> depends on the ammount. overdoing it actually increases stem cell exhaustion, and can cause specific organ damage too. > for instance any run longer than 5km contributes to vascular damage. my understanding is about ten hours of vigorous exercise is the upper limit per week. i personally do 10km a day but majority of that is not high intensity. works out to about 5-6 hours a work week and 3 hours on weekends.
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