This question was originally posted on Quora.com and was answered by Greg Hickey, Scientist and Ironman triathlete Yes and no. It depends on what you mean by “a lot.” On one hand, four of the best predictors for longevity are: Lean muscle mass Leg strength Cardiorespiratory endurance Physical mobility and flexibility All of these qualities are achieved almost exclusively through regular exercise. So regular exercise will help you live longer. In fact, physical fitness actually decreases your so-called “fitness age”, which is a better predictor of longevity than your chronological age. So if you are fifty years old but have a fitness age of thirty, you’d be expected to live longer than another fifty-year-old with a fitness age of seventy. In other words, people who are physically fit actually age slower than others. And being physically fit requires regular exercise. On the other hand, extreme endurance exercise can lead to potentially fatal heart damage. It can also compromise your lean muscle mass, leg strength and mobility, thus affecting your longevity. In this context, “extreme endurance exercise” means regularly training for and competing in events such as marathons, ultramarathons, ironman distance triathlons, and very long distance bicycle or cross-country skiing races. In other words, regularly logging 100 miles of running or 200 miles of cycling every week can lead to heart problems and an early death. Given the evidence, the best approach for longevity seems to be balancing strength, endurance and mobility training. It is quite possible to achieve the levels of physical fitness associated with longevity without extreme endurance exercise (and in the cases of lean muscle mass, leg strength and flexibility, abstaining from extreme endurance exercise is a necessity). To test how your exercise routine is likely to affect your longevity, measure your lean muscle mass, leg strength, cardiorespiratory endurance and mobility over time and modify your program to optimize your results. Source
