In my 20s and early 30s, I was an avid volleyball player. My teammate and I won a doubles tournament, and I was much better in 6-man. I was an official with the professional volleyball league. That got short-circuited as I got fully involved coaching high school basketball, which was the center of my athletic life for a while. I stopped all that to coach my sons' soccer teams, taking them to play tournaments in Europe. I became a ski racer. By my late 40s, my knees were in terrible shape--ski racing was too painful to continue. My children were grown and no longer needed a soccer coach. That was when I discovered divingnd have a backup plan ready to fall back on when the inevitable sets in
In each case I was totally immersed in an activity, and in each case when I left that activity, it was over. I sometimes tune in a volleyball game and see a sport I barely recognize. I pretty much don't even watch basketball and can't name more than a handful of the top pro players. I rarely watch a soccer game today. Skiing? Pretty much never.
If I come to the realization that my health makes scuba dangerous, I am confident that I can walk away and replace it with an activity that will consume my time just as much. I don't know what that will be, but it will be something. When I was a brand new 22-year old school teacher, I got my first coaching job, taking on the leadership of the school's chess team. I have barely played since then. Maybe I will return to that.