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Sleep deprivation takes a toll on your mind, body, and overall health in ways that may surprise you.

Research shows that chronic lack of sleep is linked to colds and flu, diabetes, heart disease, mental health, and even obesity. So it’s natural to ask: Does getting adequate sleep protect you from illness? The answer: It helps.

“Sleep is a quiescent period where the cells are doing a lot of repairing. Your hormones act differently when you’re asleep, and your immune system as well,” says Lisa Shives, MD, DABSM, founder of Northshore Sleep Medicine in Chicago. “If your immune system is out of whack, you can’t fight off illness -- and I would venture to say that you can’t repair your cells very well, either.”

Here are five key health problems that research shows are worsened by lack of sleep and may be improved by getting at least seven hours of sleep a night.

1. The Sleep Link to Colds and Flu

When you’re sleep deprived, you often feel “worn down” -- and that’s a clue that your body is vulnerable to infection. “Not getting enough sleep makes you more vulnerable to picking up illnesses and not being able to fight them off,” says Donna Arand, PhD, DABSM, clinical director of the Kettering Sleep Disorders Center in Dayton, Ohio. “What’s going on is your immune system is degraded.” The less sleep you get, the weaker your immune system is, leaving it less able to fight off colds, flu, and other infections.

Studies have even found that being sleep deprived can affect our response to vaccines. Since your immune response is suppressed, the body is slower in response to the vaccine to build up sufficient antibodies to fight off the disease.

2. The Sleep Link to Heart Disease

Former President Bill Clinton recently confessed that he thinks lack of sleep had a lot to do with his recent hospitalization to unblock a clogged artery. "I didn't sleep much for a month, that probably accelerated what was already going on," Clinton said. 

He’s probably right. “When you don’t get enough sleep, you have an inflammatory response in your cardiovascular system -- in the blood vessels and arteries -- and that’s not a good thing!” says Arand. “We see the same thing in hypertension. If that sleep deprivation continues long term, chronic inflammation has been linked to things like heart attack, stroke, and diabetes.”

3. The Sleep Link to Diabetes

The key underlying problem in type 2 diabetes is insulin resistance, where the body does not make proper use of this sugar-processing hormone. Guess what? When you’re sleep deprived, your body almost immediately develops conditions that resemble the insulin resistance of diabetes.

“In one study of young, healthy adult males, they decreased their sleep time to about four hours per night for six nights,” says Arand. “At the end of those six nights, every one of those healthy young men was showing impaired glucose tolerance, a precursor to developing diabetes.”

Another study found that people in their late 20s and early 30s who slept less than 6.5 hours per night had the insulin sensitivity of someone more than 60 years old.

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