It's not surprising that no one wants to respond to this because the reaction is probably the same as I had when I first became aware that exercise can have a down side. I do know that for years skeptics have been trying to find evidence that exercise is bad for you. And it can be. I know of a whole crowd of individuals I used to run with back in the 80's that are all hobbling around on artificial hips because they were so enamored with marathons that they kept running through pain that was trying to tell them something. I went to the bicycle right after my second stress fracture. Tonight at about 5:30 I'm going to ride with people most of whom are 30-40 years younger than I am and the pace will be quick with hills. I don't have too many riding companions who are boomers. Is that because they are smarter than I am?