In a perfect world, you'd hit the pillow, close your eyes, and doze off into an eight-hour stretch of rejuvenating, uninterrupted slumber every night. In reality, according to a recent study by the Centers for Disease Control, just one in three Americans feels like she gets enough sleep, and 50 million to 70 million suffer from chronic sleep disorders, such as sleep apnea (see “What is Sleep Apnea?” below) and restless legs syndrome (an irresistible urge to move the legs, which jolts people awake). About 30 percent of us have occasional insomnia, meaning we have trouble falling or staying asleep. And as a nation we annually fill more than 53 million prescriptions for sleep aids.

The impact tossing and turning has on your overall health is profound, new research shows. For one thing, a lack of sleep may contribute to weight issues. It boosts levels of the hormone ghrelin, a hunger trigger, and decreases levels of the hormone leptin, which signals fullness; you end up hungrier, crave calorie-dense foods, and don't feel full as quickly. Sleep deprivation also boosts levels of the stress hormone cortisol, which can drive up blood pressure and strain the heart. In fact, studies on sleep deprivation have found a higher risk of death from cardiovascular causes in people who sleep less. All the more reason to safeguard your Z's. And that doesn't just mean turning off Leno and going to bed at a reasonable hour, say experts. “Almost everything you do during the day affects the way you sleep,” says Michael Breus, PhD, author of Beauty Sleep (Plume, 2008).