8 hour sleep myth

http://www.bbc.co.uk/news/magazine-16964783

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 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. Though sleep scientists were impressed by the study, among the general public the idea that we must sleep for eight consecutive hours persists. More recently, the theory that humans slept in two distinct chunks has resurfaced, but in the rather less likely field of history.

Over the course of 20 years, historian Roger Ekirch at Virginia Tech undertook an intensive study into the human relationship with night for his book At Day's Close: Night in Times Past.

In diaries, court records, medical books and literature - from Homer's Odyssey to the anthropological account of modern tribes in Nigeria - he has found more than 500 references to a segmented sleeping pattern.

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. And these hours weren't entirely solitary - people often chatted to bed-fellows or had sex. A doctor's manual from 16th Century France even advised couples that the best time to conceive was not at the end of a long day's labour but "after the first sleep", when "they have more enjoyment" and "do it better".

I'm good with six hours, anything more I feel sluggish.

I completely fail to see how you can try to generalize the patterns of sleep that occur when people are exposed 14 hours of complete darkness to an actual day/night cycle. What was Wehr actually studying?

How much do people sleep when there is no darkness?

Originally posted by Omega Vision
http://www.bbc.co.uk/news/magazine-16964783

I'd say the myth goes even deeper than this however. The idea that there is some general "optimal" sleep pattern assumes far to much homogny in human behaviour.

for sure, for each of us there are probably optimal times and durations of sleep, and I know I don't do the "small naps" thing very well (I end up just being more and more tired after each), but there are others who are able to train their sleep patterns for much more efficient uses of their time (2h rests throughout the day, for instance).

The main issue would be how quickly you are able to cycle into REM sleep. A couple of full cycles should leave anyone feeling rested, so if you can optimize that, a couple of hours of sleep should keep you feeling alert and awake for at least a good portion of a day. For many people that type of cycling isn't possible, and if you have trouble falling asleep or things like that, it is going to be much more difficult to have "optimal" sleep patterns.

Originally posted by Symmetric Chaos
I completely fail to see how you can try to generalize the patterns of sleep that occur when people are exposed 14 hours of complete darkness to an actual day/night cycle. What was Wehr actually studying?

There have been a lot of such studies, mainly they are looking at the circadian rhythms that regulate biological daily processes.

So like, it shows that sleep isn't necessarily a response to some level of fatigue, or that fatigue is more a response to stimuli in the environment, than it is a sign for some biological need for rest. The relationship is obviously complex, as sleep is how we rest, and we would have evolved systems to support it, but at a sort of low level, you can show these things are separable.

Originally posted by Shakyamunison
How much do people sleep when there is no darkness?

iirc, people tend to revolve around a 23 hour cycle, provided they don't have any clocks. Some circadian rhythm is still programmed for a period of about a day, barring any competing stimuli.

The program might be genetic, however, as the above mentioned study shows, even if it is genetic, the environment can influence it to a huge degree (much like all psychology).

I am luckyi if I get eight hours of sleep. On my days off however I got eleven hours of sleep.

I only get 4-7 hours of sleep per night.
I almost never take naps.
The last time I got a full 8 hours of sleep was probably 5 years ago.

7 hours min for me to be alert. under 5 hours and im a basketcase.