I found this report from the BBC about how it used to be common for people to sleep in two stages rather than a straight 8 hours of sleep fascinating because I find myself increasingly falling into exactly that pattern lately.
We often worry about lying awake in the middle of the night – but it could be good for you. A growing body of evidence from both science and history suggests that the eight-hour sleep may be unnatural.
In the early 1990s, psychiatrist Thomas Wehr conducted an experiment in which a group of people were plunged into darkness for 14 hours every day for a month.
It took some time for their sleep to regulate but by the fourth week the subjects had settled into a very distinct sleeping pattern. They slept first for four hours, then woke for one or two hours before falling into a second four-hour sleep…
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, from Homer’s Odyssey to an anthropological account of modern tribes in Nigeria.
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.
Over the last few weeks I have fallen into this pattern of waking up after 4 or 5 hours of sleep, feeling awake and refreshed, then getting up, having something to eat and doing 2-4 hours of very productive work, then going back to sleep for 2-3 hours. The problem is that it’s difficult to build a schedule around that. But the time in between the intervals of sleep are very productive, I get a lot of work done that way. In fact, I am writing this during one such interval.
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.
The condition first appears in literature at the end of the 19th Century, at the same time as accounts of segmented sleep disappear.
“For most of evolution we slept a certain way,” says sleep psychologist Gregg Jacobs. “Waking up during the night is part of normal human physiology.”
The idea that we must sleep in a consolidated block could be damaging, he says, if it makes people who wake up at night anxious, as this anxiety can itself prohibit sleeps and is likely to seep into waking life too.
Russell Foster, a professor of circadian [body clock] neuroscience at Oxford, shares this point of view.
“Many people wake up at night and panic,” he says. “I tell them that what they are experiencing is a throwback to the bi-modal sleep pattern.”
I wouldn’t call it anxiety, but it has been bothering me that I can’t get back to sleep after a few hours. Maybe I should just accept it.
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Ace of Sevens
March 2, 2012 at 9:18 am (UTC -4) Link to this comment
This is what I do, too. I sleep on the couch a few hours with one kitty cat, wake up and check FTB and Facebook for a while, then go sleep in my bed with the other kitty.
blindrobin
March 2, 2012 at 9:24 am (UTC -4) Link to this comment
Throughout my life I’ve had this pattern, though schedules and the constraints of work and parenthood forced me to resist it. Now that I am single again and living alone it’s what I prefer. The time in the interval is very pleasant and productive. My mind is rested and clear, concentration and focus sharper. It’s my favorite time. I also am more rested in the morning and more alert during the day when I break the night up. Embrace it.
EnoNomi
March 2, 2012 at 9:41 am (UTC -4) Link to this comment
I’ve heard reported this was also a popular time for more intimate activites, strange they don’t mention that.
wendy
March 2, 2012 at 9:46 am (UTC -4) Link to this comment
I imagine that for most of human history, it was the one time of day you didn’t have to work.
daved
March 2, 2012 at 9:47 am (UTC -4) Link to this comment
If you go read the entire BBC article, you’ll see that they do mention it.
Mark Sherry
March 2, 2012 at 9:50 am (UTC -4) Link to this comment
As daved says, they do mention it in the article, a paragraph later:
Abby Normal
March 2, 2012 at 9:53 am (UTC -4) Link to this comment
I went through a period years ago where I had no time commitments. I earned money when I felt like it and on my schedule. I found my body fell into a 36 hour day. I be awake 24 hours, sleep 12. Of course that means that while I often woke with the sun on the horizon, I rarely knew if it was sunrise or sunset.
dingojack
March 2, 2012 at 10:00 am (UTC -4) Link to this comment
Nope – eight solid. Guess it’s not quite as ubiquitous as reported.
Dingo
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The Odyssey? – Must be in the special ‘sealed section’.
Lou Doench
March 2, 2012 at 10:01 am (UTC -4) Link to this comment
Maybe I should adopt this sleep pattern, seeing as the three year old seems intent on climbing into my bed in the middle of the night and squirming around until he’s kicking me in the face…
uncephalized
March 2, 2012 at 10:17 am (UTC -4) Link to this comment
Talk about biphasic sleep has been making its way around paleo-diet/ancestral health circles for a while. Prevailing theory seems to be that the advent of cheap artificial lighting squeezed the dark period to a shorter amount of time from its normal 10-14 hours (depending on latitude and season of course), and compressed our circadian rhythms somewhat.
I read an interesting analysis of this the other day that compared the amount of light available naturally on a moonless, half-moon and full-moon night to a regular street lit by electric lights, and various rooms in a typical house. The bottom line is that people who spend most of their time indoors and with lights on at night live in a sort of perpetual twilight, where light levels are an order of magnitude lower than full daylight, but also order(s) of magnitude brighter than a naturally-lit night. This may be wreaking havoc with the circadian rhythms responsible for regulating cortisol and melatonin (wakefulness/alertness/stress hormone and sleepy/drowsy hormone, respectively) and causing problems with duration, quality, and pattern of our sleep. This is one type of chronic stressor that chronically elevates cortisol, which can cause a host of other health problems including weight gain, primarily around the midsection where it is least healthy.
It’s very interesting actually.
@dingojack, you might find yourself falling into this pattern if you lived somewhere away from electricity for a period of a few weeks or months. A lot of people seem to “rediscover” biphasic sleep when they spend time in undeveloped countries or go on long trips into the wilderness, or during extended power outages. Some people seem to retain the pattern more robustly than others in the face of unnatural light cycles.
uncephalized
March 2, 2012 at 10:19 am (UTC -4) Link to this comment
For my part, I’ve never found myself sleeping this way regularly, but I’ve been exposed to electric lighting more or less constantly my entire life, so who knows.
rork
March 2, 2012 at 10:34 am (UTC -4) Link to this comment
I first noticed it odd that in Montaigne’s essays, he’d talk like he got up a 2AM for awhile, and that this was typical.
I’ve more often wondered about mid-day naps. I’m not sure how common that is among other apes, and if sleep patterns vary with latitude (and time of year).
garnetstar
March 2, 2012 at 10:52 am (UTC -4) Link to this comment
Once I worked on a oceanographic ship that spent a couple months doing research at sea. The schedule for all hands was six hours of work, six of sleep, around the clock.
Everyone found their sleep very refreshing and their work very focused. We got into the schedule easily, within a day or so, and had lots of energy. It was really efficient.
Of course, back on shore, I fell back into the 8-hour sleep pattern, which actually isn’t as comfortable.
athena
March 2, 2012 at 11:54 am (UTC -4) Link to this comment
Isn’t the siesta an example of this? In hotter climates, it’s healthier to work in the morning, sleep in the afternoon, then work again after sunset. Also, as we age, our nights are shorter so an afternoon nap takes care of the sleep deficit.
ftfkdad
March 2, 2012 at 12:04 pm (UTC -4) Link to this comment
This was #4 in “7 basic things you are doing wrong”, highlighted by Jason Rosenhouse last year :
http://www.cracked.com/article_19121_7-basic-things-you-wont-believe-youre-all-doing-wrong.html
There’s many more basic things we do “wrong” in our lives apart from sleeping. You know, like breathing and pooping!
democommie
March 2, 2012 at 12:24 pm (UTC -4) Link to this comment
Between getting up to piss and checking to see if any of my demonwards have been disturbed, I only get about 5-6 hours total per night. I make up for this by taking certain sleep inducing potions at one of several area taverns and napping at the bar.;>)
frog
March 2, 2012 at 2:13 pm (UTC -4) Link to this comment
I definitely want two sleep segments. When left to my own devices, my schedule seems to become “sleep from midnight to 5 am, wake up until 8am, go back to bed until noonish.”
Next time it happens, I’ll try doing something productive from 5 to 8 instead of lying in bed wishing I were asleep again.
robertfaber
March 2, 2012 at 2:18 pm (UTC -4) Link to this comment
When I was in college in the south of France, I too fell into a two sleep schedule. Classes were M-F 8 AM to noon. I’d sleep 4 hours before class and 4 hours after, leaving me roughly 4pm to 4am to do the fun tourist stuff. Never felt tired.
leni
March 2, 2012 at 3:28 pm (UTC -4) Link to this comment
Maybe this is why my typical nap lasts for about 4 hours. I know there are people who power nap and magically spring back to life after 30 minutes without an alarm, but I am definitely not one of them.
And it seems like no matter how tired I am, 10pm is like my morning.
First shift and I have never been on good terms :/
Nibi
March 4, 2012 at 5:04 pm (UTC -4) Link to this comment
I fell into the 4-4 pattern during the last couple of years when I was self-unemployed. Unfortunately, the party funds ran low, had to get a $fuckingjob, and sheer exhaustion forced me back into a full night’s sleeping pattern. I’m reminded of the opening sequence of The Gods Must Be Crazy.
healthy eating
March 4, 2012 at 11:08 am (UTC -4) Link to this comment
healthy eating…
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