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IntroductionNo one knows exactly why we sleep, but researchers continue to uncover important discoveries about the mysterious phenomenon, including some that seem counterintuitive. Here are five surprising findings about human sleep:
Interrupted sleep is worse than staying awakeSlide 2 of 11
Interrupted sleep is worse than staying awake
Not getting enough sleep may make you grouchy, but you could feel even worse if your sleep is frequently interrupted, compared to if you simply go to bed late, a recent study suggests. Researchers found that people who experience frequent interruptions during their sleep were less happy and less energetic the next day than people who went to bed late but were able to sleep continuously for a few hours.
This may be because people whose sleep is frequently interpreted spend less time in deep sleep — a restorative phase of sleep — than people who go to bed late, the researchers said.Slide 3 of 11
Modern life isn't actually stealing our sleepSlide 4 of 11
Modern life isn't actually stealing our sleep
The technologies of the past century, from light at night to electronic gadgets, are often blamed for keeping people awake long past the time they should have hit the sack. But a 2015 study suggests that modern humans don't get less sleep than their prehistoric ancestors — in fact, we may get more.
In the study, researchers looked at the sleep habits of people living in contemporary hunter-gatherer societies in parts of Africa and South America, as a proxy for our prehistoric ancestors. They found that people in these societies sleep less than 6.5 hours a night — less than the average American, who gets between 7 and 8 hours of sleep, according to the National Sleep Foundation.
"We find that contrary to much conventional wisdom, it is very likely that we do not sleep less than our distant ancestors," study author Jerome Siegel, a researchers at the University of California, Los Angeles, told Live Science in a 2015 interview.Slide 5 of 11
We sometimes sleep with half our brain more alertSlide 6 of 11
We sometimes sleep with half our brain more alert
It's known that marine animals such as dolphins sleep by shutting down just one half of their brain at a time. But a recent study found evidence of a similar, albeit less drastic, phenomenon in people. People participating in a study on sleep, on the first night that they slept in the lab, showed more activity in the left hemisphere of their brains during deep sleep than in the right hemisphere.
Having one hemisphere remain more "vigilant" during sleep than the other may be a survival strategy when humans are in a new environment — the left hemisphere may serve as a "night watch" that wakes the sleeper up if there's danger, the researchers said.Slide 7 of 11
Snowy days keep us in bed a little longerSlide 8 of 11