Plethysmography study and pulmonary function in well-trained adolescents.

The values of lung volumes (VC, FRC, TGV, FEV1.0, etc.) and airway resistances (Raw, Raw) were measured by the spirometry and plethysmography method in 35 physically well trained, healthy adolescents, aged 14 to 20 years, boys and girls coming from various schools from the Grenoble area. The data were correlated with body height and some also with age or weight through linear, exponential or power law relationships. All volumes increased with height (Ht), which was the best independent variable, with some preference for a linear representation. However the increase of lung volumes with height was also well reproduced by an exponential function proportional for all volumes to e0.020Ht in good agreement with recent results obtained for young children. Some significant sex differences were observed for lung volumes. Airway resistance measured by two different methods (Raw and Raw) decreased with height with some preference for a linear relationship. The mean airway resistance (Raw) obtained from a complete inspiration-expiration curve while the subject breathed at his own spontaneous breathing rate was systematically smaller (from 0.5 to 1 cmH2O/l/s) than Raw measured by a technique similar to the panting method. No sex differences for airway resistances or conductances were observed. Specific airway conductance was found to be age and height independent.