Our body clocks

Two interesting articles on sleep and body clocks. In the NYTimes, Daniel Randall cites research showing that the idea of getting a continuous eight hour block of sleep each night is a relatively modern invention and possibly suboptimal.

The idea that we should sleep in eight-hour chunks is relatively recent. The world’s population sleeps in various and surprising ways. Millions of Chinese workers continue to put their heads on their desks for a nap of an hour or so after lunch, for example, and daytime napping is common from India to Spain.
One of the first signs that the emphasis on a straight eight-hour sleep had outlived its usefulness arose in the early 1990s, thanks to a history professor at Virginia Tech named A. Roger Ekirch, who spent hours investigating the history of the night and began to notice strange references to sleep. A character in the “Canterbury Tales,” for instance, decides to go back to bed after her “firste sleep.” A doctor in England wrote that the time between the “first sleep” and the “second sleep” was the best time for study and reflection. And one 16th-century French physician concluded that laborers were able to conceive more children because they waited until after their “first sleep” to make love. Professor Ekirch soon learned that he wasn’t the only one who was on to the historical existence of alternate sleep cycles. In a fluke of history, Thomas A. Wehr, a psychiatrist then working at the National Institute of Mental Health in Bethesda, Md., was conducting an experiment in which subjects were deprived of artificial light. Without the illumination and distraction from light bulbs, televisions or computers, the subjects slept through the night, at least at first. But, after a while, Dr. Wehr noticed that subjects began to wake up a little after midnight, lie awake for a couple of hours, and then drift back to sleep again, in the same pattern of segmented sleep that Professor Ekirch saw referenced in historical records and early works of literature.

The article caught my eye because I've been naturally waking up after about four hours of sleep each night, spending a bit of time reading, then dropping back to sleep for a few hours. Is this my body naturally seeking a split sleep schedule? I'd assumed it was the scourge of keeping my iPad and iPhone near my bed. As soon as any early traffic noise wakes me, my impulse is to grab one of those devices to check my email. But perhaps I'm just finally settling into a more natural sleep pattern?

The other article, in the WSJ, cites a wide swath of research on optimal times of day to tackle certain tasks, from working out to sending email to creative thinking. Much of this feels like it could be the subject of a Timothy Ferriss book.