Respiratory Air Volumes and Capacities

Vital capacity (VC)

maximum volume of air that can be exhaled after taking the deepest breath possible: VC=TV+IRV+ERV

Expiratory reserve volume (ERV)

maximum volume of air that can be exhaled in addition to resting tidal volume

Inspiratory capacity (IC)

maximum volume of air that can be inhaled following exhalation of resting tidal volume: IC=TV+IRV

Inspiratory reserve volume (IRV)

maximum volume of air that can be inhaled in addition to resting tidal volume

Total lung capacity (TLC)

total volume of air that the lungs can hold: TLC=VC+RV

Tidal volume (TV)

volume of air moved in or out of the lungs during a respiratory cycle

Residual volume (RV)

volume of air that remains in the lungs at all times

Functional residual capacity (FRC)

volume of air that remains in the lungs following exhalation of resting tidal volume: FRC=ERV+RV