The purpose of this study is to determine the effects of a moderate aerobic interval training program on the functional status and psychological symptoms of women with Stage 11 breast cancer receiving adjuvant chemotherapy. The sample will consist of post-surgical women who have received at least three treatments but not more than six months of therapy. The issue of physical activity during therapy to prevent symptoms of debilitation is an important one. Aerobic training to promote functional ability in early stages of chemotherapy has not been explored in this clinical population. The sample will consist of 90 subjects with 30 in the experimental, 30 in a control group used to control for "Hawthorne" effect and 30 in a no-treatment control group.