alt.hn

8/19/2026 at 7:40:32 AM

Where Human Sleep Went Wrong

 https://nautil.us/where-human-sleep-went-wrong-1283797

by XzetaU8

8/19/2026 at 9:07:20 AM

>“No way. They’re partying all night.” But they can, because there’s no top-down pressure to go into the office at 8 a.m. They’re free to catch supplemental sleep as needed throughout the 24-hour period.

This feels like the key point to me. These societies follow their body and go to sleep when they are tried, while us in the west have to sleep at a specific time to fit our schedules.

by hastily3114

8/20/2026 at 9:42:23 AM

>while us in the west have to sleep at a specific time to fit our schedules.

This does seem to work great at group level. Considering we're in a competitive setup and all that.

I also recognize I personally benefit from others having this schedule. It would quickly go sideways if the firefighter felt like he wanted to sleep a bit more, or the police officer didn't really feel like it whenever is an emergency.

by 47635274172635

8/20/2026 at 2:27:09 PM

Firefighters and police are quite strange examples to choose, since they both have to offer 24hr support. Surely they could benefit from sporadic sleeping and shift work?

For example if they're able to have some firefighters napping at the station, whilst others keep watch for alerts, that would seem better than enforcing strict wakefulness for the whole squad so they are all tired if the call comes in at the end of a night shift?

Obviously there would have to be some communication and understanding about who stays awake and who takes a rest, but I could see it working.

by everyday7732

8/20/2026 at 4:45:15 PM

That was the low hanging fruit, after I set the stage for the real state of things. Again, we are in a competitive setup, globally, which imposes a certain gameplay. If we're not organized we're not as efficient. Or functional for that matter. You are either putrid rich and can afford to pay others to keep it together for you, or you need to do what you don't really enjoy, but must be done. As always basically. In the past we were facing famine mostly, so we had to do what we had to do. There were times for partying but we always had to do what we do not enjoy doing. It's nothing new really, it's just the way we're doing it that's different.

So coming back, what would be your solution? Because you cannot simply ignore the global competition for resources and basically power. If you slack you get taken over. As in, slacking might work for a while, sure. But that will inevitably be seen somewhere, in some numbers, statistics, resources etc. Sooner or later. What do you do then? One just needs to look at some current wars footage to get a sense of how bad it can be. Also don't get me wrong, I'm all for world peace and all that. Very hard feat though, considering human nature.

by 47635274172635

8/19/2026 at 9:24:15 AM

A single block of sleep is a relatively new behaviour, I suspect partially driven by the availability of cheap sources of light and heat. https://www.bbc.com/future/article/20220107-the-lost-medieva...

by mywacaday

8/19/2026 at 9:31:56 AM

This is a contentious theory with little actual historical backing. Most likely people have been sleeping in one block since forever.

by bopou

8/20/2026 at 12:31:47 AM

> Historical texts and recent research suggest an alternative view: that sleep can be naturally segmented into two periods across the 24h cycle – a pattern known as biphasic sleep

https://www.sciencedirect.com/science/article/pii/S138994572...

by musicale

8/20/2026 at 7:44:41 PM

I believe that "little actual historical backing" could accurately describe what evidence that publication has provided, don't you?

by bitshiftfaced

8/19/2026 at 9:37:51 AM

> Most likely people have been sleeping in one block since forever.

Does that have stronger historical backing?

by scotty79

8/19/2026 at 2:15:11 PM

There is a lack of historical writings clearly describing segmented sleep as a normal practice over monophasic sleep. If it had been the standard sleep pattern, one would expect abundant evidence for it.

Roger Ekirch’s theory, meanwhile, is based on what one could call a biased interpretation of a hand-picked selection of ambiguous sources.

by layer8

8/19/2026 at 3:19:10 PM

I asked if there's abundant evidence for monophasic sleep in historical writings. Or do we just assume it was monophasic, because there's not much written about sleep either way?

by scotty79

8/19/2026 at 3:38:27 PM

You were asking for historical backing. Sleep is definitely abundantly mentioned in historical writing, while segmented sleep is not. I take the absence of the latter as historical backing.

by layer8

8/20/2026 at 5:57:48 AM

Absence of evidence is not evidence of absence.

by fittingopposite

8/20/2026 at 6:28:41 AM

[dead]

by jnfnfkfkt

8/20/2026 at 10:47:29 AM

Monophasic sleep is mentioned, or just sleep is mentioned without hints on whether it was monophasic of polyphasic?

by scotty79

8/19/2026 at 10:10:19 PM

I wonder how much time zones and seasons impact things. For example, in my city in the winter, it is often dark for 14 straight hours. No average, healthy individual would sleep for that long on a nightly basis. So, even if one slept for 7 hours at sunset, then there would still be 7 hours of darkness remaining upon awakening.

Point being, if one slept for 4-5 hours, wake up for a similar chunk, and slept the same amount again, then that'd be a great way to pass the time one could likely not use to do outdoor labor.

by hirvi74

8/20/2026 at 8:11:56 PM

I would posit that the null hypothesis should be that uncoerced human sleep patterns and historical sleep patterns are similar to A: modern human sleep patterns, and B: the sleep patterns of a majority of diurnal mammals and especially those primates most closely related to us: namely "one big stretch of sleep while it is dark a majority of the time when not disturbed by external stimuli or illness".

If historical evidence does not do much to disambiguate this from the alternative hypothesis, then the null hypothesis would be the default presumption.

by HappMacDonald

8/19/2026 at 11:37:21 AM

It is more common in high-latitude countries. Very uncommon in lower latitude.

by j16sdiz

8/19/2026 at 5:07:06 PM

Another unbacked claim.

by IAmBroom

8/20/2026 at 6:29:58 AM

[dead]

by jnfnfkfkt

8/20/2026 at 12:22:16 AM

We have evidence that during the medieval period people did take two-sleeps. Whether this is the more "natural" organization is debatable. But it made sense for that time.

by preg_match

8/20/2026 at 6:22:48 AM

Pages 341 to 414 of size 8 font denoting the manuscripts that he sourced from would disagree with you.

by Mwntalhwalth

8/19/2026 at 11:39:32 AM

But the article discussed here also points in that direction when it mentions the importance of people on the lookout at night. The article also mentions primitive tribes partying all night, so that is yet another direction.

by mark_something

8/19/2026 at 4:28:54 PM

My boy when very young (just months) went thru a phase where in the middle of the night he would suddenly sit bolt upright, swivel his head to scan the room, and then conk out again. This was not caused by noises.

I found this reassuring and slightly amazing, that he is wired to do his part as a nighttime lookout.

by euroderf

8/19/2026 at 10:02:54 PM

Assuming you are not jesting, I am not certain I would qualify that behavior as any indication of being wired for some sort of nighttime patrol duty based on those details alone.

by hirvi74

8/20/2026 at 5:49:00 AM

Not jesting! And, point taken. But it made me wonder. It was intentional (within the limits of intentionality for an infant) and repeated.

by euroderf

8/20/2026 at 8:13:37 PM

Fascinating. Also, not that you implied this by any means, but I was not trying to say "you are wrong, I'm right." Rather, who knows? Do all behaviors happen for a reason? Idk.

by hirvi74

8/19/2026 at 5:07:14 PM

When I was in my early 20s, primitive tribes like Alpha Kappa Lambda would party all night.

That doesn't mean they didn't sleep all night, typically.

by IAmBroom

8/19/2026 at 9:58:32 PM

I would also imagine a single block of sleep is relatively new due a host of various factors. Especially when considering untreatable medical conditions, chronic pain, parasites (bed bugs, lice, etc.), lack of comfortable bedding, cohabitation with others, and plenty of other factors all had major impacts.

by hirvi74

8/19/2026 at 9:11:54 AM

I think people in HN (and in general) have to remember the central axes of evolution before digesting this kind of article. I've already seen comments like it's "odd that no species has ended up evolving a continuous maintenance system" and "sleep has a higher opportunity cost in humans" in this comments section.

This is a common, but poor framing of evolution. Remember: the only real rule with evolution is "did this evolutionary change mean they survived / reproduced more"? Evolution is not a local or global maxima solving function. I find this kind of attempt at interpreting selection common with engineers, programmers, etc.

by i_love_limes

8/19/2026 at 9:25:58 AM

Did their genes survive more, you mean. Hyper-vigilance could be maladaptive for the individual and still survive if it benefits others that carry the gene for it.

by hackernud3s

8/19/2026 at 10:30:45 AM

A bit of a digression, but I recently learned about the concept of pangenomes, of trying to map not just the genes in one individual, but the entire set of genes from a clade. It seems it matters a lot in practice for e.g. the immune system that we don't all have the same surface proteins on our cells, even if done some surface proteins are clearly better than others.

by vintermann

8/19/2026 at 9:22:38 AM

I can see why it isn't a local or global maxima solving function, but it surely can be modelled by one, right?

by yuretz

8/19/2026 at 9:43:28 AM

I'm a biologist so forgive me the poor wording, but there are "infinitely high" peaks/walls in the evolutionary landscape, as in: "the human urinary system has some evolutionary constraints and anatomical features that are not optimally designed from an engineering perspective, but they are generally functional and reflect our evolutionary history rather than deliberate design." <- this is from AI, I didn't remember the details, but the ureters or urethra take a long way around the inner part of the body because at some point it was a good route, but as we evolved it became suboptimal, but we can't just evolve to untangle all the pipes in our body and do some cable management... We're stuck with what we have (no tunneling electrons ;)).

So in that sense, a global maxima (minima?) solving function will probably not arrive at what we have, it has to take into account our evolutionary path, in its entirety (as in the whole tree.), because it is all encoded in 1 (or several) long molecules, and a radical changes would take a rewrite of many parts at the same time, which just does not happen. Maybe at some point we can do it ourselves... though I imagine there being a lot of unintended consequences in other places in the body :).

Another example is that sometimes complexity in a cell signalling cascade is simply there to get some timing right (ie delay some response), and the complexity is just there, and won't simplify by itself -> But then later the complexity may start to serve some purpose. Just like proteins that are "copypasta-ed" in the genome, leaving one copy free to mutate and attain a function, or not... etc etc.

by teekert

8/19/2026 at 9:48:36 AM

That is the difference between global and local optima. We're not at a local optimum though, our bodies can probably evolve to produce half the urine or something without changing the route, but there is no evolutionary pressure to do so.

by dtech

8/19/2026 at 9:59:27 AM

Yes, but we cannot evolve to have our urinary tracts take a more efficient route (or at least the probability is exceedingly low), even though there would be pressure to do so. (Maybe I'm misunderstanding your point)

by teekert

8/20/2026 at 1:24:39 PM

You're implying that "half the urine" describes something that could be a local optimum, but a local optimum would be something more in terms like urine output versus energy expenditure required to achieve that. But that doesn't even capture it, because you can directly control how much urine you produce - water in, water out. So what's really being optimized for is the pressure/stress/disutility function of the kidneys in the context of how much water you are intaking. Which is presumably moderated by your access to water, and higher level conscious optimization like how much water you're wanting to intake and how much urine you're wanting to produce. And that's not even capturing all the constraints in play! But it hopefully illustrates how the scope of what is being optimized for is quite large - it's not each metric in isolation, but rather some (probabilistic) utility function over the whole.

by mindslight

8/19/2026 at 10:23:20 AM

Interesting

I did not know human urinary tract was suboptimal.

Are there examples of "discontinuous" evolution where a chance mutation stumbled upon a much better way to do something that allowed a species to jump the gap?

I imagine it would be very rare because chance mutations in a single individual that confer extraordinary survival / mating advantage to offset entire population would be rare like being a superman among men.

by albert_e

8/19/2026 at 11:04:56 AM

"I imagine it would be very rare because chance mutations in a single individual that confer extraordinary survival / mating advantage to offset entire population would be rare like being a superman among men."

-> This also depends on population size, if there is a bottleneck event (ie 99.99 percent of some species dying) then among the 100's of survivors perhaps there could be a superman. Either because this person got lucky, or the rest got unlucky. But in general the distribution of traits is quite continuous, given large populations.

It's also good to keep in mind that us biologists have messy definitions, ie we call specimen A and B the same species when they produce fertile offspring. Some species produce offspring but infertile (Horse-Donkey, Lion-Tiger). But what if A and B have fertile offspring and B and C do, but A and C do not? The whole definition of species falls apart (it leads to a paradox).

We have a lot of that in biology. You need to learn to deal with it (sunglasses dropping down), and assign uncertainties to terms you learn about, they are often just our attempts to name boxes on continuous, multidimensional scales.

by teekert

8/19/2026 at 10:51:33 AM

Well, what is suboptimal... One would engineer it differently, it makes a weird, seemingly unnecessary, loop around some other tracts. However, being a biologist I can also imagine that if we'd reroute the thing in someone using surgery, that person suddenly gets more infections because bacteria find their way up the tract more easily (no idea, but could be!). The point is... It's a mess based on some earlier mess, but it works, and changing one part in this mess can lead to unpredictable results.

As for "discontinuous evolution"... Again, what is discontinuous? I'm sure there are events to be found of which the probability of them occurring is so small and the effects so large that they'd fall into someone's definition of "discontinuous". But I think there is by definition no such thing as discontinuous evolution. If it occurred, it had a non-0 probability of occurring, then again, maybe the universe is infinite and everything has a non-zero probability of occurring. This is getting philosophical haha. Maybe listen to some Mindscape podcasts (Sean Caroll).

Actually rabbits eat their excrement again. That's also probably not how an engineer would make it (or an intelligent designer would design it, since we seems to be going in that direction ;) ).

by teekert

8/19/2026 at 12:16:03 PM

Antibiotic resistance happens all the time (at least in our artificial world) and it's a life or death situation for the bacteria.

But you were probably asking for multicellular eukaryote organism; you may be interested in the concept of saltation https://en.wikipedia.org/wiki/Saltation_(biology) . Behind the concept of the thing itself it's interesting to think about the mechanism behind it. Regular evolution is gradual (point mutation leads to a maybe slightly different protein, which has only a relatively small scale effect but you gain or lose function over many generation), but for a saltatory evolution you most probably need radical changes in the DNA, like duplication (of a single gene, multiple gene or whole chromosome), horizontal exchanges, etc.

It's possible in plant but in animal more often than not it's not beneficial at all to have such event. Famously if you have an extra chromosome nr. 21 you get Down syndrome.

by PetitPrince

8/19/2026 at 12:09:23 PM

no offense, but it just sounds like you don't understand local maxima in high dimensional spaces.

a suboptimal trait evolving that still provided an overall population benefit (via survival or reproduction) with further improvement close to impossible without a multitude of large changes is literally just a local maximum in that high dimensional space that maps traits to whatever success metric you're measuring.

the infinite wall you describe is not a wall in that space. actually I originally wrote its more like a wall in the derivative space but its not quite right either, those just point straight down from the maximum.

by yeoyeo42

8/19/2026 at 12:10:31 PM

Perhaps not no, please enlighten me, where is my lack of insight?

Edit, thanx for the addition. Perhaps my issues with looking at it as "local maxima in high dimensional spaces" (even though we think of minima usually, as in a marble will find the minimum in a landscape with gravity pointing down, sorry I'm a biologist) is that with every mutation and every change in environment the landscape changes (so basically with time), is it still a useful way to think about it like that, at that point? So it not a "landscape in a high dimensional space", but rather a "high dimensional dynamic surface", like a sea?

by teekert

8/20/2026 at 8:17:11 AM

... In fact, because te landscape is so dynamic and can sometimes change within 1 to a few generations, having a brain as the primary store for behavior/customs/models/information is super advantageous compared to using DNA, as the brain is a flexible neural network and can adapt much, much quicker. No doubt this is why we are successful (ie, a dung beetle will die trying to push a stuck piece of dung, because the behavior is hard-coded and it cannot model the world and model solutions to encountered problems, and it therefore cannot pas solutions on to future generations, as we can. Perhaps a dung beetle will someday mutate to alter it's behavior when stuck, but you can see how suboptimal the whole process.)

by teekert

8/19/2026 at 10:09:00 AM

Great question! It maybe can be, but what is the maxima that is being solved for exactly? There are usually tradeoffs, the most common and prevalent is our body's immune response. If it's under-active, we might die from an infection. If it's over-active, we get diabetes, lupus, chron's, and (probably) lots of mental health disorders.

So, it's a bit context dependent, and definitely dependent on other mutations that have occurred in other parts of your DNA. Most complex diseases are "polygenic", meaning it's a culmination of quite a few factors that would contribute to a specific good or bad outcome.

So, yes, it could be modeled as a sort very context dependent with a lot of highly correlated non-independent covariates. We do use quite a lot of statistical and ML methods to understand the genome (I work in statistical genetics), but the complexity of biology has so far proved a tough nut to crack.

by i_love_limes

8/19/2026 at 11:54:44 AM

> It maybe can be, but what is the maxima that is being solved for exactly?

Survival rate/reproduction rate/rate of genes being spread?

by codethief

8/19/2026 at 12:32:54 PM

I think you're correct, but only if you add "for a given environment". It's good to develop the ability to store super efficiently fat when you're a Pacific Islander and food is scarce, but this advantageous trait becomes a liability with modern and plentiful (junk) food.

see thrify gene hypothesis; I know it's not a good explanatory theory but it's a good illustration of my point

by PetitPrince

8/19/2026 at 2:49:21 PM

Sure, the form of the function being maximized will usually depend on the environment.

by codethief

8/20/2026 at 9:44:32 AM

That was kind of my initial point... there are far too many permutations that alter what you want to maximise to consider this as a good option right now. Environment, gene-environment interactions, epigenetics, polygenecity, pleiotropy, etc, etc.

by i_love_limes

8/19/2026 at 10:20:59 AM

Great answer! Thank you!

by yuretz

8/19/2026 at 9:46:20 AM

Evolution is the ultimate "good enough". Once the required threshold is passed, pressure stops. The threshold might constantly be moving due to competition, environment etc.

by dtech

8/19/2026 at 12:54:15 PM

It can't be a global one because it is inherently local. Evolution is a process which determines the next time step (generation) from only the previous generation. It has no memory at all nor "knowledge" of other reproducing pairs.

by tempfile

8/19/2026 at 9:49:33 AM

To be precise inclusive genetic fitness not idealized bayesian optimality.

by FallCheeta7373

8/19/2026 at 1:41:22 PM

> "did this evolutionary change mean they survived / reproduced more"

You're just renaming the terms. More/less is a fitness gradient, and the thing that lives there is called an optimizer.

Evolution is a tunable-scale optimizer. It's not perfectly local, because it shotguns to avoid local optima on a (bumpy/noisy) fitness landscape. If you tune the 'shot pattern' really wide (infinite copies with infinite variation), you'd genuinely get a one-shot global optimizer at the limit. But that's not efficient nor realistic, so typically it's somewhere in between.

Uh, compare maze solvers: you've got your greedy direct route (gets stuck in the first corner) , Dijkstra (finds all the answers but takes ages), and then stuff like A*, which is a happy medium. Evolutionary algos can be used to solve mazes just the same. I think it's a bit heavier on resources than A*, but well suited to embarrassingly parallel optimization.

edit: Heh, I actually had claude build a comparative simulation. Turns out evolution is actually very slow on a single optimization axis, and gets stumped in mazes where the detour length is greater than the "temperature"/"spread"/"noise". The actual performance metrics are fascinating. But once tuned, it is able to solve mazes. Thus an optimizer. QED :-P

by Kim_Bruning

8/19/2026 at 10:13:29 AM

>18 degrees Celsius is considered optimal for sleep depth

I'm instantly skeptical of anyone making universal statements like this, because they're certainly not true for everyone, and having looked into these and similar (f/x "ideal room/office temperature"), are based on many entangled assumptions. Most of the time I expect it's just people making after-the-fact justification for doing (or imposing) what they most prefer.

by duskdozer

8/19/2026 at 11:05:30 AM

When statements like this are made usually it’s because studies would have been done comparing sleep depth at different temperatures and there would have been a statistically significant increase in sleep depth at 18 degrees Celsius in the tested group compared to groups sleeping at other temperatures.

I have no idea if that was actually done here but that’s usually how these statements are justified.

Of course we are all individuals so it may not apply to everyone but you can say that for everything in medicine. Only thing we can do is look for statistically significant differences between groups in double blind controlled studies after controlling for all other factors.

by ViktorRay

8/19/2026 at 12:54:57 PM

And every time I hear about an optimum, I think of the Bathtub Curve.

As I imagine the curve, I use a real bathtub. Where is the water deepest? At the drain, which is typically just under the faucet. Where is the optimal place to sit? Well, pretty much anywhere except there, because "deepest" (an optimum) isn't enough to accurately gauge "best place". But even if you can swing the faucet out of the way... where is the optimal place? Anywhere on the bottom, a broad, slow curve, as opposed to the steep walls or rim.

So, if 18 degrees C is the optimum, what's the standard deviation? I bet it's not 0.1 degrees. Could be 2 degrees - and that would mean concentrating on 18 degrees is a distraction, not a goal.

This is something evolutionary discussions don't address well, either. If a gene line (species) has a pressure to change, it can "settle" for any place on the bathtub floor (when the solution is shaped like that). This is another example of evolution not seeking an optimum; merely avoiding a pessimum (a word I just googled, and like!).

In fact, it doesn't even matter if it's a bathtub curve. Maybe it's a slope, like the amount of capsaicin a pepper plant carries to fight off fungus. More better - but it costs something to make, so just make enough to ensure survival. More fungus? Increase capsaicin production. There's no floor to this bathtub; it's a linear slant all the way down to maximum possible capsaicin content (which, amazingly, is about 10% by weight of the fruit cells!!!).

by IAmBroom

8/20/2026 at 12:25:33 AM

18C is more like the maximum OK temperature. But then I also gotta sleep without PJs when its that hot. Still a blanket for comfort.

Best sleep from my experience? It's usually about 5C at the thermostat, which is farthest from the window, by the time I wake up. And that's likely because it's in the basement, which is a typical NA basement, so you have the uninsulated and below the frost line basement wall there. The cold air coming in will be 0C and colder and I sleep next to the window. Winter is my happy sleep time.

by tharkun__

8/20/2026 at 4:36:07 AM

>18C is more like the maximum OK temperature.

For you, and that's kind of my point. For me, my preferred temperature would be about 28C with no blanket or a light sheet. Something like 18C can be tolerable with blankets for me, but it's certainly not "maximum comfort", even with blankets. There is too much variation and too many things that wouldn't be controlled for, like number/thickness of coverings, and other such things. Having some "best" universal temperature is just not something generalizable like this.

by duskdozer

8/20/2026 at 1:21:04 AM

If you are wearing clothing or any covering, clearly it isn’t your optimal temperature. I’m not trying to be glib here; I understand the appeal of being warm in a cool or even chilly room with air that keeps you from overheating. But that’s not sleeping at the optimal temperature; it’s choosing the sleeping setting you like.

And there are huge swaths of the world where the temperature basically never gets that low (18 C is the lowest temperature ever recorded in Kingston, Jamaica; 16 along the coast of west Africa, 18.9 in Jakarta). Even here in the southeastern US it is normal for temperatures to stay above 20 C at all times for three full months of the year (late June through early September).

Nothing wrong with liking to sleep in cold air, but it’s a preference.

by devilbunny

8/20/2026 at 3:52:53 AM

Your feeling might be different. But for me, body temperature and feeling is way different from the air I'm breathing.

I can be, actually want to be toasty warm under the blanket. But I want the air I am breathing to be fresh and cold. That is when I feel comfortable and "at peace".

I will often stick out my feet from under the blanket because it's way too toasty but the rest of my body needs to be warm.

Sure, when it's 25C I'll essentially just lay there without anything but a sheet across the chest to "feel safe" but anything else will just make me way too warm and the air I'm breathing will feel restricting.

What is really great in 25C+ temps is to be outside in a hammock without an underquilt, which cools things down considerably. But I've also slept comfortably at 0F (-18C) in a hammock. With two underquilts and a 0F sleeping bag as well as a winter tarp with doors and snow cover all around, weighing down the tarp sides (wind does suck at that temp ;)).

by tharkun__

8/20/2026 at 3:16:52 PM

I was really responding to the article’s odd claim of 18 C being the perfect sleeping temp, and your comment was so extreme in the make-it-cold direction that it seemed to be a good spot to reply. If we’re talking about “optimum” sleep temp as though such a thing has meaning beyond personal preference, then clearly it must not be cluttered with cultural detritus like depth of blankets, etc.

My wife wants it to be 20 C or lower and sleep under two blankets. I pointed out that 23 with a fan and a sheet is less energy-intensive and gives equivalent results, and she said stuff it. Not a battle worth fighting at home, but on the internet…

(Of note, the one of our dogs that loves me but worships her still sleeps next me every night, under covers, because she’s a Chihuahua and gets cold easily, and unlike my wife I sleep like a dead log.)

by devilbunny

8/19/2026 at 12:08:48 PM

yeah probably lot of study measurements and data confirming that, I'm not skeptical about it, to me it feels like something scientifically measured proven since quite some time already. of course genetics and outliers still need to be considered.

also do you know that the body temperature decreases during sleep? based on that I simply deduce and assume the more the difference between body and room temperature the more side effects arises for sleep, of course simplifying without ignoring all the rest.

by giov4

8/19/2026 at 7:26:00 PM

If you want a tried and tested heuristic it should be cold enough to make you retreat to hibernate under a mountain of blankets roughly equivalent to or exceeding the warmth of a polar bear's coat.

Then its good night, Irene

by Obscurity4340

8/19/2026 at 11:07:37 AM

[dead]

by GeoAtreides

8/19/2026 at 8:44:33 AM

>the Hadza uniformly reported high satisfaction with their sleep.

And why wouldn't they? This is (presumably) the only kind of sleep they know.

by hlynurd

8/19/2026 at 9:14:37 AM

Do you really need to know other kinds of sleep in order to know if you feel like shit after waking up or if you feel fine?

by bialpio

8/19/2026 at 10:25:01 AM

If they have no frame of reference then it seems like their general contentedness is being measured (or as another commenter indicated, their willingness to gripe.)

by hlynurd

8/19/2026 at 12:57:25 PM

Yes.

Even in your example, you propose an individual could know multiple kinds of after-sleep feelings.

by IAmBroom

8/19/2026 at 3:18:02 PM

I believe that how you feel after a night's sleep is mostly due to nutrition (long term, not just the day before).

by hobo123

8/19/2026 at 4:28:42 PM

that might be true unless we can define what nutrition can help with sleep. There's plenty of people who eat well and sleep like crap.

by agos

8/19/2026 at 9:01:30 AM

They're probably also less confronted with articles/videos/social media posts telling them they're doing it wrong and how they should sleep instead. Sometimes ignorance (or rather, not overthinking things) is bliss...

by rob74

8/19/2026 at 8:52:35 AM

Well probably us modern human only know the "8h sleep at night" kind of sleep, yet a lot of people would tell you whether they're satisfied or not with their sleep

by oulipo

8/19/2026 at 10:54:46 AM

I mean I can vary from 9 to 3 hours of sleep a night, and I can tell you I'd rather get 9 than 3. Just because I'm meant to get 8 hours a night doesn't mean I do

by voidUpdate

8/19/2026 at 10:20:19 AM

Also, they may not want to complain to strangers.

Also, we humans can get used to a lot of things and just be okay with it. For an extreme example, look at domestic abuse victims...

by readthenotes1

8/19/2026 at 12:02:25 PM

True. But the article mentions that the amplitude of their circadian rhythm is higher (which tells you how much a relevant measure like the amount of melatonin or body temperature varies in a 24 hour cycle), so that is an indication of better sleep. A low amplitude means less difference between sleeping and being awake.

by mark_something

8/19/2026 at 8:49:16 AM

This interview feels weird to me, maybe because there's lots of places where I'm thinking there's an obvious idea that isn't raised.

Like, it seems obvious to me that sleep has a higher opportunity cost in humans than most other animals. So naturally there's more evolutionary pressure in humans to sleep more efficiently.

Is this actually true? Dunno! But it was really weird that it doesn't get brought up.

by syllogism

8/19/2026 at 8:24:51 AM

> Some emerging research suggests Earth’s magnetism matters, as well. Being barefoot on the ground versus 30 stories high in a downtown skyscraper puts you in a completely different magnetic environment.

Really? My instinctive reaction to this statement is that it's quackery. Would be very interested to see headlines appear about this if it's true.

by Flashtoo

8/19/2026 at 9:09:32 AM

It's definitely quackery. There's way more "natural" magnetic variation between two different cities than between a ground floor apartment and a 30th floor apartment (see magnetic declination maps), and that's even before you get into the way-more-powerful magnetic fields generated or present in a home.

by alex43578

8/19/2026 at 8:43:28 AM

You can write pretty much anything you want after “Some emerging research suggests”

by iammrpayments

8/19/2026 at 12:10:26 PM

This is called "grounding" or "earthing" and Wikipedia doesn't pull punches in dismissing it [0]. You can buy grounding wires for your mattress or copper rivets for your shoes.

From my tissue engineering class in undergrad my 2 cents is this is maybe 95% supplements quackery and 5% genuine mystery. You can find papers that claim EM fields have cellular interactions [1]. I don't think serious scientists will touch conventional earthing, though.

[0]: https://en.wikipedia.org/wiki/Energy_medicine#Earthing

[1]: https://pubmed.ncbi.nlm.nih.gov/38068954/

by randusername

8/20/2026 at 11:40:23 AM

Hilariously, the wikipedia page suggests that the research looks less like it's "emerging" and more like it's "submerging".

by n4r9

8/19/2026 at 8:39:09 AM

More evidence this may have been written by a pigeon...

by unprovable

8/19/2026 at 8:29:49 AM

People already live in different altitudes, ie with vastly different amounts of rock between themselves and the bits of the earth that produce her magnetic field.

So colour me skeptical of this claim as well.

And while I like going barefoot for other reasons, I don't think it makes much of a difference to the magnetic fields.

by eru

8/19/2026 at 8:34:19 AM

> People already live in different altitudes, ie with vastly different amounts of rock between themselves and the bits of the earth that produce her magnetic field.

It's not really the same thing. Construction and especially the high content of charged metal (whether it's power conduits or plain old frame) may make a considerable difference.

by krige

8/19/2026 at 9:26:25 AM

What about flowing underground water when sleeping on the ground?

What about the metal frame of a bed?

by dolmen

8/19/2026 at 8:49:03 AM

Do many people sleep in such tall buildings? Obviously they exist, but I can't think of any over-20 story residential building I've ever been in. Office space, sure, but not residential.

by dotancohen

8/19/2026 at 10:35:11 AM

The amount of people who would regularly sleep in such a building is a minuscule fraction of the world population.

by nkrisc

8/19/2026 at 11:11:54 AM

See https://en.wikipedia.org/wiki/The_Pinnacle@Duxton

by eru

8/19/2026 at 4:48:46 PM

Yes, like I said, these things exist. But I ask do significant populations of humans reside in the upper floors of such structures?

by dotancohen

8/20/2026 at 1:13:13 AM

In absolute terms, yes. In relative terms, no.

by eru

8/19/2026 at 5:07:18 PM

You forgot to mention whether they slept near shakra-aligning crystals or not.

That may make a considerable difference.

And I may be a 10,000 year-old alien.

by IAmBroom

8/20/2026 at 4:10:02 AM

>I may be a 10,000 year-old alien.

That would be so disappointing, I've been picturing you as Mickey's assistant in Fantasia :)

Then again, maybe that checks?

by fuzzfactor

8/19/2026 at 12:29:50 PM

I would not jump to such conclusions, I would assume is not fully known and needs to be further understood.

on the other side, do you know we have polarized and non-polarized cells? do you know they can be affected by electromagnetism?

this two things already establish the existence of a relationship and effects between them. If we then consider that cells mechanism work based on differential of electrical or chemical potentials, and that they continuously use that for their functions, reactions or environmental compensations well...

I just think they are related and we need to understand better.

by giov4

8/21/2026 at 12:16:04 PM

Fascinating, but polarization is a red herring. Magnetism is famously the wildly-unreactive half of electromagnetism; copper is REALLY sensitive to electricity and REALLY insensitive to magnetism.

I agree ideas shouldn't be dismissed out-of-hand.

by IAmBroom

8/19/2026 at 8:59:53 AM

And Earth's magnetic field is extremely weak

by ymolodtsov

8/19/2026 at 8:49:20 AM

There might be precedent for being able to detect changes in magnetic field

https://www.pbs.org/newshour/science/dogs-poop-in-alignment-...

but then again maybe not

https://www.sciencedirect.com/science/article/abs/pii/S15587...

by krackers

8/19/2026 at 5:09:54 PM

Yeah, that first study was pure bunkum.

Some animals - migrating birds, notably - can detect magnetic fields. IIRC, sharks have close-range magnetic sensors in their gumlines.

But these are extremely rare and niche adaptations to difficult problems.

by IAmBroom

8/19/2026 at 8:31:51 AM

It's a creative innovation!

by LYFMail

8/19/2026 at 10:35:40 PM

"we’re the shortest sleeping primates, yet we pack in the most REM sleep relative to this short duration."

Nothing surprising here. We sleep in cozy comfortable beds in a locked and secure location. Of course we'd can get int REM sleep. Compare to other primates who sleep outside with the critters and predators, deep sleep could mean the end of them.

by fhn

8/20/2026 at 3:29:48 AM

My understanding is that REM isn't particularly deep. Quick web searches aren't actually defining it as more like light or deep sleep, but many of our systems are more active than other stages[1][2]. Still I don't think it's super surprising that we spend more time in REM since our brains are uniquely complex and we spend a lot of energy on perception and interpretation, which REM seems to help with [1][3]. And I would be willing to be safety and comfort also play a decent role in it as well!

1: https://www.healthline.com/health/how-much-deep-sleep-do-you... 2: https://www.health.harvard.edu/healthy-aging-and-longevity/r... 3: https://www.sleepfoundation.org/stages-of-sleep/rem-sleep

by samtheDamned

8/20/2026 at 4:00:27 AM

Probably the only primates where a significant portion spent tens of thousands of years isolated up in the Arctic during prehistoric times.

Where the sun doesn't go down every single day anyhow, and you may need to trudge across the tundra routinely for more than 24 hours at a stretch to get almost anywhere, without ever worrying about it at all.

Then they later came down and intermixed with (not) everyone else, so you never know who is going to be less tired than "normal" when they work a 36-hour day.

by fuzzfactor

8/19/2026 at 11:33:35 AM

> Most importantly, when we measured their circadian function directly, small-scale communities had much higher amplitude circadian rhythms than global north populations, which I think is why they report being happy with their sleep even though it’s more fragmented.

This could explain why I feel more rested when I wake up if I take glycine before going to bed, even though I don't sleep more.

by mark_something

8/19/2026 at 8:17:13 AM

More fragmented sleep, with people talking in the night, etc. I guess that's different from the low, unnatural, rumbles of cars and aeroplanes the majority of people have to put up with.

by montebicyclelo

8/19/2026 at 9:27:09 AM

I could only wish for low unnatural rumbles of cars. In 3rd world countries it's non stop horns and noisy motorbikes

by yard2010

8/19/2026 at 9:42:16 AM

Car horns gotta be up there as some of the worst inventions of the 20th century, noise pollution galore.

by HappyPanacea

8/19/2026 at 10:39:33 AM

It works when you have strict rules on the use of horns and people get peer pressured into adapting to the behavior of their surroundings.

by jbuhbjlnjbn

8/19/2026 at 10:36:09 AM

737s are fine its dog barking that gets me.

by abigdog

8/19/2026 at 9:22:00 AM

I actually find it easier to sleep with the sound of people talking around me, it's very comforting.

by Pearse

8/19/2026 at 8:30:10 AM

> Sleep is critical to human functioning, and yet, we sleep fewer total hours than any other ape, and are still arguably the most evolutionarily successful of the primates

> humans are weird outliers—we’re the shortest sleeping primates, yet we pack in the most REM sleep relative to this short duration

Isn't that sort of the point? Sleep is a detrimental necessity and the more efficient an organism is in needing less of it, the more effective it can be because it simply has more time to get ahead of the others?

It's still very odd that no species has ended up evolving a continuous maintenance system that can run while conscious, the benefits when hunting other animals that need sleep would be enormous, so there has to be significant evolutionary push for it. I suppose the single hemisphere sleep some marine mammals do is part of the way there, but it is at most a lazy workaround. Practically all other organs have evolved to run 24/7 for up to a century without a single break, what makes brains so universally different?

by moffkalast

8/19/2026 at 8:44:05 AM

The fact they electrically signal via chemical analogs fuelled by immersion in nutrient bearing fluid that also accretes waste products, yet is kept separate from the primary loop of the cardiovascular system by the blood-brain barrier?

by salawat

8/19/2026 at 8:51:12 AM

But why is that fundamentally different from the technobabble description of any other vital organ?

by dotancohen

8/19/2026 at 8:52:38 PM

Life has a surprising amount of detail, and if you're only curious enough to interact with the answer as 'technobabble', this does not speak well of your genuine curiosity on the subject. However, in general...

Form is shaped by function. The liver/pancreas are designed to handle the production of detoxifying/neutralizing agents that may in and of themselves kill nearby tissue, resulting in the propensity for notable regenerative capabilities. Kidneys/intestines are high surface area to provide more room for the physical processes driving selective permeability to occur, as well as habitable spaces for beneficial microbial symbiotes that aid in digestion. Skeletal/smooth cardiac muscles are optimized for energy burning to facilitate movement. Tendons/cartilaginous membranes are optimized for lubricating joints/connective tissue purposes. Tissues like the thalamus and tonsils, are there for immunity modulation and detection. Neural tissue however is all about signal propagation, and creating shifting networks of continuity that encode information and patterns, the tissue itself is just the medium, and that medium requires some process to clean out or reset the gradients in the synaptic gap. Otherwise, electrical charges cannot be consistently conveyed as flows of ions, actuated by releases of neurotransmitters into the bridge of the synaptic gap. The other constraint unique to neural tissue as well is it isn't motile, or capable of physical movement. All it can do is carry charge by a process of chemically modulated action potential building, yet also needs to have a means to carry out adjusting it's environment which coincidentally, tends to be filled with ions. Ions + coordinated patterns of charge propagation creates effective pumping infrastructure capable of creating overall fluid movement without the help of direct cardiovascular pressure, which can also facilitate the movement of non-charged molecules given sufficient ionic movement to disturb the neutral medium. However, this coordinated firing pattern to create overall ion flow isn't "information encoding to the cognitive process at hand" per se. It's just a bunch of cells getting fluid to move to get waste products to another location to get handled. None of those "knows" anything more than it's immediate environs, but based on things like quorum signalling in biofilms, it isn't outside the realm of possibility, that neural tissue has a completely chemically mediated process by which it knows "gradient blah can be shifted if everyone around me fires", and that given sufficient time and scope, you get an emergent quorum signalling based metabolic progress that selectively induces "coordinated garbage" from the information processing point of view, but very much not biologically/physically garbage point of view, in that that firing pattern clears the chalkboard so to speak for further processing.

So to answer your question: why do nerves seemingly need to stop what we want them to do (full time cogitation as directed by an emergent consciousness that their physical processes collectively facilitates)? The answer comes down to homeostatic maintenance, and work the tissue has to do because that's how it evolved. You use the same bunch of neurons, they fill the immediate space with metabolic waste products which makes further firing or usage more difficult until the waste products can be cleared. How do you clear them? Stop doing what you're doing & ion pumpas a group. Coordinated ion pumping isn't driving the pattern recognition/consciousness engine in ways that make any sense, it's just cycling fluid to refresh the operating environment to restore the substrate for unburdened cognition again.

Eukaryotic organisms are hard, maddeningly complex, and contain an astonishing amount of detail for something that for whatever reason, usually just seems to work. Could write volumes on these things for how deep the rabbit holes go.

by salawat

8/20/2026 at 10:24:49 AM

I very much appreciate you engaging me with such an informative reply! I actually would love to read volumes in that style - yet I've never seen that style applied to biology before.

by dotancohen

8/20/2026 at 7:56:39 PM

Factuality and verifiability.

by IAmBroom

8/19/2026 at 9:04:42 AM

There's a similar mechanism called USWS https://en.wikipedia.org/wiki/Unihemispheric_slow-wave_sleep (Half of the brain remains awake while the other sleeps, not an expert so please correct if wrong)

by zorrocangrejero

8/19/2026 at 10:53:12 AM

Unihemispheric sleep has been used by cults for mind control because it puts you in a vulnerable mental state (for example https://zizians.info/#unihemispheric-sleep). So anybody reading this and interested in trying it, ensure you’ve done sufficient research first.

by sd9

8/19/2026 at 8:48:10 AM 

  > It's still very odd that no species has ended up evolving a continuous maintenance system that can run while conscious
Great point. Afaik, our bodies do preserve energy when we sleep/rest. A few questions that needs to answered first:

- will gains of 24/7 hunting/foraging offset the extra energy costs? Lions sleep 16-20 hours a day, according to the internet.

- do continuous maintenance systems imply duplicate systems? If so, I have a hunch that even a mere 40% increase in energy expenditure would quickly undo the gains in waking hours.

by exceptione

8/19/2026 at 8:52:18 AM

> It's still very odd that no species has ended up evolving a continuous maintenance system that can run while conscious, the benefits when hunting other animals that need sleep would be enormous, so there has to be significant evolutionary push for it.

I disagree. Endurance hunters walk an animal down throughout a single day. Sleep isn't the bottleneck. Efficient bipedalism and sweat are enough.

by aqme28

8/20/2026 at 7:56:45 PM

> It's still very odd that no species has ended up evolving a continuous maintenance system that can run while conscious, the benefits when hunting other animals that need sleep would be enormous, so there has to be significant evolutionary push for it.

This is actually quite a conundrum.

Animals as simple as flies have been observed sleeping (diminished brain activity while resting). It is highly conserved, so it must be incredibly important.

by IAmBroom

8/19/2026 at 9:07:24 AM

The article title is "Where human sleep went wrong" but then the entire article is about how we sleep the best we ever have, we have the most high quality sleep, and all the fearmongering about sleep is basically wrong.

by tempfile

8/19/2026 at 9:50:07 AM

A nap is the same as sleep, but we don't do this. Any correlation to our southern american friends and their siestas?

by YLYvYkHeB2NRNT

8/19/2026 at 12:35:28 PM

I tried to imitate japanese people in the public transport when i was there, meaning I managed to kinda sleep/nap with eyes closed for 10-15minutes between rides and it was astonishing.

while I understand might be a more known thing, it was surprising to try it and feel very rested after that. I'm still surprised and I wonder why not the whole world does it.

of course without the music at the stops would not be possible :P

by giov4

8/19/2026 at 10:37:47 PM

Growing the GDP and Shareholder Value is more important!

by vinyl7

8/20/2026 at 4:14:14 PM

[flagged]

by MrPFT

8/19/2026 at 9:04:21 AM

> untangle what he calls the sleep paradox: Sleep is critical to human functioning, and yet, we sleep fewer total hours than any other ape

Instead of going to Tanzania you could’ve asked a sleep scientist. Sleep length has no known correlation to brain size and is known for drastic within family variation. What’s more sleep has a high within species variation too, some sleepers can survive 4 hours, others need 8. Collectively we used to sleep 9 hours in the 20th century, but it appears shorter sleep is fine too. TLDR: no one has any idea why sleep length varies and he won’t find his answers in antrophological studies in Tanzania, though luck, buddy

by usernametaken29

8/19/2026 at 10:59:42 AM

How do you think sleep scientists got their data in the first place? Some of them went to Tanzania.

by sd9

8/20/2026 at 7:56:36 PM

Cite.

by IAmBroom