by CHRIS SAMORAY
REST UP Hunter-gatherers, like the Hadza shown here, sleep about as much as people in postindustrial societies do — and maybe even a little less.
People in preindustrial societies may have less insomnia but no more shut-eye, study finds
People in the postindustrial world don’t always get a sound night sleep. But they appear to spend a similar amount of time sleeping as do people in hunter-gatherer communities in Africa and South America, a new study finds.
“It’s absolutely clear that they don’t sleep more than we do,” says Jerome Siegel, a UCLA sleep scientist.
In fact, on average, hunter-gatherers may sleep a little less.
Recommended nightly sleep for adults is typically seven to nine hours; a 2013 Gallup poll showed that most Americans get around 6.8 hours. On most nights, members of three hunter-gatherer groups — the Hadza of Tanzania, the Ju/’hoansi San of Namibia and the Tsimane of Bolivia — sleep 5.7 to 7.1 hours, Siegel and colleagues report online October 15 in Current Biology. That’s on the lower end of the sleep spectrum in postindustrial societies, the researchers say.
Evidence from the new study also suggests that these groups experience less insomnia than sleepers in postindustrial societies. (The three hunter-gatherer languages even lack a word for insomnia.)
The researchers gathered 1,000 days’ worth of data from 94 hunter-gatherers who wore watches that collected sleep data. Typically, people fell asleep several hours after sunset, and rose an hour before dawn. In interviews after the study, only 1.5 to 2.5 percent of participants reported having an insomnia problem more than once a year. That’s compared with chronic insomnia rates of 10 to 30 percent in industrial societies, the researchers note.
These groups are isolated, without the shine of streetlights or the glow of computer screens that many people blame for sleeping problems. But Siegel and other sleep researchers say that faulting modern technology might be misguided. That’s because most sleep studies take place under controlled environments in the laboratory and often fail to involve more than one group or population.
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