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

Abstract

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 (V_E/Vo₂) and alveolar ventilation (V_A/Vo₂) equivalent, and a corresponding decrease of the physiological dead space/tidal volume ratio (V_D/V_T) 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 V_E/Vo₂ increased by 22% and V_D/V_T by 169% while PAo₂-Pao₂ was unchanged. The V_T/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.

Key Words:

• Dead space
• PAo₂-Pao₂ difference
• physical training
• prepubertal boys
• pulmonary gas exchange
• pulmonary ventilation