Sleep shifts

Interesting article in the NYT (nothing political, of course):

More surprising still, Ekirch reports that for many centuries, and perhaps back to Homer, Western society slept in two shifts. People went to sleep, got up in the middle of the night for an hour or so, and then went to sleep again. Thus night — divided into a “first sleep” and “second sleep” — also included a curious intermission. “There was an extraordinary level of activity,” Ekirch told me. People got up and tended to their animals or did housekeeping. Others had sex or just lay in bed thinking, smoking a pipe, or gossiping with bedfellows. Benjamin Franklin took “cold-air baths,” reading naked in a chair.

Our conception of sleep as an unbroken block is so innate that it can seem inconceivable that people only two centuries ago should have experienced it so differently. Yet in an experiment at the National Institutes of Health a decade ago, men kept on a schedule of 10 hours of light and 14 hours of darkness — mimicking the duration of day and night during winter — fell into the same, segmented pattern. They began sleeping in two distinct, roughly four-hour stretches, with one to three hours of somnolence — just calmly lying there — in between. Some sleep disorders, namely waking up in the middle of the night and not being able to fall asleep again, “may simply be this traditional pattern, this normal pattern, reasserting itself,” Ekirch told me. “It’s the seamless sleep that we aspire to that’s the anomaly, the creation of the modern world.”

This does not surprise me at all. I spend nights like this quite often, but it is problematic because of the time compression caused by keeping to the schedules of the outside world.

By the way, I would caution against smoking a pipe while reading naked in a chair. Have one tiny red-hot tobacco leaf fall into your lap and you'll know why this is a bad idea.

via Improbable Research