News Release

Working Out The Risk For Stroke

Peer-Reviewed Publication

American Heart Association

DALLAS, Nov. 10 --- Physical activity not only reduces the likelihood of heart disease but also may decrease the risk of strokes, researchers reported today at the American Heart Association's 71st Scientific Sessions.

Lead author, Kelly R. Evenson, Ph.D., a post-doctoral fellow in epidemiology at the University of North Carolina, Chapel Hill, and her colleagues investigated 15,371 individuals 45 to 64 years old who had not had a stroke and were included in the Atherosclerosis Risk in Communities (ARIC) study.

"Individuals who were more active at work had a 49 percent lower risk of stroke than those who were more sedentary. For people with the highest levels of sports activity there was a 23 percent reduced risk, and those with very active leisure time had an 11 percent reduced risk of stroke," she says.

Researchers examined the relationship between physical activity and the risk of ischemic stroke, the most common type of stroke, which results from a clot or fatty plaque deposits in the blood vessel cutting off blood flow to the brain. Though other studies have investigated the link between physical activity and stroke risk, Evenson says it is an area of research in need of more examination. Physical activity was measured by rating participants' answers to questions about their involvement in sports, leisure and work activities. Individuals were asked how their level of activity during certain activities compared to that of other people in their age group, and whether they worked or played hard enough to break a sweat.

In grading each person's level of sports activity, researchers asked whether participants were involved in sports and if so, to list the activities. Walking was most often listed as a sport activity.

To gauge the amount of leisure activity, researchers asked participants how often they walked or rode a bicycle and how much time they spent watching television in their spare time.

Questions regarding work activity included type of occupation and the amount of time spent sitting, standing, walking or lifting heavy loads. Participants were also asked if they were tired when they came home from work. Participants were ranked for their activities in all three areas on a one-to-five scale with one being the lowest level of activity. When the researchers considered such risk factors as high blood pressure, diabetes, blood levels of fibrinogen (a protein involved in blood clotting) and body mass index (an indicator of body fat), the differences in stroke risk between active and non-active people were reduced.

"It could be that physical activity is effective in modifying these risk factors," says Evenson. "For example, people who are physically active may reduce their blood pressure and body fat and, in turn reduce their risk of stroke. "While physical inactivity is considered a risk for coronary heart disease," she says, "there is inconclusive data that says a lack of physical activity increases a person's risk of stroke."

The American Heart Association recommends that people participate in 30 minutes of moderate physical activity most days of the week. Evenson says people should be more physically active. "Certainly, physical activity is beneficial for other reasons besides stroke."

Co-authors include Wayne D. Rosamond, Ph.D.; Jianwen Cai, Ph.D.; James F. Toole, M.D.; Richard G. Hutchinson, M.D.; Eyal Shahar, M.D.; and Aaron R. Folsom, M.D.

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For more information Nov. 8-11, contact Brian Henry or Bruce Lewis at Dallas County Convention Center: (214) 853-8056.

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