Hunter gatherers with no access to technology still only sleep 6.5 hours a night
The new study, published in the Cell Press journal Current Biology, shows that three ancient groups of hunter-gatherers living in different parts of the world without any of those trappings of modern life don't get any more sleep than we do.'The short sleep in these populations challenges the belief that sleep has been greatly reduced in the 'modern world,'' said Jerome Siegel of the University of California, Los Angeles. '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 get a handle on how people slept before the modern era, Siegel and his colleagues looked to three traditional human hunter-gatherer societies: the Hadza of Tanzania, the San of Namibia, and the Tsimane of Bolivia. What they found was a surprising similarity across those three groups. '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,' Siegel says.
Group sleep time averaged between 5.7 and 7.1 hours. Those amounts are at the low end of durations reported in 'industrial societies.' Although they lack electric lights, none of the groups went to sleep with the sun. On average, they stayed up a little over three hours after the sun went down and woke up before sunrise. It appears that their sleep time may have more to do with temperature than with light.
http://www.dailymail.co.uk/sciencetech/article-3275149/Don-t-blame-Internet-lack-sleep-Researchers-say-hunter-gatherers-no-access-technology-sleep-6-5-hours-night.html