I was in an outfitter's camp a few years ago, in northern BC and the cook told me about the former owner of that concession, Wes Brown, who had just passed. He was 92 and had shot his last Elk there at 90, a tough guy with a lifetime spent in the BC wilderness.
I am 62 and I started hiking at age 10, in the wilderness surrounding my small hometown of Nelson, BC. I still backpack, hunt and all of the related stuff and fully intend to do so until at least age 90, it just requires sufficient desire.
It takes more effort/time to stay in shape now and I am much slower, but, the high mountains are not out of reach and I now have the time, finances and experience to go anywhere I want to. It's ALL about motivation and desire.