Has this evidence been examined sceptically? I've heard this theory a few times, but it always sounds like one person's obsession, and I struggle to credit it.
You are right (and very observant) that this is mostly Ekrich when you dig into it. I didn't realise this until quite recently, and I too had assumed there was a lot more work about this.
But what he's found in literature is pretty consistent, and biphasic sleep was once quite normal in a specific context: the siesta.
It's dying out in continental Europe alas -- a lost cultural touchstone -- and in the contemporary West, a siesta is short (literally a nap). But a traditional Spanish siesta is the best part of a sleep cycle -- a good couple of hours, with an hour's rest spread either side. More than enough that you could have four hours sleep overnight throughout the longer days and not be incompetent the next day.
My sleep is currently polyphasic, which is not a great time. But it has taught me that sleep in the absence of natural light (or the presence of consistent artificial light) does have a habit of going polyphasic.
I woke up at 4:15am after about five hours of sleep. I just cleaned a grill pan. I may go back to sleep again.
Sleep scientists seem pretty sure that polyphasic sleep is bad.
Question for people who sleep like this: do you live with anyone? How do they tolerate it? I can't imagine it's great to wake up to your roommate scraping pans in the kitchen on odd nights.
My dad, I think, had occasionally polyphasic sleep, and he often took on-call rota slots as a result. He'd be in the kitchen cleaning, or in his study, but since the house was big, it was rarely a problem. Sometimes he'd be napping in his study, and I know he slept easily on the train to and from work (with an efficiency that meant he woke up a minute before his stop on the way home).
When I was a student I just forced my polyphasic sleep periods into normal sleep as best I could, which typically manifests a bit like delayed sleep phase; by the middle of the week I was two hours behind everyone else, and I actually did worse in the courses that had early Friday lectures. But when you're a student, being awake or asleep at odd hours is normal enough not to be remarked upon.
As a programmer, polyphasic sleep is sometimes unnoticeable to others. These days probably more apparent in git commit logs.
I have to tell you, 4am-5am, between sleep phases, is the best time to clean a kitchen. It's vaguely contemplative and when you go into the kitchen later that day it's like the cleaning fairy did it.
Always interesting to hear other perspectives on simple stuff like this. Personally, I like doing dishes in the morning while the espresso machine heats up. It's a nice rote task my half-asleep brain can come up to speed on, I feel like I've accomplished something right out of the gate, and I didn't need to interrupt the flow of whatever I was enjoying the previous night.
Oh... what I mean is, one of the things that is interesting about the gap between the two sleeps is that your brain is awash with prolactin.
So some tasks you do in that period of time are done with a kind of lower level of objection, easier "starting", and in a contemplative start, and you're not actually tired.
Which is what also gives this "cleaning fairy" sense that nobody in particular did it.
> Question for people who sleep like this: do you live with anyone? How do they tolerate it?
I tried it and it worked, but I have a family and no, it didn't work for them, so I stopped. Couldn't get a schedule right that allowed me to be with the family for normal social interaction times, AND be at work when THEY expected me to be available for the work-team.
One college summer I worked on a highway landscape crew. They put us on a schedule of 6 am to 2:30 pm, which got us out of the hottest part of the day. I would come home, clean up, and nap until dinner, say 5:30, then have a normal evening, turning in at about 10 pm and waking up at 4:30.
It wasn't bad. I did like waking up at 4:30 on the weekend, rolling over, and going back to sleep.
And it feels bad as well. I have polyphasic periods and I'm always relieved when they end. Not sure why I don't feel too good, because I have ways to cope now, but good monophasic sleep makes me wake up rested and without a headache.
I think it feels bad because it inevitably messes up one's digestive clock (which is implicated in robustly configuring the sleep clock) and by implication, particularly with modern food, blood sugar levels.
(I suspect that the long cultural stability of the Spanish long siesta has a lot to do with the cultural stability of mealtimes -- and meal types/sizes -- that developed around it.)
The other day I felt queasy, suddenly, after lunch at a normal time -- so queasy I had to write off the day. I then proceeded to sleep for the best part of 24 hours, because all the phases seemed to merge. A literal 24 hour period, useless. Other people lived normal lives in that period; for me it just vanished.
I think blood sugar had a lot to do with that, as well as the time of year (winter in Britain) and it has definitely unnerved me.
I cope by just accepting it; trying to do things when awake. But there are things you can't really do in the middle of the night if you live in a close, quiet neighbourhood; hoovering, running laundry, shredding documents, even some printers are noisy.
Yes, accepting is big part. I read mostly and recently trying to meditate as well. Doing nothing productive to not signal that we actually should wake up. Especially bad are the nights when sleep comes after more than 2h of wake time.
I'm trying to watch it from blood sugar perspective, I'm pretty good at extending periods between meals due to intermittent fasting, but there may be connections since Im not fasting all the time.
Because it takes time to adapt fully. Your polyphasic periods are more like stopping and restarting a routine that disallow your body from adaptation. Those who adapt fully over the course of a month feel as good as you do during monophasic sleep.
Hardly a singular obsession of one person when we have both Vigil and Matins as standards of the canonical hours for much of the past two thousand years of church records.
The article outlines multiple examples of references to first and second sleep periods in official court documents, and points to sleep studies of farmers in rural areas who still 'almost wake' not long after midnight.
As a pre industrial habit it makes sense - in colder areas fires don't last all night and rising after midnight to stoke fires, check animals, etc. fits right in with rural life.
The parent post means the study of the practice, not the practice itself.
It might make sense -- I think it probably does -- but that doesn't mean that it's not true, when you dig into it, that the major study here is Ekrich and all the articles about it, articles about Ekrich.
Making intuitive sense isn't really enough. It's difficult to study the habits of the long dead, but the parent poster is right to be skeptical of the nature of coverage.
Aside from Ekrich - who can at least point to the extracts he has found in historic archives, there are sleep study results that suggest humans still have remnant night waking behaviour; these fall into the intuitive.
Which leaves what I first raised - a thousand years of documented broken sleep by monks in monestaries getting up to pray late at night and again early in the morning.
Some might write that off as hair shirt behaviour by religuous fanatics intent on punishing themselves, others might take it as evidence that people of those times were living with punctuated sleep cycles and those that went to serve their God took to praying when they woke as a matter of course.
There's also the evidence of sleep in Spain and other warmer climes, with additional sleeping during the hottest parts of the day, staying up later, sleeping less during the night and rising earlier before the sun.
It's Ekrich's hobby horse, many niche areas have few champions, but it's not exactly the case that he is drawing on forged entries with no other examples to be found.
Not that specifically but that's certainly one whisp of smoke that might be found should:
> (Has this) evidence been examined sceptically?
The implication there is that the "evidence" quoted might not exist, might be a stretch of translation, misreading of spidery handwriting, or spun whole from new cloth to fit a narrative.
I personally read "sceptically" to imply the idea of seeing whether the study falls victim to significance bias -- e.g. once you see it, you see it a lot, but is it an indicator of a widespread habit, or just a not-particularly-unusual one?
Edit: And indeed if you read on a bit about Ekrich, he suffers from sleep disorders for which he takes medication. That's a potential risk factor for significance/confirmation bias here, I'd have thought. But there's no reason to jump to the conclusion that fabrication is being suggested.
Especially since there's that one other person -- Piotr Wozniak -- who shares the idea of two sleeps but argues they are completely different to the Ekrich characterisation. Wozniak thinks the second sleep is the mid-day nap. That resonates much more with my needs.
I do wonder if the window for observing it empirically has passed. Pretty much everywhere in the world has access to artificial light — even if it is in a cheap, low-tech form like a hand-cranked LED torch. And those people who remain uncontacted have made it clear that they do not wish to be contacted.
Anecdotal / from memory, they did a study (at least) once where people didn't have artificial light (not sure if they had candles or nothing at all), and found that people naturally went to sleep when it went dark - not much else to do - but also woke up after a few hours.
But I'm not entirely sure; how much can you do awake if it's dark?
But then, it's rare for it to be truly dark, with moonlight and the like.
I wonder if this changed with the seasons. In the winter, the night is longer than normal sleep amount and might make sense putting extra time in the middle of night. In the summer, the night is shorter and would sleep through.
But what he's found in literature is pretty consistent, and biphasic sleep was once quite normal in a specific context: the siesta.
It's dying out in continental Europe alas -- a lost cultural touchstone -- and in the contemporary West, a siesta is short (literally a nap). But a traditional Spanish siesta is the best part of a sleep cycle -- a good couple of hours, with an hour's rest spread either side. More than enough that you could have four hours sleep overnight throughout the longer days and not be incompetent the next day.
My sleep is currently polyphasic, which is not a great time. But it has taught me that sleep in the absence of natural light (or the presence of consistent artificial light) does have a habit of going polyphasic.
I woke up at 4:15am after about five hours of sleep. I just cleaned a grill pan. I may go back to sleep again.
Sleep scientists seem pretty sure that polyphasic sleep is bad.