INDIVIDUALIZED TRAINING REDUCES EXCESSIVE EXERCISE HYPERVENTILATION IN ASTHMATICS

The reduction of excessive exercise hyperventilation in asthmatics is a major pathophysiological aim of retraining programmes. Excessive hyp erventilation gives rise to highly unpleasant subjective feelings and is linked to a decreased stroke volume, probably due to heart-lung int eraction. The purpose of this study was thus to determine whether indi vidualized aerobic training at ventilatory threshold decreases the ven tilatory requirement during exercise, and whether such training change s the exercise breathing patterns. Nine asthmatic children were traine d at an intensity corresponding to their individual ventilatory thresh old (V-Th) for 3 months. Nine other asthmatic children served as contr ols. After aerobic training, a significant increase in V-Th occurred ( p < 0.01). A significant reduction in ventilatory response was also ob served at any given oxygen uptake (p < 0.001). In addition, the more i ntense the exercise, the greater the ventilatory requirement savings w ere. A stepwise regression analysis showed that the amount of reductio n in ventilatory requirement is proportional to the severity of the pr e-training obstruction (p < 0.02). The post-training exercise breathin g pattern was characterized by a systematic increase in V-T and V-T/Ti for a given level of ventilation (p < 0.001). In conclusion, this stu dy shows that individualized aerobic training reduces the excessive as thmatic exercise ventilation, improves exercise breathing patterns, an d the more severe the bronchial obstruction, the greater the ventilati on savings were.