Amid the release of some recent reports suggesting high volumes of aerobic exercise may in fact be harmful, the American College of Cardiology (ACC) Sports and Exercise Cardiology Leadership Council recommended that even small amounts of physical activity are associated with a lower risk of cardiovascular disease.

The clinical perspective was published online in the Journal of the American College of Cardiology on Jan. 18.

“The possibility that too much exercise training could produce deleterious cardiac effects including myocardial fibrosis, coronary calcification, and atrial fibrillation is interesting and worthy of scientific investigation; however, overall the results, even for very active, life-long endurance athletes, is that the benefits of exercise training outweigh the risks,” the researchers wrote. “There may also be small subsets of the population with genetic predispositions to cardiac disease for whom vigorous exercise is not beneficial and may even be deleterious, although this represents a very small subset of patients. Moreover, the issue for most developed countries and the majority of their citizens is not concern about too much exercise, but rather the absence of any exercise among most of the population and among patients with [cardiovascular disease].”

The researchers cited a report from 2008 that found only half of U.S. adults met the recommended minimum of 150 minutes per week of moderate intensity or 75 minutes per week of vigorous intensity aerobic exercise. At the same time, endurance exercise races such as marathons, triathlons and bicycle races have become more popular.

“The public media has embraced the idea that exercise may harm the heart and disseminated this message, thereby diverting attention away from the benefits of exercise as a potent intervention for the primary and secondary prevention of heart disease,” Michael Scott Emery, MD, co-chair of the ACC Sports and Exercise Cardiology Council, said in a news release.

Although physicians and healthcare professionals recommend physical activity, the researchers noted that there have been no randomized trials evaluating whether physical activity prevents cardiovascular disease.

“Such a study would require an enormous sample size and study duration because of subject crossover among those volunteering for an ‘exercise study’ and because the progressively lower rates of primary [cardiovascular disease] in the general population would reduce [cardiovascular disease] endpoints,” they wrote.

Still, they said that numerous studies have demonstrated the benefit of even a low amount of exercise or physical activity. For instance, they cited a study that found standing more than two hours per day was associated with a 10 percent reduction in all-cause mortality compared with standing less than two hours per day. Another study found U.S. adults who ran 51 minutes per week (68 percent of the recommended volume) had lower cardiovascular disease mortality compared with adults who do not exercise.

“The available evidence should prompt clinicians to strongly recommend low and moderate exercise training for the majority of our patients,” they wrote. “Equally important are initiatives to promote population health at large through physical activity across the life span, as it modulates behavior from childhood into adult life.”