Ah, sleep. The ever-elusive natural health elixir that can squash a shockingly vast variety of our physical and mental ailments. Regularly getting a good night’s rest can boost your mood, sharpen your memory, and stave off anxiety, depression, and stress. It also helps you control your weight, increases your body’s immunity, and lowers your risk of heart disease, diabetes, stroke, and various types of cancers. We can go on if you want: Sleep also pumps up your libido, clears your skin, stimulates your creativity, and makes you less likely to get into car crashes, while not sleeping enough can literally make people not want to be around you and physically shrinks your brain.
But while the benefits are undisputed, the recommendations vary on just how many hours of sleep is the right amount. The oft-repeated standard is about eight hours of sleep, and the Centers for Disease Control and Prevention recommends “at least seven hours” a night (which just one in three adults actually gets, by the way). But the latest in a long line of studies on the subject has now found there actually may be an exact sweet spot for how long you should be snoozing each night to optimize one key factor: heart health. According to the new study, you need precisely six to eight hours of sleep to minimize cardiovascular risk. Any less could be bad for your heart—as could any more.
Researchers looked at how over a million adults’ sleep habits affected their likelihood of developing or dying from stroke or coronary artery disease in the next nine years. People who slept less than six hours a night had an 11 percent greater risk than those who slept six to eight hours, while people who slept more than eight hours had a surprising 33 percent greater risk. That means six to eight hours was the exact range needed to keep the heart as healthy as possible.
Perhaps surprisingly, too much rest was actually even more dangerous than too little. But that’s actually in keeping with other recent research that’s found oversleeping can have pretty awful effects on your long-term cardiovascular health: They found sleeping more than 10 hours a night could increase your risk of dying from heart disease by 49 percent and your risk of dying from a stroke by 56 percent. Clearly, you really can have too much of a good thing.
Now, this doesn’t mean you need to panic every time you miss your alarm in the morning. Occasionally oversleeping is nothing to sweat about. The point of all this research is simply that there probably is a perfect balance you should be aiming for.
“Having the odd short night or lie-in is unlikely to be detrimental to health, but evidence is accumulating that prolonged nightly sleep deprivation or excessive sleeping should be avoided,” Dr. Epameinondas Fountas, the heart study’s author, said in a news release. “The good news is that there are plenty of ways to get into the habit of getting six to eight hours a night—for example by going to bed and getting up at the same time every day.”