Inclusion Criteria:  Age 65 years or older, female Histologically confirmed Stage I, II or III breast cancer (if the patient has had more than one breast cancer, then the most recent diagnosis) Scheduled to begin adjuvant or neoadjuvant chemotherapy regimen either as standard-of-care or on study English or Spanish speaking Able to provide written, informed consent Patient-assessed ability to walk and engage in moderate physical activity Willing and able to meet all study requirements  Exclusion Criteria:  The presence of significant medical conditions that in the physician's judgement preclude participation in the exercise intervention