Researchers 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.
Upon 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. 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 used in this study, said Steven Hooker, Ph.D., the study’s lead author. This is also the first study to explore the association between CRF and risk of stroke in women.
Men in the top quartile 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, high blood pressure, diabetes and high cholesterol levels, he said. Among women, those in the higher CRF level had a 43 percent lower relative 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. One 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.
MEDICA.de; Source: American Heart Association