I used to run a lot and for a while was doing 7 miles a day but those days are long over. I’d be huffing and puffing if I ran a quarter mile today, and if I could go further my left knee would likely start protesting anyway. I used to do some serious bike riding too but the distances, pace, and technical difficulty are now decidedly casual, and I’m in process of hanging up the bikes for good anyway in favor of just walking. All that said I am in pretty good shape for my age and have more stamina and strength (even if it is diminishing) than a lot of guys my kid’s age that never do much hard work or exercise. I may be slowly losing it but an awful lot of young people these days never had it. Come a long term SHTF event I will be able to do my share of the work around here.