What is VO2peak and in what situations is it reported rather than VO2max?

• A. VO2peak is the same as VO2max.
• B. VO2peak is only measured during rest.
• C. VO2peak is the highest observed oxygen uptake in a test that may not reflect true maximal capacity; reported when a true VO2max cannot be achieved due to test limitations.
• D. VO2peak is unrelated to exercise.

Answer: (C)

VO2peak represents the highest oxygen uptake observed during a graded exercise test. It is used when a true maximal oxygen uptake, VO2max, cannot be demonstrated because the test ends before a plateau in oxygen consumption is reached or the subject cannot push to true maximum. VO2max is only established when VO2 stops increasing despite further increases in workload, signaling maximal aerobic capacity. In many practical situations—such as with certain populations (children, older adults, clinical patients) or when safety, time, or motivation limit the test—the plateau may not occur. In those cases, VO2peak is reported as the best available estimate of aerobic capacity, though it may underestimate the true VO2max. VO2peak is still about exercise and oxygen use; it isn’t measured at rest, and it isn’t unrelated to exercise.