This study will compare the measured oxygen consumption (VO2) obtained during sub-maximal exercise testing with the estimated VO2 derived from a non-exercise questionnaire.

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.

Inclusion Criteria:

• Age 18 and older
• Able to speak English
• Ambulatory [assistive devices ok]
• Preoperative Anesthesia and Surgical Screening (PASS) clinic patient with DASI score <34
• Able to provide informed consent

Exclusion Criteria:

• Acute myocardial infarction (3-5 days)
• Unstable angina
• Severe untreated arterial hypertension at rest (>200 mm Hg systolic, >120 mm Hg diastolic)
• Resting heart rate > 120 bpm
• Room air desaturation at rest on room air <85%
• Inmate of correctional facility (i.e. prisoner)
• Diagnosed history of dementia
• Inability to ambulate independently
• Considered inappropriate to participate by Principal Investigator