The myth of the eight-hour sleep

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 andhistory suggests that the eight-hour sleep may be unnatural.

In the early 1990s, psychiatrist Thomas Wehr conducted anexperiment in which a group of people were plunged into darkness for 14 hoursevery day for a month.

It took some time for their sleep to regulate but by thefourth 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 fallinginto a second four-hour sleep.

Though sleep scientists were impressed by the study, amongthe general public the idea that we must sleep for eight consecutive hourspersists.

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In 2001, historian Roger Ekirch of Virginia Tech published aseminal paper, drawn from 16 years of research, revealing a wealth ofhistorical evidence that humans used to sleep in two distinct chunks.

His book At Day's Close: Night in Times Past, published fouryears later, unearths more than 500 references to a segmented sleeping pattern- in diaries, court records, medical books and literature, from Homer's Odysseyto an anthropological account of modern tribes in Nigeria.

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

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

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

And these hours weren't entirely solitary - people oftenchatted to bed-fellows or had sex.

Between segments

Some people:

Jog and take photographs

Practise yoga

Have dinner...

A doctor's manual from 16th Century France even advisedcouples that the best time to conceive was not at the end of a long day'slabour but "after the first sleep", when "they have moreenjoyment" and "do it better".

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

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

He attributes the initial shift to improvements in streetlighting, domestic lighting and a surge in coffee houses - which were sometimesopen all night. As the night became a place for legitimate activity and as thatactivity increased, the length of time people could dedicate to rest dwindled.

When segmented sleep was the norm

"He knew this, even in the horror with which he startedfrom his first sleep, and threw up the window to dispel it by the presence ofsome object, beyond the room, which had not been, as it were, the witness ofhis dream." Charles Dickens, Barnaby Rudge (1840)

"Don Quixote followed nature, and being satisfied withhis first sleep, did not solicit more. As for Sancho, he never wanted a second,for the first lasted him from night to morning." Miguel Cervantes, DonQuixote (1615)

[if !supportLists]·     [endif]"And at the wakening of your first sleepe You shall havea hott drinke made, And at the wakening of your next sleepe Your sorrowes willhave a slake." Early English ballad, Old Robin of Portingale

[if !supportLists]·     [endif]The Tiv tribe in Nigeria employ the terms "firstsleep" and "second sleep" to refer to specific periods of the night.

Source: Roger Ekirch

In his new book, Evening's Empire, historianCraig Koslofskyputs forward an account of how this happened.

"Associations with night before the 17th Century werenot good," he says. The night was a place populated by people of disrepute- criminals, prostitutes and drunks.

"Even the wealthy, who could afford candlelight, hadbetter things to spend their money on. There was no prestige or social valueassociated with staying up all night."