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Training for Longevity: The Reverse J-Curve for Exercise.

A wealth of scientific literature backs the unique therapeutic benefits of exercise for quality of life, cardiovascular (CV) health, and longevity. Consequently, many have assumed that more exercise is always better. However, chronic excessive endurance exercise might adversely impact CV health. Ultra-endurance races can inflict acute myocardial damage, as evidenced by elevations in troponin and brain natriuretic peptide. Moreover, sudden cardiac arrest occurs more often in marathons and triathlons than in shorter races. Veteran endurance athletes often show abnormal cardiac remodeling with increased risk for myocardial fibrosis and coronary calcification. Chronic excessive exercise has been consistently associated with increased risks of atrial fibrillation (AF), and along with some attenuation of longevity benefits. The optimal dose of exercise remains unknown and probably differs among individuals. Current studies suggest that 2.5 to 5 hours/week of moderate or vigorous physical activity will confer maximal benefits; >10 hours/week may reduce these health benefits.