HealthDay News — Physical inactivity is associated with an increased risk of incident stroke, results of a large cohort study indicate.
Low self-reported physical activity was associated with a 20% increased risk for stroke compared with moderate to vigorous intensity exercise, Michele N. McDonnell, PhD, from the University of South Australia in Adelaide, and colleagues reported in Stroke.
The excess risk associated with reduced physical activity levels decreased to 14% after the researchers adjusted for traditional stroke risk factors. “Any effect of physical activity is likely to be mediated through reducing traditional risk factors,” they wrote.
Previous studies suggest regular physical activity reduces stroke risk 25% to 30% compared with little to no exercise, and the effect may vary by sex. To better understand the association between exercise and stroke risk, McDonnell and colleagues compared the associations of self-reported physical activity with incident stroke among black and white participants in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study.
Analyses involved 30,239 participants aged 45 years or older without prior stroke, and consisted of follow-up every six months for stroke events. Moderate to vigorous intensity physical activity (enough to break a sweat) at baseline was classified by frequency as none (inactivity), one to three times per week and four or more times per week.Physical activity could include leisure, commuting and occupational activities.
During an average follow-up of 5.7 years, the researchers documented 918 incidents of stroke and transient ischemic attack. Overall, 33% of participants reported physical inactivity.
Exercising at moderate to vigorous intensity correlated with a 20% reduced risk of incident stroke. The correlation was not affected by adjustment for demographic and socioeconomic factors, but was partially attenuated by adjustment for traditional stroke risk factors, such as diabetes, hypertension, BMI, alcohol use and smoking (hazard ratio, 1.14; P=0.17).
Physical activity frequency did not correlate significantly with stroke risk by sex groups, although a trend toward increased risk was observed for men who reported zero to three episodes of physical activity per week versus four or more.