Effect of Physical Training on Pulmonary Ventilation and Gas Exchange during Submaximal and Maximal Work in Boys Aged 11 to 13 Years

Pulmonary ventilation and gas exchange were studied in 9 boys aged 11 to 13 years at rest and during submaximal (500 kpm/min) and maximal exercise (750–1200 kpm/min) before and after a 16-week period of systematic physical training. Adaptation to maximal exercise was characterized by a sharp increase of the total (VE/Vo2) and alveolar ventilation (VA/Vo2) equivalent, and a corresponding decrease of the physiological dead space/tidal volume ratio (VD/VT) and PaCO2. While Pao2 was unchanged, the alveolo-arterial oxygen tension difference (PAo2.Pao2) increased significantly during maximal work. Training resulted in increased dead space ventilation and higher PAo2-Pao2 at submaximal work while oxygen uptake was unchanged. At maximal exercise, performed at a 10 % higher work load, oxygen uptake and VE/Vo2 increased by 22% and VD/VT by 169% while PAo2-Pao2 was unchanged. The VT/VC ratio had increased from 0.40 to 0.52. The physical training resulted in a significantly higher degree of ‘wasted’ ventilation which means that the boys became more comparable to adults.