Exercise Programs in Healthy Young Women at Increased Risk of Developing Breast Cancer

DISEASE CHARACTERISTICS: * Healthy women with ≥ 18% lifetime risk for breast cancer as evidenced by the following: * Documentation from a genetic counselor of a known familial breast cancer susceptibility mutation * Claus model risk of ≥18% * Predicted probability of BRCA1/2 mutation \> 25% based on the Myriad model * Documentation of a known mutation in a family member such that the Mendelian probability of a BRCA1/2 mutation would be \>25% * History of lobular carcinoma in situ * No prior prophylactic mastectomy * Leisure-time exercise energy expenditure of ≤ 500 kcal/week over the past 6 months * Hormone receptor status not specified PATIENT CHARACTERISTICS: * Premenopausal * Menstrual cycles 25-32 days in length * Intact ovaries and uterus * Gynecologic age (defined as participant's current age minus the age at which she started menstruating) of at least 4 years * Body mass index 21-50 * No history of menstrual difficulties * No history of physician-diagnosed gynecological disease (e.g., fibroids, endometriosis, or polycystic ovary syndrome) * Not pregnant * Not planning to become pregnant during the study period * No medical conditions or medications that would prohibit participation in aerobic exercise or would negatively impact the study * No history of cancer, except nonmelanoma skin cancers, and in situ cervical cancers * No eating disorders (e.g., bulimia or binge-eating disorder) * At least one year since prior smoking * Not planning to move away from…