"We found the more physically active the women were, the less likely it was that they would develop atrial fibrillation," says Dr. Perez.
According to the American Heart Association (AHA), when the heart does not beat properly, it is unable to pump blood effectively, which means the lungs, brain and other organs cannot work properly, potentially even shutting down completely.
Furthermore, when the heart's ability to work properly is diminished for long periods of time, life-threatening situations could arise. For example, blood clots can form in the heart's upper chambers, which can flow into the bloodstream and lodge in a narrowed artery resulting in a stroke.
But the researchers from this latest study, led by Dr. Marco V. Perez at the Inherited Arrhythmia Clinic at the Stanford University School of Medicine, found that post-menopausal women who are the most physically active had a 10% lower risk of developing AF, compared with women with low levels of physical activity - even if they were obese.
All women were enrolled in the Women's Health Initiative.
Most physically active women had 10% lower risk of AF
At the beginning of the study, the team asked over 81,000 post-menopausal women between the ages of 50-79 how often they walked outside for more than 10 minutes each day or how often they exercised enough to sweat.
As an indicator of exercise, the researchers used MET hours, which is a measurement of how much energy is used during exercise. For example, 9 MET hours are the equivalent of walking briskly for 30 minutes a day, 6 days a week, or cycling leisurely for 1 hour, twice a week.
After the 11-year time period during which the study took place, the researchers found that the most physically active women - those who exercised the equivalent of 9 MET hours or more each week - had a 10% lower risk of developing AF, compared with those who did not walk outside for at least 10 minutes once each week.
Additionally, women who were moderately active - those who exercised around 3 MET hours per week - experienced a 6% lower risk of developing AF. The researchers explain that walking briskly for 30 minutes, twice a week would meet this requirement.
Commenting on their findings, Dr. Perez says:
"We found the more physically active the women were, the less likely it was that they would develop atrial fibrillation. Also, the more obese the women were, the more they benefited from having greater degrees of physical activity."
Though he notes that previous research suggested strenuous exercise might increase the risk for AF, he adds that "there shouldn't be concerns about these degrees of exercise and AF in older women."
Medical News Today recently reported on a study that suggested exercising to excess increases risk of death for heart attack survivors.