Endurance sports: But no higher risk of heart damage

Jens Richter is editor-in-chief at Since July 2020, the doctor and journalist has also been responsible as COO for business operations and the strategic development of

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Do marathons and triathlons harm the heart? Several studies in recent years have fueled this concern. But now German researchers are giving the all-clear.

The assumption that intensive endurance sport could permanently damage the heart muscle was first set up around ten years ago in a study in Australia. There, scientists examined the cardiac function of triathletes, runners and extreme cyclists before and after they took part in competitions.

Menacing scars on the heart wall

Immediately after the exercise, the mobility of the right ventricle and its pumping capacity were significantly reduced in all test subjects. Some values ​​from a blood test carried out in parallel also indicated an acute overload of the heart.

These effects normalized, however, by the check-up six to eleven days later. But in those athletes whose competitions had lasted particularly long, the doctors later found signs of small scarring in the wall of the right ventricle. Such areas of connective tissue take the place of myocardial tissue when it dies. The scars could weaken the pumping power of the heart chamber and promote life-threatening cardiac arrhythmias, so the concern of doctors.

Corresponding warnings have been regularly in the media since then. And they are fueled again and again by spectacular cases of sudden cardiac death in athletes - mostly caused by the most severe cardiac arrhythmias that occur primarily in the right ventricle. Is it due to heart damage caused by exercise?

Athletes' hearts put to the test

Scientists from the Institute for Sports and Preventive Medicine at Saarland University in Saarbrücken have now taken up this question again: They examined 33 top athletes from triathlons and marathons, including a former triathlon world champion and several podium finishes in the Ironman Hawaii as well as a former winner of the Munich marathons. The athletes were an average of 47 years old and had been training for at least 20 years - for the past ten years more than ten hours a week.

The comparison group, which also comprised 33 people, was the same in terms of age structure, height and body weight, but exercised a maximum of three hours per week.

No damage to the right ventricle

In their study, the scientists used all modern examination techniques to record changes in the shape and performance of the heart chambers. However, they did not find any signs of short-term overloading of the ventricles, nor of long-term deterioration in pumping performance. In medicine, it is determined, among other things, by the so-called ejection fraction. This is understood to mean that portion of the amount of blood that the heart muscle can transport out of the filled heart chamber and into the blood vessels during a contraction.

There was no difference between the competitive athletes and the test subjects in the control group, write the researchers in their work, which recently appeared in the renowned journal "Circulation" of the American Heart Association. Only the heart weight and volume were, as expected, significantly larger in the athletes - a typical adaptation to the extra work, also known as the "sports heart". The researchers summarize that it is unlikely that even long-term and intensive endurance sports will damage the right ventricle.

Much more benefit than risk

The German Heart Foundation also points out that the positive effects of sport far outweigh any possible risks. Much more often, especially after the age of 35, calcification of the coronary arteries is the trigger for dangerous cardiac arrhythmias.

Regular endurance sport counteracts such changes - it reduces the risk of cardiovascular diseases and sudden cardiac death. However, it is important, especially for older athletes, to have their individual heart health and resilience checked regularly by means of a sports medicine check.

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