Officials warn that shoveling snow after this weekend's massive storm could be hazardous to your heart. Research shows shoveling can make the heart work as hard as during a major workout. Cold temperatures add stress by constricting blood vessels, which can in turn raise blood pressure and heart attack risk. The American Heart Association warns that shoveling is risky for those with heart disease, older adults, and even generally healthy people. They recommend going slow, taking breaks, and pushing snow instead of lifting it. Health officials in Pennsylvania have linked three deaths on Sunday to snow removal.