Inclusion Criteria:  Adult (≥ 18 years of age) patients undergoing elective abdominal oncologic resection of a confirmed or potential colorectal, hepatobiliary, or gynecologic neoplasm. Study participants must be able to provide written informed consent and authorization. Study participants must be able to understand written and verbal English, as well as to be able to communicate in English. Study participants must have an Apple iphone to use during the study period  Exclusion Criteria:  Any patient unable and/or unwilling to cooperate with all study protocols. Patients who require an assist device (walker) for ambulation. Patients that score "High" on the IPAQ questionnaire (indicating they already do at least 3 days of vigorous intensity activity (≥1500 MET minutes/week) OR ≥7 days of any combination of walking, moderate-intensity or vigorous-intensity (≥3000 MET minutes/week) Recent history of cardiac disease (within 3 months of registration) that would preclude vigorous exercise Individuals with end stage renal disease currently on dialysis Individuals with a history of liver failure as evidenced by AST, ALT or Alkaline Phosphatase ≥ 3x upper limit of normal Individuals with hemoglobin less than 11 d/gL for women and less than 14 d/gL for men Individuals with uncontrolled hypertension Women who are breastfeeding or pregnant American Society of Anesthesiologists Physical Status score ≥ 4 Any patient that needs further cardiac evaluation per ACC/AHA perioperative criteria Surgery scheduled < 3 weeks of study registration (precluding time to participate in exercise regimen) Any patient who currently uses a fitness tracker or heart rate monitoring-capable device to guide exercise Patient indicates a lack of familiarity or discomfort with using a smartphone If participation is not in the best interest of the patient, in the opinion of the treating investigator