Six Hours of Sleep Not Enough—for Nearly All

Think you can get by just fine on 6 hours of sleep a night? Unless you're part of a tiny portion of the population with a mutant gene, you better tuck yourself in a little earlier, reports USA Today. A new study in Science says 97% of the population needs about 8 hours a night to function at top form. The rest—and their numbers are ever dwindling—have a genetic mutation that blesses them with deep sleep and the need for less of it. (More sleep stories.)