What does VO2 represent in the context of physical fitness?

In the context of physical fitness, VO2 refers to the volume of oxygen that the body can utilize during intense exercise. Specifically, it measures the body's ability to extract and deliver oxygen to the muscles, which is a critical aspect of aerobic fitness. High VO2 max values indicate a greater efficiency of the cardiovascular and respiratory systems in delivering oxygen and a higher capacity for sustained physical activity. This is particularly important for activities that require endurance, as it directly correlates with an individual's aerobic endurance and overall cardiovascular health.

While the heart's output during exercise is related to VO2, it does not fully encapsulate the concept, as VO2 includes not just the heart's output but also how effectively the body utilizes the oxygen delivered. Additionally, total oxygen consumption at rest does not reflect the maximum capacity the body can achieve during physical exertion, and the level of fitness based on muscle strength is distinctly different from the assessment of aerobic capacity that VO2 provides. Hence, option A accurately represents what VO2 conveys regarding physical fitness.