IF WE HAD a pill that accomplished everything that physical activity does for overall health, we would prescribe it for everyone,” says Donald Hensrud, M.D., former medical director of the Mayo Clinic Healthy Living Program. IF WE HAD a pill that accomplished everything that physical activity does for overall health, we would prescribe it for everyone,” says Donald Hensrud, M.D., former medical director of the Mayo Clinic Healthy Living Program. Overall fitness isn’t just about breaking a