Move over Blood Pressure: Make Room for Cardiorespiratory Fitness as a Vital Sign

Cardiorespiratory fitness (CRF) describes the ability of an individual to perform physical exercise, an activity that relies on the cardiovascular system's capacity to facilitate oxygen delivery to working muscles and the pulmonary system's ability to clear carbon dioxide from the blood. Ideally, CRF is measured using cardiopulmonary stress testing (exercise with analysis of gas exchange). To enhance the feasibility of assessing CRF in large populations, prediction equations using only exercise variables were developed to provide measures of estimated CRF. More recently, nonexercise methods of assessing CRF have been developed. Using exercise (objective) methods of measuring CRF, a robust evidence base has developed describing the inverse association of CRF with total mortality, nonfatal cardiovascular events, incident cancer, cancer survival, chronic conditions, and dementia; CRF has also been shown to be inversely related to development of cardiac risk factors including hypertension. Because CRF provides a strong, graded inverse association with cardiovascular and all-cause mortality, recent American Heart Association scientific statements have vigorously promoted the concept of CRF as a vital sign: All adults should have an estimation of CRF included in their annual health care visits along with resting blood pressure (BP), heart rate, and body mass index (BMI). The addition of CRF as a vital sign provides enhanced risk prediction that can improve patient care and encourage the incorporation of physical activity (PA) programs into treatments plans aimed at improved health outcomes.