It’s common knowledge that as we get older we tend to sleep less or suffer from frequent sleep disruptions. However, researchers documenting the Hadza tribe in Northern Tanzania have come to the conclusion that restless sleep might be in fact an evolutionary survival tool. The survival mechanism evolved as the ancient hunter-gatherer tribes stood on guard against nocturnal threats.
Restless Sleep as Part of An Evolutionary Survival Tool
Researchers from the Duke University and the University of Nevada, USA teamed up with researchers from Tanzania to track the sleep patterns of the Hadza people. The Hadza are a modern-day tribe that lives in similar conditions to the ancient hunter-gatherers.
The researchers were able to gather data by strapping watches on their wrists that monitored their night-time movements. What they noticed is that there is a frequent change in the sleeping patterns between the old and the young so that at least one member of the tribe is awake. From the 20 days of study, the tribe was collectively asleep only for 18 minutes.
Researcher David Samson from the Duke University noticed that despite the restless sleep, the members felt no negative emotion about insomnia or other sleep problems that are frequent in Western societies. Moreover, Westerners get a more secure sleep than the tribe. The members sleep on the ground, next to a hearth or in huts made of branches. They have no controlled climate or synthetic lights.
Charlie Nunn, co-author, and professor of evolutionary anthropology at Duke stated:
If you’re in a lighter stage of sleep you’d be more attuned to any kind of threat in the environment.
Sleep flexibility has been observed in other animals such as birds and mice. However, it is for the first time that humans exhibited such behavior. As a result, the data makes the researchers suggest that perhaps restless sleep is an evolutionary survival tool that had helped our ancestors protect their tribes from any nocturnal threats.
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