Older adults who said they slept more than eight hours were 46% more likely to suffer strokes in the next decade than adults who slept for six to eight hours, according to an analysis published Wednesday in the journal Neurology. Even worse, the stroke risk for people who went from sleeping less than six hours to sleeping more than eight hours was nearly four times greater than for people who consistently got six to eight hours of ZZZZs. Researchers from the Department of Public Health and Primary Care at the University of Cambridge followed just under 10,000 people aged 42-81 years of age from the European Prospective Investigation into Cancer (EPIC)-Norfolk cohort over 9.5 years. Between 1998 and 2000, and again between 2002 and 2004, the study volunteers were asked how many hours they slept at night and whether they tended to sleep well. Among the 9,692 volunteers, 346 suffered at least one stroke during the years they were tracked (including 67 strokes that were fatal). After controlling for other factors that might affect stroke risk, they found that “long” sleepers (those who slept more than eight hours a night) were at significantly higher risk than “average” sleepers (those who slept for six to eight hours a night). People who slept less than six hours a day were at an 18% increased risk, but the small number of people falling in this category meant the association was not statistically significant. Previous studies have already suggested a possible association between sleep and risk of stroke, but today's study, published in the journal Neurology, is the first to provide detailed information about the British population and to examine the relationship between a change in sleep duration over time and subsequent stroke risk. People who sleep for more than eight hours a day have an increased risk of stroke, according to a study by the University of Cambridge - and this risk doubles for older people who persistently sleep longer than average. With further research, we may find that excessive sleep proves to be an early indicator of increased stroke risk, particularly among older people." In addition to studying the EPIC-Norfolk cohort, the researchers carried out a study of combined data from 11 other studies related to identify the association between sleep duration and patterns of stroke risk. Their final analysis, including 560,000 participants from seven countries, supported the findings from the EPIC-Norfolk cohort study. This risk was even greater for those whose reported sleep increased from short to long over the four years - their risk was close to four times that of people who maintained an average sleep duration.
– Sleeping more than eight hours a night? That may be too much of a good thing, because you're more likely to suffer a stroke, according to a study out of the University of Cambridge. Researchers analyzed the sleep patterns of nearly 10,000 people ages 42 to 81 in the UK, and they report in the journal Neurology that based on nearly a decade of follow-up and 346 reported strokes, older adults who sleep more than eight hours a night are 46% more likely to suffer a stroke than adults who slept six to eight hours. That risk is actually four times greater when people went from sleeping for less than six hours at the beginning of the study to more than 8 as the years passed, per a Eureka Alert press release. The researchers adjusted for several factors, including age and sex, and their findings were strikingly consistent with what they found in a review of the combined data of 11 similar studies spanning 560,000 people in seven countries. But in terms of age and sex, the Los Angeles Times notes the following: The link between the risk and sleep length was a little stronger for women, and the increased stroke risk was only seen in those eight-plus-hours sleepers who were 63 or older. The researchers caution that it remains unclear whether longer sleep duration is a symptom or cause of stroke risk. Says one, "With further research, we may find that excessive sleep proves to be an early indicator of increased stroke risk." (Experts have just revealed how much sleep you should be averaging a night based on your age.)