Metabolic changes in exercise-induced and methacholine-induced bronchoconstriction.

Metabolic and physiological responses to graded exercise and methacholine challenge were investigated in asthmatics with or without exercise-induced bronchoconstriction. The results showed that after methacholine challenge, free fatty acid levels increased only in patients with exercise-induced asthma, while they increased in both groups of asthmatics after treadmill exercise. No significant changes were noted in plasma lactic acid levels, ventilation, or oxygen consumption among the groups studied. These data suggest that asthmatics with exercise-induced bronchoconstriction may differ from other asthmatics in some of their metabolic responses.