Too much sleep tied to higher stroke risk

Sleep is good for you, right?  Well, generally, yes, but new research suggests that people who regularly sleep more than eight hours a night may have a higher risk of suffering a stroke.

To conduct their study, a research team at the University of Cambridge in the U.K. analyzed data from 9,692 people with an average age of 62 who had never experienced a stroke. Over an  follow-up period averaging 9.5 years, the participants completed two questionnaires four years apart that gathered information on how many hours they slept each night. During the follow-up period, 346 of the study participants had a stroke.

In analyzing the data, the scientists found that compared with participants who slept six to eight hours a night, those who usually slept for more than eight hours were 46 percent more likely to have a stroke. They also found that people who increased their amount of sleep from six to eight hours each night to more than eight hours during the follow-up period were four times more likely to have a stroke, compared with those who kept their sleeping time to six to eight hours a night.

The researchers suggested that the association could be due to the fact that people may have slept longer because of declining health. But they also noted that an increase in sleep duration might reflect alterations in blood flow to the brain and thus could serve as an early warning sign that a person's stroke risk was increasing.

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