Cardiovascular endurance refers to the body's ability to efficiently deliver oxygen to working muscles during sustained physical activity. It is a critical component of overall fitness, reflecting the health and efficiency of the heart, lungs, and circulatory system. Individuals with high cardiovascular endurance can perform aerobic activities, such as running or cycling, for extended periods without excessive fatigue. Improving cardiovascular endurance typically involves regular participation in aerobic exercise, which strengthens the heart and enhances overall stamina.