The many forgotten benefits of segmented sleep

Waking in the middle of the night is perfectly natural.
Waking in the middle of the night is perfectly natural.
Image: Mislav Marohnić/flickr under CC-BY
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Sleeping for an uninterrupted eight hours a night is not, in fact, natural human behavior. Recently, writer Jesse Barron described in the New York Times how he accidentally fell into a pattern of “segmented sleep,” a routine that was standard for centuries until the late 19th century. The practice—which typically involved going to bed at around 9pm to 10pm, sleeping for 3 to 3.5 hours, waking for an hour or so around midnight, and then returning for a second sleep of the same length until around dawn—fell out of fashion with the invention of artificial light, permanently changing our relationship to the natural environment.

In 1992, psychiatrist Thomas Wehr showed that when people lived in darkness for 14 hours a day for a month, they settled into a routine of segmented sleep. And in 2001, history professor Roger Ekirch, from Virginia Tech University, showed that such a pattern was the norm for many generations. He pointed to legal and medical documents that referred to a first and second sleep, and similar mentions throughout literature, including Homer, Chaucer, Austen, Dickens, and Tolstoy.

“Practically every great author” mentioned the practice, says Ekirch in an interview, and in every language in Europe.

But though we may feel perfectly happy with our modern consolidated sleep, we’ve now lost that midnight hour between sleeps, a time when we can be awake and alone with our thoughts.

“I think we’re missing out on a time of intimacy and privacy, a time of self-reflection,” says Ekirch. “We’ve lost a traditional avenue to our dreams, our subconscious.”

This time, which those in earlier centuries called “the watch,” was once used for all manner of activities. There were prayers specifically designed for the watch, and as several religious faiths saw it as a “sacred hour best suited for communicating with God,” says Ekirch. It was also a chance to reflect on vivid dreams and meditate in bed.

More active types used the hour to check on sick family members, do basic chores such as setting the table, or even use the cover of darkness to filch apples from the neighbor’s orchard. As everyone would wake at a different time, even within the same family, it was an hour typically free from social demands. Ekirch says he found the letters of one 15th century Italian woman who loved the watch, as a time “when she’s not surrounded by men, performing chores for men.” Instead, she was able to work on embroidery or compose letters in privacy.

Overall, Erkich suspects we’re less connected to our dreams as a result of no longer waking between sleeps. He says it seems “more than coincidental” that since segmented sleep became less common, dreams have “became a source of ridicule rather than instruction.”

And the consolidation of sleep, which robs us of this hour of calm isolation, could also contribute to rising stress. “I think it’s common sense,” says Ekirch. “The ability to reflect upon the preceding day in the privacy of darkness, to anticipate one’s activities for the next day.”

Doctors from previous centuries also believed in various medical benefits that came from taking medication during the watch, or changing sleeping position. One 16th century French doctor, whose view was later endorsed by several British physicians, argued that having sex between sleeps was key for couples hoping to conceive. This interval, the doctor wrote of French peasants, is when “they enjoy it more and do it better.”

Don’t get too excited about that passionate, middle-of-the-night French peasant sex though. While segmented sleep comes with plenty of benefits, Ekirch says it would be impossible to truly recreate today without depriving yourself of artificial light. Sure, you might be able to temporarily sleep in two phases, as Jesse Barton recounted. But light has “a profound impact on the human body clock,” he says, and we cannot experience the true sleeping experience of the pre-Edison era without turning off the lightbulbs that surround us—for good.

However, the successes of segmented sleep should help ease the anxieties of those who suffer from middle-of-the-night insomnia. Ekirch says that many who wake in dead of the night, but are able to return to sleep only after an hour or so, are often relieved to hear that there’s nothing wrong with them. After all, he adds, “Viewed from the high ground of history, their segmented sleep is arguably more natural than the very young, modern, artificial sleep to which we aspire.”