http://www.bbc.co.uk/news/magazine-16964783 har en knallgod artikkel om myten om 8-timers søvn, sett i et historisk perspektiv. I før-industrialismens tidalder snakket man om den første og den andre søvnen. De sov i to bolker. I tidsrummet mellom disse to bolkene ble det foreslått at elskov var bra, da hadde de jo sovet litt og var opplagte. Andre bedrev tiden med bønn, eller røyket pipe. Andre dro til og med på besøk til naboen!

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.

Though sleep scientists were impressed by the study, among the general public the idea that we must sleep for eight consecutive hours persists.
Historikeren Roger Ekirch har forsket på denne måten å sove på, den første og den andre søvnen, som for oss i dag er helt ukjent. Hvis vi ikke sover mer eller mindre sammenhengende, er både legen og pasienten enige om at det foreligger et søvnproblem. "At Day's Close: Night in Times Past" heter boka til Roger Ekirch.Han sier at det er ikke bare antallet referanser, men måten de snakker om dette fenomentet på, som gjør at man forstår at dette var helt alminnelig.

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

"Don Quixote followed nature, and being satisfied with his 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, Don Quixote (1615)

"And at the wakening of your first sleepe You shall have a hott drinke made, And at the wakening of your next sleepe Your sorrowes will have a slake." Early English ballad, Old Robin of Portingale.

The Tiv tribe in Nigeria employ the terms "first sleep" and "second sleep" to refer to specific periods of the night
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."

But the majority of doctors still fail to acknowledge that a consolidated eight-hour sleep may be unnatural.

"Over 30% of the medical problems that doctors are faced with stem directly or indirectly from sleep. But sleep has been ignored in medical training and there are very few centres where sleep is studied," he says.

Jacobs suggests that the waking period between sleeps, when people were forced into periods of rest and relaxation, could have played an important part in the human capacity to regulate stress naturally.
CBT= Cognitive Behavior Terapi, altså kognitiv terapi
http://cbtforinsomnia.com/About/gregg_jacobs.html

Russel G Foster http://en.wikipedia.org/wiki/Russell_G._Foster

Russel G Foster har også vært med på å skrive en bok sammen med Leon Kreitzman "Seasons of Life The Biological Rhythms That Enable Living Things to Thrive and Survive"