9 Facts About Sleep That Will Surprise You

More sleep = more sex? From Arianna Huffington's new book, The Sleep Revolution, a scientific and personal exploration of sleep.

1. Not getting enough sleep very visibly shows on your skin.

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An experiment in the UK tested sleep deprivation's effects on women, analyzing and photographing their skin after they slept for eight hours, then again after sleeping six hours for five nights in a row. They found fine lines and wrinkles increased by 45%, blemishes increased by 13%, and redness increased by 8%.

2. Sleep deprivation increases appetite, with one study finding that sleep-restricted subjects ate an extra 559 calories per day on average.

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They also had lower levels of the "satiety hormone" (leptin), which lowers appetite. In comparison, people who got more sleep produced less of the "hunger hormone" (ghrelin), which increases appetite.

3. Getting more sleep can lead to more sex (for women, at least).

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According to a 2015 study from Kent State University. Researchers measured women's sleep and their level of sexual desire the next day, finding that every additional hour of sleep was correlated with a 14% rise in the likelihood of having some type of sexual activity with a partner.

4. 40% of all American adults are sleep deprived, getting less than the recommended minimum of seven hours of sleep per night.

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According to a recent Gallup poll.

5. Similar polls showed that 32-60% of people in the UK, more than a third of people in Germany, and two-thirds of those in Japan do not get sufficient sleep during the week.

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6. After being awake for 17-19 hours, you may experience cognitive impairment similar to having a blood alcohol level of .05%.

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According to an Australian study.

7. If you stay awake for a few more hours beyond that, your cognitive impairment increases to the equivalent of legal drunkenness — 0.1%.

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8. Car accidents caused by sleepiness have a fatality rate and injury severity level similar to those caused by alcohol.

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According to researchers at the University of Pennsylvania.

9. But the incidence of death from all causes increases by 15% when you sleep less than five hours a night.

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Arianna Huffington's The Sleep Revolution is in stores now. To learn more, click here.

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