Cardiorespiratory fitness - Wikipedia
https://en.wikipedia.org/wiki/Cardiorespiratory_fitnessCardiorespiratory fitness (CRF) refers to the ability of the circulatory and respiratory systems to supply oxygen to skeletal muscles during sustained physical activity. The primary measure of CRF is VO2 max. In 2016, the American Heart Association published an official scientific statement advocating that CRF be categorized as a clinical vital sign and should be routinely assessed as part of clinical practice.