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We are pleased that Dr Leischik1 shares our interest in trying to elucidate the long-term clinical consequences of intense endurance exercise. It is a contentious issue which is the subject of very passionately held views. The adage: “The only person who is wrong is the person who is certain that they are right” seems appropriate when evidence is conflicted and there is no immediate means of definitively proving whether permanent right ventricular (RV) injury can occur. Dr Leischik highlights important studies which suggest that chronic RV changes are absent in some athletic groups. Rimensberger et al found no evidence of RV remodelling among 97 amateur middle-aged runners who trained around 5 h/week. However, significant RV enlargement and reduced RV reformation has been documented in much larger cohorts of young elite athletes.2 Not all athletes are equal,3 and these seemingly incongruent results might be explained by the fact that the athletes in the Teske's study were performing 4–5 times the amount of weekly training. There are many more studies than these, and we agree that there is evidence to both support and refute the idea of permanent cardiac remodelling of the RV, left ventricle (LV) and the atria. Further evidence is clearly required and we would urge investigators to approach the current uncertainty with an open mind.
The aim of our meta-analysis was not to suggest that the RV suffers permanent damage. This cannot be addressed by collating studies which solely measured transient changes in RV function. Rather, we seek to draw attention to the disproportionate effect of endurance exercise on RV function. Until recently, the LV was the sole focus of many studies. Our analysis suggests that this may be missing the point. A syndrome of proarrhythmic remodelling of the RV which seems to be associated with long-term endurance exercise training has been described in humans3 ,4 and in rats.5 We believe that it would be incorrect as clinicians and scientists to not at least entertain the possibility that high-intensity endurance exercise may be associated with these potentially life-threatening conditions.
We recall a similar debate one decade ago. Some mad scientists had provided data suggesting that endurance exercise may be associated with atrial fibrillation. Thankfully, scientific inquiry survived the commentary that the concept was not tenable.
Competing interests None.
Provenance and peer review Not commissioned; internally peer reviewed.