It's doubly curious that there hasn't been a recent resurgence. I'd expect that the WFH trend would be making it more practical and sustainable for many.
During polyphasic experiments in my youth, my biggest obstacle was always securing reliable conditions to allow the daytime naps.
It’s a good article, especially in the second half where the two theories are synthesized into a narrow, compatible summary, but the clickbait title isn’t compelling and I don’t think really describes the content.
Looks great but if you want to break up your own sleep pattern and do something useful for an hour in the middle of the night (like B.F. Skinner, who wrote for an hour from 2-3) it would be good to have some really low light for it, or a red lamp.
I believe this theory is largely thought false nowadays, or phrased too strongly at least.
I myself have weird sleep cycles. I prefer to stay up into the night and wake up around 12:00, but I vary my sleeping hours by up to 4 hours or so. I go to sleep when I feel like it, and don't feel much discomfort by falling asleep at different times. It leads to weird situations - especially in winter - where I might not see the sun more than a couple hours in 3 days despite being up and around a lot. I don't experience a lot of 'two sleeps', but they do occasionally happen.
This would almost work for me, except one of the “when I feel like sleeping” times aligns with the peak of workday, and “when I fell perfectly awake and refreshed” is too late.
Too late for whom? Apparently, not for you. With WFH, taking a nice little siesta isn't impossible (and anecdotally sounds like its more common than some would like to admit). Of course, forced to work in an office makes it harder, and probably surrounded by bosses much less sympathetic to the concept.
It was like that for me too when I worked 9-5 (or more like 6). Now I work "biphasal" days so to speak, from 12:00-16:00 and sometime later in the evening for a couple hours. I find that splitting it up helps me be more productive, I have more of my "software development energy" to spend. I'm lucky that my work offers very flexible hours since we hire around the globe and nobody in my team minds that I review their MRs in the middle of the night.
I usually use the day hours as "open office time" for support requests and meetings, and the later time as "proper work time". This helps me avoid context switches.
>this theory is largely thought false nowadays, or phrased too strongly at least.
What theory? The article doesn't really claim that this kind of sleep is better or more natural, just that it was incredibly common. Is the idea that it was common now thought to be false?
The "it was incredibly common" part is the theory. I don't know if anyone else besides Roger Ekirch supports it, which doesn't mean it's false of course. Our ignorance of things past is gigantic and not helped by the fact that history (and stories) tend to be constantly rewritten.
I don't know about commonly thought to be false because I'm not sure it's commonly thought about at all, but it's a theory with considerable weaknesses
Ekirch hypothesis: Early humans had two distinct phases of sleep with an important gap between. Lack of in-depth discussion or even a name for that gap in any language is actually evidence of it being so common it wasn't worth commenting on. It disappeared - again without comment - because of widely available artificial light, although it actually makes less sense to dedicate midnight hours to stuff like household chores and reading in the middle of the night without easy light sources, especially in northern European summer when it's about the only time there isn't daylight.
Null hypothesis: early humans slept much like today's humans, sometimes waking or being woken in the night, occasionally even intentionally but generally not making a big deal of it and trying to sleep through. People sometimes described periods of broken sleep as "first sleep", "second sleep" and even "third sleep" but commentary on the practise of biphasic sleep and importance of midnight waking is harder to find because most people didn't do it that way. A lot of references to "first sleep" can be found if you search digitized records with that string and its foreign language equivalents, but so can references to obviously non-systematic things like "first injury" or "first marriage". You can't generalise human behaviour in the absence of electricity from one tribe that does have a midnight break when numerous others studied don't.
Erkich's own words, both his original paper and his website, acknowledge the lack of a distinct name. He suggested generic terms "watch" and "watching" may have been used throughout a long period of British history to describe the hypothesised universal period of wakefulness based on one primary source each. One appears to be a prayer which refers to "between one morning watch and another" without hinting what a "morning watch" is, another is a devotional text calling on people to watch their first waking thoughts are set on God, where there are rather obvious alternative interpretations of the words "watch" and "first"...
The notion of "witching hour" is predicated on the idea that spirit activity takes place when most people are asleep, and "the wee small hours" is a reference to the entire period between midnight and dawn. If the closest word a language had to "lunch" was "afternoon", I'd probably conclude that culture generally didn't have an important midday meal!
If your claim concerns common habits of populations with limited or no artificial light sources, observational studies of multiple populations with no artificial light sources is a superior way of assessing it than a prior study which imposed very specific periods of light deprivation on a study sample accustomed to nightly routines governed by available light to see how their behaviour changed.
Specifying that as something isn't directly testable, it's better that a bold new theory should actually be the null hypothesis isn't how science works! We've observed a lot of populations with little or no natural light and there is no reason to cherry pick the one or two which actually conform to Ekirch's proposed "standard" form of sleep. I mean, for a start, assuming "pre industrial revolution photoperiods" generally matched the ones in Wehr's study involves pretending that seasons don't exist in most of the places Ekirch's soured material came from!
> A lot of references to "first sleep" can be found if you search digitized records with that string and its foreign language equivalents, but so can references to obviously non-systematic things like "first injury" or "first marriage"
This hypothesis would also have to explain why we don't say things like "first sleep" anymore, even though we do say things like "first injury" or "first marriage".
We don't talk about first sleeps but you'll still find plenty of modern references to "first sleep", "second sleep" and even "third sleep" in modern text too, from book titles to scholarly articles on sleep cycles
This article is about the 17th century (with some references going back further). Does Ekirch write also about early homo sapiens? Earlier ancestors? I am not nitpicking, just wondering if that term is used intentionally.
It has always struck me as an unlikely hypothesis. While I'm not a historian, I do get some insight into the Elizabethan period in particular by a very close familiarity with its plays. Shakespeare never mentions it, and he does talk about sleep quite a bit.
One example that comes to mind, from Henry V:
But, like a lackey, from the rise to set
Sweats in the eye of Phoebus and all night
Sleeps in Elysium
Hal doesn't say "All night sleeps in Elysium except for that bit where he wakes up in the middle of it". He's explicitly referring to untroubled, continuous sleep for most people (as compared to his own insomnia from worry about his kingdom).
I haven't done an exhaustive survey, but I don't believe Shakespeare characters ever wake in the middle of the night unless there is something to disturb them. They may drink late, or chimneys may come crashing down around them, but nobody ever says "Hey, see you in a few hours when we're both awake".
This is obviously far from conclusive. But the man writes about sleep often enough that I'd have expected at least some hint of it.
> The article doesn't really claim that this kind of sleep is better or more natural
It does:
"the benefits of dividing up sleep"
"single periods of slumber might not be 'natural'."
THIS article soft-peddles such claims biphasic sleep is better and more natural ONLY because those theories have been largely discredited since it was first put forward. Try an older article:
"Ekirch believes many sleeping problems may have roots in the human body's natural preference for segmented sleep"
"a consolidated eight-hour sleep may be unnatural"
> The article doesn't really claim that this kind of sleep is better or more natural, just that it was incredibly common. (Emphasis mine.)
For a start, the article suggests that it wasn't just common but actually the dominant pattern of sleep, but the evidence seems a bit thin on that. Moreover, it says that "Ekirch began to suspect that the method had been ... an ancient default that we inherited from our prehistoric ancestors". But I seem to remember an anthropologist on a TV programme (many years ago so I forget which one sadly) saying this isn't obvserved in isolated tribal cultures today, so we can reasonable expect that our pre-agriculture anscestors wouldn't have slept this way.
Edit: A reply to a sibling comment found a good citation: https://www.theatlantic.com/science/archive/2015/10/the-many... Interestingly, like the BBC article it mentions Ekirch as the proponent of the two sleeps theory. So I wonder if the whole idea is the pet theory of this one person.
Hehe, yes. Since the literature is split I can offer my anecdata from living in low light conditions (in the mountains of Eastern Europe with no electricity):
It happens rarely. But enough times that one might notice it. If you experiment with lucid dreaming, you realize that the time you usually wake up is in between your REM cycles at the 4 hour mark. If you take a 15 minute break from sleep in your bed at this time, then fall asleep while trying to keep your mind awake (by, say, counting backwards, or just "willing it"), you can fall directly into a lucid dream. If you try this at the beginning of your sleep, you just fall into a long sleep paralysis and hypnagogia session. Your next REM cycle is too far away.
So, yes, it's real. But I think it's more likely that it was experienced much like nowadays, as a rare occurrence rather than a standard.
An interesting data point: even today, the Liturgy of the Hours, which is the regiment of prayer for Christian monks and nuns, contains prayers for the middle of the night.
I used to sleep like this too, for around 15 years (20-35yo). Then I began to experience many-day insomnias, or inability to wake up until my body feels like it. Troubles with digestion, immune system, motivation and mental state in general (all interlinked). Checking my hormone levels was like rolling dice every time. My endocrinologist, gastroenterologist, neurologist, psychotherapist all told me that if I don't correct my sleep cycles and get married, I'll suffer even more. I did the former half a year ago and feel much better.
It doesn't have to be connected, maybe my health would deteriorate independently of sleep or alone factors, but doctors say that it puts you into the risk group at the very least. I'd say be careful, but 5-10 years ago I'd also waved it away as irrelevant :)
> I prefer to stay up into the night and wake up around 12:00, but I vary my sleeping hours by up to 4 hours or so. I go to sleep when I feel like it, and don't feel much discomfort by falling asleep at different times.
Yep. Exactly the same here. I tend to wake up 7-9 hours after I go to sleep (usually between 00-04:00) no matter when that happens. With very rare occurences of two part sleep. No side effects by 45, but I do exercise.
Come to think of it, I may get two part sleep more often than I think, because I do wake up during the sleep period. But most of the time I ignore it and fall asleep again in a couple minutes.
It may be thought of false, but historic documents from many European countries mention and detail it as the common habit. There is no theory or claim about its benefits, just that it was habitual.
The most interesting thing about this to me is how it shoes just how little are know and likely will ever know about historical life.
This entire concept was just forgotten for centuries, and even now we can just sort of guess that it happened but are unsure why. How many other parts of daily life were just never written down? All our historical sources are so absurdly biased towards a wealthy few that our conceptions of historical life are inherently flawed.
We're not really sure what actually happens when two phalanxes meet. We're also not sure how the Romans swapped lines of men out during combat. Lots of the details about ancient combat just werent written about in detail and its not something we can (ethically) test
How would you unethically test ancient combat tactics? Unless you mean have people try it until it seems to work, in which case, I'm sure you would find many willing LARPers
I think the issue is that LARPing battle is a poor substitute for what the body can take and how people respond to real pain and damage. We might be getting to the point that we can get somewhat of a foot take on the damage with VR eventually.
I've been playing Blade and Sorcery in VR for a week or so. It's scary at first, but after a while I don't mind getting hit and play in a way that I would never do with my own body at risk. In the real world I'd get somewhere up high with a bow, but I run around like Conan the Barbarian in the game.
You also have to grow up in a society that is completely alien to ours, your entire outlook on life, how long you might live, and how willing you are to give up your life is different.
Imagine living in a world where how tough you are, how well you can fight determines everything about your status in the world.
The conjecture is that people will not willingly throw themselves on a line of spears and so the phalanxes would stop short of actually hitting each other. I don't think larpers would be able to test that well. I'm not sure how you would test that unethically
I feel like a great deal of melee warfare involved group A smashing itself upon group B. Phalanxes, as I understand it, were effective because they were particularly good at this part. So given that we already had lots of other varieties of troops throwing themselves at the spears, why do we doubt that other phalanxes would specifically be unwilling to do the same?
The idea is that a phalanx trained under the assumption that their formation was nearly invincible as long as they were experienced enough and worked together well. Both the members of the phalanxes and the generals would be hesitant to risk that by sending them against another phalanx where they lose all their inherent advantage and would need to fight in a different way.
..and these things were of major concern to important, literate people whose writings we do have.
What actually happens when two phalanxes meet was (intermittently) a really major determinant of world events for a long time. It was top of mind for Alexander, Cesar, and other generals and kings until the renaissance. Generals who wrote about pikes and shields and war stuff. Still, we don't know.
What we do know about pre-modern warfare though is that people generally didn't want to die, didn't want to kill each other and many times battles ended with one of the two armies losing morale and fleeing or surrendering. Individual battles could also last for days with very little time actually being spent physically clashing.
Two phalanxes meeting face-to-face with neither side drastically outnumbering the other was likely the worst case scenario because it meant a war of attrition rather than a quick and decisive victory.
It's also an interesting reflection on the historical moment we've find ourselves in. I'm sure the records of normal/daily life have been steadily increasing even before the computer age as earlier technologies made it cheaper to record these things but it feels like in my lifetime we have transitioned almost instantaneously to having more data than we could possibly ever sift through about every aspect of peoples' lives. What will history look like to future generations who have access to such a historical record?
I think you may also be overestimating the quantity of current data that will actually survive. Computer records are pretty ephemeral unless actively maintained and archived.
We could be living in a modern dark ages. Just imagine the treasure trove that will be lost when YouTube or the internet archive blinks offline for the last time. That's part of why I think patents are valuable. There will be multiple copies of a discrete set of systematized records of 'invention' or at the least just writings of people from this age. I estimate a good chance that the US patent database outlives the internet, for example.
My theory is kids sleep through the night, so adults would wake up in the middle of the night to have sex since it was the only time they could have privacy in their own room cave/hut/abode.
I blame it on alcohol. If I drink I’m always up for a few hours in the middle of the night. And I’m quite sure they were doing a lot of that back in that time.
Ah yes. Having an evening drink, falling asleep at like 9PM, and then waking up wide awake at midnight to dick around for a few hours until finally falling back asleep at like 3 AM. It still happens to me from time to time.
> And I’m quite sure they were doing a lot of that back in that time.
Technically, they were all drinking alcohol because water was unsafe. However, beer at least had half the alcohol content that it has today and the wine was strongly watered. For women and children they even added water to the beer.
Googled it once. The information should still be available.
Oh, so it's not just me. I've always interpreted it as the first sleep (hah) being my body being busy trying to sober up and the second sleep being the actual normal sleep now that the body can focus on something other than getting rid of all that poison.
Of course actual blood alcohol takes longer to go down than that but no matter how much I had, I'd invariably feel significantly more sober after the initial sleep than if I just stayed awake and stopped drinking.
Given that alcoholic drinks (especially various concoctions we'd hardly recognize as "beer" today) were fairly widespread especially when pure water was not always potable, I wouldn't be surprised if this didn't at least factor in for some of the reports. Then again this doesn't explain the observation of polyphasic sleep developing under experimental conditions.
If my cats are any indication of their larger wilder relatives, 1-3am is prime attack time. Might have been beneficial to be on guard during those hours when the felines were larger and more murderous.
The article does not mention it, but mothers with small children have to nurse babies every couple of hours, even at night. So given that in middle ages, families had "copious numbers of children" (quote from the article), it is for sure that mothers would need to get up to feed a baby. And then possibly the whole family would woke up too. And if multiple generations were living in the same house, then even more probably there were babies too. I can imagine such a basic need being the root of the habit.
Babies, on average, only need multiple feedings a night through the first few months. Even if there was a new baby for one mother every year, that would be multiple feedings only for 3 months out of every 12 months.
Just like parents today, people would power through that, and not make that a habitual sleeping pattern.
I am not saying this makes the hypothesis of the origin being in parenthood true, just that it does not make it false either :)
The parent not caring for the baby learns to sleep through. My wife and I swap roles when we wean babies, we need just a couple nights to get used to the changed role.
Sleep through baby crying? I found my own babies cries to be a complete NMI.
When we had infants I'd go back to sleep pretty well instantly (co-sleeping, with baby on a side-cot at bed level; baby breastfed, not by me) but in general one would wake to the little snuffles that precede the crying (I guess that helps to calm them before they get in a tizzy [in a state, brought on by their own actions, crying in this case]).
I sleep through thunderstorms without stirring.
I'm a few years out from dealing with crying babies and still if there's crying in the background, that sounds like one of my kids, I'll pop-up like a meerkat. The sound even gets though (non noise-cancelling) headphones when I'm gaming, though I won't know what I've heard until I take them off.
It helps if the father is a night owl who works from home. Back when we had a baby (20 now) I preemptively bottle fed her at 2 am. She didn't wake up other than sucking from the bottle. Neither did her mother who was sleeping next to her.
Hah as a husband and father whose wife coslept and exclusively breastfed for the first year, this has little merit. My wife one day commented on how it was great how our 6 month old daughter slept through the night and didn’t complain or ask for food. My wife quite literally breast fed in her sleep.
Waking up to feed the baby is a very WEIRD way of looking at the world.
I'm not sure how typical your experience is. My daughter needed to be fed every few hours for the first 11 months. Both my wife and I were freaking zombies. It was rough on us. My wife would basically get a couple of hours every time the baby went down, but no long and peaceful sleep.
In talking with friends, it would seem like our experience was extra crappy and yours is uncharacteristically mild. So the reality may be that many have to wake up at least once in the night to feed, so 2nd sleep kinda makes sense to me here. Not that I'm saying it's where the phrase comes from.
Out of my very limited anecdotal experience (two small children), it mostly relates to how well fed they are: unfortunately, both of our two kids are bad eaters (the first just wouldn't eat enough, ever, even today at 5yo; the second is just extremely picky but eats plenty of what she likes). The older kid kept waking up in the middle of the night even at 3 yo (not to ask for food, but when we were sure he got stuffed in the evening, never did he wake up). The younger slept through the night at 10 months a few times, but as she gets pickier, those are actually less frequent now at 15 months than back then.
I am sure we could train them with some sort of food scarcity approach (this is the only thing there is to eat; now is the only time you can eat) to teach them to eat enough of the food that's there, but that'd take a psychological toll for a few weeks on us that we aren't able/willing to take on.
They have training centers for this now? I'm genuinely horrified. I'm aware there are different meanings to "sleep training" depending on who talks about it, but the way you imply they use the term ("stop going to them", i.e. let them cry it out) it's just a cutesy way to say "neglect".
There's a reason parents pick up this version (i.e. the "let them cry it out" version, not the "create a safe and comfortable environment to allow them to self-regulate when they wake up" one) of so-called sleep training from books, "experts" and now apparently also training centers, whereas co-sleeping needs to be actively discouraged to stop parents from doing it intuitively.
I'm not saying every parent who doesn't co-sleep with their child is engaging in child abuse, but many mainstream forms of "sleep training" (especially the informal ones) very much boil down to "neglect your infant until they learn not to broadcast their needs because nobody will take care of them".
I'm also not saying that OP's account is representative of all co-sleeping parents. Co-sleeping (with breast-feeding) simply allows for reducing interruptions from nightly feeding in a way that is hardly replicable without it.
"Let them cry it out" being neglect isn't a strong opinion, it's the literal definition. A lot of neglect and abuse has been socially normalized but that doesn't make it not that: thankfully corporeal punishment has been outlawed in most Western countries although many parents and educators still struggle understanding that punishment itself is ineffective.
That children who are subject to any given for of abuse or neglect don't "seem" harmed by it, doesn't make it harmless either. I think we've all heard people who hit their kids argue that "my dad hit me when I was a kid and it didn't do my any harm either" and don't accept that as a justification anymore.
I'm not saying people who do this (because they are taught to do it) are bad people. I'm saying what they are doing is bad and that there are training centers who sell neglect as "sleep training" (which can refer to other things) are bad.
I don't know why you think "do you even have kids" is a gotcha but yeah, I have kids, I also have nephews and I have friends who have children. Would you insist that someone isn't allowed to speak on whether it's okay to hit your wife if they aren't married, too? That someone telling you off for leaving your dog in the car on a hot day has no right to criticize you because they don't own a dog themselves?
It varies quite a lot. One of my kids was needy all night long for most of a year, the other one started sleeping through the night maybe six weeks after we brought her home.
I've often thought that much of the difference between poor/adequate/great parents is the personality of the kid(s). Have a really easy one and then you think you're some of rockstar parent. Then number two comes along and shatters your delusions.
On top of sleeping, I like to add eating as very important to your own perception of how good a parent you are. :D
To be honest, with my two kids, how much they eat influences their sleep heavily as well. Unfortunately, my first has always eaten too little (he'd happily have his broccoli too, but never enough to be consider him fed), and the second is very picky (she eats a lot of what she likes, none of what she doesn't). When they eat well, they usually sleep well too.
I'm in that place right now. 8 month old son, wakes up every 1-2 hours at night. Not even to feed, just.....wakes up and cries until you settle him. Feeding sometimes helps sometimes doesn't - but it doesn't change the fact that you have to wake up for him.
My wife is a complete zombie, I don't think she had more than continious 3 hours of sleep for at least 6 months now. I would cut my own arm off to make this situation improve at this point.
The way my wife and I had it with my first was for me to start taking care of my boy at 6am when he wakes up and let her sleep until 9am every morning, when I'd start work (from home). If you can find a time where the boy does not need her (eg. those times when he's fussy but not hungry), that's the best you can do.
Sometimes that's not an option, but this worked great with our first (we couldn't do it with our second, so my wife is more of a zombie this time even though the daughter is a better sleeper on average).
I do exactly that - she leaves him with me 6-7am and then I look after him until I have to start working around 9pm. And while yes, it provides her with some much needed sleep, it's still nothing in the grand scheme of things. I think as a human you really need that uninterrupted 6h+ of sleep at least every now and then, and not having it for months at the time just absolutely wrecks you as a person.
Really sorry to hear that. We had a nightmare scenario at about 11 months where she howled all through the night and my wife cried pretty hard too as there wasn't anything we could do. We cut a trip short and just drove 5 hours back home (the next day) to get our daughter back to familiar surroundings if it meant sleep for us. She then slept through the night and more or less has done that since. We felt so much better, although I remember checking in on her often to make sure she was ok as she'd never slept that long. I really hope you catch a similar break sometime soon. It might also help when they start to get a more varied diet that isn't just milk, so they aren't always hungry if that makes sense (I'm definitely not any kind of expert though and not giving advice).
I think you misunderstood him. Parent poster said that their child was breast fed during the night, his wife just did not wake up for it, but slept through the suckling.
Given that, power point of this thread, people pretty much went to bed at sunset, at European latitude that would mean a long night much of the year with kids wanting food and adults being sufficiently rested late at night. Once satiated amid a quiet daze of food/sex/meditation, they’d likely doze back off until daybreak. Two sleeps seems quite sensible without electricity’s prolonged days.
The mother would either sleep with the baby or have it easily retrievable without significantly stirring. Dozing while nursing would provide some compromise between rest for her and the household, and enjoying/enduring some thinking time.
They are less noisy, often enough to stay below the threshold that wakes others nearby. Sleep quality is a probabilistic game, as it sounds like we both know. :)
The comment about contemplative dozing comes from my wife. I’ll pass on your feedback.
I have had some great insights when I can't fall a sleep, in that brain fog you mention, sometimes where the feeling of my own self somehow disappears, seeing everything less through the lens of the self-protective consciousness, then I could suddenly understand and solve some nagging issues.
But the toll is high, not sleeping properly ruins your life. And most of the time it's definitely not insights, but the opposite. For me, it's not something to seek out.
It’s funny that you mention that. When I was reading the article, it occurred to me how biphasic (or multiphasic) sleep resembles the schedule of a newborn’s parents. To me the lack of artificial lighting is a more compelling explanation, but who knows there could be many factors that contributed to the habit.
Multiple generations also slept on the same bed, I'm surprised the theory is two sleeps and not multiple sleeps. Not that humans haven't habituated to group sleeps in tight quarters, but one bed feels qualitatively different than a bunch of tired submariners cramped in individual bunks or some similar arrangement.
This chart is just bullshit, there's absolutely no way a 15 week old baby sleeps from 11pm to 7am, then from 8am to 12pm, and then _another_ 4 hour nap from 2-6pm??, that's absolutely insane. Like, a doctor would be extremely worried about this baby
The chart is slightly misleading, in the sense that the ranges shown are more like the very strong average sleeping patterns across babies. It doesn't mean that none of them woke up for a quick feed. But even without a feed, sleeping from 11pm-7am, is certainly not abnormal.
16 hours of sleep also falls within normal for a 15 week old baby for most sources I've seen, so I'm not sure why you'd be worried? I had a look, and my daughter was around 15-16 hours. No big naps during the day, but she slept 7pm-6am maybe waking twice for feeding.
As a parent of an 8 month old baby who wakes up literally every hour - what is that solid line from 10pm till 6am at around 10 weeks :P Feels like fantasy
Considering this has been in the news for 10 years and pretty much no one does it, not even a weird sub community, we can safely say this is not a legitimate sleeping pattern for humans.
Speak for yourself. I personally do it, it's fantastic. But it does get me a little out of sync with the rest of the world, but with time differences etc. it's not a big deal.
I'm sure a LOT of people do it, and if you turn off your alarm clock and having to get up at x time, and going to sleep at y time, to be 'refreshed' etc, you'd notice the benefit yourself.
Just sleep when you're tired, eat when you're hungry. Trying to have rigid rules around all this does more to damage peoples health than anything else.
Ever since working from home during the pandemic sleeping from like 2am-6am at night and like 4pm-6pm has become pretty common for me. Not sure if that counts as "biphasic" or just a very long nap but definitely seems fine to me.
My parents (mid 50s) have been doing this for 5-10 years. It just kind of came about naturally with their workdays starting late and them being night owls, and they leaned into it. It's weird enough that I imagine many of the people who do this don't really talk about it with strangers.
I wonder how things were in the more northern areas, where daylight was almost constant in the summer and barely existing in the winter. People seem to have survived there for long times, and must have adapted to different sleeping patterns.
Just to add to the chorus of modern reasons this might happen, when I was going through pretty bad spinal disc degeneration, I almost always woke up after somewhere between 3-4 hours of sleep. I just couldn't go any longer until I was in too much pain and needed to move about, ice it, take more meds, whatever I could do. That isn't the case any more because of spinal fusion surgery that wasn't an option in the medieval era. I'm sure pretty bad pain you just kind of tried to ignore but could never really get rid of was a common thing back in the day when corrective surgery didn't exist and reliable pain meds didn't either. Alcohol helps, but also disrupts sleep.
This article got me thinking, if artificial light forever changed the way people sleep, what other modern changes have also altered life or physical characteristics of people long ago. 200 years ago everyone had perfectly straight teeth, some think heavily blended/processed foods may have lead to under developed jaws and crooked teeth for alot of modern people or possibly high sugar, its not known but something in the modern era changed our teeth structure for the worse.
Didn’t people lose teeth more often back then as well? Which would naturally lead to more gaps in the mouth and thus less crowding to push teeth inward.
The problem and solution has been known for almost a century now; check out the book 'Nutrition and Physical Degeneration' by Weston Price. 'The Dental Diet' is also solid reading.
I'm still working through the book, but the tl;dr is that it mostly just comes down to nutritional deficiency. People in the past ate pretty much strictly nutrient-dense foods, people today eat a lot of junk food, empty carbs, and generally foods that just aren't nutrient dense compared to what our ancestors ate (mostly vegetables and meats).
We're still discovering new plant molecules and the effects they have on us all the time. Supplements are never going to be able to completely make up for a diet lacking in real whole plant food & animal meat.
With respect to the question about underdeveloped jaws, that development takes place primarily during your childhood, so if you didn't have optimal nutrition at that stage you won't be able to fix that retroactively.
Maybe this? "Melatonin synthesis in rice seedlings in vivo is enhanced at high temperatures and under dark conditions due to increased serotonin N-acetyltransferase and N-acetylserotonin methyltransferase activities"
"The opposite effect occurred during the night, in which the positive effect of darkness on melatonin synthesis was counteracted by the negative effect of a low temperature."
People for the last 10k years in agrarian societies mostly ate cereal grains, with a few exceptions like Mesoamerica where they ate beans, squash, and a cereal grain. Hunter gatherers eat a stunning variety of diets and archeology suggests this has always been true. In polar regions people subsist primarily on meat and animal fat, in other places primarily shellfish and small fish.
Regarding teeth, one thought is that over/underbite was less frequent before cutlery became commonplace. Our ancestors had to bite/tear their food using their incisors and canines a lot more than we do, which meant their jaws would strengthen in the biting position - thus with their lower and upper incisors aligned.
Personally I wonder if this would affect speech as well, so perhaps out ancestors sounded different too?
On the point of teeth (and bones), going hungry increase growth hormone, which was good for the skeleton and thus straight teeth. You see this today with dogs prone to hip dysplasia, as a puppy they were likely overfed with not enough tryptophan (60mg converts to 1mg nicotinic acid in humans) or nicotinic acid (vitamin b3) in their diet, ergo not enough growth hormone and so you get Labradors and other dogs getting hip dysplasia.
Dont we see two sleeps in the older generations, known colloquially as the afternoon nap?
Japense kids with depression, were found to be driven to school where as those that walked to school for just 10-15mins iirc didnt get depressed according to one study. Blue light stimulates or helps increase the serotonin in the brain which creates wakefulness.
Its like blue light from computer monitors can keep people awake for longer at night which is why M$ introduce the blue light monitor which is a rip off of the original AFAIK of https://justgetflux.com/
Food preservation and international commerce have eliminated seasonal diets. All of our fruits and vegetables used to be largely seasonal with only a handful that could be kept edible in cellars before canning. Meats, dairy and eggs too had seasonal ebbs and flows -- you'd slaughter your hogs in the fall as their forage ran out, your cows might dry up, your chickens probably stopped laying. Winter diets would grow steadily more monotonous and you might spend a few weeks going hungry.
The range of our diet had also globalized. Potatoes are now a staple worldwide, and tomatoes flavor dishes around the world from where they were developed. Spices aren't very exotic, even if some of us like our food plain.
And salt! Salt had gone from a spice and vital preservative with a value comparable to hard currency to something we throw on roads in the winter.
> 200 years ago everyone had perfectly straight teeth
Wait what? Citation needed please, I googled this and couldn't find anything. Our teeth were definitely bad 100 years ago, since we have images and video from that far back. The bad teeth are something that really struck me in "They Shall Not Grow Old": https://youtu.be/IrabKK9Bhds?t=57
I've heard this theory before but the argument for universalness of this in all the previous ones were less than convincing because they only used European sources, This is the first article that looks at material from non-Western cultures and therefore makes a stronger argument that this may be a natural phenomenon rather than a cultural one.
I don't buy this as some universal phenomenon. Because I have very little control over when I sleep or how long. If my body wanted to sleep in two shifts it sure as hell would. But instead I sleep about 6 or 7 hours in one shift.
coincidentally, this was a fairly large plot element in the book i've just finished reading, colson whitehead's "harlem shuffle" (excellent book, recommended). the protagonist switched to a split sleep pattern to get some extra hours during the night to do things his day job didn't give him time for, and which would take away from his family if he did them in the evening.
Right? Let’s not forget all of the terribleness that existed at the same time as this biphasic cycle, my inner skeptic tells me either this is the cause or the effect of some of that terribleness.
This is a common misconception. Generally when we talk about life expectancy being low, this has to do with extremely high infant and child mortality. Once you survived your early childhood, life expectancy wasn't significantly lower.
What I find interesting is how there are references to a second sleep in literature, such as Charles Dickens and Don Quixote.
Whether it's cultural or biological remains to be seen, but it definitely seem to be common enough that it didn't merit explaining, except as a casual reference.
I often fall asleep with my clothes on and TV on. Wake up in the middle of the night, take shower, brush my teeth and go to bed again. I feel more rested those nights that this happens.
253 comments
[ 4.4 ms ] story [ 296 ms ] threadHumans used to sleep in two shifts - https://news.ycombinator.com/item?id=27334769 - May 2021 (60 comments)
The History of Sleep - https://news.ycombinator.com/item?id=9501610 - May 2015 (11 comments)
We used to sleep twice each night - https://news.ycombinator.com/item?id=5542453 - April 2013 (107 comments)
Rethinking Sleep - https://news.ycombinator.com/item?id=4558569 - Sept 2012 (60 comments)
The myth of the eight-hour sleep - https://news.ycombinator.com/item?id=3620742 - Feb 2012 (161 comments)
Can anybody find others?
https://hn.algolia.com/?q=polyphasic
During polyphasic experiments in my youth, my biggest obstacle was always securing reliable conditions to allow the daytime naps.
“When Bandogs Howle and Spirits Walk” in Smithsonian Magazine - from January 2001!
https://www.smithsonianmag.com/science-nature/when-bandogs-h...
I myself have weird sleep cycles. I prefer to stay up into the night and wake up around 12:00, but I vary my sleeping hours by up to 4 hours or so. I go to sleep when I feel like it, and don't feel much discomfort by falling asleep at different times. It leads to weird situations - especially in winter - where I might not see the sun more than a couple hours in 3 days despite being up and around a lot. I don't experience a lot of 'two sleeps', but they do occasionally happen.
I usually use the day hours as "open office time" for support requests and meetings, and the later time as "proper work time". This helps me avoid context switches.
What theory? The article doesn't really claim that this kind of sleep is better or more natural, just that it was incredibly common. Is the idea that it was common now thought to be false?
Ekirch hypothesis: Early humans had two distinct phases of sleep with an important gap between. Lack of in-depth discussion or even a name for that gap in any language is actually evidence of it being so common it wasn't worth commenting on. It disappeared - again without comment - because of widely available artificial light, although it actually makes less sense to dedicate midnight hours to stuff like household chores and reading in the middle of the night without easy light sources, especially in northern European summer when it's about the only time there isn't daylight.
Null hypothesis: early humans slept much like today's humans, sometimes waking or being woken in the night, occasionally even intentionally but generally not making a big deal of it and trying to sleep through. People sometimes described periods of broken sleep as "first sleep", "second sleep" and even "third sleep" but commentary on the practise of biphasic sleep and importance of midnight waking is harder to find because most people didn't do it that way. A lot of references to "first sleep" can be found if you search digitized records with that string and its foreign language equivalents, but so can references to obviously non-systematic things like "first injury" or "first marriage". You can't generalise human behaviour in the absence of electricity from one tribe that does have a midnight break when numerous others studied don't.
From the article:
> The period of wakefulness that followed was known as "the watch"
Other terms for that time of night:
The witching hour (which almost sounds like a corruption of "the watch") - https://en.wikipedia.org/wiki/Witching_hour
Wee small hours - https://en.wiktionary.org/wiki/wee_small_hours
The notion of "witching hour" is predicated on the idea that spirit activity takes place when most people are asleep, and "the wee small hours" is a reference to the entire period between midnight and dawn. If the closest word a language had to "lunch" was "afternoon", I'd probably conclude that culture generally didn't have an important midday meal!
https://sites.oxy.edu/clint/physio/article/SleepWeHaveLostPr... https://sites.google.com/vt.edu/roger-ekirch/sleep-research/...
That's a terrible null hypothesis, as there is no reproducible, controllable test for it, other than a time machine.
A better one might be "people exposed to pre-industrial revolution photoperiods (<12h per day) will settle into a biphasic sleep pattern".
This was empirically tested with a small N (https://onlinelibrary.wiley.com/doi/10.1111/j.1365-2869.1992...). At least it's testable.
https://www.theatlantic.com/science/archive/2015/10/the-many...
This hypothesis would also have to explain why we don't say things like "first sleep" anymore, even though we do say things like "first injury" or "first marriage".
This article is about the 17th century (with some references going back further). Does Ekirch write also about early homo sapiens? Earlier ancestors? I am not nitpicking, just wondering if that term is used intentionally.
One example that comes to mind, from Henry V:
Hal doesn't say "All night sleeps in Elysium except for that bit where he wakes up in the middle of it". He's explicitly referring to untroubled, continuous sleep for most people (as compared to his own insomnia from worry about his kingdom).I haven't done an exhaustive survey, but I don't believe Shakespeare characters ever wake in the middle of the night unless there is something to disturb them. They may drink late, or chimneys may come crashing down around them, but nobody ever says "Hey, see you in a few hours when we're both awake".
This is obviously far from conclusive. But the man writes about sleep often enough that I'd have expected at least some hint of it.
It does:
"the benefits of dividing up sleep"
"single periods of slumber might not be 'natural'."
THIS article soft-peddles such claims biphasic sleep is better and more natural ONLY because those theories have been largely discredited since it was first put forward. Try an older article:
"Ekirch believes many sleeping problems may have roots in the human body's natural preference for segmented sleep"
"a consolidated eight-hour sleep may be unnatural"
https://www.bbc.com/news/magazine-16964783
> Is the idea that it was common now thought to be false?
Yes, that part is likely false, too:
https://www.theatlantic.com/science/archive/2015/10/the-many...
For a start, the article suggests that it wasn't just common but actually the dominant pattern of sleep, but the evidence seems a bit thin on that. Moreover, it says that "Ekirch began to suspect that the method had been ... an ancient default that we inherited from our prehistoric ancestors". But I seem to remember an anthropologist on a TV programme (many years ago so I forget which one sadly) saying this isn't obvserved in isolated tribal cultures today, so we can reasonable expect that our pre-agriculture anscestors wouldn't have slept this way.
Edit: A reply to a sibling comment found a good citation: https://www.theatlantic.com/science/archive/2015/10/the-many... Interestingly, like the BBC article it mentions Ekirch as the proponent of the two sleeps theory. So I wonder if the whole idea is the pet theory of this one person.
It happens rarely. But enough times that one might notice it. If you experiment with lucid dreaming, you realize that the time you usually wake up is in between your REM cycles at the 4 hour mark. If you take a 15 minute break from sleep in your bed at this time, then fall asleep while trying to keep your mind awake (by, say, counting backwards, or just "willing it"), you can fall directly into a lucid dream. If you try this at the beginning of your sleep, you just fall into a long sleep paralysis and hypnagogia session. Your next REM cycle is too far away.
So, yes, it's real. But I think it's more likely that it was experienced much like nowadays, as a rare occurrence rather than a standard.
It doesn't have to be connected, maybe my health would deteriorate independently of sleep or alone factors, but doctors say that it puts you into the risk group at the very least. I'd say be careful, but 5-10 years ago I'd also waved it away as irrelevant :)
Yep. Exactly the same here. I tend to wake up 7-9 hours after I go to sleep (usually between 00-04:00) no matter when that happens. With very rare occurences of two part sleep. No side effects by 45, but I do exercise.
Come to think of it, I may get two part sleep more often than I think, because I do wake up during the sleep period. But most of the time I ignore it and fall asleep again in a couple minutes.
[1] https://news.ycombinator.com/item?id=21546850
[Edit] - Ok, I read the review and I can see why you added YMMV.
"two sleeps" was pure fact for a very long time.
This entire concept was just forgotten for centuries, and even now we can just sort of guess that it happened but are unsure why. How many other parts of daily life were just never written down? All our historical sources are so absurdly biased towards a wealthy few that our conceptions of historical life are inherently flawed.
Imagine living in a world where how tough you are, how well you can fight determines everything about your status in the world.
What actually happens when two phalanxes meet was (intermittently) a really major determinant of world events for a long time. It was top of mind for Alexander, Cesar, and other generals and kings until the renaissance. Generals who wrote about pikes and shields and war stuff. Still, we don't know.
Two phalanxes meeting face-to-face with neither side drastically outnumbering the other was likely the worst case scenario because it meant a war of attrition rather than a quick and decisive victory.
Technically, they were all drinking alcohol because water was unsafe. However, beer at least had half the alcohol content that it has today and the wine was strongly watered. For women and children they even added water to the beer.
Googled it once. The information should still be available.
almost no one here is willing to admit, in the heat of a discussion, that they don't know everything about the topic at hand, and it is maddening.
Of course actual blood alcohol takes longer to go down than that but no matter how much I had, I'd invariably feel significantly more sober after the initial sleep than if I just stayed awake and stopped drinking.
Given that alcoholic drinks (especially various concoctions we'd hardly recognize as "beer" today) were fairly widespread especially when pure water was not always potable, I wouldn't be surprised if this didn't at least factor in for some of the reports. Then again this doesn't explain the observation of polyphasic sleep developing under experimental conditions.
Just like parents today, people would power through that, and not make that a habitual sleeping pattern.
I am not saying this makes the hypothesis of the origin being in parenthood true, just that it does not make it false either :)
When we had infants I'd go back to sleep pretty well instantly (co-sleeping, with baby on a side-cot at bed level; baby breastfed, not by me) but in general one would wake to the little snuffles that precede the crying (I guess that helps to calm them before they get in a tizzy [in a state, brought on by their own actions, crying in this case]).
I sleep through thunderstorms without stirring.
I'm a few years out from dealing with crying babies and still if there's crying in the background, that sounds like one of my kids, I'll pop-up like a meerkat. The sound even gets though (non noise-cancelling) headphones when I'm gaming, though I won't know what I've heard until I take them off.
Waking up to feed the baby is a very WEIRD way of looking at the world.
In talking with friends, it would seem like our experience was extra crappy and yours is uncharacteristically mild. So the reality may be that many have to wake up at least once in the night to feed, so 2nd sleep kinda makes sense to me here. Not that I'm saying it's where the phrase comes from.
Turns out if you stop feeding them or going to them in the middle of the night, they adapt and sleep through in less than a week.
I am sure we could train them with some sort of food scarcity approach (this is the only thing there is to eat; now is the only time you can eat) to teach them to eat enough of the food that's there, but that'd take a psychological toll for a few weeks on us that we aren't able/willing to take on.
There's a reason parents pick up this version (i.e. the "let them cry it out" version, not the "create a safe and comfortable environment to allow them to self-regulate when they wake up" one) of so-called sleep training from books, "experts" and now apparently also training centers, whereas co-sleeping needs to be actively discouraged to stop parents from doing it intuitively.
I'm not saying every parent who doesn't co-sleep with their child is engaging in child abuse, but many mainstream forms of "sleep training" (especially the informal ones) very much boil down to "neglect your infant until they learn not to broadcast their needs because nobody will take care of them".
I'm also not saying that OP's account is representative of all co-sleeping parents. Co-sleeping (with breast-feeding) simply allows for reducing interruptions from nightly feeding in a way that is hardly replicable without it.
That children who are subject to any given for of abuse or neglect don't "seem" harmed by it, doesn't make it harmless either. I think we've all heard people who hit their kids argue that "my dad hit me when I was a kid and it didn't do my any harm either" and don't accept that as a justification anymore.
I'm not saying people who do this (because they are taught to do it) are bad people. I'm saying what they are doing is bad and that there are training centers who sell neglect as "sleep training" (which can refer to other things) are bad.
I don't know why you think "do you even have kids" is a gotcha but yeah, I have kids, I also have nephews and I have friends who have children. Would you insist that someone isn't allowed to speak on whether it's okay to hit your wife if they aren't married, too? That someone telling you off for leaving your dog in the car on a hot day has no right to criticize you because they don't own a dog themselves?
Saying "no" to a request for attention and/or milk at 2AM (for a 1 year-old) is not neglect, it's just setting a healthy boundary.
I'd even be willing to go one step further and say that insisting your partner do this is abusive.
I've often thought that much of the difference between poor/adequate/great parents is the personality of the kid(s). Have a really easy one and then you think you're some of rockstar parent. Then number two comes along and shatters your delusions.
To be honest, with my two kids, how much they eat influences their sleep heavily as well. Unfortunately, my first has always eaten too little (he'd happily have his broccoli too, but never enough to be consider him fed), and the second is very picky (she eats a lot of what she likes, none of what she doesn't). When they eat well, they usually sleep well too.
My wife is a complete zombie, I don't think she had more than continious 3 hours of sleep for at least 6 months now. I would cut my own arm off to make this situation improve at this point.
Sometimes that's not an option, but this worked great with our first (we couldn't do it with our second, so my wife is more of a zombie this time even though the daughter is a better sleeper on average).
Hang in there! It won't be that way forever.
Daughter slept they the night from day one.
Son was up hungry every night at 2am.
Given that, power point of this thread, people pretty much went to bed at sunset, at European latitude that would mean a long night much of the year with kids wanting food and adults being sufficiently rested late at night. Once satiated amid a quiet daze of food/sex/meditation, they’d likely doze back off until daybreak. Two sleeps seems quite sensible without electricity’s prolonged days.
> Dozing while nursing .... and enjoying/enduring some thinking time.
Nah, it is just brain fog from slee deprivation. It is not free thinking time, it is "Jeeez I want to sleep" time.
The comment about contemplative dozing comes from my wife. I’ll pass on your feedback.
But the toll is high, not sleeping properly ruins your life. And most of the time it's definitely not insights, but the opposite. For me, it's not something to seek out.
http://www.eiman.tv/misc/somnrytm.jpg
Since the text is in Swedish, here's roughly what it says: Every row is a day, black is sleep, white is awake.
one of my four children slept 18 hours per day, in three 6-hour sessions, for many months.
16 hours of sleep also falls within normal for a 15 week old baby for most sources I've seen, so I'm not sure why you'd be worried? I had a look, and my daughter was around 15-16 hours. No big naps during the day, but she slept 7pm-6am maybe waking twice for feeding.
They're sleeping _way_ too much for 15 weeks. two 3-4 hour naps?? 8 hours overnight is definitely possible but rare
I've heard of sleep patterns like that but always thought it's just marketing.
I'm sure a LOT of people do it, and if you turn off your alarm clock and having to get up at x time, and going to sleep at y time, to be 'refreshed' etc, you'd notice the benefit yourself.
Just sleep when you're tired, eat when you're hungry. Trying to have rigid rules around all this does more to damage peoples health than anything else.
Never heard of the medieval studies before this.
What makes you think that? That's not what evidence has ever suggested. https://www.usatoday.com/story/news/nation/2014/01/06/tooth-...
I'm still working through the book, but the tl;dr is that it mostly just comes down to nutritional deficiency. People in the past ate pretty much strictly nutrient-dense foods, people today eat a lot of junk food, empty carbs, and generally foods that just aren't nutrient dense compared to what our ancestors ate (mostly vegetables and meats).
With respect to the question about underdeveloped jaws, that development takes place primarily during your childhood, so if you didn't have optimal nutrition at that stage you won't be able to fix that retroactively.
https://doi.org/10.1111/jpi.12111
Seems suspect.
Personally I wonder if this would affect speech as well, so perhaps out ancestors sounded different too?
https://www.smithsonianmag.com/science-nature/ability-pronou...
Dont we see two sleeps in the older generations, known colloquially as the afternoon nap?
Japense kids with depression, were found to be driven to school where as those that walked to school for just 10-15mins iirc didnt get depressed according to one study. Blue light stimulates or helps increase the serotonin in the brain which creates wakefulness.
Its like blue light from computer monitors can keep people awake for longer at night which is why M$ introduce the blue light monitor which is a rip off of the original AFAIK of https://justgetflux.com/
Interrupted sleep in the middle of the night for a bit is something I always thought was a normal occurrence as you got older, based on my family.
The range of our diet had also globalized. Potatoes are now a staple worldwide, and tomatoes flavor dishes around the world from where they were developed. Spices aren't very exotic, even if some of us like our food plain.
And salt! Salt had gone from a spice and vital preservative with a value comparable to hard currency to something we throw on roads in the winter.
Wait what? Citation needed please, I googled this and couldn't find anything. Our teeth were definitely bad 100 years ago, since we have images and video from that far back. The bad teeth are something that really struck me in "They Shall Not Grow Old": https://youtu.be/IrabKK9Bhds?t=57
Edit: Okay I see a Scientific American article about this here: https://www.scientificamerican.com/article/why-we-have-so-ma... so that means in 100 years we went from perfect teeth to terrible? Dang
I’ll do some work and be back asleep by 2 or 3.
My kids will be up at 6:30 and it’s all good with me.
When my kids get older, my sleep patterns will change again I’m sure, as they did when we entered into parenthood.
Fighting for sleep feels like an argument with reality, my kids are young and up periodically throughout the night.
c’est la vie
https://en.wikipedia.org/wiki/Fixed_prayer_times#Christianit...
Whether it's cultural or biological remains to be seen, but it definitely seem to be common enough that it didn't merit explaining, except as a casual reference.