Insomnia has a protective function

The often interrupted sleep of older people could be a legacy of human history.

Bad sleep: An old man on the sofa.

Canadian anthropologists present in the Proceedings of the Royal Society B a theory that irregular sleep-rhythms of primitive peoples were protective of the group.

The researchers investigated the sleep behavior of the people of the Hadza in Tanzania. They still live like hunters and collectors 10,000 years ago in groups of 20 to 30 people. There is no organized night watch at the Hadza. But the sleep rhythms - especially the older ones - are asynchronous, so that at least one group member is always awake and can be alarmed if necessary.

The researchers suspect that sleep disorders in old age in modern humans could go back to this original protective function.