Thursday, March 3, 2011

Life-Long Endurance Exercise and Myocardial Fibrosis - A Potential Danger for Endurance Athletes

Habitual aerobic exercise has long been the cornerstone of what was considered a "healthy" lifestyle. Yet, lately, scientists are not only questioning the time-efficacy of these training regimens (there are studies showing that one can achieve similar metabolic adaptations with short high intensity interval training), there is also cumulative evidence that indicates that life-long engagement in endurance exercises may even be detrimental to your health.

In a recent study by Wilson et al. (Wilson. 2011)  "twelve lifelong veteran male endurance athletes (mean ± SD [range] age: 56 ± 6 yr [50-67]), 20 age-matched veteran controls (60 ± 5 y; [52 - 69]) and 17 younger male endurance athletes (31 ± 5 years [26-40]) without significant co-morbidities underwent cardiac magnetic resonance (CMR) imaging to assess cardiac morphology and function." The results of the CMR were disquieting - to say the least:
In 6 (50%) of the veteran athletes LGE [late gadolinium enhancement, short LGE indicates the presence of fibroses as a consequence of minor tissue ruptures] of CMR indicated the presence of myocardial fibrosis (4 veteran athletes with LGE of non-specific cause, 1 probable previous myocarditis and 1 probable previous silent myocardial infarction). There was no LGE in the veteran controls or young athletes. The prevalence of LGE in veteran athletes was not associated with age, height, weight or BSA (p>0.05), but was significantly associated with the number of years spent training (p<0.001), number of competitive marathons (p<0.001) and ultra-endurance (>50 miles) marathons (p<0.007) completed.
In fact, this study is only part of the accumulating evidence against the health benefits of (ultra-)endurance and or excessive aerobic training. Weight lifting and intense, but short sprint-intervals, on the other hand, turn out to be a healthier and much more effective way of keeping lean and healthy up into the older ages.