Historian A. Roger Ekirch was writing a book about the history of night and was dreading having to write the chapter on sleep.
“I thought it would be boring,” said Ekirch, a professor of history at Virginia Tech and author of At Day’s Close: Night in Times Past. “I thought it was a biological constant. I thought I wouldn’t have enough information to fill an entire chapter.”
Instead, Ekirch would stumble upon a pattern of sleep that stretched back to ancient times. Instead of sleeping in one “consolidated” block of eight hours or so, people would commonly sleep in two nightly segments. They would go to bed after dark, then wake up for about an hour around midnight, then return to sleep.
“I knew I was on to something strange — a form of sleep I had never run across before,” said Ekirch, who found references to “first” and “second” sleep in historical records ranging from literature to correspondence, newspaper articles to criminal court depositions in the public records office in London. He discovered references in at least a dozen European languages that suggested people regarded this pattern of slumber to be so unremarkable, they didn’t have to explain it. In 1690, the philosopher John Locke noted that “all men sleep by intervals.”
In this hour of wakefulness, people would do things by the light of the moon and stars or the weak illumination provided by rush lights. They did chores, took medicine, shifted themselves from their right side to the left to aid digestion. They chatted, prayed, stole firewood from a neighbour or had leisurely sex. The time between first and second sleep was considered a particularly good time for the labouring class to conceive children.
“This research turns the whole notion of what is normal sleep on its head,” said Ekirch.
Segmented sleep started to slip in the 19th century with the introduction of whale oil lights, gas lights and, finally, electrical illumination.
“Artificial light has an incredible effect on the circadian pacemaker,” said Ekirch. “It pushed sleep times back to 11 p.m. or midnight. The first sleep became more longer, the period of wakefulness shorter and the second sleep more compressed.”
At the same time, the ethos of the industrial revolution prized the values of productivity, efficiency and profit. As artificial illumination became more and more common and first sleep was pushed back later, people got up and went to work rather than enter into second sleep. There was even an “early rising” social movement that suggested oversleeping was bad for the health. Newspapers and periodicals suggested that workers could earn more money over a lifetime simply by waking up an hour or two earlier. According to another report, a man held back a bequest in his will to his nephews until they could satisfy his executors that they would wake up by 5 a.m. in summer and 7 a.m. in winter.
The transition period to consolidated sleep was long and erratic, but once a consolidated sleep was considered the norm early in the 20th century, there was no turning back, said Ekirch. At best, sleep was seen as a necessary evil. “Only the lazy slept.”
Medical books show that insomnia emerged as a medical problem only in the late 19th century and early 20th century. There was a sudden epidemic of insomnia in the early 20th century. Waking up in the middle of the night was considered unnatural, but Ekirch believes it’s a powerful remnant or echo of a pre-industrial pattern of sleep that was dominant in the western world since time immemorial.
Ekirch said his findings have been widely embraced by sleep science researchers, who have found parallels in lab research. In the 1990s, Dr. Thomas Wehr, a psychiatrist at the U.S. National Institute of Mental Health, followed 15 young male volunteers who were deprived of artificial light. After a few weeks, the men’s sleeps became segmented.
“As a society, we need to have a conversation about normal sleep,” said research Dr. Siobhan Banks, co-director of the Behaviour-Brain-Body Research Centre, at the University of South Australia. “We don’t need to sleep in one particular way. As long as we get enough sleep, we can structure it in different ways. But it needs to be done using good sleep science.”
Some people do wake at night and this is natural. “It’s normal to have periods of wakefulness, but in today’s society because we don’t go to bed at sundown and only allow an exact time for sleep, these wakings can feel problematic,” said Banks.
“If you allow enough time for sleep, it doesn’t really matter how it is split — it’s the total amount that counts. However people rarely allow themselves eight hours for sleep, as you would probably need nine to 10 hours in bed split over two periods to achieve this.”
Sleep maintenance insomnia — waking too early and struggling to get back to sleep — may be a persistent reminder of a long-dominant pattern of sleeping, said Ekirch.
He believes that if people knew waking up in the middle of the night isn’t abnormal, they wouldn’t stress about getting up in the middle of the night. “A number have written to me. It lessens their anxiety.”
That said, the good old days were hardly the golden era for sleeping deeply and well. Henry Fuseli’s 1782 Gothic painting The Nightmare depicts a sleeping woman flung across a bed with an imp-like creature on her chest and a horse with glowing eyes in the background. At the time, a “mare” was an evil spirit that tortured people while they slept.
People living centuries ago had to sleep lightly, said Ekirch. They needed to be vigilant about home invasion and fire. They got up to tend to sick children, they suffered from toothaches and the onslaught of bedbugs, lice and fleas. They feared nocturnal visits by Satan and his minions.
It’s much better today, he argues.
“Despite all the publicity given to sleep deprivation, never before in human history have conditions been better to promote human slumber,” said Ekirch. “If there was anything such as the golden age of sleep, it would be today. If we don’t think of it that way, it’s our own fault. The irony is that the less we sleep, the more perfect we expect that sleep to be. We think we can cheat sleep, then buy a $3,000 Swedish mattress and caffeinate ourselves.”
There’s no going back to segmented sleep. But Ekirch believes his historical research has called into question whether consolidated sleep is a product of modern times. And he’s tickled over how his findings in the historical record have been replicated by sleep researchers.
“I’m not a scientist. I struggled in high school chemistry. I could barely light the Bunsen burner. To say I contributed to a better understanding of sleep by resurrecting this older pattern is very fulfilling. But totally unexpected.”
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