Researchers at the American College of Cardiology in Chicago presented findings last weekend suggesting that sleeping less than six or more than eight hours a night doubles the risk cardiovascular complications. Specifically, less than 6 hours of sleep per night doubles the chances of stroke and heart attack, compared with those getting six to eight hours of sleep a night, and makes it 60 percent more likely for developing congestive heart failure. On the other hand, sleeping more than eight hours per night doubles the risk of having angina as those sleeping six to eight hours, and a leads to a 10 percent higher risk of having coronary artery disease.
For more on this study, read the American Medical Association news report.