Have you ever wondered if you're sleeping "normally"? It turns out there's some debate about what constututes normal sleep.
Most of us assume that the normal and correct way for human adults to sleep is by having an uninterrupted period of night sleep with no awakenings. Stephanie Hegarty of the BBC World Service describes this pattern as "the myth of the eight-hour sleep."
We often worry about lying awake in the middle of the night --but it could be good for us. A growing body of evidence from both science and history suggests that the eight-hour sleep may be unnatural.
Sleep psychologist Gregg D. Jacobs, a pioneer in nondrug treatment of insomnia (cognitive-behavioral therapy) who works at the Sleep Disorders Center at the University of Massachusetts Medical School, says that for most of human evolution, people slept in a certain way. "Waking up during the night is part of normal human physiology," Jacobs remarks.
Drawing on documents from the ancient, medieval, and modern world, historian A. Roger Ekirch of Virginia Tech concurs. Before the Industrial Revolution, Ekirch says, people usually slept in several distinct phases divided by periods in which they stayed awake. The pattern is known as segmented sleep, divided sleep, bimodal sleep pattern, or interrupted sleep. The afernoon siesta is a related phenomenon.
Ekirch has found over 500 references to the segmented sleeping pattern in medical books, diaries, court records, and literature from Homer's Odyssey to modern tribal Nigeria. In medieval England, the two main phases were known as "first sleep" (or "dead sleep"), beginning several hours after dusk, and "second sleep" (or "morning sleep") following an hour or two of being awake. For example, Miguel Cervantes described Don Quixote as a man satisfied with his first sleep, and Charles Dickens used the term in Barnaby Rudge.
During the waking period of the "wee hours," most people used the toilet and went back to bed, talking, making love, reading, writing, or praying until the second sleep came along. Others got up, smoked, ate a late dinner, or even visited neighbors. In the 1500s, French doctors saw the wakeful hours as the best time to conceive because people enjoyed sexual activity more after a rest and actually performed better.
Jacobs suggests that when people rested and relaxed between sleeps, they regulated their own stress naturally. The pattern stopped being thought of as normal during the Industrial Revolution, when street lights became common, homes turned to gas and electric lighting, and staying out late became a common activity.
It's hard to think of television as improving these sleeping habits. Russell Foster, who teaches circadian [body clock] neuroscience at Oxford University, describes the modern outlook: "Many people wake up at night and panic. I tell them that what they are experiencing is a throwback to the bi-modal sleep pattern."So maybe you're not really an insomniac. In fact, maybe you're just "normal."
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