Exercise Reduces Stroke Risk

NEW YORK (Reuters Health) - Staying active during leisure activities appears to reduce the risk of all types of stroke, while walking or biking to work may protect people from the most common type of stroke, according to new study findings released Thursday.

A group of researchers based in Finland found that people who were physically active for at least 4 hours per week in activities such as walking or gardening -- defined as moderate exercisers -- were 14 percent less likely to experience a stroke over a nearly 20-year period. Engaging in at least 3 hours of vigorous exercise such as running or swimming reduced the risk of stroke by 26 percent.

These findings suggest that, when it comes to exercise, "more is better, to a reasonable extent," study author Dr. Gang Hu of the National Public Health Institute in Helsinki, Finland, told Reuters Health.

In the journal Stroke, Hu and colleagues note that a large body of research suggests that exercise protects people from cardiovascular disease. What activity does to the risk of stroke, however, remains less clear, they note.

To investigate whether different types of activity have different effects on stroke risk, the researchers followed 47,721 Finnish adults for an average of 19 years, noting their activity levels and who experienced a stroke. They found that the more active people were in their free time, the less likely they were to experience any type of stroke.

People who were moderately active in their free time were 13 percent less likely than relatively inactive adults to experience ischemic stroke, the most common type, in which a clot or narrowed artery cuts off blood flow in the brain.

Moderate exercisers were also13 and 23 percent less at risk of subarachnoid hemorrhage and intracerebral hemorrhage, respectively, two less common forms of stroke.

Frequent leisure-time exercisers, however, had a 20 percent lower risk of ischemic stroke, and a 54 and 37 percent lower risk of subarachnoid and intracerebral hemorrhages, respectively.

And people who mixed things up by engaging in two or three types of exercise were slightly less likely to experience stroke than people who stuck with only one type of activity.

Active commuters were 14 percent less likely to experience ischemic stroke during the study period, but showed no lower risk of the other stroke types.

Hu explained that exercise may help prevent stroke by reducing risk factors for stroke, including high blood pressure, diabetes, and obesity.

"Data from our and other observational studies suggest that the clinical and public health message regarding exercise for the prevention of stroke should remain 30 minutes per day of moderate-intensity activity, such as walking, cycling, light gardening, fishing, etc.," Hu noted.

SOURCE: Stroke, September 2005.