|A modification of Salvador Dali's "Sleep" (original via orangee)|
“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.
[...] 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 [psychiatrist Thomas] 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.'"
— Stephanie Hagarty, BBC News Magazine
“[…] It seemed that, given a chance to be free of modern life, the body would naturally settle into a split sleep schedule. Subjects grew to like experiencing nighttime in a new way. Once they broke their conception of what form sleep should come in, they looked forward to the time in the middle of the night as a chance for deep thinking of all kinds, whether in the form of self-reflection, getting a jump on the next day or amorous activity. Most of us, however, do not treat middle-of-the-night awakenings as a sign of a normal, functioning brain.
Doctors who peddle sleep aid products and call for more sleep may unintentionally reinforce the idea that there is something wrong or off-kilter about interrupted sleep cycles. Sleep anxiety is a common result: we know we should be getting a good night’s rest but imagine we are doing something wrong if we awaken in the middle of the night. [...]
This, despite the fact that a number of recent studies suggest that any deep sleep — whether in an eight-hour block or a 30-minute nap — primes our brains to function at a higher level, letting us come up with better ideas, find solutions to puzzles more quickly, identify patterns faster and recall information more accurately. In a NASA-financed study, for example, a team of researchers led by David F. Dinges, a professor at the University of Pennsylvania, found that letting subjects nap for as little as 24 minutes improved their cognitive performance.”
– David K. Randall, The New York Times