Cardiorespiratory response to physical conditioning in children with bronchial asthma.

The relationship of physical conditioning to changes in static lung volumes (hyperinflation) and airway dynamics (bronchoconstriction) as well as to ventilatory gas exchange, heart rate reserve, breathing reserves, and working capacity at a heart rate of 170/min (WC 170) was evaluated in 23 children (16 girls, 7 boys) between 6 and 15 years of age who had perennial asthma. Lung function tests including incremental cycle ergooxymetry were performed before and after a 15-week period of regular physical training (RPT). Lung function data obtained after RPT showed a significant improvement (P less than 0.05) in both hyperinflation and specific airway conductance, whereas oxygen consumption only increased related to lean body mass and heart rate. However, WC 170 and work tolerance during the endurance phase of the exercise test were significantly increased (P less than 0.05 and less than 0.01, respectively). In view of the relationship that has recently been found between exercise tolerance and lung mechanics in adults, the decreased hyperinflation and bronchoconstriction observed in our population after RPT is striking. This finding was presumably a consequence of the effect of RPT on breathing technique and chest wall mechanics. Ventilation of the lungs may improve because of mobilization of the costovertebral articulations, inspiratory muscle relaxation, an optimized force-length relationship of the respiratory muscles, and closer linkage between the diaphragm and intercostal muscles. Therefore, RPT might be an effective addition to standard drug regimens in the management of childhood asthma.