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

As far as I know, there are no significant risks of having too much muscle mass.

If anything it should be good. When you grow older that's exacty what disappears. Therefore it seems that your increased muscle mass will be able to attenuate some of the problems related to ageing.

There is a point when you cross the line. Althoguh I do not know what it is. But there are heart risks of having to support your mass, regardless of it being fat or muscle. Sure muscle is still better but you still weigh 300 lbs.

I agree that your cardiovascular system was not designed to carry 300 pounds, whether it is fat or muscle. But, this is a moot point as I don't think it is possible to be a lean 6', 300# even with anabolic steroids.

I just realised that 300 pounds is 130+ kg!

Definately Agree.

OK, thanks for all of the replies. I guess it might be unhealthy to be Jimmy Marku and other similar people, then, at 5'10" and 305 lb (2007 World's Strongest Man).

Bodybuilders.com - Pro Profiles - Ronnie Coleman Pro Bodybuilding Profile.

Ronnie Coleman weighs 300lbs at competition weight, so YES it is possible.

Although it is worth knowing that once the pros get to this sort of weight, when they 'do cardio' its normally stationary bike or uphill walking because their joints just wont handle running on a treadmill anymore.

I think you mean Britains strongest man

I think I misread the line in Wikipedia article that said he just qualified for the 2007 World's Strongest Man, but he didn't actually win first place.

Xav: Wow, that's impressive

Not that everything others said isn't correct, but this is true to an extent also. If you're doing serious endurance training plus strength training, your body will chose the endurance vs. muscle growth. Just saying.