Modern life’s sleep troubles – the chronic bleary-eyed state that many of us live in – have long been blamed on our industrial society. The city lights, long work hours, commutes, caffeine, the Internet. Sleep researchers have had a tendency to harken back to a simpler time when humans were able to fully recharge by sleeping and waking to the rhythms of the sun.

It turns out that may not be quite right. In fact, it now appears that our ancestors may not have been getting the doctor-recommended 8 hours of sleep either.

In a study published in Current Biology this week, researchers traveled to remote corners of the planet to scrutinize the sleep patterns of some of the world’s last remaining hunter-gatherers – the Hadza of Tanzania, the San of Namibia, and the Tsimane of Bolivia. Cut off from electricity, media and other distractions, these pre-industrial societies are thought to experience the same sort of natural sleep ancient humans enjoyed more than 10,000 years ago.

Located in a woodland-savannah habitat 2 degrees south of the equator, the Hazda gather their wild foods each day.

What they found was a striking uniformity in their sleep patterns despite their geographic isolation. On average, people in the tribes sleep a little less than 6.5 hours a night, do not take naps and don’t go to sleep when it gets dark.

Jerome Siegel, director of the University of California at Los Angeles’s Center for Sleep Research, and his colleagues explained that this suggests that sleep may not be environmental or cultural, but “central to the physiology of humans” living in the tropical latitudes where our species evolved.

“The short sleep in these populations challenges the belief that sleep has been greatly reduced in the ‘modern world,'” Siegel said. “This has important implications for the idea that we need to take sleeping pills because sleep has been reduced from its ‘natural level’ by the widespread use of electricity, TV, the Internet, and so on.”