Plasma adenosine concentration increases during exercise: A possible contributing factor in exercise-induced bronchoconstriction in asthma

We investigated whether the level of plasma adenosine (ADO) changed during exercise and whether this could be related to exercise-induced bronchoconstriction. Baseline levels of ADO did not differ, but exercise resulted in higher ADO in patients with asthma than in healthy subjects (86 ± 35 vs 59 ± 16 nmol/L; P < .001). In patients with asthma, the increase in ADO was related to decreases in FEV 1 ( r 2 = 0.475; P < .05) and SaO 2 ( r 2 = 0.693; P < .05). These data suggest that adenosine might be involved in the development of exercise-induced bronchoconstriction. (J Allergy Clin Immunol 2002;109:446-8.)