Structural and physiological age-associated changes in aging lungs.

The tissues of the lungs undergo changes with age that lead to an increase in alveolar size without any destruction of alveolar walls. This lowers the alveolar surface tension and so reduces the elastic recoil of the lungs, which in turn causes a reduction in maximum achievable flow in the airways during the breathing cycle. Muscle performance diminishes with age and the chest wall becomes stiffer, which together lead to an increased residual volume and also counter the possible increase in total lung capacity (TLC) from the reduced elastic recoil. Exercise performance falls with age, with a small decrease in arterial oxygenation that stabilizes over the age of 70 years. Predicting lung function for the elderly is not easy, and basing clinical decisions on percent of predicted may lead to age, sex, and height bias. Focusing on what function remains can allow survival predictions to guide decisions on treatment options. © Thieme Medical Publishers.