Humans don't actually need eight hours' sleep

Eight hours' sleep: it might be a goal for many people, but the majority of us rarely get more than seven hours.
We can all stop feeling bad about it, though, after new research suggested the idea of eight hours' sleep is actually a myth. In fact, our ancestors got by on about six and a half hours.

Researchers at the University of California, Los Angeles, studied the sleeping habits of tribes in Tanzania, Namibia and Bolivia to find out what kind of sleeping habits early humans would have had.
But although it had previously been assumed people used to go to bed at sunset, the researchers found the people they were studying stayed up for an average of three hours and 20 minutes after the sun went down.

And there was no evidence six and a half hours' sleep took a toll on people's health. In fact, the researchers pointed out that studies have found tribal people have lower levels of obesity, blood pressure and atherosclerosis (fatty deposits in the arteries) than those in industrialised societies.

While the findings suggested people in industrialised nations tend to have maintained the sleep habits we evolved for (rather than, as previously thought, being much worse sleepers than our forebears), they did confirm other conventional wisdom about what helps people sleep, such as keeping your bedroom cool, having a consistent wake-up time and getting light in the 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,” said Gandhi Yetish, a PhD candidate at the University of New Mexico who spent 10 months with the Tsimane tribe in Bolivia.

“But now for the first time we’re showing that’s not true.”

“Rather than saying modern culture has interfered with the natural sleep period, this is a case in which modern culture, with its electric light and temperature control, was able to restore the natural sleep period, which is a single period in traditional humans today and therefore likely in our evolutionary ancestors as well,” added Jerome Siegel, leader of the research team.