Cardiovascular fitness is defined as the ability of the heart, lungs, and circulatory system to supply oxygen during sustained physical activity. It is a critical component of overall health and is often measured through activities like running, cycling, or swimming. Good cardiovascular fitness improves endurance, decreases the risk of heart disease, and enhances overall metabolic function. Achieving and maintaining cardiovascular fitness requires a combination of regular aerobic exercise, a balanced diet, and adequate rest to support heart and lung health.