TO AGE WELL, WALK. This study doesn’t seem especially strong to me. It started with sedentary old people, and while I’m sure they benefited at least somewhat from moving around more, the benefit is actually not all that huge here. The thing is, the best time to start exercising, like the best time to plant a tree, is 20 years ago. Or, when you’re 82, 60 years ago.

I remember something my grandmother said to me in her last year as I headed off to the gym: “Getting in shape for your old age, are you? You’d better!”