What is expiratory reserve volume?

• A. Largest amount of air that can be forcibly exhaled, normal is 1-1.2 L.
• B. Amount of air that can be forcibly inhaled after normal inspiration, normal is 3.3 L.
• C. The amount of air that cannot be forcibly exhaled.
• D. Air remaining after residual volume.

Answer: (A)

Expiratory reserve volume is the extra amount of air you can forcibly exhale after you have completed a normal exhale. It reflects how much you can push out beyond a typical breath, using the strength of the expiratory muscles and the elastic recoil of the lungs. In healthy adults, this is about 1 to 1.2 liters, though it can vary with body size, age, and conditioning.

This is distinct from the inspiratory reserve volume, which is the extra air you can inhale after a normal inhalation, and from the residual volume, which is the air that remains in the lungs after a maximal exhale and cannot be forcibly expelled.