Is there such a thing as too much exercise? That depends on what you mean by “too much.” If you exercise so much that your body doesn’t recover in time, then your body weakens and your propensity for injury increases. But can you exercise to the point wherein the amount of exercise you do has an inverse relationship to how long you live? In other words, is there an amount of exercise which increases your mortality rate?
In the past, there were a few studies that seem to insinuate a higher mortality rate when you exercise too much. At the center of the study were hardcore endurance athletes (marathon and ultramarathon runners) who trained as much as most people worked. The studies showed that athletes who overtrained had cardiovascular abnormalities like arrhythmias or fibrosis (scarring). However, later studies show that these cardiovascular abnormalities do not cause an increase in the mortality rate or increased incidence of cardiovascular disease. In fact, hardcore endurance athletes still have a much lower mortality rate than those who are not active at all.
So is there such a thing as too much exercise? I don’t think that is really the right question to ask as studies have shown that even hardcore athletes who train hours upon hours a day do not have a higher mortality rate. Perhaps the better question to ask is if there is a diminishing return on exercise, wherein if you pass a certain point, it does not make you any healthier or increase your likelihood of living longer? To that point, yes there is an optimal amount of exercise.
Doctors recommend 150 minutes of moderate activity of 75 minutes of vigorous activity. Moderate activity includes walking, gardening, house work, and the likes. Vigorous activity includes jogging, playing competitive basketball, and the likes. But the most benefit seem to come from getting 3-5 times the recommended exercise.
In an analysis of 660,000 people people ages 21 to 98 that were tracked over a 14-year period, researchers found that those who did the recommended amount of exercise were 31 percent less likely to die during the 14-year study period. However, those that got 3 to 5 times the recommended exercise were 39 percent less likely to die during the study period.
So exercise beyond the 3-5 times the recommended amount seem to be the optimal amount of exercise in terms of longevity. In addition, gym rats and athletes who exercise up to 10 times the recommended amount do not see an increase incidence in mortality than those who just exercise the recommended amount. Additionally, those who got less than the recommended amount but still got some exercise were still 20 percent less likely to die during the 14-year period.
So the optimal amount of exercise seems to be 450 to 750 minutes (7.5 to 12.5 hours) of moderate activity or 225 to 375 minutes (3.75 to 6.25 hours) of vigorous activity. But those who exercised much more do not seem have a higher mortality rate than those who exercise the recommended amount.
As we have talked about plenty on this site, exercise is a major component of healthy living. Not only does it help you live longer, but it helps boost your immune system, alleviates stress, assist in preventing premature (cellular) aging, and improves your brain function. The benefits of exercise are so vast that there is really no reason to not exercise. Getting the recommended amount of exercise does not take too much time (or effort) out of your week. Remember, moderate exercise includes simple tasks like household chores and gardening. So it doesn’t matter what you do for exercise, just get out there and start moving your body if you aren’t already.
Tl;dr version: No, but there is an optimal amount of exercise (7.5 to 12.5 hours of moderate exercise or 3.75 to 6.25 hours of vigorous exercise)