Atrial fibrillation: Endurance sports at elite level drastically increase risk

Regular physical activity, especially endurance training, reduces the risk of cardiovascular disease and has numerous other benefits. This statement is entirely true for the vast majority of people. However, study results recently published in the "European Heart Journal" suggest a limitation to this basic rule for former elite athletes in certain sports. The study demonstrates a drastically increased risk of atrial fibrillation among former top endurance athletes.

Atrial fibrillation (AF) is the most common cardiac arrhythmia, and its prevalence increases with age. According to information from the German Institute for Quality and Efficiency in Health Care (IQWiG), approximately 2 percent of the population is affected by AF, and the figure is approximately 8 percent of those over 65. In the long term, AF increases the risk of heart failure and stroke.

Known risk factors for AF include heavy or frequent alcohol consumption, smoking, diabetes mellitus, high blood pressure, significant obesity, and sleep apnea – largely behaviors or factors not typically associated with competitive athletes. However, since previous studies had shown an increased risk of AF in (former) endurance athletes, a team led by Dr. Darragh Flannery from the University of Melbourne in Australia re-examined the connection.

They recruited 121 former competitive rowers aged between 45 and 80 (median 62 years) who had rowed at the international elite level for at least ten years and compared them with a total of 11,495 matched controls without a competitive sports career from the UK Biobank. They found that 26 of the former rowers (21.5 percent) had AF, compared to only 364 controls (3.2 percent). Four years later, six more rowers had developed AF (6.3 percent), compared to 252 controls (2.3 percent).

This increased risk was apparently primarily due to increased cardiac remodeling, which the authors were also able to confirm, rather than genetic factors: AF risk genes were rarely found among rowers overall (2.7 percent) and were no more common in those with AF than in those without. Despite a comparable cardiovascular risk profile, a higher proportion of former athletes than controls had already suffered a stroke, namely 3.3 percent versus 1.1 percent.

"As a clinical physician, I wasn't surprised that rowers develop atrial fibrillation more frequently," senior author Professor Dr. André La Gerche commented on the results to the news site "Medscape." However, he was surprised by the magnitude of the difference, the cardiologist continued. Further lessons from the study include that the risk remains elevated for years after the end of an athlete's career and that this is not solely due to genetic factors.

Given these findings, cardiologists should more frequently screen masters rowers for AF, said Dr. Jeffrey Hsu, a cardiologist at the University of California, Los Angeles, who was not involved in the study. Masters rowers are people age 27 and older who participate in the sport. As in other sports, rowing has competitions specifically for older participants, called masters regattas .