How often we turn passionate about exercising and land up doing more than  recommended! Here is a study stating you are in for trouble if so.

Team@CMHF

Regular exercise can increase life expectancy by an average of 7 years compared with a sedentary lifestyle, according to an editorial by Sharma and Zaidi, . Even modest doses of exercise can reduce the risk for mortality.

Endurance athletes may perform physical activity at levels 5 to 10 times greater than the exercise recommendations for preventing coronary atherosclerosis. Previous research suggests that athletes maintain indices of systolic and diastolic function associated with healthy cardiac function, although up to half of marathon runners can demonstrate elevated levels of serum cardiac troponin (cTnI).

This finding, along with a higher risk for atrial fibrillation among endurance athletes, has led to questions regarding whether endurance training among athletes is truly heart healthy. The current study by La Gerche and colleagues examines cardiac function among endurance athletes to address this issue.

Intense physical exercise appears to cause transient dysfunction of the right ventricle, and while the short-term recovery is complete, researchers say the ventricle, often neglected in cardiac research in favor of the more-often-studied left ventricle, could be a weak point in endurance athletes.

“For athletes, they want their heart functioning as well as possible for as long as possible,” lead investigator Dr André La Gerche

The study, included 40 athletes who recently completed an endurance event that lasted anywhere between three and 11 hours, such as a marathon, triathlon, or alpine-skiing event. , La Gerche said that biochemical abnormalities, such as troponin elevations, have long been documented in endurance athletes, but echocardiography often showed the heart was normal. In addition, most of the current research has been directed toward the effects of exercise on left ventricular function, with studies showing that there is some chronic left ventricular remodeling resulting from long-term endurance training,.

Measures of Right Ventricular Function in 40 Athletes
In this study, the researchers measured cTnI and B-type natriuretic peptide levels and assessed 3-D volume, ejection fraction, and systolic strain rate with echocardiography, as well as quantified myocardial fibrosis on cardiac magnetic resonance (CMR) imaging using delayed gadolinium enhancement, in the 40 athletes immediately and one week after their endurance event.

Relative to their baseline measurements, right ventricular volumes increased and all other measures of right ventricular function decreased following the endurance event. In contrast, left ventricular volumes were reduced and function was preserved from baseline.

La Gerche said that in strenuous physical exercise, such as in marathons or Ironman triathlons, pulmonary arterial pressure increases, more so than in systemic circulation, and with this increased strain the right ventricle is “bearing the brunt” of the workload. “If the right ventricle is having to work hard, and it has to do this for three, five, eight, or 10 hours, we would expect that this would create greater fatigue and have the potential for damage.”

In an editorial accompanying the study, Drs Sanjay Sharma and Abbas Zaidi  note that there are more than 500 marathon races in the US and Europe each year, and this figure is only increasing. The past 30 years have been somewhat paradoxical in the sense that obesity and morbidity caused by lack of exercise is on the rise, yet the number of individuals participating in ultra–long-distance events has increased. Regarding the current study, Sharma and Zaidi say that more detailed studies are needed, including longitudinal studies, to determine the long-term effects of endurance activities in some athletes.

Unsure of the Implications Right Now
Right now, La Gerche and colleagues are unsure of the implications of the right ventricle enlargement, although there are some causes of concern. Animal studies have shown that strenuous physical exercise caused right ventricular changes, and these were associated with serious arrhythmias. In humans, there are no prospective studies evaluating the effects of right ventricular changes, but one study, led by Dr Hein Heidbüchel (University Hospitals Leuven, Belgium), also an author of this paper, found complex right ventricular arrhythmias in cyclists, said La Gerche.

“There is a bunch of circumstantial evidence all pointing to the right ventricle,” he said.

Ref: http://www.medscape.org/viewarticle/756248?src=cmemp