"There is no way you can look great if you are sleep deprived," says Lorencin. And though Bank admits, "we don't fully understand sleep and the complex biochemical things that go on during it," he adds that whatever is going on is critical. When your body is fighting to say awake "muscle tone relaxes so you look saggy, blood pressure drops which robs skin of color and you're prone to puffiness due to poor circulation," he says. Yet more reasons to get the recommended seven to eight hours of sleep a night.