Which pulmonary function parameter does not change with aging?

• A. Total lung capacity remains constant throughout aging
• B. Residual volume increases
• C. Vital capacity decreases
• D. Functional residual capacity increases

Answer: (A)

As people age, the lungs and chest wall undergo changes that favor more air remaining in the lungs after a breath, but these changes tend to cancel out when considering total capacity. The best answer reflects that total lung capacity stays about the same across adulthood because increases in residual volume offset decreases in vital capacity.

Residual volume rises with age due to decreased elastic recoil of the lungs and less effective expiratory effort, leading to more air trapped at the end of expiration. Functional residual capacity also increases for the same reason, since it’s the sum of RV and expiratory reserve volume. Vital capacity, on the other hand, declines because the maximal amount of air you can inhale and exhale is reduced with aging.

Since total lung capacity equals the sum of vital capacity and residual volume (TLC = VC + RV), the rise in RV and FRC is offset by the decline in VC, leaving TLC relatively unchanged in healthy aging.