What measurement indicates the efficiency of the cardiovascular system?

Maximal oxygen uptake, also known as VO2 max, is a critical measurement for assessing the efficiency of the cardiovascular system because it reflects the maximum rate at which the heart, lungs, and muscles can utilize oxygen during intense exercise. This metric provides insight into how well the cardiovascular system can supply oxygen to the working muscles and is influenced by various factors including heart size, stroke volume, and the efficiency of oxygen extraction in the muscles.

A higher VO2 max indicates better cardiovascular fitness and endurance, meaning the individual's cardiovascular system is more efficient at delivering oxygen and removing carbon dioxide. This capacity is essential for athletic performance and overall health, particularly during prolonged physical activities.

In contrast, while resting heart rate can provide some information about cardiovascular fitness—lower resting rates are typically indicative of better cardiovascular health—it does not measure the maximal capacity of the system like VO2 max does. Muscular strength assesses the ability of muscles to exert force, which is not directly related to cardiovascular efficiency. Similarly, body fat percentage relates more to body composition and general health rather than to the direct functioning of the cardiovascular system.