Lighting Steals Your Sleep

It's not surprising that people went to sleep earlier in the days before electric light. But there's evidence they also slept much differently than today. People may have slept in shifts, as most animals do. Some evidence for that came from Dr. Thomas A. Wehr at the National Institute of Mental Health.

In the 1990's, he observed sleep patterns of adults. They were isolated in a room with 14-hour long periods of darkness. That resembles a nighttime without electric lights. Dr. Wehr discovered that participants began to sleep in two phases. First they'd sleep for about four hours; then they'd be awake for one to three hours; then four more hours of sleep. Participants described the waking interval as a very tranquil one of quiet attentiveness. Historians have found people referring to "first sleep" and "second sleep" as far back as Homer.

Wehr suggests that the use of modern lighting has made us "chronically sleep deprived." Some of us need to be taught how to get a good night's sleep.