Exercise May Be Good Medicine for Irregular Heartbeat

Exercise appears to help control an irregular heartbeat known as atrial fibrillation in obese people, a new study shows.

Australian researchers found that “cardiorespiratory fitness” reduced the risk that this potentially dangerous heartbeat will return by as much as 84% - even more than losing weight. Cardiorespiratory fitness refers to the ability of the heart and lungs to supply oxygen to the body during sustained physical activity.

“This study adds to a growing body of evidence that aggressive risk factor management with increased physical activity should be an integral component of management of atrial fibrillation,” said lead researcher Dr.

Prashanthan Sanders, director of the Center for Heart Rhythm Disorders at the University of Adelaide in Australia.

Atrial fibrillation, the most common abnormal heart rhythm, affects about 2.7 million Americans, according to the American Heart Association. Obesity and inactivity are risk factors for atrial fibrillation, which can lead to stroke, the researchers pointed out.

The report was published online August 24 in the Journal of the American College of Cardiology.
For the study, Sanders and colleagues assigned 308 patients with atrial fibrillation to one of three groups based on their level of fitness: low, adequate, or high fitness. All had a body mass index (BMI) of 27 or more, meaning they were overweight or obese.

The groups were followed for about four years to see how their level of fitness affected the recurrence of the abnormal heartbeat. Patients were also offered a doctor-led weight loss and exercise program.



After four years of follow-up, 84% in the high fitness group no longer had atrial fibrillation, compared with 76% in the adequate group and 17% in the low fitness group, the researchers found.

Saunders’ team also found that for every increase in “metabolic equivalent” – a measure of the amount of oxygen used at rest – the risk of atrial fibrillation recurrence was reduce 20%.

“Increased physical activity to gain cardiorespiratory fitness is associated with a reduction in atrial fibrillation burden and maintenance of a normal heart rhythm,” Sanders said.

But Thompson, author of an accompanying journal editorial, added that becoming fit should not be equated with habitual physical activity.

“Among individuals who have done tons of exercise for their whole lives, like lifelong endurance athletes,” he said, increasing levels of physical activity might possibly raise the risk of atrial fibrillation. The problem for most folks, however, is not too much exercise but getting even a little bit of exercise,” he added.

My Take:
Exercise may be the most important factor in resolving and preventing AF (atrial fibrillation). Even in a “lifelong endurance athlete” like me. The key for the athlete is to avoid too much high intensity exercise, not stop exercising. As part of my treatment for AF I have modified my workouts to spend more time in my aerobic zone (much like Orange Theory). I also limit my time above my aerobic limit to less than 10 minutes of continuous exercise. Finally, although my Vmax (maximum heart rate) is 157, I don’t allow it to go over 150. Along with the nutritional protocol I have developed, I have been totally asymptomatic for over six months.

The Bottom Line:
Regular exercise is vital to general health and becomes even more important in disease. If you are not exercising daily, start slowly, but start. Find a partner (or two), vary the activity, and become engaged in the effort.

Source: August 24, 2015 National Institutes of Health