Assuming I eat healthily, do cardiovascular exercise, and don't take any harmful supplements, is it unhealthy to gain so much muscle so that I weigh 280 pounds, or 300, or whatever would be a large amount (given I am 6 feet tall)? Or since I would be doing cardiovascular exercise as well, would my body not allow me to put on so much muscle mass that it would harm me? Does anybody know of people who had a large amount of muscle mass, have lived a long time and are still healthy when they are older? Have any studies been done on this? I haven't really found much evidence either way. Thanks