Your New #1 Stay-Healthy Mission: Get More Sleep

By Lauren Wiener

Think you don’t have time for eight hours of z’s a night? Here are seven reasons-including trimming your waistline and improving your skin-why you need to fit it in.

We’re a nation of busy women, so while we’re whittling down our to-do lists, sleep often gets the pink slip first. Surveys from the National Sleep Foundation in Washington, D.C., show that women snooze nearly 90 minutes less than the eight hours a night most experts consider a healthy standard. "As a 24-7 society we have this notion that sleep is a waste of time," says James Maas, Ph.D., professor of psychology at Cornell University and author of Power Sleep. In fact, we seem to admire and envy so-called short sleepers like Martha Stewart and Donald Trump, who claim to run their empires on just four hours a night. But when we cheat on sleep, we’re actually jeopardizing our health, making us likelier to catch colds-or develop diabetes. Still not convinced you need to hit the hay earlier? Let the evidence speak for itself.

1 Keep off those extra pounds

Scientists at the Columbia University Medical Center recently discovered that people who logged five hours of sleep a night were 60 percent more likely to be significantly overweight than those who managed to get seven to nine hours. One reason behind the bulge: Tired people eat more. "Sleep deprivation increases hunger by altering levels of leptin and gherelin, hormones that regulate appetite," explains study author James E. Gangwisch, Ph.D. Another theory, according to a new article in the journal Obesity Reviews, poses that the more hours you’re awake, the more you’ll eat. The author suggests that you can cut 6 percent of your daily calorie intake-that’s 120 calories from a 2,000-calorie diet-by sleeping eight hours a night instead of seven.

2 Muscle up your memory

"During sleep, your mind processes everything you’ve learned that day," says Jeffrey Ellenbogen, Ph.D., an associate neurologist at Harvard Medical School. So pulling an all-nighter to nail tomorrow’s presentation is not an effective strategy. "You’re better off reviewing what you can, then getting enough rest so the details can sink in." Recent studies show that different stages of sleep may improve various aspects of memory. In new research from the journal Nature, German scientists found that late stages of non-REM sleep (the non-dreaming phases that comprise most of our sleep) help us consolidate and recall the facts we’ve just acquired. And in another recent study, Canadian researchers discovered that an earlier stage of non-REM sleep increased significantly after people learned how-to tasks-like a new knitting stitch or cooking technique-just before going to bed. After noting that the participants completed the activities 20 percent faster the next morning, the researchers concluded that shut-eye helps keep our reflexes sharp