 Stress is a big topic, and of course we hear about it all the time, but stress, they say now, may really undermine the heart benefits of exercise. So teens who have trouble coping with stress may face an increased risk for future heart trouble that even exercise can't erase, a new study suggests. It looks like the inability to cope well with stress contributes to the risk of heart disease. Lead researcher Scott Montgomery looked at this. He's a professor of epidemiology at