Years and years ago I saw a TV show about the Boston Marathon. One of the people they interviewed was the last runner to finish. A physician, I would guess ar

Years and years ago I saw a TV show about the Boston Marathon. One of the people they interviewed was the last runner to finish. A physician, I would guess around 45 to 50. It was already dark out! So he was not fast, maybe not much more than a walking pace, but he seemed happy so nothing to complain about. The original book on Aerobics, the author emphasized you can get all the aerobic exercise you need at an ordinary walking pace if you take enough time. Especially important for older people and the overweight. The obsession with "20 minutes of vigorous exercise" may well do more harm than good.