VO2peak

VO2peak is the highest rate of oxygen consumption achieved during an incremental exercise test, reflecting the peak capacity of the cardiorespiratory system to deliver and utilize oxygen in active muscles. It is commonly measured during a cardiopulmonary exercise test (CPET) with gas-exchange analysis and is expressed in milliliters of oxygen per kilogram of body mass per minute (ml/kg/min) or liters per minute (L/min).

VO2peak is not always equal to a true VO2max. VO2max refers to the maximal achievable oxygen uptake, usually indicated by a plateau in VO2 despite increasing workload. In many individuals, especially children, older adults, or when effort is submaximal, no plateau is observed and the highest tested value is reported as VO2peak.

Determinants of VO2peak include cardiac output, the arterial-venous difference for oxygen, skeletal muscle oxidative capacity, capillary density, mitochondrial content, and hemoglobin concentration. Training tends to raise VO2peak mainly through improvements in cardiac function and peripheral muscle adaptations. Values vary widely with age, sex, body size, and training status; well-trained endurance athletes often achieve substantially higher VO2peak than sedentary individuals.

VO2peak has clinical and athletic relevance. It serves as a prognostic indicator in heart failure, chronic obstructive pulmonary disease, and metabolic disorders, and it is used to tailor and monitor aerobic training programs. Limitations include dependence on effort and test protocol, potential day-to-day variability, and the fact that a peak value may not represent true maximal capacity if a plateau is not reached.