Early Humans Probably Didn’t Get Much Sleep

Modern wisdom dictates that you should get at least seven or eight hours of sleep a night, but very few Americans spend that much time snoozing in reality. Experts blame stress and our reliance on technology that emits bright artificial light, keeping us awake. 

Those theories mesh well with the contemporary cultural obsession with how modern, industrial life has failed us—in 2013, the most frequently searched diet online was the paleo diet, a fad that involves swearing off anything our stone-age ancestors didn’t eat, including grains and legumes. However, when it comes to modern sleep patterns, the prehistoric way of doing things might not have been much different than our current habits. 

A new study in Current Biology analyzes the sleep habits of traditional hunter-gatherer communities in Tanzania, Namibia, and Bolivia. A team of researchers from UCLA and several other institutions examined 94 people from groups like Hadza, the San, and the Tsimane as a way to study what pre-industrial sleep habits may have looked like.

They found that contrary to popular myth, the hunter-gatherer societies didn’t go to bed right after the sun went down. They stayed awake an average of three and a half hours after it got dark, showing that it’s not just electric lighting that keeps us up into the night. They also slept less than seven hours a night, getting an average of six and a half hours of sleep per day, with no naps. They typically slept six hours during the summer, and seven in the winter.

And contrary to the idea that historically, people slept in two phases, waking up during the night for a while before going back to bed, the groups studied rarely woke up during the night. Instead, they slept until temperatures hit their lowest point in a 24-hour period, waking up around the same time each morning. 

"There's this expectation that we should all be sleeping eight or nine hours a night and that if you took away modern technology people would be sleeping more," lead author Gandhi Yetish explains in a press release. While these modern peoples could very well have different habits than prehistoric groups, the study does show that technology isn’t necessarily what’s keeping people from sleeping longer. The groups studied live near the equator, and it’s possible that when people migrated away from equatorial Africa and into northern regions like Europe, longer nights led to longer periods of sleep. 

But just because many hunter-gatherers don’t get a lot of shut-eye doesn’t mean you should follow their example. Our prehistoric ancestors likely had more to keep them up at night than the average person in a modern industrialized nation does—like getting eaten or starving. Sleep is super important for your health, your memory, and more. Without it, you’ll be not just groggy, but more likely to gain weight or even have a stroke. Embrace that undisturbed eight hours of rest as one of the best inventions of the industrial world.