Current News Releases
Feb. 21, 2008
Public health researchers: Fitness is vital in preventing strokes
A moderate level of aerobic fitness significantly reduces the stroke risk for men and women, according to a University of South Carolina study being presented Feb. 21 at the American Stroke Association's International Conference in New Orleans.
"Fitness has a protective effect regardless of the presence or absence of other stroke risk factors, including family history of cardiovascular disease, diabetes, high blood pressure, elevated cholesterol levels and high body-mass index," said Dr. Steven Hooker, director of the Prevention Research Center at the university's Arnold School of Public Health and the study's lead author.
The study is the first to suggest that a significant, independent association may exist between cardiorespiratory fitness (CRF) and fatal and nonfatal stroke in men and nonfatal stroke in women. It also is the first to explore the association between CRF and stroke risk in women, who are more likely than men to die from stroke, he said.
Researchers analyzed data from more than 60,000 people (46,405 men and 15,282 women) who participated in the Aerobics Center Longitudinal Study between 1970 and 2001 at the Cooper Aerobics Center in Dallas. The participants, ages 18 - 100 and free of known cardiovascular disease when they entered the study, were followed for an average of 18 years. During that time, 863 people (692 men, 171 women) had strokes.
At the beginning of the study, each participant walked on a treadmill at an increasing grade and/or speed until they reached exhaustion. This determined the CRF level.
Although many previous studies have looked at an association between self-reported physical activities and cardiovascular disease, few have used direct measurements such as the CRF measure, Hooker said.
"This measurement gives us more in-depth information about the link between physical activity and strokes and adds to the growing body of scientific information about the health benefits of fitness," he said.
And that's good news for Americans. The American Stroke Association reports that approximately 780,000 U.S. adults will have a stroke each year. Strokes are the No. 3 cause of death and a leading cause of serious, long-term disability in the United States. About 150,000 people die from strokes.
"The study is particularly relevant for South Carolina, which is in the middle of the nation's stroke belt and has one of the nation's highest stroke rates," Hooker said.
Among the study's findings:
- Men in the top 25 percent of CRF level had a 40 percent lower risk of stroke compared with men in the lowest 25 percent.
- Among women, those in the higher CRF level had a 43 percent lower risk than those in the lowest fitness level.
- The overall stroke risk dropped substantially at the moderate CRF level, with the protective effect persisting nearly unchanged through higher fitness levels. That corresponds to 30 minutes or more of brisk walking, or an equivalent aerobic activity, five days a week.
"We found that a low-to-moderate amount of aerobic fitness for men and women throughout their adult years would be enough to substantially reduce stroke risk," Hooker said. "Although stroke death rates have declined, the public-health burden of stroke-related disabilities is large and may even increase as the nation's population ages."
