You know that yoga is relaxing—but did you know that a certain type of yoga may alleviate the dangerous heart condition atrial fibrillation? Here’s the story…

Background: Atrial fibrillation (AF) is the most common form of cardiac arrhythmia. An electrical malfunction causes episodes in which the heart starts beating too slowly, too quickly or irregularly. Sometimes patients feel an uncomfortable fluttering or thumping in the chest, faintness, dizziness and/or shortness of breath…sometimes there are no symptoms. AF increases stroke risk because blood left in the heart’s upper chambers during abnormal contractions can form a clot that could break off and travel to the brain. Medicines such as beta-blockers help control heart rate and rhythm, but they don’t work for everyone and they can have troubling side effects.

New study: Yoga has been shown to have beneficial effects on cardiovascular health, but no one had previously studied its effects on AF—so researchers decided to do just that. Participants included 49 adults with paroxysmal AF (recurrent episodes that end by themselves) who had not practiced yoga during the previous six months. At the start of the study, they all completed questionnaires that assessed their quality of life and levels of depression and anxiety. All were taking AF medication, which they stayed on throughout the study.

Next came a three-month observation period. Whenever a participant felt AF symptoms, he or she reported the symptoms and also used a handheld cardiac event-monitoring device that recorded heart-rhythm data. On days when a participant did not have any symptoms, he created a heart-rhythm data recording anyway. Researchers then compared reported symptoms to the recordings.

Next, participants began a three-month program of Iyengar yoga, which comprises breathing control exercises…yoga postures that are held for 30 to 60 seconds each…and meditation/relaxation techniques. Twice-weekly, 60-minute group classes were led by certified yoga professionals. Participants also were given an instructional DVD and were encouraged to practice yoga daily on their own. During this period, participants continued to report AF symptoms and to use their cardiac-event monitors as before.

Finally, at the end of three months of yoga, participants again completed questionnaires to assess their quality of life, depression and anxiety.

Results: The yoga helped. The average number of symptomatic AF events (when the monitoring device data matched a participant’s symptom report) per patient dropped from 3.8 during the observation period to 2.1 during the yoga period. In addition, the average number of episodes in which a patient perceived symptoms but the device did not register a problem dropped from 2.9 to 1.4…and the average number of episodes in which no symptoms were felt but the device indicated that an event had occurred dropped from .12 to .04.

Heart health improved in other ways, too. After three months of yoga, participants’ average heart rate fell from 67 to 62 beats per minute. In addition, their blood pressure dropped significantly—the average systolic blood pressure (the top number of a blood pressure reading) went from 135 to 128 and the average diastolic pressure (the bottom number) fell from 81 to 74.

In addition, the average rating for depression went from 31 to 26, while the average anxiety score dropped from 34 to 25. Many quality-of-life measures improved as well.

What explains these various improvements? Researchers suggested that one way yoga may help is by minimizing the extreme fluctuations in the autonomic nervous system (the system that regulates, among other things, how the heart functions) that seem to precede an AF event. Further research is needed to determine whether other types of yoga—or indeed, other types of exercise—would be equally beneficial.

In the meantime: The results are encouraging enough to suggest that people with AF talk with their doctors about adding yoga to their treatment regimens. You can find a teacher in your area on the Web site of the Iyengar Yoga National Association of the United States.