Abstract

To determine the effects of long term exercise on respiratory muscle strength, maximal inspiratory (Pl max) and expiratory (PE max) pressures, pulmonary volumes and capacities and anthropometric parameters were measured in a group of 101 male runners aged 16 to 58 years. The runners exhibited significantly (p less than 0.05) lower PE max (202 +/- 41 cm H2O and significantly greater residual lung volumes (RV) (2.08 +/- 0.49 L) than predicted values for normal subjects of similar height and age. Forced vital capacities were not different (p greater than 0.05) from values reported for normal non-smoking populations. These data suggest that running may cause a non-pathological increase in RV, perhaps mediated by reductions in expiratory muscle strength. Additionally, current RV regression equations developed for normal subjects may be inappropriate for use in running populations.