With all my recent emphasis on high mileage, I thought I might be scaring some people away. But I do a lot more exercise than is necessary because it is my hobby and I enjoy it. For people that may be a little less nuts about exercise than me, how much is enough for healthy aging? I think this is pretty much answered by the typical recommendations, which is about 150 minutes a week of moderate activity like walking or equivalent, or 75 minutes of more vigorous activity. I also think it is a good idea to keep up your strength and work on balance. If you find something you enjoy, more is fine.

And it is never too late to start as Patty Branch, who started exercising at 66, demonstrates.