A good night's sleep isn't just about hitting the ground running in the morning. If you get the seven to nine hours experts advise, you can expect these added benefits:

Fewer sniffles

People who get less than 7 hours per night are three times likelier to catch colds, according to a Journal of the American Medical Association study. Reason: Sleep boosts immunity; too little impairs it.

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A trimmer waistline

People who logged seven to nine hours a night had an average BMI of 24.8—almost 2 points lower than the average BMI of those who slept less, University of Washington researchers found. Too-little sleep may throw off hormones that regulate appetite.

Lower risk of heart disease and diabetes

Lack of sleep is associated with higher levels of stress hormones that may raise blood pressure and affect glucose metabolism. A new study found that the risk for high blood pressure among insomniacs who slept less than five hours per night was 500 times greater than those who logged more than six hours. And insomniacs who slept less than five hours were three times likelier to have diabetes, compared with those without insomnia who slept more than six hours.

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