Cardiovascular fitness is best described as the endurance of what body systems?

• A. Heart and lungs
• B. Muscles only
• C. Joints
• D. Nervous system

Answer: (A)

Cardiovascular fitness is about how efficiently the heart and lungs can sustain oxygen delivery to the body during ongoing activity. When you exercise, the heart pumps blood more rapidly, the lungs work to take in and transfer oxygen, and the blood vessels transport this oxygen-rich blood to working muscles. The better this cardio-respiratory system endures, the longer you can perform aerobic activity before fatigue limits you. Muscles have their own endurance, but that describes muscular endurance, not the capacity of the cardio-respiratory system. Joints and the nervous system matter for movement and coordination, yet cardiovascular fitness specifically centers on the endurance of the heart and lungs.