Exercise May Guard Against Irregular Heartbeat
This study involved more than 80,000 participants with the Women's Health Initiative, an observational health study involving women aged 50 to 79. Observational studies can only show if there is an association between factors and cannot prove cause-and-effect relationships.
At the start of the study, researchers asked the women how often they walked outside for more than 10 minutes daily or how often they engaged in physical activity hard enough to sweat.
After 11 years, the researchers found that the most physically active women had a 10 percent lower risk of developing atrial fibrillation compared to those who didn't walk outside for 10 minutes at least once each week.
The women with the highest protection took part in physical activity equivalent to walking briskly for 30 minutes six days a week, or bicycling at a leisurely pace for an hour twice a week, researchers said.
Moderately physically active women had at least a 6 percent lower risk of developing atrial fibrillation. Walking briskly for 30 minutes twice a week would provide this benefit, the study authors said.
Strenuous exercise also reduced risk of atrial fibrillation. Women who undertook activity equivalent to running a couple of hours a week had a 9 percent lower risk, the study found.
Obesity still was linked to an overall increased risk of atrial fibrillation, but the investigators found that obese women who exercised a lot cut their risk in half.
Active obese women had a 17 percent increased risk of the disorder, compared to a 44 percent increased risk for obese women who took part in little to no physical activity, the study found.
Physical activity likely decreases risk of the heart rhythm disorder by lowering blood pressure and reducing inflammation in the body, Tomaselli and Perez said.
Exercise also might help limit physical changes that occur in the heart as a result of aging or obesity, which in turn increase the risk of atrial fibrillation and heart disease, Perez said.
If obese women start losing weight as a result of their exercise, the benefits likely will be even greater, Tomaselli said.