The primary function of the cardiovascular system in relation to fitness is to transport oxygen and nutrients to tissues while removing waste products. This system plays a crucial role in delivering oxygen to working muscles during exercise, enabling peak performance and recovery. A well-functioning cardiovascular system enhances overall endurance, supports efficient metabolic processes, and aids in the delivery of hormones. Regular exercise strengthens the heart and blood vessels, improving their efficiency and increasing blood flow, which is essential for maintaining optimum fitness levels.