Veteran male endurance athletes who have spent many years training at high intensity may face a higher risk of serious heart rhythm problems during exercise, according to new research from the University of Leeds funded by the British Heart Foundation. The study suggests that this increased risk is linked not to how much or how hard these athletes train, but to whether they already have scarring in their heart muscle.
The research focused on male endurance athletes aged over 50, a group that accounts for the vast majority of sudden cardiac deaths occurring during sport. The team set out to determine whether high levels of exercise could trigger a potentially life-threatening heart rhythm disturbance known as ventricular tachycardia in these athletes. Their findings indicate that exercise itself is not inherently dangerous, but it may act as a trigger for abnormal rhythms in individuals who already have underlying heart damage.
In the study, the researchers closely monitored 106 healthy male endurance athletes who had been running or cycling for more than 10 hours a week for at least 15 years. Participants wore smart watches and heart rate monitors to track all their physical activity, while implantable loop recorders placed under the skin continuously recorded their heart rhythms. This allowed the researchers to precisely match episodes of abnormal heart rhythm with specific periods of exercise.
Over the two-year study period, around one in four participants experienced ventricular tachycardia during or shortly after exercise. Most of these episodes were non-sustained, meaning they were brief and usually less dangerous, but they can still act as warning signs for more serious events. Importantly, around three-quarters of the athletes who experienced these abnormal rhythms were found to have scarring in their hearts. The few longer and more dangerous sustained episodes of ventricular tachycardia all occurred during exercise and exclusively in athletes with heart scarring.
Crucially, the researchers found no evidence that those who developed abnormal heart rhythms were training more frequently or at higher intensity than those who did not. This reinforces the conclusion that exercise alone is not the cause of the problem. Instead, the presence of scar tissue appears to increase vulnerability, with physical exertion acting as a trigger rather than the underlying source of risk.
Many of the athletes were unaware that they had heart scarring before taking part in the study, highlighting the importance of regular cardiac health checks for older male endurance athletes. Heart scarring can result from previous heart attacks, underlying disease, or many years of intense endurance exercise, and it may remain undetected without specialist screening.
The researchers also emphasise the value of wearable technology for athletes who wish to monitor their heart health. Sudden, unexplained spikes in heart rate, especially when accompanied by symptoms such as feeling unwell or light-headed, should prompt athletes to reduce intensity or seek medical advice. The study is the first to combine long-term wearable activity data with continuous heart rhythm monitoring, and the team hopes it will inform future research in other athletic populations, including women and younger athletes.
More information: Wasim Javed et al, The Timing and Relationship of Ventricular Arrhythmia with Exercise Patterns in Veteran Male Endurance Athletes, European Journal of Preventive Cardiology. DOI: 10.1093/eurjpc/zwag021
Journal information: European Journal of Preventive Cardiology Provided by University of Leeds
