A new study conducted by scientists from the University of Leeds has shown that male endurance athletes over the age of 50 who have trained at a high level for many years may face an increased risk of serious heart problems during physical exertion.

The study results were published in the European Journal of Preventive Cardiology.

The researchers followed 106 runners and cyclists aged over 50 who had been training regularly for more than 10 hours per week for at least 15 years. All participants were generally considered healthy, but during long-term follow-up using wearable devices and implantable cardiac monitors, the scientists were able to correlate physical activity data with real-time heart rhythm recordings.

Over the observation period, approximately one in four athletes experienced episodes of rapid heart rhythm (ventricular tachycardia) during or immediately after training. Although most of these episodes were relatively short and did not lead to severe consequences, they may nonetheless serve as warning signs of more serious cardiac disorders.

Most importantly, the vast majority of athletes with such rhythm disturbances showed signs of scarring of the heart muscle (myocardial fibrosis). Three out of four participants with arrhythmia episodes had myocardial scarring, whereas those without such episodes showed no evidence of scarring. This suggests that it is not physical activity itself that causes the problem, but rather long-standing structural changes in the heart that may accumulate over years and make athletes more susceptible to dangerous arrhythmias under stress.

The researchers emphasize that regular physical activity at moderate levels remains one of the most powerful ways to strengthen the cardiovascular system. However, their findings point to the need for additional medical monitoring of veteran athletes, particularly those who have trained intensively for decades. Regular cardiological examinations and the use of wearable cardiac monitors may help identify early signs of abnormalities and reduce risks.

The researchers also note that many men over the age of 40 experience heart problems suddenly and without obvious symptoms. Therefore, paying close attention to one’s condition—especially if dizziness, palpitations, or shortness of breath occur during exercise—can be crucial for preventing complications.

Overall, the study highlights that while sport is important and beneficial, aging and long-term high training loads can create new challenges for those who have spent many years prioritizing fitness and endurance.