A Study on the Effects of Exercise on Side Effects From Treatment for Gastrointestinal Cancers

Inclusion Criteria: * Aged ≥18 years * Diagnosed with colorectal or esophago/gastric solid tumors as defined by one of the following: * Histological confirmation * As per standard of care imaging * Scheduled to receive neoadjuvant chemotherapy or chemotherapy for newly diagnosed metastatic disease * Performing ≤90 minutes of structured moderate-intensity or strenuous-intensity exercise per week, as evaluated by self-report * Willingness to comply with all study-related procedures * Cleared for exercise participation as per screening clearance via the Physical Activity Readiness Questionnaire Exclusion Criteria: * Enrollment onto any other lifestyle interventional investigational study, except interventions determined by the PI not to confound study outcomes * Receiving treatment for any other diagnosis of invasive cancer * Mental impairment leading to inability to cooperate * Any other condition or intercurrent illness that, in the opinion of the investigator, makes the subject a poor candidate for study participation