Isnt gym about looking good/becoming stronger/live your passion type of thing? I dont think lifting is particularly healthy, is it?
Weight training without overload, which means trainings you could do months in a row without overtraining, are largely beneficial. This is recreational sports
Weight training which incorporates overload, which means a period in which you lift more than you can recover from when sustaining too long, and deload to quickly redapt, and repeat, is still beneficial. This is dedicated sports
Weight training with the view to be competitive and find your physical limits, is less healthy than recreational sports, but still better than doing nothing at all. This is competitive sports.
Having that said, competitive weight sporters, are known to recover far quicker from just about anything especially when rehabilitation is required
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Sarcopena as said by @Seven is indeed a great example. So is the resistance to testosterone level decay. Weight training will make it drop much slower.