Gut Microbe Composition, Exercise, and Breast Breast Cancer Survivors

Inclusion criteria: * Women ages 18 to 74 years with a history of breast cancer stage 0, I, II, or III, * ≥ 1-year post-completion of primary treatment for breast cancer (chemotherapy and/or radiation), * Average fatigue over the past week rated as ≥3 on a 1 to 10 Likert scale, cut point chosen because it is a clinically meaningful cutpoint,93 * English speaking, * Physician medical clearance for study participation, * Able to ambulate without assistance, * No antibiotics for the past 90 days, * Willing to avoid taking probiotics for the duration of the study * Peak VO2 \<30 ml/kg/min (note: will measure peak VO2 if the participant meets all other criteria and consents to lab-based screening). Exclusion criteria: * Metastatic or recurrent cancer * Another diagnosis of cancer in the past 5 years (not including skin or cervical cancer in situ), 3) * Unstable angina * New York Heart Association class II, III, or IV congestive heart failure * Uncontrolled asthma * Interstitial lung disease * Current steroid use * Having been told by a physician to only do exercise prescribed by a physician * Dementia or organic brain syndrome * Schizophrenia or active psychosis * Connective tissue or rheumatologic disease (i.e., systemic lupus erythematosus, rheumatoid arthritis, amyloidosis, Reiter's syndrome, psoriatic arthritis, mixed connective tissue disease, Sjögren's syndrome, CREST syndrome, polymyositis, dermatomyositis, progressive systemic sclerosis, vasculitis, polymyalgia rheumati…