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The effects on cognition of sleeping 4 hours per night for 12-14 days (guzey.com)
407 points by luu on May 18, 2020 | hide | past | favorite | 352 comments

When I go many days in a row without enough sleep, I find that my cognitive abilities (i.e. what I am capable of doing) does not seem to significantly decline--as judged by things I build and people I interact with.

But, my endurance of focus (the amount of time for which I can perform at a high level) does suffer.

The weird thing is that it doesn't feel like I can't keep going... it's just that I sort of somehow don't keep going. I find my mind wandering more easily, checking in on social media more, and then time passing more quickly when I do. I'm more likely to look up from Twitter or HN and be surprised at the time.

In short I don't seem to be any dumber while doing something, but number of things I get done in a typical time periods declines.

As I have come to understand this impact, it has given me greater empathy for addicts. My brain doesn't feel like a tired muscle, or like I'm doing anything wrong in the moment. It's only later, when I look back, that I realize I was making bad decisions and losing time. It has just reinforced how hard it is to use decision-making to recover from a situation where the brain has already been compromised by bad decisions.

> I find that my cognitive abilities (i.e. what I am capable of doing) does not seem to significantly decline

It's very common. Studies on sleep deprivation report that subjects do not feel their cognitive abilities decline. However, measuring cognition using objective tests does show a significant decrease in these abilities.

This is by far the most important thing for HN to learn about this. The default level of self deception on this front is enormous.

Seriously. The experiments with oxygen deprivation are very telling on this front. There's literally a button to press before you black out to give you oxygen, and people don't press it. Simple tasks, like identifying playing cards, people fail at, yet are convinced they've correctly identified the card. Our brains are amazing at lying to us.

I think the other part to remember is that the author of the article is 22. I didn't need sleep either when I was his age. I don't mean he's naive, just that a 22-year-old can abuse their body without too many negative consequences. As someone in my late 30s, I definitely feel it when I only get 4 hours of sleep.

That was my first thought as well (I"m in my late 30s too). When I was in college I could pull several all-nighters in a row without feeling too bad, or get 5-6 hours a sleep a night nearly indefinitely without too much trouble.

Nowadays... not so much.

I don't know what type of drugs you guys were eating in your 20's but if I pulled an all-nighter, I was absolutely ruined the next day and a bit the day after that. Even in my teens.

While consuming no drugs other than caffeine, I was regularly able to work for up to three days without sleep in my early twenties. At 48, I’m much more affected by my sleep schedule. Young people are simply more resilient, some more than others.

To pile on the anecdata: an all-nighter in my 20s was something feasible, even going through the next day (as in, day+night+day feeling fully awake, then resume usual behavior with normal night's sleep, and no further effects); at 25, this became harder, with a crash in the afternoon, at 30, an all-nighter meant sleeping through the next day, and currently just not getting at least 6 hrs of sleep will crash me the next afternoon. sigh

To be honest in my early 20s, I'd do no sleep the entire finals week just cramming for shit... then take a three day nap.

Another anecdote. When I was 19 I did a quick conversion job for a company. I'd take an early train down on a Monday morning, worked about 20 hours a day with just a quick nap each night on the reception sofa, and then a train home of Friday. I did that for two weeks, I was shattered but got through it OK.

Yup. Also in late 30s, and damn. I used to pull off all-nighters no problem in my 20s. Last night, I needed to do some work that didn't get done before, and by 2am, I was falling asleep in front of my keyboard. Ah, naivete of the young. :)

YES. Becoming a parent in my mid-30s taught me many things, including just how much more energy I had in my 20s

Maybe there is some wisdom in getting married/having kids at an younger age. I know, it is way more complicated than that..

I don't think it's quite the same as self-deception. The way I understood it is that it's more like alcohol: the first thing to go is your ability to judge for yourself whether your judgment is impaired.

It is fair to say that using your cognition to measure your own cognitive decline is unreliable ;-)

I discovered this for myself when I realized that while on 4 hours of sleep, I could power through stuff with the aid of enough caffeine and feel at least marginally productive...

...but I started leaving typos in everything.

That really doesn't sound like much, right? Honestly, though, it genuinely freaked me out a little, existentially, the first time I noticed. I was one of those nerds who got to a state spelling bee as a kid, and I've always been a voracious reader. I've had spell-check turned off since forever because it would inevitably be the spell-check that was wrong about niche terms.

But without enough sleep, all of that competence that I usually just take for granted vanishes. I end up with 'good moerning' and 'how are yoiu' and 'paass the salt', and I don't even notice I'm doing it until I look back at what I've written and double-take.

And that's just with casual writing, probably one of the lowest-overhead mental tasks possible for many people. God only knows what kind of disaster would result from me trying to drive or operate heavy machinery in that state.

I've had a similar experience with artificially masking my energy levels.

I stop reading what I've written and introducing a large number of typos; the grammar becomes weird; etc.

This is why it's important to allow yourself to be exhausted and to notice exhaustion: your little mental model of yourself is incredibly inaccurate. You need to be constantly alert to keep it updated, and if you don't, you will collapse.

Why did you leave out the end of their quote about the metrics they use to judge their perception upon?

"--as judged by things I build and people I interact with."

I mean, I agree that sleep deprivation seems to induce temporary cognitive performance problems, but you're reinforcing a point that the parent seems to already understand -- that self perception is useless without objective performance metrics.

Parent gave their opinion, reinforced by anecdotal evidence that they believe is an objective measure of their performance.

Perhaps what should really be mentioned is that perhaps the metrics by which they are judging their cognitive performance are not as broad a test of those characteristics as one might believe.

I wonder if recognizing your cognitive decline is a cultural issue or something else; it couldn't be more clear that I am unable traverse many layers of abstraction when I havent slept enough; it was also apparent to everyone in my physics undergrad that they couldn't handle statistical mechanics with sleep deprivation.

Wearing sleep-depravation as a badge-of-honor seems like an American quirk.

> Wearing sleep-depravation as a badge-of-honor seems like an American quirk.

Not entirely an American thing, given the the common sight of a salaryman asleep on a train or cafe all over Japan. But given those 2 were the Largest Economies in the World for the last decades, and only recently JP was surpassed by CN in the middle of the last one, it makes sense.

Having done it myself, I think its definitely an experience people should have in their Lifetime outside of University or raising a child it really makes you more empathetic towards other people in difficult situations later on in Life. We on HN may choose startup life for one reason or another, but I know left with a better understanding of the Human condition afterward and come to see that its worth encouraging people who want to strive at something and actually put the work in.

My guess is post-industrial economies require next-level abstraction which is more mentally demanding and hence requires better rest and nutrition. Back when "produce more stuff more efficiently!" was the mantra it was easier to focus on incremental gains. Now the answers aren't so easy.

> My guess is post-industrial economies require next-level abstraction which is more mentally demanding and hence requires better rest and nutrition. Back when "produce more stuff more efficiently!" was the mantra it was easier to focus on incremental gains. Now the answers aren't so easy.

That's overstating the Work culture in either situation, in my opinion; in Japan its typical to have to stay only until the boss leaves, and the drinking culture that follows is mainly to curry favour with the higher-ups to climb the corporate latter. If that counts as 'abstraction' to you, I'm not sure what to make of your 'post industrial' POV.

In the US corporate World, which is the only one I have any experience with, 'playing the game' is often more important than actual skill or merit. Which is why I despised my time within it.

I'm not hired to be your drinking buddy or be a confidant, I'm a hired-gun for your project and only really there to offset my living expenses and bootstrap the more cool and interesting things I do in my Life.

Making work be or seem anything other than 'work' requires a lot of de-compartmentalization for me and encumbering a person to a do so seems hardly 'abstract' to me and the more it becomes remote the better. That isn't to say I don't drink the Kool-aid for the things I'm passionate about, but that is hardly, if ever, found in the Corp World--this is pretty much how I left so disillusioned at IBM, despite being a Thinkpad fanboy.

Sleep deprivation and cognitive ability is studied pretty heavily in aviation. Most airlines have mechanisms for pilots to self report fatigue events, events where because of operational needs the crew ends up working extended hours. There comes a point in the day where the pilots are asked if they’re ok to continue.

It’s amazing that often times in the reports, which are generally done a day later, the pilots will state that they probably shouldn’t have continued. However, in the moment where they made that decision, they didn’t feel all that tired. We ask the pilots to make a critical decision about themselves at precisely the time where they may not have the best judgment.

I did a flight safety training course and the video clips of people right before they pass out from anoxia are entertaining and educational.

Here's one from the FAA: https://www.youtube.com/watch?v=hSrGfElyfVE

I really don't like how you quoted half a sentence there in a way that gives a misleading sense of agreement.

Yeah, I think I should have been more specific that I'm judging against the things I usually need to complete for work--which do not necessarily take my utmost brilliance. I haven't been rigorously tested on low sleep.

What I wonder is how it affects your average performance, sure it effects your peak performance, but how often do you really need peak?

Could you point me to some of these studies, ie. one that's a good starting reference.

The definitive reference for all things sleep is “why we sleep” by Matthew Walker. It’s a fantastic read, highly recommended. It single handedly moved getting enough sleep from a similar category to “I should probably eat less salt” to “this is the single most important thing for my health” for me.

I recall reading something linked on HN some months ago where someone dissected that book rather brutally, pointing out inaccuracies, flat-out lies, instances of ignoring inconvenient data, and conclusions drawn without any supporting evidence, so... not sure I'd treat that as gospel.

Oh, looks like it was by the same author as the article we're discussing: https://guzey.com/books/why-we-sleep/

Yeah, I just saw that in this thread, and replied to a sibling: https://news.ycombinator.com/item?id=23230713

FWIW TFA's author is vehemently opposed to Matthew Walker's book.

(Disclaimer - I'm not. I found much of the content interesting and compelling.)

Yes, I saw that following links from this thread, and have spent more of the morning than I should have reading it and the various threads discussing it.

I think the criticism seems valid, and it probably means I shouldn't use the book as a reply to people asking for scientific evidence (like the comment I replied to). That said, I don't think it detracts from the main argument of the book, or the main revelation for me, which is that most people don't realise how damaging lack of sleep is. I would still recommend it to a lay friend on that basis.

>It single handedly moved getting enough sleep from a similar category to “I should probably eat less salt” to “this is the single most important thing for my health” for me.

>That said, I don't think it detracts from the main argument of the book, or the main revelation for me, which is that most people don't realise how damaging lack of sleep is.

I don't get this. You find that the book you believe provides the arguments for the damaging effects of sleep and based on which you dramatically changed your life is bullshit but somehow this fact doesn't detract from its main argument and you are still going to recommend it to your friends?

Well, I wouldn't use the word "bullshit" to describe the book.

Reading (most of) the book caused me to change my priorities from basically "I don't care about how much sleep I get" to "getting enough sleep is an important priority for me". Presumably you would agree that that is a positive effect.

Sure, I have nothing against getting enough sleep but the book's first 10 pages contain so much misinformation and given that Walker outright falsifies the data in the book (https://guzey.com/books/why-we-sleep/#appendix-what-do-you-d...) I would struggle to call it anything other than bullshit.

Sorry, what is TFA?

"The Fine Article" (other words beginning with F might be substituted) = the article/link discussed

Thank you

slashdot terminology for the article being discussed.

FWIW the abbreviation has been around a wee bit longer than slashdot.

I dont know any off hand but Mathew Walkers book "Why we sleep" talks about them. Apparently there are more road traffic accidents the day after the clocks change in spring when many people loose an hours sleep.

Immensely frustrating how many people are citing his book in a thread about one of your own blog posts, of all places. I was so glad to see your post about it at the time, and this experiment is an interesting follow up.

"Why We Sleep" is everything wrong with "science" today, and as a person who also isn't a huge fan of sleeping, I'm desperate to understand the real drawbacks to a lack of sleep. That dumpster fire of a book has set back honest research on the subject by years.

Just venting, as I know you agree. Thanks again for your contributions to sanity.


It's kind of a long article, but I can't see anything in it that refutes the point about road accidents.

I did not look into his claims about road accidents but given that Walker misrepresents and so much of the research (and sometimes falsifies it) on sleep, I would not be willing to believe such claim simply based on him saying this in the book.

I find that quite a weak argument, it sounds like "he said some things wrong, everything he says must be wrong".

As far as I remember he cited peer reviewed articles. Anyway a quick search turned up this:


Reminds me of people I’ve encountered who think they’re better at X while on $DRUG. Almost for sure, in my experience with these people, it’s definitely not true, though they’re convinced of it.

People driving while high are especially frustrating, because they’ve convinced themselves that there better drivers.

It depends on the activity, individual, the drug and dosage. There isn’t a generalisation that can be made because there are so many variables.

Take something that requires more mental focus but do not rely on reaction times, like pool, I definitely play better when I’ve been drinking as I get less distracted when going down on a shot and less anxious about my performance. And pool is a small enough table where the negative effects of drinking tend not to overcompensate (unlike snooker where more than 1 pint will hamper my game).

For some activities it’s more about mental focus on that single activity where as driving is about multitasking and reactions. Qualities drugs tend to hamper rather then enhance.

People who think they're right when they're wrong are frustrating for anything. Try talking with conspiracy theorists about the science behind vaccines and COVID-19 these days? I have. I'm apparently a sheep that easily trusts the mainstream media and will probably be first in line to kill myself when vaccines become publicly available, only so that Bill Gates and Anthony Fauci can become richer.

See also: "I'm better at pool after 3 beers."

Yeah, no you're not.

A few beers makes you better at anything hindered by anxiety. For many people, that's playing pool at the bar in front of others. Or speaking a foreign language. Or holding conversation.

Also anything requiring lack of tremors. For instance, alcohol is considered a performance enhancing drug in sport shooting (http://www.faqs.org/sports-science/Sc-Sp/Shooting.html last paragraph).

I think a beer can help with anxiety. A few beers just results in overconfidence.

I will admit it helps with conversation if you don’t normally talk and you’re around equally drunk people, but a few beers plus a crowd of sober people doesn’t work as well as most people think it does.

I would say it depends on your alcohol tolerance. I get tipsy if I have a beer. Other friends don't show any signs at 3 beers.

> A few beers makes you better at anything hindered by anxiety.

No, it doesn't. It eliminates the anxiety. It doesn't enhance performance. It modifies your perception of your performance.

Definitely relate to the foreign language part, especially when trying to speak casually after primarily learning from a structured classroom setting.

I used to be on my local pub's darts league team. When I was first playing, objectively, my best accuracy was after 3-4 pints. A couple years in, my best accuracy was after about a pint and a half. The effect was most noticeable with the "Around the World" game we used for practice, as Around the World forces you to keep throwing the darts at one number until you hit that number. Other games, such as 601, 301, and Cricket give you points for hitting things you're not aiming at, so inaccuracy is more hidden in those games.

I suspect part of it was state-dependent practice. I'd practice throwing darts in a bar, much of the practice was after drinking several pints, so I practised my release timing with alcohol.

I also suspect that part of it was the muscle relaxant effect of a moderate amount of alcohol probably does help improve the consistency of motion in releasing the dart.

I'm actually inclined to disagree here -- I think after a couple of beers it's reasonable to assume someone might be better at pool. Firstly you're both physically and mentally more relaxed and often more confident too so I think it's completely plauisble theres a couple of beers sweet spot for playing pool.

I dunno. I realize Balmer peak is a semi-joke, but I really enjoy bowling and used to go once a week or so with friends. Some days we'd get a pitcher of beer, some times we wouldn't. My third game is reliably better if we bought a pitcher. So who knows! Lots of confounding questions there. (three beers, though, my bowling probably gets much worse reliably)

Better compared to other players at the moment or compared to your sober self? Because it could also just mean you handle alcohol better than friends you play with.

Jokes aside, fully agreed. You just gotta get enough alcohol that your confidence and peacefulness are up (which would cause you to play better), but not to the point where negative effects of alcohol overpower the positive ones. And that's a tricky one to balance.

There's a very funny Mitchell and Webb sketch on this very subject:


Yes you are (well, it's ~1.5 pints for me). Just don't drink that 4th beer or it's all over.

Edit: Don't just take my word for it. https://www.wired.com/2015/05/big-question-booze-help-play-b...

Lots of people here obviously also think this, but I maintain that they're wrong. Consider what the Wired article you linked actually says:

> In a 1993 study, he found that hand-eye coordination deteriorated immediately after a player's first drink, but balance and accuracy improved at a BAC of 0.02 (beyond that, performance fell off).

A BAC of 0.02 is like, I dunno, less than half a beer? (And even then the article suggests a mixed bag.) I have no trouble believing that very small doses of alcohol could relax the imbiber in a way that's useful. But I suspect most of the people here who think I'm wrong are referring to larger doses not measured in fractions-of-a-single-beer.

And, again, I very much doubt it.

Your ability to do almost anything falls off beyond the 0.02 point mentioned in the article. What's actually on display here is that people are very bad at evaluating how alcohol affects them. None of the claims here would survive unbiased testing.

.02 BAC is about a 12oz beer for the average male. Given that there is a lag between drinking that first beer and having the alcohol absorbed into the bloodstream, I find it entirely plausible that 1.5 pints in could correspond with a pool player's peak performance.

They've already consumed enough alcohol to move past the sweet spot but it isn't yet affecting their performance.

Good point about the lag.

I don't know about pool, but I know I'm better at Tetris and racing sims after 1 or 2 drinks.

When sober, when things don't go well, the stress leads me to trying to take stupid shortcuts (like braking later and later before the corners) that don't work. With a bit of alcohol, it seems there's a bit less stress and I'm better at doing things the right way.

With more alcohol, the negative effects start to dominate. Slower reflexes, too aggressive driving.

With sufficient effort I can focus on driving the right way while sober, which works even better of course.

To be clear: the only racing in real life I do is the occasional karting session, which I do only when sober!

Bill Werbeniuk[1] might disagree.

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

Actually, I accidentally found I am better at pool with like 3/4 of a beer. Something about being in that relaxed but pre-inebriated state.

I suck at pool, and I know it.

After three beer, I still suck at pool, but I don't care.

So yeah, I play better.

I think that's what other recent psychological/neurological research has found too (citation needed--but do remember reading about it recently from multiple sources).

It figures that everyone each has their individual baseline "propensity to stay focused"--and sleep deprivation degrades someone's focus below that. You take a normal person and sleep deprive them, and their "propensity to stay focused" is lowered, but still might fall within an acceptable/functional range.

One theory that's gaining traction is that people with ADHD have a somewhat lower baseline than average, and when you throw in sleep deprivation, their "propensity to focus" falls into dysfunctional territory. Ergo, ADHD might have a large sleep component.

In all cases (which corroborates with your experiences), they found that people are really poor at actively self-detecting those fluctuations.

> Ergo, ADHD might have a large sleep component.

Yeah, I can count on one hand the number of times in my life when I woke up in the morning, even after a good night of sleep, and felt "refreshed". I didn't even know what that meant until I had a conversation with a coworker who just hops out of bed and is "on" immediately. Feels like there is a connection with my ADHD diagnosis.

Happens to me roughly once per year, twice in a good year. Usually I am too busy enjoying the novelty of it to put it to good use getting things done.

A fitbit has been lifechanging for me on that front. Get one, and ruthelessly focus on improving your sleep.

I have three layers of blinds (get portable blackout blinds); I use earplugs; I try to keep the room temp low.

My mood, ability to think clearly, happiness etc. is very sensitive to my moving-average quality of sleep.

I think a week or two of "fair" (fitbits levels) sleep is a catastrophe for me -- I need a high average.

Yeah I’ve gone through all of the sleep optimizations—eye mask, chilipad, blu-blocker shades two hours before bed, wake-up light—and it has produced marginal improvements that I still maintain but nothing revolutionary.

I know that caffeine consumption can be a big issue, but that’s a lost cause. Caffeine is like crack for someone with ADHD, and I’ve given up on trying to quit given my current demanding lifestyle. Maybe one day when my to-do list is shorter.

Try one of those wake-up lights if you can. Bright light in the morning can really help with waking up smoothly, or at least getting you into a relaxed half-awake state that makes an alarm less jarring.

Anecdotal source: Having a (tiny but well-angled) skylight does wonders for me in the summer months.

Did you manage to improve it, feeling refreshed after waking up?

For me it's not just "focus on task" but also tasks with multiple interacting components (sounds like programming?). Lack of sleep makes it very hard to follow interacting chains of cause and effect.

I do find that for whatever reason the right amount of sleep deprivation makes me more upbeat and social (and silly). Like somehow the anxious, analytical part of me gets switched off first so the well-rested parts that rarely get used can steal the show.

Oh god, this explains so many things. My wife is suffering ten times worse from the maternity related sleep deprivation than what other moms report. I'll talk to her about more active sleep management.

>One theory that's gaining traction is that people with ADHD have a somewhat lower baseline than average, and when you throw in sleep deprivation, their "propensity to focus" falls into dysfunctional territory

Part of the criteria for diagnosis is that your symptoms are persistent and chronic enough such that your life is impaired. That's already squarely in dysfunctional territory without sleep problems.

Given ADHD affects all of your executive functions, it tends to impact all facets of your life. You're 400% more likely to be obese than someone who is non-ADHD. With that comes obstructive sleep apnea. With that comes less sleep and more problems.

So, ADHD has its own special way of making itself worse.

I came here to say this. I can still get stuff done and answer questions, but I have the attention span of a goldfish.

May be more of the same but I find my filter also declines substantially, so I basically turn into a colossal pain in the rear to deal with. Longer-fused patience or optimistic thinking becomes short fuse rage and negativity. There is no bandwidth to deal with multiple things at once or compartment, and no bandwidth to ingest any signal except the thing in front of you in your mindset.

Not a place I’d recommend if you can avoid it.

> The weird thing is that it doesn't feel like I can't keep going... it's just that I sort of somehow don't keep going. I find my mind wandering more easily

That's exactly what I experience if I have a few too many days where my sleep is interrupted or I sleep badly. I already give myself very little leeway there, where I usually have about 5.5 to 6.5 hours before I need to wake up (I fall asleep very quickly), so it's a fairly good gauge of time). If something wakes me earlier than expected, it affects me the next day.

I find that coffee makes this harder to determine, as I'll still feel alert that next day, just as if I had better sleep, but I'll be less productive overall in all the ways you mentioned. I can still think coherently, but I appear to be able to do so about the same thing for a much shorter period before being distracted with something else.

> As I have come to understand this impact, it has given me greater empathy for addicts. My brain doesn't feel like a tired muscle, or like I'm doing anything wrong in the moment.

That's a very astute observation. I've noticed before that more sleep makes me more productive, yet there's always that allure to staying up a bit later and reading a little bit more in the book I'm reading (which is almost always the problem), or watching a little bit more, etc.

Like an addiction (I assume), the path from non-problematic behavior to problematic behavior is somewhat gradual, and noticing the problem is somewhat impaired by the negative effects of the problem itself. I don't set out to sleep very little, it just gradually gets worse where I'm skimping on sleep more and more often, until it's fairly consistent, and then I eventually notice and break out of it. Then the cycle repeats, but I generally spend far more time with little sleep than adequate sleep overall.

I came here to say this as well. Me exactly.

Your last point really resonated with me. I've seen a very good friend crash his entire life by a string of bad decisions that led to him being constantly under pressure and burned out.

Ironically the use of some strong nootropics helped him cut the corner and work himself in a saner situation from which he could use to start coming back on his feet.

I have experienced something similar after I've been ill. For example, day 1 and 2 I'm just doing my work and don't feel ill yet, then day 3 I get ill and have to stay home from work.

Afterwards I notice that my work from day 1 and 2 is way below average and can more or less be discarded, while I did not notice this at the time.

That's early phase sleep deprivation for me. Distinct from late phase, where I'll forget a sentence the second I hear the next one. Just completely shot short term memory until I find time to sleep for 10 hours, sometimes a few days later. Comes around the day after a deadline.

> The weird thing is that it doesn't feel like I can't keep going... it's just that I sort of somehow don't keep going

Sounds a lot like an unfalsifiable hypothesis. Which means it can simply be a question of your perception of a phenomenon, not an objective truth of it.

I’ve been under sleeping and I play a lot of games. Poker, go, call of duty war zone. My performance in all of them suffers. I actually don’t allow myself to play poker anymore unless I have two nights of full rest.

Since a few years ago (when I read Why We Sleep [0]) I’ve made it my priority above all else to allow myself 8 hours of sleep, even if I don’t ‘use’ all of it. With more sleep, an innumerable amount of things are better (as read in the book), but subjectively I noticed the following after about a month straight of good sleep:

* Pain was far more manageable (IBS, MMA injuries)

* Sleep was more restorative when I woke up

* Emotions far more regulated (less irritable)

* Quicker to come up with on the spot jokes, or come up with a refutation to an argument

* Gym performance +30% at least

* Gym recovery faster

* Short and long term memory improvement

* Less health flair ups

* Reduction in brain fog

It’s hard to notice these differences subjectively unless you know what it’s like when you’re “optimized”

Following a keto (or carnivore with a focus on ketosis) diet leads to a further boost across the dimensions mentioned above.

I think many people outside of self-optimization don’t realize what they’re sacrificing when they choose to forego sleep. Even total productivity is enhanced, despite working less hours due to sleeping.

[0] https://en.m.wikipedia.org/wiki/Why_We_Sleep

The author of the OP is not a fan of Why We Sleep, having found many errors and misrepresentations [1].

[1] https://guzey.com/books/why-we-sleep/

I had just purchased and starting reading the book when this was first posted here. I haven't spent much time to look into either side, but I stopped reading the book because I felt like I may be filling my mind with false information. And I bought it in the first place thinking an expert was going to teach the most important things we know so far about sleep. It bums me to think about this.

I can summarize what both the original author, and what the person wrote criticizing agree on. Yes, sleep is required. Get enough sleep that you feel rested.

A lot of the critique was around the 8 hours, and the conclusions about what happens if you get less.

Anecdotally, I never sleep 8+ hours. I also get up without an alarm clock every single day. I'm not going to stress that I normally sleep ~7 hours and feel rested when I wake up. I know on the rare occasions if I get less than 6 hours, I'm going to be really tired that night.

One problem with this approach is that if you've always had dysfunctional sleep, you don't understand what "feeling rested" really means. I had undiagnosed sleep apnea until my late 20s, and it was insane what a difference getting a CPAP made. I literally couldn't conceptualize how fatigued I had been all of my life until I had something to compare it against, and when I finally started getting restorative sleep my whole life changed.

Yup, exactly this. It feels normal to you, because that's how it's always been and no matter what you do, you never actually get a good night's sleep. I dealt with severe obstructive sleep apnea from my late teens to my mid twenties. I have no idea how I was able to study and graduate college, looking back. I got a CPAP and later corrective surgery and it's completely changed my life. Think about how you feel when you get half your normal sleep. Looking back, that's how I felt every single day.

How did you realize you needed to get a CPAP?

not OP, but if you have sleep apnea, you typically snore very loudly. You may not realize you're doing this because you're asleep and alone, but if you sleep with someone, they will definitely let you know something is wrong and a dr will tell you to get a CPAP machine.

It depends on the type. The most common type, Obstructive Sleep Apnea sounds way worse than loud snoring. If you've ever heard it, it's like the person is suffocating while they sleep (because they almost are).

It's not so much the false information (lack of evidence for major claims) but the amount of anxiety it causes around sleep which is very counterproductive. The author makes it seem like you will never recover from the deleterious health effects from not getting enough sleep.

I read all of it, and enjoyed it. I think its worth reading. At the very least, it will get you to appreciate sleep as an open biological question. The critiques were about his data presentation and stuff like that, not the topic of sleep itself.

I did not know that, thanks. Time to read the article and threads dang posted.

Even the wikipedia article you linked to in your comment mentions my critique of the book!

Haha I didn't want to paste in the Google overlord link so I just blindly sent the matching wiki page

Just recently since I've been working from home all the time, I realized I don't actually need an alarm to get up, since I don't need to leave the house at a predetermined time to beat traffic and get to the office at a reasonable time. Getting up at the same time in the morning was just habit.

Instead now I have an alarm to go bed, and I get up when I feel rested.

If your schedule/living situation allows, keeping a window open for early morning sunlight to rise helps to reduce the initial haze quickly if present at all.

I set an alarm for 9am so I don't oversleep but usually get up well before that.

I would imagine the group of people who immediately accepted everything this book claimed as fact and went on to immediately adjust their lifestyles to match may have a strong correlation with the group of people who are more susceptible to the placebo effect.

I didn't make it through the first chapter before I started looking into the accuracy of the claims he was making. Some of them were clearly bananas.

>I would imagine the group of people who immediately accepted everything this book claimed as fact and went on to immediately adjust their lifestyles to match may have a strong correlation with the group of people who are more susceptible to the placebo effect.

This is a very interesting point.

Guzey of guzey_arena fame?


>> or carnivore with a focus on ketosis

Following a "carnivore" diet is a really terrible idea. Unless you're an Inuit living in the frozen north, you should eat some greens.

Going on 3 years now, with comprehensive blood tests taken every 3-4 months for 2 years. Never had better markers for inflammation (below error threshold), cardiac health, liver health, etc.

Tried keto (proper), vegan, vegetarian, low-FODMAP, paleo, all without success. Found a forum of other IBS people, and decided to risk going against mainstream 'authority' such as the American Heart Association.

So far, feel better than I ever have, on all markers I could measure objectively, and subjectively.

Whats a terrible idea is to have fats linked to heart disease in a massive lie that spanned decades, breed fruit for higher sugar, then say sugar from fruit is fine and healthy, but refined sugar should be moderated (even then its not discouraged). Or in the face of (currently anecdotal, I agree) evidence of dozens and dozens of chronic, autoimmune diseases cured by a carnivore diet from thousands of people. (Harvard Survey finished collecting data end of April)

Cured meaning we've removed the inflammatory foods causing the chronic illness. At least see it as an elimination diet, to where a user can add foods back in, and find out whats causing the adverse symptoms initially.

But science remains dogmatic, as history shows, for better or worse.

Do you eat nose-to-tail? I hear a lot about people’s carnivore diets and they sound mostly like an “animal flesh diet,” which is lacking in myriad key micronutrients. It seems one would absolutely need to supplement animal flesh with kidney, liver, heart, etc... I’m curious to hear your experience.

I spent the first year and a half only doing ground beef, and sirloin tips/ribeye (grass and grain fed). More recently I begun stocking up on ground beef (shipped from a grass fed pasture), and on days I eat nose-to-tail will make a 3lb meat loaf with 1/3 a mix of ground liver, kidney, heart, 1/3 75/25 ground beef, and 1/3 55/45 ground beef with heart. Other days I'll have ribeye for my two meals.

Before the meat loaf I tried liver numerous times, usually calf liver, cooked more on the rare side as it was far more palatable. Oddly enough, and others have similar experiences, on days I ate the liver, I was satiated much sooner, and had roughly 30% less muscle meat for that day.

I was on the same page as you when I looked into the diet initially, but from the myriad of resources I've skimmed, or trusted other's review over, it seems we really are in the dark with nutritional science.

Countless epidemiological nutrition studies attempt to show causality, regardless of the amount of confounding factors they attempt to account for, then prescribe guidelines that are inherently flawed. Gwern.net has a great article on this [0]

My point is, there are most likely many other mechanisms our bodies have in it's 'arsenal' to sustain homeostasis that we have yet to map out, due to ethical, economic, and practical limitations of truly randomized, placebo-controlled, double-blind nutritional studies.

That is to say, despite on paper the typical muscle-meat carnivore diet lacks nutritional variety, we see anecdotally people are generally flourishing on this diet. This I think is a significant counter example to our current model of nutrition, and will hopefully spur further research.

[0]: https://www.gwern.net/Causality

Not OP but I've been doing carnivore as well for the last year, and I don't eat across the board. I generally eat Ribeyes and can share a lot of the same benefits he's mentioned. Red meat in particular actually has a fair amount of the vitamins you need such as vitamin-c and the less you cook it the more they're preserved which is why I go on the rarer side of things.

> Whats a terrible idea is to have fats linked to heart disease in a massive lie that spanned decades, ...

THIS. Combine with NYT article on the sugar lie[1] and we have a disturbing picture that in the least betrays incompetence. Also there is a lot of evidence from Robert Sapolsky's work with baboons that atherosclerosis has little to do with blood cholesterol and is much more about stress[2]

The main takeaways for me are: eat stuff that looks like food - meat and veggies. Fruit has fructose which must be processed by the liver and split into sucrose and glucose so keep the fruit and HFCS to a minimum. And don't stress (too much). And move your body. Walk 30 min a day, do some pushups, just do something.



Inuits did not adapt to their diet. Maasai adapted well but still not enough to avoid severe atherosclerotic build up, there's Maasai people ~20 years old dying from atherosclerosis.

It's not just AHA recommendations based on epidemiological studies, it's also the vast amount of data showing that unfortunately, cultural diets high in animal fat and protein eventually get the best of you.

Scientifically watching these kinds of interventions and showing they have positive outcomes still does not mean that practicing the intervention long-term is fine.

Do you have a title or link for that Harvard survey?

The study recently concluded it's data gathering, but here's a post that outlined the study for a subreddit I follow:


> It seems that there’s very high variation in how people respond to sleep deprivation.

There you go. It's the tyranny of averages: when variation between humans is greater than the effect of the intervention.

This reminds me of reading The How of Happiness and learning that happiness is basically 50% genetics, 10% circumstances and 40% behavior. The author frames that 40% as a really big number, but I thought about it the other way around: if you're unlucky enough to be born into the bottom decile of genetic happiness, then you could do everything right and still be less happy than someone with really good happiness genes who does everything wrong.

Some people get smashed by any lack of sleep, and some people (most notably short sleepers) are totally fine with as little as 4 hours a night. There is no advice that works for both kinds, and formulating advice based on averages is committing a grave fallacy.

I suppose the world of health research is plagued by this erroneous assumption that humans are more or less the same. In some ways sure, but in many ways we are profoundly different.

> I suppose the world of health research is plagued by this erroneous assumption that humans are more or less the same. In some ways sure, but in many ways we are profoundly different.

Sidenote: I came to the conclusion, that this is the crux of all generalizations when it comes to humans. Not all policies will be good for all people. The ideal country might be very different for you and me. Also our diets, the way we build relationships, how we should train our bodies or what constitutes moral lives.

I ain't no fancy pants happiness author but I'd posit that happiness is 70% stupidity and 30% circumstance.

You can be poor and happy or rich and happy, but the smarter you are the less likely either of those are true. Though being rich certainly helps.

Why would it be less likely to be rich and happy the smarter you are?

If you're smarter, it means you can learn more efficiently. If you learn more efficiently, you get a deeper understanding of the world.

If you understand how something works, you stop having the wrong expectations, so you're less likely to be unhappy.

> If you learn more efficiently, you get a deeper understanding of the world.

This is often a problem. Some say ignorance is bliss, and I am not sure they are wrong.

> If you understand how something works, you stop having the wrong expectations, so you're less likely to be unhappy.

While one may not have the wrong expectations, it can be painful sometimes to see how deep the rot goes and how that rot impacts people’s lives deeply (often negatively).

Additionally, changing the rot may be outside of your sphere of influence, so feelings of helplessness are possible.

Perhaps understanding how things work is leading to the unhappiness.

There are lots of big problems in the world, too big to be fixed by a single person. Dwelling on these can be depressing, they don't say that ignorance is bliss without a reason.

> you stop having the wrong expectations, so you're less likely to be unhappy

This seems like a big leap in logic.

Can you point out how?

Here's an exaggerated example: are you upset because you can't fly like a bird? Probably not, because you know that the world doesn't work that way.

A more subtle example: If you understand why people act the way they act, you stop being angry when they act in a way that is harmful to others or themselves. It doesn't mean you just let them do it. You stop them if you can. But it doesn't make you unhappy. Just like it doesn't make you unhappy if a wild animal attacks you when go into its cage, for example.

If my dog or friend or family member would die, I'd be unhappy. Understanding that death is natural wouldn't do much to that unhappiness. Maybe someday I'd get over it, or maybe not, but either way, it wouldn't be because I gained some deeper understanding of life and death.

> it doesn't make you unhappy if a wild animal attacks you when go into its cage

Maybe we have different definitions of unhappiness at play here, because being attacked by an animal would definitely make me unhappy. I mean at the moment it would mostly make me fear for my life, but afterward when dealing with the damages I got, I think I would be quite unhappy, and understanding that really I'm the one to blame wouldn't help. It could make me more unhappy, leaving me kicking myself for doing something so stupid.

I wouldn't blame the animal if that's what you mean, but that's different from happiness/unhappiness.

> are you upset because you can't fly like a bird

I think that's more because my hopes and dreams are shaped by the environment that I've grown up in and, living amongst other humans that can't fly like a bird, the possibility of doing that has never occurred to me, at least not for seriously enough to become an issue of happiness.

Had I been a born an elephant with huge ears that all my so-called elephant friends would torment me for... yeah it would make me pretty unhappy if those ears wouldn't at least give me the ability to fly.

Research in general pretty much has to work this way. You're trying to identify "laws" or rules that govern reality. Outliers are interesting, but in general we expect to find many instances of some phenomenon—which means that by default we're looking for cause-and-effect relationships that apply in "most cases."

It's also worth mentioning that it's very easy for people to convince themselves that they're special or different when they actually aren't. Our own psychology is very unreliable. So while your point is well taken, people should also not assume they're the exception to the rule, even if they might be.

You're absolutely right, and I agree that the default assumption should be that humans are exactly the same. We aren't, of course, but abstracting away those details has worked quite well for centuries of scientific progress in medicine.

I've always mused that we could somehow recover some of the "wasted" time of sleeping. 8 hours every night - a third of a human's lifespan - is just so much time.

Sadly, I've never found any positive research that there's any way to do it safely. When I was younger I found schedules like the Uberman[0] and was amazed by the claim: only 2 hours of sleep a day required, as long as you stuck to a pretty rigid schedule and were disciplined about napping on time. I never had the scheduling freedom available to actually give it a go, and accounts of others trying it seemed to indicate that it was actually pretty awful to keep up.

This article seems promising, but it's a relatively short experiment. Would be interesting to see what happened after a year of 4 hour sleep. Based on the author's description, sounds like their body was trying to force them asleep at every turn and they had to fight through it. That would be hard to maintain long-term.

I truly wish one day we can isolate and synthesize whatever magical thing happens during sleep and recover some useful time. This seems much more practical than life-expectancy extension to me. As long as, of course, employers don't take it upon themselves to increase the workday as well. I'd rather sleep than work.

[0]: https://polyphasic.net/schedules/uberman/

I’d say that the idea that we can recover wasted time sleeping is predicated on the idea that sleep is not a useful thing to do with our time. I think the current consensus is that there is actually many different things that our bodies and minds do while sleeping, so you couldn’t isolate one benefit of sleep and replicate it, you’d have to replicate five or ten different benefits of sleep, or more.

If you want to recover some time, try Soylent, moving closer to the office, hiring a maid to do the cleaning, etc. Assuming that these are within your means, you can recover quite a bit of time that way.

+1 to a maid. You can get someone to clean, do laundry, and possibly cook 2x a week for less than $10k ($200 week * 50 weeks) a year in a mid-sized metro. Possibly even cheaper.

Any couple that bickers about cleaning at all should try a maid before a divorce or couples counseling.

I agree, but don't expect to escape from an argument --person A wants to subcontract work A considers boring and menial, instead of contributing their effort to work A has been shirking for x years, now they want to spend A+B money etc. Specific performative compliance may be required before outsourcing negotiations commence.

-1 to having a stranger wander through your place and things while you're not at home. As a commenter on this site you should be well aware that any computer security precautions are forfeit when physical access is available.

Get a roomba.

-1 to having a robot wander through your place and things while you're not at home. As a commenter on this site you should be well aware that any computer security precautions are forfeit when a robot, capable of interfacing with your computer without even entering a password, is allowed physical access to your home.

Hire a maid.

Sure ask the roomba to iron clothes too and watch it while it goes up the walls your kids dirtied up. Check with people with kids on the verge of collapse - if you can afford it, its a godsend (in Asia, you probably can afford it atleast part-time).

Nobody said allowing access to the helper while nobody is around. Weekend help for a few hours is a thing. You can rest and relax while they are around. Just don't be dumb enough to tempt them by leaving a purse full of cash on the table. Even the best of the people can fall prey to a moment of weakness.

I gave it a try, with the only person I could trust (a family member) that was willing to work as a maid.

They quality of the work eventually went down. Fewer nooks and crannies were cleaner each passing week, there were also "cleaning mistakes" that happened that led to a roach infestation happening (or not being prevented from spreading), such as wet dishes inside the pantry.

I just moved to an smaller apartment and will just clean it myself, maybe will ask my GF to help me out.

Like in most other jobs, the quality of work does deteriorate. People get bored, take their employers for granted, cut corners and so on. In case of family, things are more complicated.

For domestic work, you usually can't offer them a career progression path to keep them interested. So the alternative is rotation. Though trust is definitely an issue, if your location has maid agencies that arrange for this kind of work, that aspect can be mostly addressed.

I did uberman in grad school, kept it up for a few months. It technically did give me more hours in the day, however most of that free time was spent on either making sure my schedule was arranged well enough for my sleep times, or sitting around reading a book quietly at 3am because everyone else including my roommate is asleep and all businesses are closed.

The benefits weren't really as pronounced as I was hoping for. Then if you end up missing one of your scheduled sleep times it really effects you and throws you off for a day or two.

I did biphasic for awhile and had a lot of the same issues. I DID get more hours, and I enjoyed doing it, but my family did not. It was impossible for me to do a full time job + family time + biphasic, and have the least bit of wiggle room for a dinner out, or a movie, or anything that took longer than planned.

I'm back to standard 7-8/night.

I am a big fan of sleeping. It makes sense to try to optimize how you use your time awake than to try to do everything in a sleep-deprived state. I've definitely spent days after 4 hours of sleep pounding away at code, seeming to be productive, and then waking up the next morning, thinking "wtf is this garbage", and then deleting it. That's 16 hours wasted, to save 4 hours in bed. Doesn't seem like a good deal to me.

I think if you really want to micro-optimize, you need to be able to set up quantitative metrics and then start playing with variables, and then make very small changes. Maybe you only need 7.5 hours of sleep, not 8. If you are set up to measure the differences in mood, wakefulness, etc., then you can probably detect when you've not gotten enough sleep. But, you might not like the results. Rather than fight them, you probably have to embrace them (or seek medical intervention).

Have you tried lucid dreaming? I’ve been a lucid dreamer since I was a kid but I didn’t know what it was called and I thought that’s how everyone’s dreams work. Somewhere along the way in law school I started using my dreams to study. I’d slow-walk through hypothetical fact patterns or anticipate getting cold-called to recite a case we’d read. It’s been incredibly helpful and once I realized my classmates had no idea wtf I meant by “I literally study in my dreams” I found all sorts of groups online who have different techniques you can try.

I still use lucid dreaming for all sorts of things like practicing for presentations or running through meetings that I know will be difficult. I’ve found its most useful (for me at least) when prepping for interactive or adversarial situations because it forces some part of the brain to “be” both sides: the question asker and answerer.

I have, but I wake up after every lucid dream, so I need to spend more time in bed to get a full length sleep.

And it only last a few minutes, so there is not enough time to study. Even if there was, I am always more interesting in flying around.

And most of the time I only reach a half-lucid state. Like tonight I got stuck in a time loop in a train station. Like I could not leave, because I did not have the right ticket or travel card. Then on a random train the ticket inspector wanted to arrest me. I was aware enough to realize that I could control the environment and could wish the ticket inspector away, but that just triggered the time loop and put me back in the train station where I started.

I actually think the infinite loop, while frustrating, is a good sign! As a kid I had a recurring dream just about every night (I’m talking years) about infinite escalators. I’d ride an escalator up and get off only to find several more to choose from to continue riding up. No matter what escalators I chose there were always more. No end. No way out. It was pretty stressful for my elementary school self.

I had a psychologist relative who tried to help me with my “nightmares” by telling me to just accept the escalator dream instead of being frustrated by it. Somehow it worked, instead of getting frustrated by the endless escalators I eventually figured out how to just dutifully ride in peace until I woke up.

Of course that was super boring, but once I stopped frantically searching for the “right way” to do the escalators I started to figure out all the cool things I could do to entertain myself on the infinite escalator rides. I still use an escalator to “start” my lucid dreams if that makes sense. Maybe you’ll similarly take the train to lucid dreams?

All that is to say that I think the loops are actually the perfect way to practice if you can manage to abandon the problem-solving urge. Easier said than done, I know. Best of luck!

I've been doing something similar with my sleep paralysis demons. Once I realized that they are a figment of my imagination, I trained myself to conjure a demon who has the knowledge of my physics professor. Instead of clawing at my feet while muffled screams fail to escape my paralyzed larynx, he holds an informal office hours where we can work through this week's problem set.

Yes, see my comment here: https://news.ycombinator.com/item?id=23228264

I use lucid dreaming to simulate various scenarios, sometimes have fun with superpowers, usually telekinesis.

The problem I see with this kind of studies is that they don't measure long-term effects, and oh boy - do they exist. Its the topic I can be used as a bad example. When I was around 16, I found that my ideal sleep schedule was doing 20h awake and 6h sleeping. In those 20h, I'd spend around 13h in front of a monitor (monochrome, so less eye strain), and the rest doing the usual stuff (reading, eating, etc). I kept it for as long as I could (around 3 months), until it stared interfering with "life schedules" such as school. So instead of returning to the usual 8h sleep, I started sleeping when I could. It lasted a couple of years, until the brain couldn't take it anymore. After that, I spent the biggest part of 6 months sleeping (would be awake around 4-6h a day) and medicated (as far as I recall, no explicit sedatives). Fast forward a couple of years, and I'd do "marathons" like 20-40h awake, but then with 10-12h sleep time. Periodically, I'd need to sleep "a day" (usually around 14-16h) to feel recovered. In the past 6 or so years, my sleep schedules have been pretty normal, but I sill need to sometimes sleep "a day" (at weekends), and its very difficult for me to sleep only 8h a night. When I'm on vacations, I usually sleep around 12h as often as I can. Messing with sleep schedules (granted, in an extreme way) has had a profound negative impact in my life, and past 20 years, I still suffer consequences from my youth mistakes. The benefits I reaped from having "extra time" are dim compared to the long-term consequences not only on my health, but also on my personal life.

There are other schedules on that site that are far tamer, such as Everyman 1: sleep 6 hours at night, one 20-min nap during the day, which you could do on a lunch break. The fact that many think polyphasic sleep is only Uberman or other nap-based schedules is disappointing to see. There are whole gradations from 9 hours (two 4.5 hour sleeps, not necessarily reduction of total sleep time, but it gives better sleep for some) to Uberman or Tesla (~2 hour total sleep time), which by the way is not known to be stable over a longer time period, a fact that the polyphasic community willingly accepts.

It is particularly disappointing to see because, just as you say, I'd also like to see more research on sleep and perhaps synthesizing its effects into a compound, but if people dismiss these alternate sleep schedules, we may not fully understand what the brain is doing during sleep, as fewer researchers are incentivized to study it, thinking it's just BS, which hurts the field overall.

> I've always mused that we could somehow recover some of the "wasted" time of sleeping. 8 hours every night - a third of a human's lifespan - is just so much time

8 hours - I wish!

Since starting freelancing full time I've been lucky enough to not need to get up at any particular time and ditched the alarm clock - but unlucky enough to find out that it takes me around 9-10 hours of sleep to wake up naturally.

Unfortunately, after getting used to it, waking to alarm now feels like torture (well, it did before too, now that I think about it).

So much time. Every day.

Do you just sleep in a dark room until you wake up? I too want to ditch my normal alarm clock and I've been looking into light alarm clocks. These slowly grow brighter over time to try to wake you like natural light would, rather than using sound. I have not gotten one yet because unfortunately many of them seem overpriced or require using a mobile app with them, but I think the idea still stands.

> Do you just sleep in a dark room until you wake up?

Yes. Although I have no trouble sleeping even if the room isn't dark. Falling asleep is usually a little harder if it's not dark, but once I'm asleep the light doesn't wake me up, unless it's really bright (like sun shining directly through the fully open window).

Maybe light alarm would awake me, not sure how bright they are.

What time do you go to sleep? Also any hints of sleep apnoe?

I tried all kinds of schedules, currently from 4-5 to around 14h.

Regarding apnea - no perceptible stoppage of breathing during the night according to my partner, but I do snore sometimes. I was getting ready to do a sleep study just before the pandemic hit, I hope I will be able to do it soon.

Hypothyroidism? It's a simple blood test, you'll be able to get it done even now.

My thyroid hormone levels are normal, I've had them tested a few times (for reasons unrelated to sleep).

> I've always mused that we could somehow recover some of the "wasted" time of sleeping. 8 hours every night - a third of a human's lifespan - is just so much time.

Given the option, would you want to be slower and less energetic if you could stay up 24/7? We seem to make a trade-off. We sleep for 8 hours so that we can be at optimal performance the rest of the time.

> Uberman

I have never seen anyone that could sustain this. This is probably by design, the body has several mechanisms to make you go to bed. If not doing so was actually beneficial, it is likely that adaptations to this end would be more common.

> I truly wish one day we can isolate and synthesize whatever magical thing happens during sleep and recover some useful time.

Even our real world machines require maintenance stops. Don't hold your breath. Maybe we could make this more efficient in the future and speed up the processes.

That has never been wasted time for me so I disagree on your sentiment. Sleeping is a very fulfilling and engaging activity. I would rather not have the pace set by an expectation of increased "productivity".

Honestly, at least sleep makes me feel good. Distractions (like HN) make me feel worse at the end.

I have come to the (non-scientific) conclusion that this is probably genetic. I know some people who sleep a lot less than me and seem to be fine with that. I am not fine with less sleep, but I wish I was because I would love to have the extra hours each day.

I thought of this for the first time when listening to a Freakonomics podcast series interviewing major company CEOs. Several of them mentioned schedules where they average 3-5 hours sleep per night, forever. They all seemed to think that was fine.

I think I would be severely ill, maybe even literally die, if I averaged 3-5 hours sleep for a duration of many months.

When listening to that series it hit me, maybe this is a genetic thing. In the same way that you kind of need to be tall to make it into the NBA, maybe you need the "minimal sleep is okay" gene to make it as a CEO or rocketship founder. People with those genes get anywhere from 10-20 hours more time per work week than I do, and that's a big advantage over one week, let alone compounded over a career.

I don't know what the research says about this, but my lived experience makes me think it's pretty likely, and unfortunately that also means I may have to be more realistic about what my body is and is not capable of.

Yes, genetic factors are possible. For example, last year a new gene interaction was discovered for people who need less sleep: https://www.nih.gov/news-events/nih-research-matters/gene-id...

I think it's more likely some people can just power through lack of sleep. I've recently started trying to sleep more 6-7+ hours after a decade of doing the 3-5 hours thing.

I just feel better now with more sleep and while I certainly could perform at a high level with less sleep I had to exert more energy the longer the day went on to stay focused.

Genetic? Maybe, or just really good discipline and work ethic?

Well, yes, but this is a bit of a false dichotomy.

It’s obvious that capacity for discipline and work ethic are not entirely independent of genetic factors.

But it's always 30'C and plantains and mangos hang from trees! Why worry!?

It isn't work ethic, the difference for me between full night sleep and 6 hours is night and day-- my memory barely works if I have 6 hours, doesn't matter how hard I want it to work, I simply cannot recall words for things that are trivial to bring forth when I'm operating on 8 hours.

Was his assessment basically just playing video games? I've noticed that's an activity I can do proficiently for an extended duration on very little sleep (along with things like "bulk" coding) but there are others I'm awful at unless I'm well rested (eg. complex planning, creative efforts like songwriting) and I've found my communication skills start to become impaired when I'm really sleep deprived.

I'd be curious to see how he performs on a broader spectrum of cognitive and even physical assessments.

I have exactly what you say. My hypothesis is that your cortex/tertiary brain functions shut down and all that's left is your limbic system and the brainstem. We do a lot of learning in our basal ganglia and cerebellum (pavlov-esque stuff and similar things). That stays more active.

I once made a giant switch statement of 150 lines at my first coding job, and I thought I did a job well done. The next day I came back, well rested, only to realize that I could replace the whole thing with an already existing csv file and a for loop.

Whoopsie :)

How I differ from your experience: there's a certain sleep deprivation sweet spot where my "outbound communication" (e.g. talking or sympathy) skills are better, because I'm a bit less inhibited. My "inboud communication" (e.g. listening or empathy) do suffer a bit. I've noticed I become more of a doer (is that how you write it?). Normally, I overthink things, according to others. That's not the case when I'm mildly sleep deprived. Then I am: optimistic, charging in head first and get the job done! Boom! Yea, kinda like that, I think I'd be a good sales guy on mild sleep deprivation. Oh, and I don't worry about the consequences too much :)

When I get too sleep deprived my communication skills do take a hit.

Thanks for sharing! Yep, I can relate to a lot of that.

On occasion I've noticed slight deprivation seem to stimulate my performance in some tasks. It's accompanied by a feeling of being wired and on a roll. That mildly elated "let's get 'er done!" ferver. I always assumed it was adrenaline pumping through my system to keep me going, as a (poor?) substitute for rest. Like the body's coffee.

Also seen cases where it similarly lowered my inhibitions (almost like a mild buzz). But once I'm significantly deprived, my vocabulary starts to become reduced - I have trouble remembering the word I really want (I know it's there, just not what it is), and resort to a more basic one that's less precise. It's generally the "outbound" side that suffers. I think it's also in part that my multitasking gets worse. In a normal conversation I'll be listening, and at the same time processing what's being said in the context of the conversation and my own experiences, as well as thinking ahead to formulate the phrasing for my response. When I'm really tired, I don't multitask as well (it takes more focus to perform the primary task I'm doing, e.g. listening and retaining short-term memory, and if I try to juggle too many things at once I'll lose concentration). I've learned when it's a better time to go get some rest than get pulled into a discussion about that complex $100 million merger or a deep dive talking about feelings with my partner ;-).

What type of video games? That matters a lot to me. I can play a turn-based game like Civilization completely fine on little sleep (measuring the quality of play objectively, like by productivity or victory within a certain number of turns.) Soft real-time games like say a Mario platformer are a little worse but playable if I'm tired. Hard real-time games with very tight and sensitive timing like Guitar Hero or high-level Tetris are unplayable at anywhere near peak form if I'm not fully rested.

Games requiring long term focus, chess for example, I personally have difficulty playing when sleep deprived, even though it is turn based. I find I play at ~200 rating points lower on low sleep.

Agreed. Many a late sleepless night have I blown 200 points or more on frustrating blitz games. I would regularly play a game or two during lunch breaks, climb a good bit, then stay up too late one night and rage throw my points into the abyss.

I think it's an inverted U curve.

Games that require fast response and planning suffer on one extreme, and abstract thinking games like chess suffer on the other.

The real question is whether this penalty goes away once you adjust to your new sleep schedule.

Adrenaline goes a long way for me. I had trouble waking up for 9am classes in college, coffee didn't help, but 8am CounterStrike did.

Lower communication skills on sleep deprivation are apparent to other people much sooner then to the sleep deprived person. Same goes for drop mood regulation skills. This effect is even larger as other people adjust to drop in those communication and mood regulation skills (e.g. will avoid communication and definitely wont even try harder or more stressful topics.).

I have this as repeated observation from time when I lived with sleep deprived gamer.

This gotta be my favorite comment in the entire thread. I take three tests: PVT, a video game, SAT -- and I get accused of "just playing video games" and told to perform a broader spectrum of assessments.

Fair point!

I'm not familiar with PVT, and from the description I thought it seemed itself like a simple (if boring) videogame - or at least measured a subset of similar skills, like reaction time and attention lapse.

Didn't mean to come across as dismissive; I really am interested in broader metrics on this stuff. But don't deprive yourself again just for our sake. Thanks for your work, for reiterating the SAT piece, and for stimulating some great HN discussion.

(ps. You attributed some of the minor, sleep-deprived PVT and SAT deterioration to "getting lost in thought". Do you think you'd encounter the same degree of boredom or drifting focus if you did them again post-experiment, in a well-rested state?)

PVT is a standard in psychology task used to assess sleepiness - no relation to video games

Note that the "getting lost in thought" happened when I slept 8 hours not 4. I think it just came to me taking hours upon hours of very similar tasks.

>I was extremely bored in the last 2 days of taking control measurements and sometimes got distracted and lost in thought, which resulted in me getting 3 and 4 lapses per session (as can be seen on Figure 1). I do not believe that these lapses represent my lack of alertness. ...

>The last low control score on the verbal section is a result of me becoming very bored with taking the SAT 5 days in a row, getting lost in thought for 10 minutes, and having to rush.

I will continue to experiment with sleep, mostly for myself :) and I'm planning to test memory and skill acquisition next time -- these are the two things people say are affected the most, so I'll try to figure out if that is true for me.

I had this same thought reading it. Anecdotal but my experience with prolonged sleep deprevation was a noticeable decline in my design capabilities.

I'm actually refactoring some of the code/sub systems I created during that time now and some solutions are very wacky...creative, but a super weird way to approach it.

Sleep deprivation might not have been the only contributor, but there a noticeable change in our code base during that time and I distinctly remember worrying about my sleep

For me it depends on the video game. I've noticed that I'm much more resilient to cognitive disruptors in counterstrike than I am in Starcraft.

Starcraft 2 seems to be very sensitive to my cognitive state. When I've been looked back at my starcraft 2 score, I see it jump right before and during a really productive week.

I also see it drop or stall from a lack of sleep before I notice it in my day to day life or work.

I believe learning requires good sleep. TFA's experiment did not measure learning capacity.

This is one of those posts I wish I could downvote 1000 times. It's the brogrammer equivalent of fake news: 22-yo kid "makes science" with a sample of 1, some videogames, and a few charts.

You are 22 year old. Your body is at peak condition, built to go out and hunt for days on little food and little sleep. Of course it will work more or less fine for a few weeks.

I'm the author of this study.

>It's the brogrammer equivalent of fake news: 22-yo kid "makes science" with a sample of 1, some videogames, and a few charts.

>You are 22 year old. Your body is at peak condition, built to go out and hunt for days on little food and little sleep. Of course it will work more or less fine for a few weeks.

I like this comment because its author can't decide whether my study is the "equivalent of fake news" or whether its results are obviously true.

You are clearly unfamiliar with the process of mass-producing fake news. It typically takes “common sense” and proceeds to mislead it through bad paths. Which is exactly what you do with this “study”: you over-analyze a situation that is relatively obvious, with a sample of 1, and simply by doing so you effectively suggest to generalize its results - which is wrong.

You dropping a caveat mid-page in a single sentence is also the same thing tabloids do: make a big title about something, then state the opposite somewhere in the actual small-print article.

If I had the opportunity, I would not only downvote you a 1000 times, I would outright ban you from Hacker News. Your comments are uncharitable, careless, and abrasive.

>you over-analyze a situation that is relatively obvious, with a sample of 1, and simply by doing so you effectively suggest to generalize its results - which is wrong.

>You dropping a caveat mid-page in a single sentence is also the same thing scummy tabloids do: make a big title about something, then state the opposite somewhere in the actual small-print article.

The title of my study is:

>The Effects on Cognition of Sleeping 4 Hours per Night for 12-14 Days: a Pre-Registered Self-Experiment

Which clearly tells the reader that this is a n=1 study. I'm not just dropping a caveat mid-page. If you somehow missed this, it's your problem, not mine.

I think you're doing a disservice to the author's pretty in-depth self-study. The author even states at the beginning of their article:

> I believe that this experiment provides strong evidence that I experienced no major cognitive impairment

(emphasis mine)

> I’m wary of generalizing my results to other people and welcome independent replications of this experiment.

All the limitations you mention are already explicit in the text.

You have any other studies demonstrating lack of cognitive decline in 22 year olds on 4 hours sleep? Otherwise, you're just poo pooing on someone having actually having done the damn experiment. Yeah, n=1, but it's better than your n=0.

There are plenty of studies on sleep, all with larger samples and more rigorous approaches.

Can you link to some pre-registered studies of impact of sleep deprivation on cognitive performance?

I asked:

>Can you link to some pre-registered studies of impact of sleep deprivation on cognitive performance?

None of the studies you linked are pre-registered.

It's not meant to be science. It's a geek experimenting with his body. Hacking your sleeping patterns is a classic that all geeks do at some point in their journey.

I suspect the author would disagree with your assessment, seeing how precisely he laid out the entire piece to appear as science.

I find it concerning how many people in this thread immediately jump from believing Why We Sleep is truthful to the book is complete bullshit because guzey says so. Indeed, some good points are raised by him but at the end of the day he's just another fucking guy with a blog. The entire field deserves more study but the responses on here feel like Grandma on Facebook passing on something she read because it feels right.

> I slept 4 hours a night for 14 days and didn’t find any effects on cognition (assessed via Psychomotor Vigilance Task, a custom first-person shooter scenario, and SAT).

Remember kids, the only difference between screwing around and science is writing it down.

So all my late nights playing video games as a teenager could've been justified had I only phrased it as "doing a PVT for cognitive studies"?!

You would have to systematically write the circumstances and resulting observations down

I read about the Uberman sleep schedule stuff myself when I was younger and trying to recover time I "wasted" sleeping. I ended up trying Uberman myself (15 minute naps, 6x per day).

I did a decent amount of prep work. I talked to my doctor (who basically said as long as I'm not falling asleep while driving, go for it). I set up ways to track my cognitive abilities around work (remote software engineer at the time). I started tracking kill-to-death ratio in favorite first person shooter (I thought it was a good measure of my innovation, as you can't use the same tricks for very long against human opponents). I also started tracking my weight, strength, endurance, and food intake.

It was hard to get into the schedule, and it never really clicked and held. Eventually I found the schedule to be frustrating and difficult from a social perspective. So I ended up dropping it a little over a year after I started.

So yeah, a little over a year.

When I analyzed my numbers I didn't see any particular hits in any of the areas. Work stayed stable (I actually got promoted about 9 months in, so I'm fairly confident about that). My kill-to-death ratio in the FPS climbed steadily along a similar trajectory as it had before I started. I found I was eating more (from ~2300 calories per day to almost 3000 calories to day), but my weight stayed level. Strength and endurance went up slightly, but that's probably more because I was checking them regularly versus not doing any exercise leading up to it.

Would I suggest it to others? No. There were other issues I had with the plan, more societal. And it was frustrating to not be able to focus on something for more than 3.5 hours at a time. But it certainly was an interesting time.

Was adaptation to Uberman staggeringly difficult? I tried it multiple times, each time thinking I had come up with the perfect system to push through, and each time failing. On my final attempt I would go for bike rides to stay awake and would actually doze off for a few seconds at a time ("microsleeps") even while riding.

I concluded that physiology determined whether or not something like Uberman is even possible for a given human being, and I don't have the right physiology. I have a close friend who tells me that he "doesn't get jet lag" and seems to have other resistance to circadian disruptions, so I've always thought that he would be perfect for Uberman but he's not interested so I can't really test my theory.

> Was adaptation to Uberman staggeringly difficult?

Not sure which adaptation. For dropping into the mechanics of actually sleeping it was hard, but manageable. I spent a solid 48 hours awake. That ended at ~9:40 AM and I gave my spouse strict instructions to get me up at 10:00. I fell asleep instantly, and she had trouble getting me up in 20 minutes, but we got there. The second nap I had a couple shots of espresso right before I went down, and that helped me get back up. The worst part was that first night. I was sorely tempted. After a weekend I had kind of fallen in a rut, but it helped to be out and about for a bit, just so that I was stimulated enough to not feel sleepy. After about two weeks I had fallen into something that felt normal. Sleeping was kind of a chore then.

Adapting other parts of my life were harder. Close friends knew what was up, so when we went to a party or something I'd take my naps in a car, or another room. During the year I'd say I skipped half a dozen naps, and it was always a battle of willpower to not be completely derailed. I didn't drink, because I didn't want that to be a reason I skipped a nap.

These were the reasons I ultimately decided to stop, but it was never really a stable situation. Missing a single nap would throw me off so hard that it was a battle to go back into it.

I did it too for a few months. Felt great just doesn't work with society at all. 3h+ blocks are useful, especially when you need to get somewhere in a bigger city. And missing a nap is like missing a night of sleep, except it's not that easy to catch up without screwing your schedule. I did not have problem not being able to focus on something for 3h (btw AFAIR it was 2.5h for me? with 24 mins sleep). Nap felt like a pause, I could continue coding as if I went to the bathroom. Very much unlike me needing 1h in the morning to establish where exactly up and down are.

For startups - forget it unless you are going alone with no funding. Meetings just don't work. Nap have to be at exact times. It just doesn't work with social norms we have.

Also, switching is hell. It's a torture.

> I did not have problem not being able to focus on something for 3h (btw AFAIR it was 2.5h for me? with 24 mins sleep).

I didn't have problems focusing for 3 hours. But when I was amped about what I was working on, it was frustrating to have to pause for a nap.

I think I originally scheduled 30 minutes for each nap, but I found myself waking up right before my alarm would go off, and it got easier to fall asleep, so I ended up with 20 minutes scheduled, 15 minutes of sleep.

> Would I suggest it to others? No. There were other issues I had with the plan, more societal. And it was frustrating to not be able to focus on something for more than 3.5 hours at a time. But it certainly was an interesting time.

This mirrors what I found in airforce studies about the uberman schedule. The overall gist was: The uberman schedule, if executed well, gives a person more time in a day awake without severe drawbacks. Whatever "severe" means.

However, they also found that dudes following the uber schedule suffered more from interrupts in sleep schedules. On a singular 6-8 hour sleep situation, you can go 13-16 hours with little pause or sleep without much trouble. More with some trouble. Candidates on the uberman schedule crashed a lot harder on sleep deprivation.

This jives with my experience. When I missed a nap, I'd crash hard about 2 hours later. I'd end up taking a 2 hour nap, and then fight to get back on the schedule.

The idea of using gaming stats like FPS kill-to-death ratio as a passive measure of cognitive function is fascinating to me. Along the lines of other passive stats like smart scales and fitness trackers.

Obviously, there are specific tests you can do, but it's difficult to integrate those into your daily routines to generate consistent stats.

It's not a perfect long term measure. Generally over time, an online games community becomes better on average by two factors: good people getting better, and bad people quitting the game. Unless you are actively getting better in step with the community, stagnation means becoming a relatively worse player.

Time of day is a large factor in many games too. The day and night communities have a very different spread of players. You'd need to control for that.

Having recently had a baby, 4 hours of presumably uninterrupted sleep per night is an absolutely amazing prospect! Luxury!

What I noticed was it was not so much a lack of sleep, but how the sleep is interrupted that was the killer. After a few days of barely sleeping longer than 30 mins at a time I found that memory was hugely impacted, and even trivial mental arithmetic required concentration. I suspect this is to do with not being able to get into the appropriate "deep sleep" cycles or something-something-REM sleep?

If you are up for it, please try the experiment again with 4 hours of sleep randomly broken up into 10-60 minute chunks (random variability is important - i.e you go to sleep not knowing how long you've got) distributed throughout the day, with a minimum of 60 minutes between each chunk. Enjoy :)

I think this is the interesting question. I'm an extremely deep sleeper and almost nothing wakes me up while I'm sleeping, but I've found that I naturally sleep significantly longer if my bedroom has too much light or there's a significant amount of noise around me while I'm asleep. So despite not actually waking up consciously, I think I sometimes end up in this partial wake state where I'm not getting proper REM sleep and as a result, not actually getting the rest I need.

It wouldn't surprise me if this is often the case for people who feel they need more sleep. Having proper blackout shades and full silence (via ear plugs or otherwise) during sleep allows me to sleep a significantly shorter period of time as measured by however long I end up staying asleep. I typically don't use an alarm, so it's fascinating to be able to notice that natural difference in how long my body seems to need before booting back up.

Interesting anecdote - the pandemic is what triggered my awareness of this effect. When I'm at home alone sleeping (typically into the late morning, I'm a night owl), my dog will sleep with me. When my girlfriend started working from home from early in the morning, he would wake up with her and bark loudly at the occasional activity outside. I suddenly couldn't wake up on my normal schedule, even though I wasn't actually consciously woken up by the barking. The thought occurred to me that it could still be the barking and something related to the depth of the sleep, so I tried ear plugs + having my girlfriend close the bedroom door. Suddenly I was back to sleeping normal hours. Years of strange sleeping pattern problems were explained in an instant.

Guzey had another blog post on Matthew Walker's sleep book posted on HN a while back. I thought it was a bad faith critique, from my own biophysics perspective. We had some back and forth, guzey seemed nice & respectful enough, but I still had my misgivings about the critique. Sleep is very much an open question.

HN seems to really love maximizing cognition and the overall efficiency of their life. That said, if you want to try this experiment yourself, know this: sleep also affects mood, memory, and longevity (e.g. dementia). Chronic sleep deprivation is not good for you.

It's so strange to see "independent researchers" attempt to poke holes by any means in an argument meant to protect people from the ill effects of sleep deprivation, yet provide zero non-anecdotal evidence to support lack of sleep being beneficial.

Discounting Walker's argument with "he's not thorough" and then providing a "study" done by one person with no professional research experience appears fine for HN

Eh, I understand the motivation though - I think a lot of people on here are young, driven programmer-types who resent sleep because they see it as inefficient. I think they're mistaken, but the drive to experiment on yourself is understandable if you're in that cutthroat world.

I remember your arguments and they were bad. Here as well you claim the causal relationship between sleep and longevity while we have 0 good studies demonstrating it.

Those interested can look at our Why We Sleep discussion here: https://news.ycombinator.com/item?id=21903746

I found the critique very convincing. What do you disagree with?

> Sleep is very much an open question.

Walker's book is very much at odds with that statement.

I guess it depends on what you mean by convincing. If by convincing you mean Walker played fast and loose with some of his data presentation, then I'd have a hard time disagreeing. He was also pushing the marketing circuit hard back when that blog post went up (NPR, Rogan, etc). Which can make him feel like a snake oil salesman. So I understand the suspicion

But if by convincing you mean that guzey brought us back to square one - that is, sleep might not be as important as we think - then I don't think its a convincing critique.

Yes by convincing I mean it convinced me that Walker is a quack. Way beyond suspicion. As an author he didn't only waste the time I spent reading his book. He put bullshit in my head. I can't fully protect myself against that, but I don't generally give people a second chance on it.

I didn't get a "sleep less" message from the critique. Just a "don't read Walker" message. It feels weirdly patronizing to suggest that the critique is wrong when you just fear people will sleep less after reading it. Why not say that right away?

"Why We Sleep" by Matthew Walker summarizes quite a lot of research on sleep. It leaves little doubt - we currently know of no safe way to significantly cut down sleep.

I haven't seen the research presented in that book being refuted.

I think this book is mostly bullshit - the same author that wrote the linked HN post dug into that book and there was a ton of manipulative data and just straight up false claims. [0]

I get a pretty strong pseudoscience vibe from it.

From a previous post:

I got a strong motivated reasoning/bullshit vibe from Walker in this interview: https://www.npr.org/2018/07/20/630792401/sleep-scientist-war...

Particularly this section:

> “Sleep is not like the bank. So you can't accumulate debt and then try and pay it off at a later point in time. And the reason is this - we know that if I were to deprive you of sleep for an entire night - take away eight hours - and then in the subsequent nights, I give you all of the sleep that you want - however much you wish to consume - you never get back all that you lost. You will sleep longer, but you will never achieve that full eight-hour repayment as it were. So the brain has no capacity to get back that lost sleep...”

I don’t think this follows - seems likely to me that sleep is not some linear time thing and that there’s a standard overhead that doesn’t need to be repeated to extend and make up the time. This feels like a symptom of not understanding the mechanism and making a bad assumption.

I also found the “I won’t mention the cognitive failures I can detect” irritating. If there’s some actual thing to mention, say it - this kind of thing sets off alarms for me.

It doesn’t surprise me that the rest is similarly bad.

[0]: https://guzey.com/books/why-we-sleep/

>I get a pretty strong pseudoscience vibe from it.

I don't quite know how to categorize complaining about pseudoscience based on a "vibe".

It's not quite irony... maybe it's just humorous. As a member of the post Alanis Morissette generation I guess I can no longer recognize irony.

By 'vibe' I mean a ton of statements that sound likely to be false or at least would surprise me if they were true that aren't backed up when you look closer. The fact that the information is surprising isn't bad itself, but it spikes curiosity - then when I look deeper there isn't much actually there to support the surprising claims and what is there has a ton of issues.

There's a lot of 'wow, isn't that interesting' talk and deference to authority on an 'important' issue, but little talk of the actual mechanisms of how things work, little consideration of obvious counter examples that could be an explanation (like the one in my comment).

The sense is that the argument is driven by motivated reasoning instead of trying to understand what's true. Basically starting with a position and forcing the data to fit your pre-existing position.

It feels like I'm being conned by someone making up bullshit for status or some other agenda (maybe just sunk costs into an existing theory). Often bullshit and complex interesting topics can sound similar at first and it's helpful to have some sense for telling the difference. Otherwise you wander around impressed by 'energy crystals' and worried about 5g.

What agenda could be served by convincing people to get enough sleep?

Walker has clearly made a huge name for himself and sold a significant number of books by skewing the evidence to make his thesis sound more substantial than it is

It's less about the specific content, and more about continuing to push something without good science behind it.

For example: I think X is true, I cherry pick data to back up X and publish a book on it. This book gets a lot of attention and is good for my career, but it's based on bad science and misleads people. This is a theory I identify myself with along with my success and my own career, if its ideas are invalidated that reflects negatively on me and my abilities (and potentially the ability to support myself). There's an incentive to rationalize or continue pushing the bad science which slows down figuring out what's really true. This has happened a ton of times throughout history.

In this specific situation the benign case is people sleep more and it doesn't matter (or it helps), in the pathological case people are anxious about their lack of sleep and it negatively effects their life or they sleep more than they personally need and it turns out over-sleeping is co-morbid with depression and causes other issues.

In the general case popularizing bad science has knock on effects that make it harder for people to get funding to study ideas the contradict the popular, but incorrect zeitgeist of what's commonly thought to be 'true'. It can also lead people down rabbit holes that can take a long time to crawl out of and make it take longer for people to understand what is actually true.

You can't just hand wave this away by saying "I know X is true, therefore it doesn't matter if the data is a little problematic. X is true and it's good for people to know that". A lot of times X turns out not to be true, not to be entirely true, etc.

I don't know if you can call it an agenda but I think there's something like a 'wellness' or moderation bias in these fields. The idea that you need to balance out hard work, slow down, and so on.

For example, as it turns out there is little evidence that stretching actually does anything, yet a lot of experts used to recommend it for decades. Same with nutrition, 'balanced diets', workouts at low heart rates and so on.

What do you mean that stretching doesn't do anything? Any links to such evidence? It's a pretty simple experiment to stretch every day for a month and measure your flexibility gains, so that's quite a bold claim. Do you mean it has no direct impact on your health?


it actually has negative impact on health and injury in people who do static stretches in particular is significantly increased. (as is in people with high levels of flexibility in general)

Nowadays stretches as a warmup are not recommended any more.

Pseudoscience isn't about "vibes" though, its about mis-using scientific concepts in disingenuous ways.

I get the “vibe” because of the misuse. I regret using the colloquialism since people seem to have such a strong reaction to it. I just meant my skepticism went up from what I was hearing.

I find this argument odd for a couple reasons.

First, if you "can't get back lost sleep", wouldn't that mean that you were tired forever? I'm definitely more tired after 24 hours awake than 18. But I can sleep and get back to normal.

Second, I once stayed up for almost 3 days straight. At the end of that, I slept for 24 hours straight. I woke up the next evening as if it were a normal morning, fully refreshed. (I went to bed about 5pm, and woke up about 5pm the next day.)

If I didn't "bank" my tiredness and pay it back with sleep, how is that even possible?

Sleep is essential for memory and skill consolidation. What they mean by not being able to recover sleep is that if you (for example) try to learn something while sleep deprived, more of those memories will be lost the next day. Sleeping extra on the weekend will not make those memories come back. The benefits of sleep are "lost" forever.

If that's what they meant then isn't that what they should have said?

What you're saying makes sense, but it's very different from what was said in that interview.

Grandparent's description is exactly how I read the interview too.

there have been complaints by serious people about the work in this book, see


now, it's obvious to me that if I don't get 8 hours of sleep a night, my brain stops functioning properly and my entire life goes to shit very quickly. So I was happy to see a very popular book advocating sleeping well, and hopeful that if lots of people read it, they might have more respect for other people's sleep schedules.

The critic, Alexey Guzey, seems to be a guy who needs less sleep than I do, and also a guy who is into life-hacking/self-improvement type stuff. There's definitely a type of person who thinks "sleep is for the weak". I think he probably does have a bias towards sleeping less.

But I think the problems he points out about the book are pretty serious.

In particular, it seems that claims around sleep and longevity and other health outcomes (e.g. injury rates, cancer) are often unreliable or based on misinterpreted studies, and one case involves eliding data that contradicts the result.

Now, having myself experienced chronic sleep deprivation, and dealt with people who think they don't need to sleep but definitely do, I think the basic argument of the book is probably correct. But as the last line of that post quotes, "Good ideas do not need a lot of lies told about them to gain public acceptance".


For those interested in someone who created a refutation to Matthew Walker's "Why We Sleep"

I wouldn't say this is refuting even a minority of claims in the book. It appears to be a thorough fact check of a small percentage of claims, some of which is going after the author over wording and inconsistencies. It's fair criticism, but by no means invalidates a majority of the information regarding sleep that Walker presents

After finding that the part of the book which actually got fact-checked is full of falsehoods and contains outright falsifications, your conclusion is "well, the rest of it must be fine"?

Except there are cases where Walker went so far as to remove portions of a graph to support his argument. This kind of manipulation shouldn't be allowed to stand and it's frustrating (though not surprising) to see a book that relies on this sort of dishonesty get so much uncritical attention and praise. I can't put it any better than Andrew Gelman:

"If the data didn’t matter, then why did you include them in your damn book in the first place? If the removal of the bar from the graph didn’t matter, then why did you remove the damn bar?"


Okay, he removed the 5 hour bar. I get what the author in your link is upset about, leaving out data points. But imo that's not good enough to make me throw out all the information in that book.

It sounds like the author is upset a book about getting enough sleep is getting so much attention. If they're upset at the way Walker misrepresents information, then I'd hate to see the author's blood pressure while feverishly researching the bias of every article they come across

I'm genuinely surprised someone could read that whole blog post (I'm assuming here) and come away with that conclusion. Gelman addresses this so directly in the article:

"Recall the Javert paradox. It’s completely reasonable to write about scientific misconduct, and yes sometimes we have to scream a bit to get heard over all the chatter of the scientist-as-hero press." ... "But we need real expertise, not fake expertise. I’ve said it before and I’ll say it again: Gresham, baby, Gresham. If we don’t contest the fake expertise, I’m seriously worried it will be crowding out the real stuff."

There is good research and there is bad research. The latter should not be given a pass just because all research has some amount of bias.

This refutation is authored by the same person who conducted the study to which these comments are attached :)

I did some digging and it is pretty solid to me. It's sad that Walker did not respond to this.

He did (poorly) and not in a single easily read location.

Proof of digging?

An educational and insightful book, but it had me losing sleep because I got so anxious on needing more sleep. Talk about irony!

I think you shouldn't have to worry about it, a lot of claims in that book don't hold up to scrutiny: https://guzey.com/books/why-we-sleep/

This 100%. I've read the book twice, coming back to certain chapters more than twice, because it's dense with information. It's scary really. The single most impactful thing you can do as a human for your life is to prioritize 8 hours of sleep per night, full stop.

> because it's dense with information.

It also appears to be dense with misinformation.

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