What is Vital Capacity?

• A. the amount of air in the lungs at rest
• B. the residual volume after a full exhale
• C. the maximal amount of air lungs receive IN and then push OUT after a respiratory cycle
• D. the total lung capacity

Answer: (C)

Vital Capacity is the maximum amount of air the lungs can move in one forced breath: you inhale as deeply as possible and then exhale as fully as possible. It equals the sum of tidal volume (air moved in a normal breath), inspiratory reserve volume (additional air you can inhale beyond a normal breath), and expiratory reserve volume (air you can exhale beyond a normal breath). It does not include residual volume, the air that remains in the lungs after a full exhale. That’s why it’s different from total lung capacity, which adds the residual volume to the vital capacity. The description that captures this idea is the one describing the maximal amount of air the lungs can receive in and then push out in a single respiratory effort.