Exercise-induced bronchospasm in nonasthmatic obese children.

The frequency, degree, and pattern of bronchial reactivity to exercise were compared in 13 obese and 14 control children, ages 6 to 10 years, with no history of asthma. Spirometry was performed before and every three minutes after a seven-minute exercise challenge on a treadmill. There were 11 obese children and 6 controls who had at least a 15% fall in at least one of three monitored pulmonary function parameters (P < .05). The group mean percentage falls in FEV1 and FEF25%-75% were significantly greater in the obese group than in the controls. The pattern of bronchospasm, occurring soon after the exercise challenge, is consistent with that found in the known asthmatic population. A significant correlation was found between triceps skin-fold thickness and degree of fall in FEF25%-75% (r = .55, P < .005). This study demonstrated that significantly greater frequency and degree of bronchospasm of the smaller airways occur in obese children, partially related to the amount of subcutaneous fat. Whether exercise-induced bronchospasm leads to exercise avoidance and obesity or whether obesity causes or enhances bronchial hyperreactivity to exercise requires further study.