Plasma catecholamines during exercise-induced bronchoconstriction in bronchial asthma.

Abstract

Plasma levels of adrenaline [epinephrine] and noradrenaline [norepinephrine] during and after submaximal exercise in patients with bronchial asthma were investigated. Three groups were studied comprising 10 patients with exercise-induced bronchoconstriction (EIB), 10 asthmatic patients without EIB and 4 normal control subjects. Plasma catecholamines were measured at rest, at the end of exercise and 5 and 15 min after exercise. Changes in airway resistance were assessed by measuring peak expiratory flow rate. Significant differences in catecholamine levels between reacting and non-reacting patients were found. In 10 patients developing EIB, adrenaline and noradrenaline levels rose significantly by the end of exercise and remained elevated up to the 5th min of recovery. The rise in catecholamine levels in nonreacting asthmatics was insignificant. In control subjects noradrenaline increased significantly by the end of exercise.