August 21, 2014
News Review From Harvard Medical School -- Exercise May Deter Heart Rhythm Problem
Exercise may help older women to avoid an abnormal heart rhythm, a new study suggests. The study focused on atrial fibrillation. In people with this irregular rhythm, the upper chambers of the heart quiver instead of contracting in a regular pattern. This can increase the risk of blood clots and stroke. The new study included more than 80,000 women. When the study began, the women were 50 to 79 years old. Researchers asked them how often they walked outside or exercised enough to sweat. Eleven years later, the most active women had a 10% lower rate of atrial fibrillation than those who walked less than 10 minutes a week. The most active women did exercise equal to 3 hours of brisk walking or 2 hours of slow cycling each week. The reduction in risk was similar for women who got more strenuous exercise -- about 2 hours of running a week. Among inactive women, those who were obese had a 44% higher risk of the disorder than those of normal weight. For obese women, being active cut the difference in risk to about 17%. The Journal of the American Heart Association published the study. HealthDay News wrote about it August 20.
By Robert H. Shmerling, M.D.
Harvard Medical School
What Is the Doctor's Reaction?
If you're a woman past the age of menopause, you can add a new benefit to the list of those bestowed by exercise. It appears that exercise may lower your risk of developing an abnormal heart rhythm.
That's the conclusion of a study just published in the Journal of the American Heart Association. Researchers first asked more than 81,000 women (average age: 63) about their level of physical activity. Then they determined how many women developed atrial fibrillation in the next 11 years.
Atrial fibrillation is an irregular heartbeat. Usually, the upper chambers of the heart (the atria) contract in a regular, coordinated way. With atrial fibrillation, they quiver randomly instead. Some people don't notice the abnormal heart rhythm. Others have palpitations, shortness of breath or other symptoms.
Atrial fibrillation increases the risk that blood clots will form inside the heart. A clot can travel to the brain or other parts of the body. A clot in the brain can cause a stroke.
The researchers found that:
- The most active women had the lowest rates of atrial fibrillation.
- Exercise equal to running 2 hours a week was linked with a 9% lower risk of atrial fibrillation, compared with those who got the least exercise.
- Exercise equal to brisk walking 3 hours a week was linked with a 10% lower risk of atrial fibrillation.
- Exercise equal to brisk walking 1 hour a week was linked with a 6% lower risk of atrial fibrillation.
- Atrial fibrillation was more common among obese women. But exercise reduced this tendency.
These findings are important because atrial fibrillation can be a dangerous condition. And previous research suggested that strenuous activity might actually increase the risk of atrial fibrillation.
Treatments are available to control the irregular rhythm and to prevent clots. But they don't always work, and side effects are common. That's why news that physical activity can reduce the risk of atrial fibrillation is important. And, of course, exercise has many other health benefits.
What Changes Can I Make Now?
The message of this study is clear: get moving. If you generally don't exercise, it's important to start slowly. Then gradually increase your activity levels. If you have heart disease or other medical problems or if you aren't sure whether you can exercise safely, talk to your doctor first.
To increase your physical activity:
- Find an activity or exercise program you like. You'll be more likely to stick with it.
- Make exercise a routine part of your day.
- Start slowly with low-impact aerobic exercises, such as walking or biking.
- Get an exercise partner. This will make it more enjoyable and harder to skip.
- Increase your "non-exercise" activity. For example, take the stairs instead of the elevator. Or choose the parking spot that's a bit farther away from where you are headed.
Know what health factors increase the risk of atrial fibrillation. These include:
- Rheumatic heart disease (rheumatic fever in the past that affected the heart and its valves)
- Heart and blood vessel disease (such as angina or past heart attack)
- High blood pressure
- Excessive alcohol intake
- An overactive thyroid gland
- Advanced age
- Lack of exercise (as suggested by this new study)
Changes you make could reduce your risk of atrial fibrillation. For example, you can exercise more or get treatment for high blood pressure.
What Can I Expect Looking to the Future?
I believe that the list of health benefits linked to exercise will continue to grow. Future research could show which types of exercise are best to protect against atrial fibrillation. This latest research only included women. I look forward to research that also looks at the relationship between exercise and atrial fibrillation among men.