Losing out on sleep may increase the risk of having a stroke. This news comes from a study at the University of Alabama at Birmingham’s School of Medicine where researchers found a fourfold risk of stroke among normal-weight people who sleep fewer than six hours a night. None of the study participants suffered from sleep apnea, a disorder that is known to increase the risk of stroke among overweight people. Researchers gathered data on more than 5,600 people who were part of a larger study of racial and geographical differences in stroke. The lead researcher noted that lack of sleep can increase inflammation and cause increases in blood pressure and the release of certain hormones, and speculated that these factors may combine to boost the risk for stroke. The study was presented at the annual meeting of the Associated Professional Sleep Societies. Curiously, the study didn’t find any additional increased risk of stroke in overweight and obese people who slept six hours or less. Until further studies can examine this analysis of data, the increased risk seen in normal weight people can only be viewed as an association, not cause and effect.