Age-related changes in static maximal inspiratory and expiratory pressures

We evaluated 240 consecutive subjects (aged 20-91) without cardiopulmonary, endocrine or, neuromuscular disease consecutively regarding pulmonary function (TLC, VC, FEV1, RV) and static maximal inspiratory (PImax) and expiratory (PEmax) pressures. PImax and PEmax declined with advancing age. PImax correlated with grip strength, VC, FEV1, height, weight, and RV/TLC. PEmax also correlated with grip strength, TLC, VC, FEV1, height, and weight. Age, height, weight, and grip strength were entered stepwise into multiple linear regression models with PImax or PEmax as the dependent variable. Stepwise regression analysis revealed that grip strength was an independent predictor for both PImax and PEmax. However, age itself was not an independent predictor for PImax or PEmax. These results suggest that static maximal respiratory pressures decrease with aging, and that age-dependent changes in respiratory muscle function may depend on other factors, including lung volume, skeletal muscle status, and body composition.