.

[1] https://en.wikipedia.org/wiki/Progressive_muscle_relaxation

I heard soldiers use a similar technique to be able to sleep while in stressdul situations (e.g. during a siege) I try it as well and while i havent got it down as well as you have it works well for me 80% of the time

That's a nice routine, but the alarm going off sounds to me like pulling out the power cable while the hard drive is defragmenting or while the OS is applying updates.

Well done sir, this is a well crafted analogy

all depends on the alarm. I took the time to find a gentle one and it's probably why I nap a lot more often now. There's still the danger of it putting my day to a dead stop but quite often it feels like a net good. Also sleep on the floor to help prevent a deep sleep

How can you achieve that? I just can't nap, it takes me around an hour to fall asleep.

You don't need to actually fall asleep for a nap to be beneficial. I like to lay on the floor, feet up, and alarm set. 10-15 minutes and I feel completely refreshed.

This isn't a replacement for actual sleep, but I've never been a napper and the above I found super useful for me.

I second that, even closing the eyes for 10–15 min feels refreshing. Learned that when our kid was younger.

I literally described how I achieve it. I don't "try to fall asleep", that never works.

Black nothingness doesn't work for me, I think of loud ocean waves bashing against rocks.

I listen to my tinnitus.

Same. Self hosted white noise. Forever.

11.5khz so not as white noisy as I'd like. Got turned up to 11 last month, reshuffling my life deck. Learning awesome new coping skills and burning thru todo lists.

What you are doing is called yoganidra, popularly known as guided meditation. You prepare your body, your mind, relax all your muscles, determine what this session is about(relaxing), visualize something that helps you not get distracted and the next thing you know is you are deep into nothingness.

And its smart to not stretch it beyond 20-25mins, our single sleep cycle generally is between 90-120mins, of which the first 20-25mins is the a first stages of non-REM sleep(this gets shorter after the first sleep cycle in a way) in which our body is relaxing but our mind relaxing but fairly active. This is light sleep. Beyond this stage we slowly enter into deep sleep stages in which if you wake up you feel very groggy, if you find yourself waking up feeling groggy, its better to finish the complete sleep cycle of ~90mins, like a complete sleep cycles.

It's neither guided nor a meditation. It's a physical trick to make my body fall asleep.

Those things are not mutually exclusive.

Doesn't matter, you achieve meditative state guided by your actions. It doesn't need to be external nor is there a strict guideline to be in the state of meditation.

Yup very similar to you. 15 minute Power Nap and feel super good a few minutes after.

Perfect to do anywhere but not in the office. Now that RTO is plasteted all over

I like this guided NSDR session with Andrew Huberman. He pulls you out after 10 minutes in a nice way that gently reintroduces your CNS to reality.

https://youtu.be/AKGrmY8OSHM

I used to do it in army. Just roughly 20mins of nap and warmth can really get you back on the feet, just enough boost to survive the day. And after some time you don't even need to set the alarm, you just wake up, brain learns the routine.

>if I nap longer I'll end up super groggy the rest of the day

this basically comes down to human sleep cycle, if you get woken up during deep sleep you will feel like shit. So you either have to go for a short nap like you are doing or around 90 minutes

Jealous - as someone with Insomnia I will never be able to do this.

Obviously this may or may not work for you. What worked for me is finally letting of this thought that I can’t sleep. Started keeping the devices and distraction away and just trying to sleep, by lying down and closing my eyes and doing nothing else. Even if thoughts kept hitting I just kept in bed, eyes closed. Kept at it. Started improving. Now it’s much better. Again, this may not work for you. Just thought I’ll share.

But even if I couldn’t sleep and sometimes I still can’t - at least now I have stopped worrying when I can’t sleep. It relaxes me a lot.

Although I wouldn't qualify it as insomnia, I usually have troubles sleeping due to racing and intrusive thoughts. One thing that worked is counting backwards from 40; whenever my mind drifts, I start from 40 again. Eventually, it (or I) succeeds.

The ideal time to nap is 18-25 minutes as you said, but I find it hard to fall asleep at the "right" time. So it's always a trouble to set the alarm for me.

I strongly suspect that you don't need to actually get into a sleeping state for an attempted nap to be beneficial. It loosens the bolts of the mind a bit. As long as you can stop attending to the signals of the outside world, you free up a little brain power to do a little relaxation/mental de-fragmentation. The problem is that sometimes people feel if they didn't drift off that it was a waste of their time (usually it's people who are always busy who feel the loss of 15 minutes as the most damaging), and feel worse off after. The key idea is to be able to up-regulate or down-regulate your mental energy expenditure per unit time (or 'power') as you feel necessary. If napping affects your sleep schedule negatively, it's because you feel it gives you too high an energy level at an inappropriate time, i.e. that it negatively affects your ability to manage your energy level better at will.

I nap regularly and sometimes even a flash nap (?) where I fall asleep for what feels like only 30-60 seconds, and I can still feel quite recharged.

Same here. Methinks that even just losing consciousness does something to recharge the mind.

One of the things I learned from researching sleep in preparation of becoming a parent is that sleep is sleep. Rest is not sleep. To get the benefits of sleep, you have to sleep.

Resting does give you benefits, but they are not those of sleep. You cannot replace sleep with rest and expect anything comparable. I don't remember the primary source but I do know it was emphasised in sleep management policies in military contexts.

That said, I agree with your overall theme. Get some relaxation and don't worry so much about the sleeping. It takes training to learn how to nap, especially in the high-stimulus environments of today. But if you stress over sleep, well, that surely won't get you to sleep!

> One of the things I learned from researching sleep in preparation of becoming a parent is that sleep is sleep. Rest is not sleep. To get the benefits of sleep, you have to sleep.

I agree with the parent comment you replied to.

There's a middle mental relaxation state that is not deep sleep, which will give enormous benefits for mental freshness aftwerwards. I identify it when my mind is no longer "driven" by my conscious process but is wandering off, and I am awake and aware of this status.

>I am awake and aware of this status.

I really enjoy this state, but I find it hard to keep it going for very long. Pretty soon I think about how great it is that I'm not thinking, and it's all over.

Recognizing that you are thinking of nothing and especially being aware that period is now over is forward progress. Keep at it and you will be able to "meditate" much longer.

For me achieving a successful nap means getting to the stage of dreaming. If I wake up from a vivid weirdness (dreams don't make sense most of the time), then it's certain I'll feel energetic in about half an hour.

Otherwise it's some form of rest rest but I still feel tired. It's extremely annoying trying to concentrate when feeling tired.

This would be somewhat like meditation, from how you describe it :-)

I’d often sit in my car at lunchtimes and do a guided meditation.

It did help during my corporate days.

All known evidence points against this

I’ve read several articles recently that say the opposite, so I did a quick search and found multiple studies that seem to contradict you almost immediately. For instance:

https://pubmed.ncbi.nlm.nih.gov/19379769/

https://pubmed.ncbi.nlm.nih.gov/29717187/

https://pubmed.ncbi.nlm.nih.gov/29883710/

https://pubmed.ncbi.nlm.nih.gov/31852988/

https://pubmed.ncbi.nlm.nih.gov/34011516/

I’m certainly not arguing that the science is settled on this, but it seems far too strong a statement to say that “all known evidence points against this” when I could find several studies supporting OP’s point pretty much instantly.

No one said that rest does nothing, but rest is still totally different from actual sleep. You aren't getting the benefits of sleep from resting. People here just want to think that it's true, because it sounds convenient

Not sure if it's worth bringing up but I intended for my earlier comment to be about how rest is not awful just because it's not full sleep. Which, somehow, seems to be the opposite of what people think I said. Go figure.

It's beneficial in a way that is totally orthogonal to the ways in which sleeping is beneficial. If you just try and rest and never sleep, you will have all the negatives of total sleep deprivation

That is true

After years of being on this site I strongly suspect there is absolutely no correlation between being a good software engineer and being able to extrapolate into other fields without also putting in about the same amount of studying time. A lot of people in our field are extremely logical, but there are so many posts like this where decades of research are ignored from other very smart people in favor of conclusions drawn from thinking "logically" about the problem for ten minutes similar to Aristotle. Every so often someone happens upon a good conclusion, but not usually. There are so many studies, over decades, showing these thoughts to have no grounding.

A lot of words to insult the OP but nothing helpful or clarifying added to the conversation.

The HN way.

The Dunning and Krueger approved way.

I actually find it a helpful reminder. "People spout shit. Don't just blindly trust it". Otherwise, you end up chasing things, thinking they help, when there is little evidence backing it up other than someone's opinion.

But very true regardless. Reading HN for health advice is like talking to your barber about stock options. A way to spend time but not to get information to work off of

Personally I really reject the notion that an area of knowledge is strictly reserved only to those who are "officially", if you will, acknowledged as experts. On the one hand, there are many, many studies and bodies of research and so on once accepted that later have been proven wrong and even deceitful in purpose, so there go your "experts". And in the other hand there are countless examples of people sharing knowledge on topics they are "not experts" in. These are maybe more difficult to document, for obvious reasons, but at least at a personal level I've had enough of them to become keen on listening to personal anecdotes and "the wisdom of the village elders" if you get my meaning.

> There are so many studies, over decades, showing these thoughts to have no grounding.

Can you be a little bit more specific? I'd be interested to hear what the counterpoint is as personally I feel refreshed after a 15 min lie down in the back of my car at work, even if I didn't perceptibly fall asleep.

OTOH, if "simple logic" (or, often enough, thinking from first principles) seems solid, and no one seems able to point out a specific error in logic or a specific faulty assumption, and all the criticism boils down to "smart people write smart papers on this therefore you know nothing therefore you are wrong" - I'll put my bet on the "simple logic".

So you are betting on stuff that just sounds OK (because there is huge lack of knowledge)?

You can make as bullshit claims as you want that will be logically sound

The best examples of this are conspiracy theories

Conspiracy theories make several bad assumptions that are easy to spot once you know what they are. Sure, that's knowledge, but arguably generic one.

What I'm saying is, "you don't know a thing 'cause it's not your field" is a good heuristic in absence of any extra information, but if the logic is sound, the author seems to have high generic skills in reasoning/logic/rationality and good model of the world, and no one closer to the field is raising any specific objections, then that heuristic breaks down, as it's becoming more likely that the author got the gist of it right.

I wouldnt rely nor use this approach at all, it is not only dangerous but feels useless

>logic is sound, the author seems to have high generic skills in reasoning/logic/rationality and good model of the world

What is good model of the world? The one that is coherent with yours?

Ive witnesses too many stupid ideas based on this "sounds logically" that Im fully against suggestions like this

But there is solution!

Just put effort into learning your stuff, so you aint gonna have to make a guess and waste time convincing yourself how rational your "not so educated guess" may sound

I think you two are collectively very close to describing “science”. It’s good to acknowledge what we don’t definitively know, but generating testable hypothesis or theories based on experiences and known phenomena is an important step.

There are topics we don’t know the truth on, so we have to theorize. For instance, dark matter, or origins of Covid, or evolution, even. We could throw our hands in the air and say “we don’t know anything”, but part of coming into knowledge is taking an educated guess on the answer, testing it, and being right or wrong. From there, we recalibrate.

The problem comes when people dogmatically defend their old, disproven hypotheses in the face of insurmountable evidence. Not situations where people have valid critiques or are skeptical, but situations which are pretty open-and-shut. For instance, flat earth has always seemed to me to be a very obviously wrong theory.

Before the Snowden leaks, it was generally considered to be a conspiracy theory, that the NSA hacks allmost everyone, ignoring any law.

But to technical people, it was a sound theory, that proofed out to be right.

That's the difference between a theory that lizard people invented Covid, or that Kubrick shot the moon landing. Those theories fall apart very quickly, if you apply logic.

So I am no fan of appeal to authority arguments. If the experts are real experts, then they can use logic, to simply show where the layperson's arguments are flawed, where it is missing context or deep understanding of the field and point in the right direction. But if they cannot - then maybe the layperson has a point.

Of which many have turned out to be, surprise surprise, very real and true.

I love your logic, but can you provide a source?

Sure, I agree with all that. Although, I have two heuristics:

- 1. listening to my body's tiredness is probably a safer general strategy than pushing myself to the brink as a general strategy. It would be extremely surprising if this was not the case, going in the face of thousands of years of folk wisdom and decades of research. I'd welcome that finding since it'd be a rich source of future discoveries, turning much of common wisdom about sleep and rest upside-down

- 2. it confirms my biases about the ideas I've liked and cherry-picked from [0], [1], [2], and [3] :^) - I'm willing to update my beliefs in the face of new analyses/results, but is there really any epistemological way for me to try to derive real life benefit in a valuation-free way? At some point one makes a lossy approximation of reality in one's desired habits. At some level this is scientism, sure, since it's dangerous to assume one's observations are reality itself, but, it keeps me happy enough with the results. And it's fun to watch the meshing together of ideas over the years, as research pierces deeper into the world's veil..

I'm not the arbiter of the mechanics of internal bodily conscious experience, however, so, grains of salt and all that ¯\_(ツ)_/¯

[0] Partial sleep in the context of augmentation of brain function (2014), https://pubmed.ncbi.nlm.nih.gov/24822040/

[1] The visceral theory of sleep (2013), https://pubmed.ncbi.nlm.nih.gov/23697225/

[2] Integrated Information and State Differentiation (2016), https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4923128/

[3] Topographic-dynamic reorganisation model of dreams (TRoD) – A spatiotemporal approach (2023), https://www.sciencedirect.com/science/article/abs/pii/S01497...

Aristotle, well-known for thinking about things for only 10 minutes.

So true. And in fact I would argue that it is more often than not the opposite (they apply logic to things that are not, in fact, at all straightforward logical - like biology)

What research says that resting without napping has no benefits?

It was always so draining going for lunch with work colleagues, that couldn't stop talking about work and tried to eat as fast as possible.

It doesnt work for me

Lying in bed trying to sleep doesnt count as sleep

Huberman is constantly talking about the benefits in the literature of non-sleep deep rest (NSDR) and yoga nidra so I tend to believe the science backs you up too.

I read somewhere that growth hormone gets released after a proper nap (not just rest, maybe 30 min or so). Body builders, and actors preparing for roles where they bulk up need to take several naps a day. I don't have a source handy, unfortunately.

That sounds like an plausible excuse of two groups who buy HGH

As explained to me by a sleep doctor, sometimes people do feel as if they didn't sleep after a nap, but still feel rested. We often don't remember stage 1 or 2 sleep but that doesn't mean we didn't sleep.

So yes, a nap is valuable even if you feel you didn't drift off, but it is not necessary to invoke mental energy expenditure as an explanation.

Whether or not this is “backed up by science” (as replies have focused on), my own personal long term experiment says that for me this is absolutely the case. At a certain lull in the day I can either take some time to relax and feel rejuvenated for the remainder, or I can expect to drag throughout. “Loosen the bolts” is an apt metaphor and exactly how I feel.

The number one reason why I appreciate remote work is there's zero social stigma to taking a power nap.

you touch on a fatal flaw of the current approach to RTO.

you know what we need? business hammocks!

I'm one of the few people that use the "nap pods" in my building. I definitely a little weird in doing it but some days it's just my better for everyone if I take a brief nap and return to work more rested

Can you share more info on these nap pods? I've never seen those on where I live. Genuinely interested

Google famously had nap pods: https://www.theguardian.com/business-to-business/2017/dec/04...

What was freaking cool one place I worked was a gym in the same building that had a quiet room.

But some spare space, air beds, eye masks/ear plugs would do the trick.

The key of motivation is trust.

By any chance you work at Globex Corporation?

No thanks, I'd rather work from home instead of living at the office.

One of my pre-pandemic in-office employers had a few hammocks around... Just saying...

And it's synergistic with making private spacves to accomodate praying or expressing milk.

So are private offices, win win.

Popular sit/stand desk company Uplift literally sells hammocks that can be strung under their (wider) desks:

https://www.upliftdesk.com/under-desk-hammock-by-uplift-desk...

I stuck a 4ft diameter bean-bag-esque chair in my office. I encourage others to do the same!

I sneak off to the parking garage at lunch time to have a Power Nap in the back of my car. Tinted windows mean I'm totally invisible, and I can get 25 min of good rest. It is a highlight of my day

Do you drive a Rolls Royce Phantom?

Haha nope, Tesla Model 3. The back seat is juuust wide enough to lie down in the back for a nap. I’m 6’2” so it wouldn’t be comfortable overnight but for half an hour it is enough.

A woman at work recently told me she naps in her car after her daily walk. It made me think that I could probably put the back seat down in my car and put an inflatable mattress on it and nap anywhere.

If I made a habit of sleeping in my car, I would consider one of these:

https://backseatbivy.com

In fact, I have considered one in case I just want to (for example) drive to a trailhead the night before for an early morning start, and catch some sleep in the car without setting up a tent and all.

In parts of Asia, it's common for workers to bring a sleeping bag, office lights turned off during lunch break, and take a nap.

In the US, I used to sneak away for a nap during lunch. It's amazing how much more energy I have in the afternoon.

I think naps should be encouraged by managers in American work places. For example, give a small bonus to people who take 15-30 minute naps. I know if I ever run a company, I'd have a nap policy and provide safe spaces for workers to nap. A long time ago, bosses discovered that coffee increased productivity. I don't see why 15-30 minute naps shouldn't be encouraged by bosses.

Most people are somewhat sleep deprived, whether it's insomnia, anxiety, long commute, parenting, etc. For me, if I didn't get more 7 hours of sleep the night before, my productivity is half of a normal day. A nap can boost a worker's productivity significantly for half a day. It's better than stuffing yourself with coffee, which is unhealthy and provides more of a nervous energy than productive energy in my opinion.

When I went to China for work my coworkers office chairs laid all the way back, parallel to the floor. The lights kicked off for an hour after lunch for a nap. Meanwhile my manager and I worked in the dark...

If I were your boss, I'd tell you to follow up that nap with a coffee and then GET BACK TO WORK :)

But.. there is the alternative theory of the "caffeine nap" a.k.a. "coffee nap" - that you have coffee just before your nap, and then the coffee's first effect (dilating blood vessels) helps you fall asleep before the second effect (increased alertness) kicks in.

I've been napping my entire life. When I had to go into the office I always went into a Starbucks, ordered the cheapest drink of their filthy selection, then went to their biggest sofa, put on my headphones with classical music on, leaned back and had a nap. On the way back to the office I'd grab a takeaway meal and then eat by my desk.

in an office you can't even close your eyes for longer than 10 seconds with the intention to visualize something or think deeply without someone asking if everything is alright.

In my experience, even better than a 30 minute nap is a 15-30 minute Non-sleep Deep Rest (NSDR) or yoga nidra session (popularized by Andrew Huberman). It's a guided meditation of sorts where you do a body scan; as the narrator names different body parts you place your attention on the sensation at that body part. By occupying your mind on physical sensation, in conjunction with slow, deep breaths, you're able to consistently and efficiently achieve a relaxed, restful state.

So at noon I set my slack status to avocado emoji "eating lunch," pop a caffeine pill, then lay down with an eye mask and noise cancelling headphones for half an hour while an Australian woman tells me what to feel.

> So at noon I set my slack status to avocado emoji "eating lunch," pop a caffeine pill, then lay down with an eye mask and noise cancelling headphones for half an hour while an Australian woman tells me what to feel.

This sounds like something a 2020 Patrick Bateman's would write.

I used do it, but with Ritalin! (Prescription for ADHD)

Smiling Mind app, sit in my car, nice and relaxed and quiet.

It made my corporate afternoons tolerable and productive, and avoided the post lunch time lull!

Huh, that is definitely not the same as napping...

"popping a caffeine pill"?

The caffeine takes about half an hour to kick in. When I was in college I would drink a cup of coffee then take a half hour nap. I woke up feeling great and ready to work.

I expect as the caffeine takes a while to metabolize. They'll get the rest naturally from their body, and about 30 minutes later when they're ready to wake up - the caffeine will also be kicking in to give a nice jump start.

A study I read yonks ago concluded that consuming caffeine and then taking a short nap made it very effective at increasing productivity.

A coffee nap has a stronger effect than coffee or nap alone.

For me a nap is enough, usually set the timer to 12 minutes but feel energized after 10.

Caffeine withdrawal takes two weeks but was worth it. My ADD gets worse on it. Combined with Methylphenidat it feels like trying to drive full throttle into a dead end with a drawn handbrake.

Here is an interesting guide from the Royal College of Physicians (UK) that recommends a caffeine nap to help with the night shift.

The sections on Napping, and also the section on Caffeine are interesting. The gist of it is the caffeine will take 20 minutes or so to take effect, so by combining it with a short nap you get a double whammy.

https://www.dgeducationcentre.co.uk/wp-content/uploads/2016/...

I generated this 15 minutes audio file 20 years ago and it's still my go-to for quick meditation breaks. It never fails to put me into a trance.

[link redacted]

Very interesting, thanks for sharing

Thanks, trying this out right now on my lunch break. What's the idea behind this overlayed helicopter sound?

Well, the software that I generated it with says it's "brainwaves".

I remember reading up on it back in the day and I couldn't figure out if it was woo woo or something with proper scientific backing. I have since then tried a number of apps that claim to do the same but which don't work for me. This piece of audio works for me, so that's why I keep it around :-)

The Australian Smiling Mind app is excellent for this!

I’d sit in my car at lunch time and do a body scan.

It helped when in corporate land.

> In my experience, even better than a 30 minute nap is a 15-30 minute Non-sleep Deep Rest (NSDR) or yoga nidra session

this is a published study that measured physical brain size over the long term, and not a suggestion that you'll feel better. What you are suggesting is not comparable in any way.

I'm not sure if it's NSDR but my best naps are those where I'm not sure if I've been asleep or not. After lunch, I just put the mid day news on TV and close my eyes while listening to the presenters.

Why the caffeine? Is that not counter productive?

If you do find that beneficial you might want to try the nicer japanese green teas - they have higher amounts of L-Theanine which has relaxing effects on the brain (and of course caffeine as well). Works much better for focus than just caffeine alone in my case

Caffeine naps are awesome, you just have to fall asleep before the caffeine wakes you up, but you wake up caffeinated. If I do it too tired though, I can sleep past my alarm, caffeine won't necessarily wake me up from a sleep, but will make me feel very groggy if I don't wake up before it's peak is passed.

Since no one has posted it, here’s the article [1] (at least the preprint version)

Two things I noted:

1) While there was an association with increased brain size, no correlation was found with cognitive function

2) This study was done with Mendelian Randomization, where they find a gene that affects how much people nap, without affecting other things that could change the results. I don’t know that much about MR, but maybe someone else could weigh in on how fallible it is in a case like this (how can we know that a gene that affects napping, which is initiated by the brain, doesn’t affect the brain in other ways).

[1] https://www.medrxiv.org/content/10.1101/2021.09.28.21264215v...

published version: https://www.sleephealthjournal.org/article/S2352-7218(23)000...

> Overall, we observed evidence of an association between genetically-instrumented daytime napping and larger total brain volume, but no evidence of an association between habitual daytime napping and hippocampal volume, reaction time or visual memory.

Yeah, this is big brain time.

Does this mean that if you take too many naps your brain will eventually inflate so much it'll start pressing onto the skull and give you headaches, or just that people with larger brain volume seem to have more of a tendency to nap?

Thanks for that!

> While there was an association with increased brain size, no correlation was found with cognitive function.

Somehow "Daytime naps cause swelling of brain, no tangible benefits" doesn't sound the same...

Humans are naturally biphasic sleepers.

Pre-industrialization, humans would wake up at sunrise, go to bed quite early, and wake up for a couple hours in the middle of the night to have sex, chat, or do light activities like reading or writing (this is where the phrase "burning the midnight oil" congress from). When societies industrialized, most of this went away because people needed to be in one physical location (the factory) for an entire work day.

The important thing is that the human brain isn't built to be active for 16 or 17 hours nonstop. Some cultures that understand this take siestas, but I'd argue that even the mediation or prayer breaks in other cultures can be enough to punctuate the day and give the mind a chance to decompress a bit.

What's your source for that specific biphasic schedule? Piotr Wozniak has quite convincing hormonal evidence that seems to indicate to me that humans are meant for a full night of sleep and a nap -- which is still biphasic, but not in the sense you describe.

Hard to imagine anything different. Without light and frequent bordem (no phones etc.), very unlike to stay awake for 15 hours straight.

I don't think either of us are claiming 15 hours straight.

GGP is claiming something along the lines of AAAAAAAAAAAASSSSSSAASSSS repeated, with A=awake and S=sleeping hours, which is 12 hours straight at most.

What I remember Wozniak claiming is something like AAAAAAASAAAAAAAASSSSSSSS, which would be 8 hours straight at most.

AAAAAAAAAAAASSSSSSAASSSS = A12, S6, A2, S4

AAAAAAASAAAAAAAASSSSSSSS = A7, S1, A8, S8

Cats sleep 16 hours a day so I guess it might work out as something like ASSASSASSASSASSASSASSASS. You're welcome.

Humans: AAAAAAAAAAAAAAAASSSSSSSS

Cats: ASSASSASSASSASSASSASSASS

Sounds about right.

The Thomas Wehr experiment [1] in the 90s (which showed that people settle into 2 distinct periods of sleep throughout the night when they're removed from all artificial light), as well as Roger Ekirch's [2] historical research (which documented the mentioning of "first sleep" and "second sleep" throughout many cultures in pre-industrial society).

[1] https://en.wikipedia.org/wiki/Thomas_Wehr#Research

[2] https://harpers.org/archive/2013/08/segmented-sleep/

Thanks! It's hard to tell from a glance how realistic the Wehr experiment was in terms of simulating a workday, but I'll look into it!

The historic research seems focused primarily on the biphasicity of sleep, but I'll see if I can find out what evidence there are for specific biphasic schedules.

The problem is that we don't all have the same sleep schedules, which makes sense so the tribe would naturally have some people awake at all times to watch for predators. This doesn't mesh with our modern world where everyone needs to conform to the majority's work schedule. Trying to find a universal inherent schedule that everyone can follow to the letter is fundamentally based on wrong assumptions.

Our modern world has people working the night shift, service workers that finish around midnight (restaurants) or in the middle of the night (bars), people on vacation or who don't work and stay up late, night people who get to make up their own schedule, etc.

The fact that working a 9-5 is the social norm doesn't mean everyone does that.

We did that during the agrarian period before modern times, but evidence suggests that hunter-gatherers did not do it, or at least much less, instead staying up late at the camp fire.

How do you wake up in the middle of the night without artificial light? What are you doing at that time?

Maybe in Europe. In sub tropical and tropical places, people just went to bed at 8p and woke up at 4a throughout the year.

I have heard this argument but also the argument that the reason people woke up in the middle of the night was to stoke a fire (or other heating device). Personally I am not entirely convinced.

I am a believer in some people being more tuned to night owls or morning people however (not that it is super firmly set in stone - just a bit of a trend). There is also the theory that this benefited smaller societies since having a few people awake at all hours while others slept would have been good for noticing threats.

Combining these two thoughts actually may be the answer - perhaps we are not biphasic but that few hour window in the middle of the night was driven by the night owls and the morning peoples drive to socialize with one another (sex, eating, etc as you say)

Semi-OT, but it's funny how as a kid I found it very annoying when adults tried to get me to take a nap, but as an adult I love them.

On the other hand, as a kid I found it very annoying and as an adult I still find them annoying. I always wake up from them groggy and in a complete panic, feeling like I've overslept an entire day and am late for something. Totally not worth it, give me a full night's sleep over that any day.

One size does not fit all. FWIW, I also wake up from naps feeling slightly zombified, but I bounce back relatively quickly.

A good tool for rejuvenating yourself for the second half of the day, equivalent to a short nap, is what is called "NSDR" or non-sleep deep rest. Huberman has a guided session for this on youtube: https://youtu.be/AKGrmY8OSHM

I have always found guides of this type to be a little oppressive - I spend more time trying to figure out if I’m doing everything right to match the explanation of whatever the guide says than meditating.

I think we are damaged by school. The teacher was always there to make sure we followed instructions correctly, rarely to provider guidance for our benefit.

> I spend more time trying to figure out if I’m doing everything right to match the explanation

When I started doing guided meditation (via Headspace) the person properly explained beforehand that this is normal at the beginning: we can be too self conscious (and self judgemental), and learning to follow the prompt without thinking too much about doing it "right" is part of the process.

I seem to recall it was explained like: "when you're watching a movie, typically you don't think about your self watching a movie, you just... watch the movie"

I think it's useful in beginner-intermediate meditation as a lot of people don't necessarily have the wiring innately to follow up on the actions required. For example, doing a full body scan if you're a newcomer is probably very difficult without guidance

Yeah. That's why working from home is soooo good. How many times in the past there were days I was struggling and feeling sleepy/tired in the office, sitting there, not being productive. Now, when something like this happens, 15 minutes nap/lying in bed helps to recharge batteries for the rest of the day.

I've prioritized my sleep heavily since starting WFH many years ago. It's been great.

I don't even get out of bed till 1pm at the earliest when WFH

Best thing for me is the extra 2 hours gained by not commuting. Saves so much stress.

Working in China, the whole office shuts down after work and everyone pulls out their foldable beds and naps for 30 minutes. I'm sitting here commenting on HN like a dummy.

> the whole office shuts down after work

At noon? or evening?

lunch time

yes, lunch time.

that sounds nice, but doesn't China also have a culture of working insane hours? (9-9-6)

Apparently that might be specific to the Chinese tech industry.

I am actually working in a tech company - the hours are better than our US (SF) office... I am super jealous.

Another thing we can learn from them.

~ However, the scientists recommend keeping naps to less than half an hour

That's misleading as nap length isn't something they looked into. Seems like it's based on other studies.

Pilots flying long flights are generally limited to 45 minute naps, because after that time you start getting into deep sleep. Waking up from it can leave you feeling more tired than before the nap.

I always learned you should either sleep 30 minutes or less, or 90 minutes or more, to prevent waking up in the middle of REM sleep and feeling more tired than when you started.

It really depends on the person. Those guidelines are a good starting point, especially for those who nap infrequently. When I was taking a siesta every day, I’d sleep about an hour with a full REM cycle and wake up easy.

No citation at hand, but one study recommended sub 15 minute naps. I set my timer to 12 but usually want to get up after 10 minutes.

Depends per person but some people go into deep sleep around an hour, some 45 like you say, etc. Best to just experiment. From personal experience I give my alarm a bit more time just because I know it takes me a long time to fall asleep.

If going for longer than say 45 though I need a minimum of 2 - 2.5 hours or it will just make things work. But a 2 to 2.5 hour nap can also really make a difference if truly exhausted.

As I went through my 30s, I started to value naps more and more. I would recommend keeping a sleeping journal though. If your naps are interfering with getting a solid 8hrs of sleep at night you should probably forgo the nap in favor of deeper REM at night.

>But they said a daytime sleep was hard in many careers, with work culture often frowning on the practice.

Depends on the country's culture. Some countries embrace this, and even close down shops/businesses temporarily for nap/lunch time.

I occasionally take a quick <15m nap after lunch. What's interesting is that I don't fall fully asleep - I'm more in a halfway (hypnagogic) state. I'm kind of drifting between states of consciousness. I'm _mostly_ aware I'm reclined on the sofa, and I just let my thoughts go wherever they want. I can start myself on a particular daydream, but pretty quickly my mind wanders off without me realising. Sometimes I can pull it back - I guess as I drift into a bit more consciousness - but soon it's off again as the sleepiness takes hold.

It's a pretty fun experience. The daydreams are wild.

Is staying up until 2am and having a disrupted sleep cycle good for your brain? Based on my own experience I would say not.

Are you saying naps lead to staying up later? I haven’t notice that to be the case. Naps don’t seem to affect my normal sleep schedule much.

That is what I am saying. If I take a nap I will stay up a minimum 2 hours later. Not by choice, but by simply not being tired. I will say that before I got on CPAP I could nap and also go to bed at my normal time, but now that I have higher quality sleep at night naps are just unneeded and disruptive.

There's lots of research about bi-phasic sleep. It may not be so bad to get 6 hours at night and another 90 minutes during the day. That's 5 REM cycles.

Personally I have noticed that for me best is something like 6.5-7h of sleep and and 15-30 minute nap on the day. Of course I usually go with just 7-8h of sleep at night because getting nap has stigma and you just cannot do it every day.

> getting nap has stigma

Hopefully this will be gone someday. To a future where taking a nap is seen as increasing well being (and productivity). Hm, a mandated nap could help.

Interesting you put it that way, the 5 REM cycles throughout the day. From what I read, even for bi-phasic or multi-phasic sleep to work one needs to have a routine of REM cycles that make up at least 6 REM cycles. So if you do 3 REM cycles at night and 2 and 1 later in the day, it should be same rather than doing 6 in one night and then 2-2-2 the other day.

I find this kind of surprising. I feel like I've almost never gotten 6 REM cycles ever. The recommended 8 hours is only enough time for 5 REM cycles, no? You need 9 hours for 6 REM cycles since they're ~90 minutes each.

I experienced this as well. The key for me is to only nap if I'm really tired and to limit the nap at 20 minutes max (although usually I wake up after 10-15 minutes) and to avoid napping too late. If it's after 2:30pm I don't nap even if I'm tired.

I think we light sleepers have conditioned our brain to work that way, generally the idea of a mid day nap is to get more energy to be able to do more.

But I think what happens is (for me at least) if I take a nap I am fresh but it still feels like a mini-reset. I do not tend to get back to work immediately, my brain still needs some time to adjust to waking up mid day. So I have done less but feel relaxed and have too much energy to sleep early. Then I go to night owl mode, work and fall asleep 2-3am feeling very tired.

So not ideal of night owls who thrive in the second half of the day, I guess?

If I take a nap, I nap for a long time and that leads to sleeping late. It disrupts my regular sleeping cycle.

Yep I’m willing to accept that naps work for some people, but for me, I’m not going to fall asleep unless I’m tired enough for much more than a ‘quick’ / Power Nap. I wake up feeling awful because I’ve been woken up early. It’s bad enough to wake early in the morning, I’ve got the whole day to recover from it, but if I wake up early in the afternoon? The rest of my day is shit. Naps simply don’t fit into any kind of schedule for me.

Limit it to sub 15 minutes. If you fall asleep it is to long and you'll might feel awful, since you'll you have a 66.6% to come out of REM or deep sleep.

how?

I mean, practically speaking, how do you control how long you spend asleep?

Let's say I decide to take a nap - I lay down, I set my alarm for 15 minutes, then spend the next 10 minutes waiting to fall asleep. Just as I've finally drifted off, I'm jolted back awake by my alarm going off 5 minutes later. Is that supposed to make me feel better?

Because for me, that awful wrenching feeling of being forced awake when you haven't had enough sleep, you can feel it in your eyes, in your chest, the fuzziness in your head and sluggishness in your movement - it's all simply worse than just feeling tired. Because you're still tired - you barely slept for five minutes - and now it's worse, because you tasted sleep, then had it snatched back away from you.

How is it possible to make yourself only sleep fifteen minutes or less, and wake up feeling better than when you went to sleep? how is that supposed to work?

> I mean, practically speaking, how do you control how long you spend asleep?

No idea.

I rarely if ever "sleep" when napping. That is totally fine though, because lying down with eyes closed, sleepmask and headphones with something soothing on, is enough to make me feel better.

> then spend the next 10 minutes waiting to fall asleep

Stop doing that. You are stressing yourself trying to reach a (the wrong?) goal.

> that awful wrenching feeling of being forced awake when you haven't had enough sleep

On days like this i take several naps.

Hope this helps.

It just seems like too many variables to make blanket statements.

I am at the point in life I am not on anyone's schedule and it is still highly variable.

I love naps but I slept great last night and pretty much woke up at the ideal time for me for the day. I can tell right now 20 minutes after getting up that I wouldn't be able to take a nap if I wanted to. On other days though, I could take a 2 hour nap that completely trashes my sleep schedule and I am up to 3am.

I always set an alarm for 25 minutes. If I sleep longer I’m going to be groggy for the rest of the day.

Ditto!

I have the same if it's too late, or too long. So 15-20 min, max till 3:30pm work for me. Did you try that?

Could it be because your regular sleeping cycle is actually keeping you in a state of sleep deprivation?

Same! I want a device that waits until I fall asleep (the scientifically proven optimal kind of sleep) and then starts a timer for an optimal nap.

About 18 months ago, my boss gave me a spectacular espresso machine as an end-of-year gift. It is extravagant and delightful.

If you have access to espresso -- and like it, which helps! -- then you may find that the midday "espresso catnap" works as well for you as it does for me.

1. Brew and consume an espresso. 2. Immediately lie down. Do whatever else helps you switch off for a nap -- white noise, headphones, eye mask, whatever.

I don't even set an alarm. I'll be awake and alert in 20-30 minutes, feeling significantly refreshed. It's like magic. Obviously bodies are different and there are lots of reasons this might not work for you, but it's apparently a fairly common midday-nap approach.

Studies like this one https://www.sciencenews.org/article/scientists-spinal-fluid-... suggest that visual (at least, and perhaps other) stimulation increases blood flow in the brain, and the lack thereof can increase the flow of cerebrospinal fluid, which flushes out toxic substances. This study was done with waking subjects, but the article points out that the process is much more pronounced in sleep.

Perhaps this process occurs in naps as well, helping to refresh the brain on a biochemical level.

I have only about 20-40 mins of deep sleep out of 7.5hrs according to my Apple Watch S5. Recently I found out I can easily double my deep sleep by having a one hour nap in the afternoon. It messes up my night bed time though.

Might just be that your watch is inaccurate - I would say try a different sleep app to start. I found they varied somewhat (this is on Android).

I think I actually got the best accuracy by placing a fitness tracking band around my ankle (I used a mi band) with the phone next to my head.

I nap almost every day now. It's been good for my mental health for sure.

Everyone's moved on to React or Vue, so you get plenty of downtime for sure

j/k ;)

One of the positive things that came from the pandemic for me was that we were forced to work remotely, and that gave me an opportunity to nap at noon.

It's made such a big difference in my life in that I no longer feel completely dead in the afternoon or require that second cup of coffee to keep going. It's almost like I get a second "day".

Car naps at lunch are pretty popular where I work

I don't know if they're popular at my work but they're certainly popular in my car.

Car naps are functionally equivalent to suicide in Texas in the summer.

Remote work is great for me, because I can take a 5 minute nap after lunch. I feel much better the whole afternoon.

This is only true if one isn't handling their diet and exercise correctly and therefore lacks the energy to make it through an entire day without a recharge. Taking care of things things will also reduce the need for night time sleep significantly without any impact on cognitive performance

I like the idea in general but I just can't manage to fall asleep quickly at night after a nap. Any tips?

The “military method” can reportedly get you to fall asleep in a few minutes.

https://bigthink.com/neuropsych/military-method-sleep/

I don't actually fall asleep, but every day after work I lay down on my bed for about 10 minutes. Sometimes I close my eyes and sometimes I just stare at the ceiling, but I just breathe and relax. Really helps me get into "home mode" and out of "work mode".

I’d be interested to see napping compared to getting more sleep at night. My guess is napping is beneficial to the average person because the average person does not get enough sleep. My personal belief is if someone needs an alarm to wake up, they’re not getting enough sleep.

Now as I'm working from home, taking is daytime nap is way much easier.

Also I used to take a nap right away after lunch, but it's not good for my digestive system. So I usually wait 2-3 hours after lunch to take my nap.

Paper available here: https://oa.mg/work/10.1101/2021.09.28.21264215

Alternative interpretation: people with larger brains tend to nap more

Coffee Nap is probably amongst the top 3 refreshing things I know of.

This always breaks my brain. From what I have read about sleep and the effects on caffeine on sleep, coffee nap seems to work in a very different way than just having coffee when you feel sleepy.

Some research suggests, it boosts your energy level as caffeine doesn't have to compete with adenosine (which make us sleepy)as by sleeping adenosine levels drop. But I always wondered how the boost works, when infact you could just have a nap and then drink coffee and the same thing should happen.

Anyway, I need to read more about this someday.

I discovered medicine naps as a child, and worked out caffeine naps when I got older.

Staying home if you’re sick is best, but if you have to get up and do something during the day, setting your alarm early, and taking whatever OTC medication you planned to manage your system, then going back to sleep for at least a half hour, means that the second time you wake up you don’t feel like you’ve been hit by a truck. It’s easier to get your ass out of bed and get ready for the day.

This is weird to me, I've always (based on my local news articles) and from what I've previously read that power naps is bad for your brain and can cause alzheimer.

What should I believe?

Biphasic sleeping is great! Highly recommend the book Why We Sleep by Matthew Walker, or at least watch his brief Ted talk. Honestly will change your life, for the better.

> nappers' brains were 15 cubic centimetres (0.9 cubic inches) larger

I can hardly believe this, but I'll sure be quoting it in my defence henceforth!

It's not about daytime or lunchtime. It's about how deep is your sleep.

Like deep learning, deep sleeping is the best thing you could do for your brain.

Lie down, throw on my noise cancelling headphones, set a timer and put on a podcast about ancient civs. Perfect everytime.

I take 60-90 mins naps, whichever day I can. I feel refresh and can focus more.

I’ve never heard of a study with this architecture before.

If you're interested in this type of study this is the name of the method: https://en.wikipedia.org/wiki/Mendelian_randomization

When I just read the article I glad to see the method I learned during my thesis has produced some mainstream knowledge. Happy to see that! It's basically "nature's randomized control trial" since you assume genes to be assigned randomly. The treatment and control group just vary in terms of this one set of SNPs, which are used as instrumental variables. In this case, comparing a genetic population of nappers to one of non-nappers. They don't have to measure their actual nap time because the genetics serve as proxy.

Yeah honestly I don't need science to tell me that.

tell that to my boss

It’s acceptable in businesses in most cultures outside of the Anglosphere.

Does it not depend on how hot the country is?

having everything I need and doing whatever I want is wonderful for my brain

"Rest cures all."

I am astonished that people just start to realize this.

Reply on news.ycombinator.com