I don't believe any amount of exercise is going to firm up a size 38 DD or DDD. As I understand it, the muscle is in the chest wall (pectorals?) and the soft tissue that actaully forms and shapes the breast is basically...fat. That's kind of like people doing sit-ups to lose weight in their stomach. Sit-ups will firm the abdominal muscles underneath the fat...it won't get rid of it.

I'm 5'1 and a 34 DD, have never had children, and still have the sagging problem. I met with a plastic surgeon and plan to have a lift this winter.