Interesting stuff: historical research has shown that in the past, people used to sleep in two segments of four hours, with a waking period in between, rather than eight hours straight. This used to be the normal sleeping pattern until the late seventeenth century! Only by the 1920s, the eight-hour schedule had become the norm.
Different explanations, such as the development of street lights, account for this change. Historical documents also show that people used to do a lot in between two segments of sleep, such as pray, eat, write, have sex, visit the neighbours, etc. It may very well be that the current modern mass problem of insomnia results from the incapability of people to actually sleep for eight hours straight, which may be unnatural.
I’m pretty convinced that the modern-day demands of working life (getting up early in the morning, going to bed early in the night) are a straightjacket that is very unnatural for a lot of people who are naturally inclined to be ‘evening people’. This research shows that this wasn’t always the case, but rather coincided with the advent of modernity.
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.
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”.
Ekirch found that references to the first and second sleep started to disappear during the late 17th Century. This started among the urban upper classes in northern Europe and over the course of the next 200 years filtered down to the rest of Western society.
By the 1920s the idea of a first and second sleep had receded entirely from our social consciousness.
He attributes the initial shift to improvements in street lighting, domestic lighting and a surge in coffee houses – which were sometimes open all night. As the night became a place for legitimate activity and as that activity increased, the length of time people could dedicate to rest dwindled.