Well, as a swimmer for many years due to back issues, I cannot recommend it highly enough. You can even do martial arts in the water if you choose. Benefits of one, with the safety of the other.

It sucks to have the will to do something only to have your body unable to to allow you to chance. Especially when otherwise healthy people waste their days sitting on their butts. But, we cannot choose the hands we are dealt, we can only do our best with what we have to work with.
Undefeated in all of Asia!