Humans evolved to get better sleep in less time

Insomniacs take heart: Humans sleep shorter and deeper than our closest animal relatives. According to a new study, the secret is that our sleep is more efficient.

Humans spend less time in light stages of sleep and more time in deeper stages of sleep. For example, Rem stage is about 25% of our sleep, whereas in other primates is only about the 5%.

But why have we developed the ability of sleeping less and better? One of the proposals is that sleeping in the ground, reduces dangerous situations compared to sleeping in trees as our ancestors may have done. In early humans sleeping in the ground and sleeping near fire are linked, and that reduced the predators causing dangerous situations and leting early humans sleep deeper. Of course it has nothing to do with our nowadays confortable beds, we are really lucky! But we have to be grateful to our ancestors, the ability of sleeping less hours allows us to invest more time in other activities.