It’s difficult to get health authorities to talk about the disconnect between their official recommendations and the scientific evidence that underlies it because they want to encourage us to exercise, even if their primary reason for doing so is highly debatable. Steve Blair, for instance, a University of South Carolina exercise scientist and a co-author of the AHA-ACSM guidelines, says he was “short, fat, and bald” when he started running in his thirties and he is short, fatter, and balder now, at age 68. In the intervening years, he estimates, he has run close to 80,000 miles and gained about 30 pounds.
When I asked Blair whether he thought he might be leaner had he run even more, he had to think about it. “I don’t see how I could have been more active,” he said. “Thirty years ago, I was running 50 miles a week. I had no time to do more. But if I could have gone out over the last couple of decades for two to three hours a day, maybe I would not have gained this weight.” And maybe he would have anyway. If we trust the AHA-ACSM report he co-authored, there is little reason to believe that the amount he runs makes any difference. Nonetheless, Blair personally believes he would be fatter still if he hadn’t been running. Why?
