ERV values decreases with increases in age. The volume of air in lungs after maximum exhalation. Averages are usually between 1.0 to 1.2 liters for women and 1.2 to 1.4 for men. RV tends to increase with age and cannot be measured directly. It is commonly measured indirectly via the helium dilution method.
Vital capacity is related to age, height, and gender.
The total volume of air that can be voluntarily moved during one breath, from maximum inspiration to maximum expiration. Values vary considerably with body size and body positions during the measurement. It represents the middle and large airways and indicates expiratory power. The average rate of flow during the middle half of a forced expiratory volume. This value reflects the medium and smaller sized airways.