A defined chest and rippling back muscles are common goals for male gym-goers. While that might sound superficial, there are plenty of good reasons to work on your upper body – and looking toned is only one of them. We use these muscles all day long: for pushing open a door, for lifting our children (or grandchildren) off the floor; and for breathing. Now, a new study has revealed a surprising new reason to train your torso: it could reduce your risk of a heart attack.