What does cardiovascular fitness refer to?

Cardiovascular fitness specifically refers to the ability of the heart and lungs to efficiently supply oxygen to the muscles during sustained physical activity. This involves the efficient functioning of the cardiovascular and respiratory systems, which work together to deliver oxygen-rich blood to the tissues and remove carbon dioxide and other metabolic wastes. When someone engages in activities that raise their heart rate over an extended period, such as running, swimming, or cycling, cardiovascular fitness plays a crucial role in determining how long they can sustain these activities.

The other options, while related to fitness, do not accurately define cardiovascular fitness. The first option focuses on muscular strength rather than cardiovascular capabilities. The third option mentions long-distance running, which is a manifestation of cardiovascular fitness but does not encapsulate the broad concept itself. Lastly, the ability to recover from intense activity pertains to recovery fitness, which is a different aspect of physical conditioning. Therefore, the definition emphasizing the heart and lungs' role in oxygen supply during sustained activity is the most accurate description of cardiovascular fitness.