New study refutes earlier claims on effects of endurance training on the heart.

Years ago, before the sophisticated medical tests available today such as MRIs, doctors were concerned about a condition they referred to as “athlete’s heart.” They mistakenly theorized that regular endurance training caused a pathological process resulting in thickening of the heart’s walls and likened it to a serious congenital condition known as hypertrophic cardiomyopathy.

While prolonged continuous endurance training year after year does indeed remodel the heart, it was later determined that the adaptations causing a larger left and right ventricle were actually indications of a larger stroke volume and a decreased resting heart rate—a positive adaptation to training.

Nonetheless, debate has persisted throughout the years as to whether intense endurance training (bouts longer than one hour) could lead to cardiovascular damage. In particular, a 2012 Belgian study concluded that “Repeated bouts of intensive endurance exercise at the elite level may result in the pathological enlargement of the right ventricle and is associated with potential health hazards including sudden cardia death.” They specially observed enlargement and reduced functionality of the right ventricle in long-term competitive endurance athletes. This study stirred up considerable debate among medical experts.

Although the medical community remained divided, it still caused anxiety in runners and triathletes. But more recent research has refuted the earlier Belgian study claims of heart damage. Researchers at Saarland University in Germany examined 33 elite master athletes (including former Olympians and Ironman competitors) who continued to train at a high level for 30 years or more. For a control group, they compared 33 non-endurance exercising men.

Here’s the good news from that study. The scientists confirmed that the hearts of the trained endurance athletes were indeed larger and stronger than those in the control group. “But they found no evidence of lasting damage, pathological enlargement or functional impairment of either the right or left ventricle in the athletes who had been doing long-term intensive elite-level endurance exercise.”

The study was significant because by studying masters endurance athletes, the researchers were able to overcome the absence of long-term MRIs as a research tool, and therefore represented the best means of investigating the long-term impact of many years of high-level endurance training.

Doubtless there will be subsequent studies and the debate will continue. But one thing the entire medical community agrees on: The benefits of regular exercise outweigh the risks.

Upcoming races: Saturday, October 22 at 9:30 a.m., the Key2Free Run4Freedom 5K at the Legacy Pavilion in San Gabrielle Park, Georgetown. Saturday, October 22 at 9:00 a.m., The Great Pumpkin Dash 5K Run at Country Estates, San Marcos. Sunday, October 23 at 7:30 a.m., the Austin Runners Club Daisy Dash 5K at Upper Cougar Creek, Ernest Robles Way in Sunset Valley.