Doctors Orders

The Doctor Said "Go To Sleep"

Sleep is good for you. Your mom tried to convince you when you were growing up, and now that you’re grown up that luxury sleep may elude us. So what happens when age-old culprits like insomnia or sleep apnea—or newer ones like a jam-packed schedule—and overstimulation cause you to toss and turn? That’s right, they may affect your health—particularly your heart and your waistline.

Research is pretty clear on this point: sleep is crucial for good health. It helps memory and mood, keeps you trim, strengthens your immune system, fights inflammation, and keeps your heart and blood vessels in tip-top shape. We can all tell when that co-worker or boss had been skimping on sleep. 

"When you're sleeping you're regulating hormone levels, you're regulating insulin levels, your blood pressure is being kept under control, there are a lot of things going on, and if you're not getting enough sleep you're throwing these things out of whack," says Shelby Freedman Harris, PsyD, director of behavioral sleep medicine at Montefiore Medical Centers Sleep-Wake Disorders Center in New York City.

While you're snoozing, the body repairs damaged tissue, produces crucial hormones, and strengthens memories—a process called consolidation, which helps you perform a new skill better after sleeping than you would if you spent an equivalent amount of time awake. (Take that, all-nighters!)

Is lack of sleep making you fat?

Sleep deprivation reduces sensitivity to insulin, the key blood-sugar-regulating hormone, while making it harder metabolize blood sugar properly. Lack of sleep also boosts levels of hormones that make us hungry, while reducing secretion of the hormones that help us feel full. 

When people are sleep deprived and eat a cookie, their blood sugar goes higher and they're more resistant to the effect of insulin than if they ate the same cookie after a good nights sleep, says Dr. Czeisler. "If youre on a diet to lose weight and you're sleeping five to six hours a night, 75% of the weight you lose will be lean body mass."

That means just 25% of the weight you're losing is fat, he added; when people sleep enough, fat accounts for 50% of weight lost.