I'm just thinking that some of the longest living people are monks. They don't really exercise that much.
If you walk everywhere every day, do most of your daily chores by hand, and don't sit in an office all day, you are likely getting plenty of exercise even if you never touch a set of weights or treadmill.
Monks traditionally and currently do hard manual labour. They may work on a garden, farm, distilling equipment, artisanal endeavours such as carpentry. Monks (and nuns as well) have to do all the work in a monastery, which includes the daily chores, the cooking and cleaning. What did you expect, that they have servants to do that for them?
Plus, most healthy religious communities believe in real recreation on days of rest, and so they engage in athletics and sports as well. It's actually absurd to conceive of monks who are sedentary or lazy, no matter what the time period or region they may occupy.
"Survivorship bias or survival bias is the logical error of concentrating on entities that passed a selection process while overlooking those that did not."
A classic example of something like it, is during WW I the British saw a lot of airplanes were coming back with fuselage damage. So they started reinforcing the fuselage. Why this is a logical mistake is that these were the surviving airplanes.
I'll raise you: if you exercise regularly you'll be able to exercise more in the future and stay healthier.
That reminds me of my father (currently 76) who got a large dog. Now he walks it (or the dog walks him) for miles twice per day and his doc is extatic because that got rid of quite a few of his old age problems.
I know a guy who almost became a zen monk. By march he writes the allotted number of scientific papers for the year (he works for a govt lab). He's the editor of the top journal in his field.
Meanwhile, he's self taught himself philosophy and teaches it (pro bono?) at a University you've heard of.
He also reads >150 books / year
Cal State Humboldt?
He writes the list down and at the end of every year he sends it to me (I asked him to). It ain't light reading.