When my father died at age 87 his body was still in pretty good shape for his age. However he developed dementia and although part of it might have been unavoidable my sisters and I tend to believe his becoming sedentary could have been a strong contributing factor.
I am 61 and although I have some lung problems the rest of my body is OK, outside of the normal aches and pains which comes with age. I play video games quite often and I still do a lot of studying. I am a fairly decent video game player, not quite as sharp as I was a few years back, but still my hand and eye coordination is not bad. Other than the obvious enjoyment of playing I also feel if nothing else goes wrong it will help me retain my mental faculties as the years progress. Now I guess that my not turn out to be what happens but I believe doing what I can to help sure can't be a bad road to go.