[Comparison of exercise and histamine provocation tests in patients with bronchial asthma]

Fifty-eight asthmatic patients (22 men and 36 women), aged 17 to 61 years, participated in this study. Thirty-two of them had atopic asthma. Exercise test and histamine inhalation challenge test were performed in all subjects. Patients exercised on a bicycle ergometer for 6-8 min. to increase the heart rate to 80% of predicted maximal heart rate. Twenty-three patients had a bronchospasm following exercise. The PC20 values in patients with exercise induced asthma (Me = 0.35 mg/ml) were significantly lower (p = 0.006) than in subjects without exercise induced asthma (Me = 1.89 mg/ml). There was low but statistically significant correlation between PC20 and delta FEV1 after exercise (R(s) = 0.32; p = 0.01). These results suggest that there are not only similarities but also differences in pathomechanisms of bronchial hyperreactivity to histamine and exercise-induced bronchoconstriction. The lack of statistically significant correlation between diurnal PEF variation and PC20 values suggest that the former parameter cannot be considered as an useful marker of nonspecific bronchial hyperreactivity.