Shovel duty today? Don't overdo it. Shoveling can kill you, especially when the snow is wet and heavy. A 1993 study in The New England Journal of Medicine looked at 1,228 heart attack victims and found that out-of-shape people increased their risk of a heart attack a hundredfold when they shoveled snow. Regular exercisers doubled their risk. The overall danger is mercifully low. But why flirt with death? Warm up first. Lift small loads. Take plenty of breaks, and don't try to do it all at once. Better yet, hire a kid.