Has modern life really reduced our sleep to less than our ancestors used to get?
In fact the sleep habits of ancient hunter-gatherer societies were little different to our own, a new study finds.
They probably slept 6.5 hours a night, didn’t take any naps or go to bed at sunset.
Dr Jerome Siegel, one of the study’s authors, said:
“The short sleep in these populations challenges the belief that sleep has been greatly reduced in the modern world.
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.”
To reach these conclusions researchers examined three traditional hunter-gatherer societies: the Hadza of Tanzania, the San of Namibia, and the Tsimane of Bolivia.
The scientists followed 94 people from these societies over 1,165 days.
Dr Siegel explained the results:
“Despite varying genetics, histories, and environments, we find that all three groups show a similar sleep organization, suggesting that they express core human sleep patterns, probably characteristic of pre-modern-era Homo sapiens.”
The hunter-gatherers slept on average between 5.7 and 7.1 hours per night.
These are similar — or even a little less — than the average sleep times reported by people in modern industrialised societies.
The hunter-gatherers also slept an extra hour in the winter.
One crucial difference was found, though.
Unlike those in modern societies, very few hunter-gatherer suffer from long-term insomnia.
They don’t even have a word for ‘insomnia’.
Dr Siegel thinks this might provide a clue to treating insomnia:
“Mimicking aspects of the natural environment experienced by these groups might be effective in treating certain modern sleep disorders, particularly insomnia, a disorder affecting more than 20 percent of the US population.”
Mr Gandhi Yetish the study’s first author, who spent 10 months with the Tsimane:
“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.
But now for the first time we’re showing that’s not true.”
The study was published in the journal Current Biology (Yetish et al., 2015).
→ Explore PsyBlog’s ebooks, all written by Dr Jeremy Dean:
Sleep image from Shutterstock