Evolution Allowed Humans To Get Better Sleep In Less Time

Humans don't actually get as much sleep as their closest animal relatives, according to a recent study.

Researchers found that while other primate species need anywhere from 14 to 17 hours a night, humans are much shorter sleepers, with most adults between the ages of 18-64 needing 7-9 hours of sleep per night, according to the National Sleep Foundation.

"Humans are unique in having shorter, higher quality sleep," said David Samson, co-author of the study, in a news release.

During the study, researchers created a database of sleeping patterns that included 21 species of primates. Then, they used statistical techniques to determine each species' position in the primate family tree.

The main difference for why we need shorter sleep periods than others is that, simply put, our sleep is more efficient. We spend a smaller portion sleeping in lighter stages-allowing for longer periods of deeper sleep that leave us more thoroughly rested in a shorter span of time. In fact, about 25 percent of our overall sleep is spent in rapid eye movement (REM) sleep-a deep stage of sleep. Other primates might only spend about five percent of their sleep in REM.

Researchers believe our shorter but longer periods in deep sleep may have something to do with our transition of sleeping in "tree beds" to sleeping on the ground. Once on the ground, our ancestors joined groups and starting making fires-helping them become better able to ward off predators, which likely enabled them to get the most of their sleep in the shortest time possible.

The study is published in the journal Evolutionary Anthropology.

Related Articles

Over 9 Hours Of Sleep A Night May Increase Risk of Early Mortality

Cell Growth, Brain Activity Zapped By Lack Of Sleep

For more great science stories and general news, please visit our sister site, Headlines and Global News (HNGN).