Exercise can't hold off the effects of aging, but it can improve an elderly person's chances of hanging onto an independent lifestyle, researchers said, citing a new study that brought both good and bad news. A treadmill test given to different age groups showed that as people aged, their aerobic capacity — the amount of oxygen consumed while exercising — declined at higher rates with each passing decade whether they exercised or not. The researchers knew the rate of decline would worsen with age, but they were surprised by the magnitude, said Dr. Jerome L. Fleg, a cardiologist who is...