What does the term "cardiovascular endurance" refer to?

Cardiovascular endurance specifically refers to the body's capability to sustain prolonged physical activity by efficiently supplying oxygen to the muscles through the combined efforts of the heart and lungs. This endurance is crucial during activities such as running, cycling, or swimming, where the body requires a consistent flow of oxygen to keep the muscles functioning over an extended period.

When the heart pumps oxygen-rich blood throughout the body, it enables the muscles to perform endurance tasks without fatigue. This physiological process involves both aerobic capacity, which is heavily influenced by cardiovascular health, and the efficiency of the respiratory system in delivering oxygen and removing carbon dioxide. In contrast, the other options are related to different aspects of fitness or physical health, such as muscular endurance, heart muscle strength, and flexibility, but they do not capture the essence of cardiovascular endurance as it specifically relates to oxygen transport and utilization during sustained activities.