It is well established that cardiorespiratory fitness (CRF) is inversely associated with numerous morbidities independent of age, biological sex, race or ethnicity, and commonly obtained risk factors. More recent evidence also demonstrates that the addition of CRF to multivariable risk prediction algorithms used to estimate cardiovascular disease risk improves risk stratification. However, it is neither feasible nor appropriate to perform an exercise test to quantify CRF during most routine clinical encounters. A growing number of studies have suggested that CRF can be assessed pragmatically and reasonably accurately without performing a maximal exercise test. The concept that CRF can be substantially improved in response to regular exercise consistent with consensus recommendations underscores the recommendation that CRF should be a routine measure—a vital sign—across health care settings. Herein, we provide a brief, narrative overview of the evidence in support of this recommendation.