Effects of Exercise in Patients With Metastatic Breast Cancer

Inclusion Criteria: * Diagnosis of breast cancer stage IV * ECOG (Eastern Cooperative Oncology Group scale) performance status ≤ 2 * Able and willing to perform the exercise program and wear the activity tracker Exclusion Criteria: * A potential subject who meets any of the following criteria is not eligible for enrolment into this study: * Unstable bone metastases inducing skeletal fragility as determined by the treating clinician * Untreated symptomatic known brain metastasis * Estimated life expectancy \< 6 months as determined by the treating clinician * Serious active infection * Too physically active (i.e. \>210 minutes/week of moderate-to-vigorous intentional exercise * Severe neurologic or cardiac impairment according ACSM criteria * Uncontrolled severe respiratory insufficiency as determined by the treating clinician or if the patient is dependent on oxygen suppletion in rest or during exercise * Uncontrolled severe pain * Any other contraindications for exercise as determined by the treating physician * Any circumstances that would impede adherence to study requirements or ability to give informed consent, as determined by the treating clinician * Pregnancy