Fatigue Interventions in Cancer (Exercise Intervention)

Inclusion Criteria:

* Diagnosed with advanced prostate cancer
* Currently treated with hormone therapy-based regimen, including selective estrogen receptor modulators (SERMs), aromatase inhibitors, selective estrogen receptor down regulators (SERDs), CYP17A1 inhibitors, gonadotrophin releasing hormone (GnRH) agonists/antagonists, and antiandrogens; concurrent anti-HER2 therapy and other targeted therapy (e.g., CDK4/6 inhibitor, mTOR inhibitor) is permitted; must have started the current regimen at least 4 weeks prior to enrollment
* A response of at least 4 on a 10 point scale (with 0 = not tired at all and 10 = extremely tired) to the question ?how tired did you feel in the past week??
* Sedentary activity pattern (Average \< 90 minutes per week of moderate-to-vigorous intensity sports activity based on patient self-report) within the past year
* Physically able to exercise and physician consent to start an exercise program
* Regular access to a computer with internet service
* Must be able to read and understand English
* Able to provide informed consent and willing to sign an approved consent form that conforms to federal and institutional guidelines

Exclusion Criteria:

* Evidence of disease progression at the time of enrollment
* Treatment with cytotoxic chemotherapy within 3 months prior to enrollment
* Prior cognitive-behavioral therapy