Not getting enough shut-eye might increase your risk of developing or dying from heart disease or stroke, according to a new review of studies.

Sleeping less than six hours a night increased the risk of developing or dying from heart disease by 48 percent, and the risk of developing or dying from stroke by 15 percent, said study researcher Dr. Francesco P. Cappuccio, of the University of Warwick Medical School in England.

Too little sleep could contribute to coronary heart disease and stroke by increasing "blood pressure and cholesterol, induction of obesity and Type 2 diabetes and activation of low-grade inflammation," Cappuccio told MyHealthNewsDaily.

Cappuccio and his colleagues looked at data from 15 past studies that included 474,684 participants followed for between seven and 25 years. They identified a total of 4,169 cases of coronary heart disease, 3,478 cases of stroke and 8,420 cases of heart disease.

The people in the studies were asked how many hours of sleep they got in the past week. Those who reported getting six or fewer hours of sleep a night had a greater risk of heart disease or stroke than those who had seven or eight hours of sleep a night, the study said.

People who slept nine or more hours a night also faced an increased risk of heart disease, the study said. Their risk was 41 percent higher than those who slept seven or eight hours.

Researchers couldn't quantify how many consecutive nights of too little or too much sleep were needed to have the adverse health effects, because the people in the study reported their own sleep habits, Cappuccio said.

The findings only apply to adults, Cappuccio said. In general, children should get about 10 or 11 hours of sleep a night, teens ages 10 to 17 should get 8.5 to 9.25 hours and adults should get seven to nine hours , according to the National Sleep Foundation.

Past studies also suggest sleep duration is linked with health. A 2003 article in the journal Diabetes Care showed that sleeping for five or fewer hours a night is linked with the development of diabetes.

A number of studies, including a 2008 study in the journal Sleep by Cappuccio, found that children who got a short night's sleep were more likely to be obese than kids who slept 10 or more hours a night. And a 2008 study in the American Journal of Clinical Nutrition showed that elderly women who slept fewer than five hours a night or more than eight or nine hours a night were more likely to be obese than those who sleep six or seven hours a night.

The new study was published today (Feb. 8) in the European Heart Journal.

Pass it on: Sleeping six or fewer hours a night is associated with an increased risk of developing or dying from coronary heart disease or stroke.

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