11 May 2012

Is an 8-hour sleep a modern artificial construct ?

Excerpts from a long article at the BBC:
In 2001, historian Roger Ekirch of Virginia Tech published a seminal paper, drawn from 16 years of research, revealing a wealth of historical evidence that humans used to sleep in two distinct chunks.

His book At Day's Close: Night in Times Past, published four years later, unearths more than 500 references to a segmented sleeping pattern - in diaries, court records, medical books and literature...

Much like the experience of Wehr's subjects, these references describe a first sleep which began about two hours after dusk, followed by waking period of one or two hours and then a second sleep.

"It's not just the number of references - it is the way they refer to it, as if it was common knowledge," Ekirch says.

During this waking period people were quite active. They often got up, went to the toilet or smoked tobacco and some even visited neighbours. Most people stayed in bed, read, wrote and often prayed. Countless prayer manuals from the late 15th Century offered special prayers for the hours in between sleeps...

Ekirch found that references to the first and second sleep started to disappear during the late 17th Century. This started among the urban upper classes in northern Europe and over the course of the next 200 years filtered down to the rest of Western society.

By the 1920s the idea of a first and second sleep had receded entirely from our social consciousness...

Today, most people seem to have adapted quite well to the eight-hour sleep, but Ekirch believes many sleeping problems may have roots in the human body's natural preference for segmented sleep as well as the ubiquity of artificial light.

This could be the root of a condition called sleep maintenance insomnia, where people wake during the night and have trouble getting back to sleep, he suggests. 
I've requested the book from the library; if it's good, I may review it in a future post.

Update:  I finally did read the book; it's very interesting, very comprehensive, but seems to me to be sort of a compilation of a thousand anecdotes rather than a tightly constructed report, so I haven't added it to my list of recommended books.   The book covers many aspects of the sociology of night, not just the sleep patterns discussed above.  Re that subject matter, a hat tip to Alex, who sent me a link to an essay at The Age which offers an extended discussion of segmented sleep, as reported in the book:
"By segmented sleep, I am referring to a pattern whereby individuals typically slept in two phases of perhaps three to 3½ hours each in length bridged by an intervening period of wakefulness. The transformation to our much younger, modern mode of slumber took place gradually and erratically over the course of the 19th century in Western societies."

Though it's an alien concept to us today, references to two sleeps can be found as far back as the Old Testament and Homer's Odyssey, and, more recently, in Don Quixote and Charles Dickens's Barnaby Rudge. The period between the two wasn't always a solitary affair, with people gathering to talk, have sex or visit the neighbours. But, the introduction of affordable light sources – from candlelight to public oil lamps – blurred the distinction between daytime and night-time activities and sleep patterns soon followed...

"The social and cultural factors that reshaped sleeping patterns are called nocturnalisation," Kofolsky told me. "Nocturnalisation, defined as the increasing social and symbolic uses of the night, began to reshape sleeping habits, meal times, and all other structures of daily life beginning around 1650. Just as some Europeans at this time sought wealth, prestige, and power through colonisation of space, so too Europeans began to colonise the night, expanding their daytime activities into the night while developing new uses for lighting and darkness and leading to a compression of the first and second sleep into one block."

Over the course of the next 250 years the trend filtered throughout the rest of Western society and by 1920 the concept of the first and second sleep had been eradicated from our collective memory...
More at the link.

Reposted from February 2012 to add the update.


  1. I read that book years ago, when it first came out. I was very unimpressed. I will be curious to hear your opinion. Heck, I'll send you my copy.


    1. Thanks, Chuck, buy no need. Library computer says book is on its way to me. That's what libraries are for.

  2. I read Bill Bryson's "At Home" last year and started thinking hard about my sleep life. I've had insomnia off and on since high school, and was in the middle of a very long bout of it. I was tired all the time. Nothing helped me sleep: not well-timed exercise, hot baths, meditation, medication. Nothing.

    I've always been a night owl, even as a young kid. I am most productive at night, eat the most in the evening (and have zero appetite for breakfast). So I decided I'd make a new rule for myself: I will sleep when I am sleepy.

    I have the luxury of working for myself, and for the last six months I've been sleeping when sleepy. My sleep flows through a pretty rhythmic schedule all week -- in the middle of the week I'm usually up until 3-7 in the morning, sleep for a while, wake up again. I often wake up in the late morning, do a few hours of light work, and then "finish" sleeping.

    It. Is. Amazing. And those are my thoughts on sleep -- it feels much more natural to let my body guide my sleep schedule.

    1. Does your decision to "sleep when . . . sleepy" have anything to do with your screen name (Cat)? =) That's what my cat does.

  3. Yep, I work for myself and work is slow during the winter. I find myself getting sleepy around 8'ish and then again around 1 am. If I go to sleep then I will wake up around 9.

    Maybe I should catch the first sleepy wave, get up and do non-electronic stuff, then finish my sleep.

    I also am very productive at night.

  4. I actually just finished reading this book. When I heard about the First and Second Sleep concept, it was a revelation to me. I no longer have to feel "guilty" about not sleeping 8 hours straight through. It is not something "wrong" that I should try to fix. I almost always wake at 1 or 2 in the morning and stay wakeful for an hour or two or three, then go back to sleep, usually with vivid dream segments.

    We've been trained into this solid sleep idea through our culture of industrialized work schedules and what a person should do to be an on-time, productive (supposedly) worker bee, along with having artificial light to keep us more awake in the earlier part of each night. Like other commenters, I work for myself now and can usually adjust my schedule to better fit my natural cycles.

    This book has a lot of listed details in the forms of quotations from early (Middle Ages forward) personal documents and gets rather dense with them. I would have liked more interpretation and context from the author than he gave, but it is nevertheless fascinating to come to a more complete picture of what it meant to have absolutely no artificial light at night other than weak candles and weaker rush lights. It was referred to as the Night Season because it was so completely different from the daytime world everyone lived in. An entire social culture and sets of rules were in place that we have naturally discarded.

    We have a lot of advantages at night now, but we are also missing a lot that our ancestors took for granted.

    --commenting as Anonymous because site won't let me post otherwise. David Crews - david@crewscreative.com

    1. Thanks, David. The description sounds reminiscent of William Manchester's "A World Lit Only by Fire," which I thought was fascinating.

      If you'd like to get your name to replace "anonymous," when you "select profile" for a comment you should be able to choose "Name/URL" and then type in your name; you don't have to provide a URL.

    2. Thanks, Stan.
      I had not heard of that book. I'll look it up and read it at night by my artificial light!
      I usually do comment with Name/URL, but this time it kept saying my URL contains illegal characters, which it doesn't. Also tried logging in from my new Wordpress blog ID, but it did not work either. Still won't let me for this reply . . . :(
      So, I'm Anon-E-Mouse once more.

  5. The documentary "Mythic Journeys" has a segment about this subject, but I think the wakeful period was referred to as "second night". I'm excited to find another resource and hope my library system has a copy. Thanks Stan!

  6. I wonder if the presence of artificial lighting is the cause of having two distinct sleeps dying out?

    I recently spent some time in a campsite in the Northern Territory, and after your eyes have spend a few hours adjusting to the dark, even by just starlight there is enough light to move around safely. If the moon is out then you feel as if you can see almost as well as if it was daylight.

    But if you have turn on any source of artificial light on for even a few minutes it will absolutely ruin your night vision for the next hour or so, and all you can do is keep still and likely fall asleep.

    The timeline is about right for the introduction of streetlighting I believe.

  7. This seems an overcomplicated bit of research.

    Why can't we just look at present day non-electric cultures? There are still a few around. See how they sleep.

  8. Being an Old Hippie -- that is, having spent some time living in a tipi -- I have long thought that folks who did this (tipi dwelling) full time,long ago, did not, and could not expect to, have a deep sleep all night long, particularly in the winter: although tipis can be quite cozy when pitched correctly, someone still has to wake up every hour or so to keep the fire going (they can also be quite chilly if the fire goes out. ["Oh, oh oh, Sabrina, you've let the fire go out."]) And there's the possibility that there might be someone out there trying to steal your horses.

  9. When you do updates like this, putting (Update) in the title is good for RSS readers, but my eye skips over it while scrolling. Maybe the first line of the post could be a hyperlink that says "Click here to skip to the update" so I don't find myself rereading the whole thing not knowing I've seen it before?

    1. I think you're right. I often put update in the title, but didn't this time because it would drag over to a second line, which is visually unattractive. Re the hyperlinks, it depends on how much energy I'm willing to expend (and frankly I'm not sure how to hyperlink to a lower position on my own post...)

  10. I'd be tempted to try the two-sleep pattern, as I often find that I get very sleepy around 7-8 in the evening but then once the feeling passes I can work on late into the night. I find the dead of night is a great time to be up and about, drawing and sipping tea and just enjoying the fact that everyone else is out cold. My one worry would be that once I started the wakeful period after the first sleep, I wouldn't know when to quit and would end up being awake almost until morning, which would leave me zombified at work. Still, would be interesting to have a few obligation-free months to experiment.

    I've always been exceptionally curious about and drawn to the claims that one can subsist on a mere 15-20 minutes of sleep every four hours, which frees up a potential goldmine of free time, but haven't looked into it seriously enough to know if it's a credible system.


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