Regular exercise reduces the chances of stroke among men and women older than 45, a new study shows.

Investigators from the University of Alabama at Birmingham looked at data from a large longitudinal study of American men and women ages 45 and older. Among 27,000 black and white study participants in the Reasons for Geographic and Racial Differences in Stroke cohort, those with lower levels of physical activity were 20 percent more likely to suffer stroke.

In the analysis, researchers placed study subjects into three categories, including those who exercised vigorously at more than four times per week, those who exercised moderately at one to three times per week, and those who were mostly sedentary.

After 5.7 years, those who were least active had a 20 percent higher chance of suffering stroke, while those who exercised most were less likely than others to experience stroke or stroke-related illness.

The researchers said the findings applied more to men than women, although there's room for debate.

"There has been some research to suggest that women perhaps benefit from less intense exercise, like walking, but seeing as we didn't ask this question in our study we really can't speculate any more than that," Michelle McDonnell, lead investigator, told reporters.

The long-term study bolsters findings from previous work showing that exercise reduces risk of stroke by improving the health of blood vessels while lowering such risk factors as hypertension and obesity.

Virginia Howard, a senior researchers on the project, emphasized the influence of exercise on high blood pressure and diabetes, which are typical risk factors for stroke.

"These findings confirm past results of studies done in only men or only women in limited geographical areas," Howard said. "By using [this] cohort, our study was able to use a larger and more diverse population to show that participating in regular physical activity is associated with lower stroke risk."

Interestingly, researchers reported that exactly one-third of the study population reported little to no levels of exercise.

Source: McDonnell, Michelle N., Hillier, Susan L., Judd, Suzanne E., Howard, Virginia J. Physical Activity Frequency And Ris Of Incident Stroke In A National U.S. Study Of Blacks And Whites. Stroke. 2013.