Individualized training reduces excessive exercise hyperventilation in asthmatics

Abstract

The reduction of excessive exercise hyperventilation in asthmatics is a major pathophysiological aim of retraining programmes. Excessive hyperventilation gives rise to highly unpleasant subjective feelings and is linked to a decreased stroke volume, probably due to heart-lung interaction. The purpose of this study was thus to determine whether invididualized aerobic training at ventilatory threshold decreases the ventilatory requirement during exercise, and whether such training changes the exercise breathing pattern. Nine asthmatic children were trained at an intensity corresponding to their individual ventilatory threshold (VTh) for 3 months. Nine other asthmatic children served as controls. After aerobic training, a significant increase in VTh occurred (p < 0.01). A significant reduction in ventilatory response was also observed at any given oxygen uptake (p < 0.001). In addition, the more intense the exercise, the greater the ventilatory requirement savings were. A stepwise regression analysis showed that the amount of reduction in ventilatory requirement is proportional to the severity of the pre-training obstruction (p < 0.02). The post-training exercise breathing pattern was characterized by a systematic increase in VT and VT/Ti for a given level of ventilation (p < 0.001). In conclusion, this study shows that individualized aerobic training reduces the excessive asthmatic exercise ventilation, improves exercise breathing patterns, and the more severe the bronchial obstruction, the greater the ventilation savings were. © Williams & Wilkins 1995. All Rights Reserved.