Do We Get Less Sleep than our Ancestors?

Ever since people started staying up late in the night to the light from electric bulbs, other people have been worried about what this was doing to our sleep patterns. Either we're not sleeping enough, or the sleep we get is not deep enough because of all the artificial light around us. Recent anthropological studies have done a lot to ease this worry. First, it has been discovered that most hunter-gatherers don't sleep straight through those long, dark nights, but are often awake at midnight after an evening's nap. (This is apparently when most sex happens among people who live in communal houses.) And now someone has equipped hunter-gatherers with digital monitors to find out how much they sleep:

A new study of sleep patterns in hunter-gatherer adults in Africa and South America has found they get no more sleep than people living in industrialized nations—an average of just 6.9 to 8.5 hours every night. What’s more, they rarely nap. Yet, these adults are healthy and don’t feel sleep-deprived, according to a report today in Current Biology. The striking uniformity in the sleep duration and habits of three far-flung groups in Bolivia, Tanzania, and South Africa busts several myths about how much sleep our ancestors got—and what is optimum for modern humans.

So relax -- you're probably sleeping enough.