Moderate Level Of Aerobic Fitness May Lower Stroke Risk
moderate level of aerobic fitness can significantly reduce stroke risk
for men and women, according to a large, long-running study of more
than 60,000 people.
780,000 U.S. adults suffer a stroke each year, and stroke is a leading
cause of serious, long-term disability in the United States, according
to the American Stroke Association. Stroke is often fatal, claiming
about 150,000 lives and ranking as the No. 3 cause of death.
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 Steven Hooker, Ph.D., the study’s
study is the first to suggest that there may be a significant
independent association between cardiorespiratory fitness (CRF) and
fatal and nonfatal stroke in men and nonfatal stroke in women," said
Hooker, director of the Prevention Research Center at the University of
South Carolina Arnold School of Public Health, Columbia, S.C.
analyzed data on 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 to 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 and 171 women
— had strokes.
entering the study, each participant took a test to measure CRF in
which they walked on a treadmill at increasing grade and/or speed until
they reached their maximal aerobic capacity.
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 used in this study,
Hooker said. This is also the first study to explore the association
between CRF and risk of stroke in women.
in the top quartile (25 percent) of CRF level had a 40 percent lower
relative risk of stroke compared to men in the lowest quartile. That
inverse relationship remained after adjusting for other factors such as
smoking, alcohol intake, family history of cardiovascular disease, body
mass index (an estimation of body fatness), high blood pressure,
diabetes and high cholesterol levels, he said.
women, those in the higher CRF level had a 43 percent lower relative
risk than those in the lowest fitness level.
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.
found that a low-to-moderate amount of aerobic fitness for men and
women across the whole adult age spectrum would be enough to
substantially reduce stroke risk," Hooker said.
stroke death rates have declined over the past few decades, the public
health burden of stroke-related disabilities continues to be large and
may even increase in coming years, as the population ages."
activity is a major modifiable cardiovascular disease risk factor.
Increasing the nation’s CRF through regular physical activity
could be a vital weapon to lower the incidence of stroke in men and
women, he said.
of the study’s limitations is that most of the participants
were white, well-educated and middle-upper income, he said. He
recommended that data be collected from other populations.
include Xuemei Sui, M.D.; Natalie Colabianchi, Ph.D.; John Vena, Ph.D.;
James Laditka, Ph.D.; Michael J. LaMonte, Ph.D.; and Steven N. Blair,
study, presented at the American Stroke Association’s
International Stroke Conference 2008, was supported by National
Institutes of Health grants and the Communities Foundation of Texas.
The American Heart Association/American Stroke Association has a
national movement, Start!, that encourages all
Americans to incorporate regular physical activity into their
lives. The hub of the Start! movement is MyStart! Online, a free, Web-based
fitness and nutrition tracker that offers constant,
measurable, personal improvement. Visit it at: heart.org/start.
more information on the American Stroke Association, visit www.strokeassociation.org.