Development & Validation of Preoperative Objective Physiological Evaluation

All surgical patients presenting at the Preoperative Anesthesia \& Surgical Screening (PASS Clinic) will complete the Duke Activity Status Index (DASI) self-reported questionnaire as standard of care. If the DASI score is 34 or greater, the patients will not be considered for the study. If the DASI score is 33 or lower, the patient will be considered as a potential study participant. Eligible study participants will then complete a sub-maximal exercise test (Six Minute Step Test, 6MST) with measured VO2. The VO2 is an integral part of preoperative assessment of cardiorespiratory fitness (CRF). A low CRF is associated with a higher incidence of post-operative complications and mortality. The study will evaluate the ability to estimate VO2 from exercise-derived measurement with questionnaire-derived estimation.