Exercise and life expectancy

Abstract

Chi Pang Wen and colleagues1Wen CP Wai JP Tsai MK et al.Minimum amount of physical activity for reduced mortality and extended life expectancy: a prospective cohort study.Lancet. 2011; 378: 1244-1253Summary Full Text Full Text PDF PubMed Scopus (1161) Google Scholar report dose-dependent improvements in survival associated with increasing amounts of daily physical activity. We agree that inadequate physical activity is a major and growing problem worldwide, but we are concerned that excessive strenuous exercise could be deleterious. Wen and colleagues' survival curves suggest that reduction in long-term all-cause mortality peaks at 45% with about 50 min of vigorous physical activity per day. The shape of the Kaplan-Meyer survival curve for vigorous physical activity shows that the mortality benefit plateaus abruptly at 50 min and raises the question of whether longer durations of daily vigorous physical activity might diminish some of the benefits. Physical exercise has many characteristics of a powerful drug and can be highly effective for the prevention and treatment of many chronic diseases, including coronary heart disease, hypertension, obesity, depression, and diabetes.2O'Keefe JH Vogel R Lavie CJ Cordain L Exercise like a hunter-gatherer: a prescription for organic physical fitness.Prog Cardiovasc Dis. 2011; 53: 471-479Summary Full Text Full Text PDF PubMed Scopus (53) Google Scholar However, as with any drug, a safe upper dose limit exists, beyond which the adverse effects (musculoskeletal trauma, cardiovascular stress, etc) of physical exercise could outweigh its benefits. Indeed, a growing body of scientific evidence suggests that excessive chronic strenuous endurance exercise (such as training for and competing in marathons and long triathlons) could predispose to adverse cardiac remodelling and subsequent adverse cardiovascular effects.3Breuckmann F Mohlenkamp S Nassenstein K et al.Myocardial late gadolinium enhancement: prevalence, pattern, and prognostic relevance in marathon runners.Radiology. 2009; 251: 50-57Crossref PubMed Scopus (192) Google Scholar, 4Oxborough D Birch K Shave R George K “Exercise-induced cardiac fatigue”—a review of the echocardiographic literature.Echocardiography. 2010; 27: 1130-1140Crossref PubMed Scopus (71) Google Scholar, 5Nassenstein K Breuckmann F Lehmann N et al.Left ventricular volumes and mass in marathon runners and their association with cardiovascular risk factors.Int J Cardiovasc Imaging. 2009; 25: 71-79Crossref PubMed Scopus (20) Google Scholar We are curious as to whether Wen and colleagues have data about long-term survival in individuals who did vigorous exercise for more than 50 min per day. Do the mortality benefits begin to erode away as the daily time spent doing vigorous physical activity increases beyond 1 h? We declare that we have no conflicts of interest. Exercise and life expectancy – Authors' replyWe thank Lennert Veerman and colleagues for giving us the opportunity to clarify the relation between summary mortality ratios and extended life expectancy. There are several reasons why these are not totally comparable. Full-Text PDF