VanHaitsma, T. A., Mickleborough, T. D., Lindley, M. R., Kocega, D., & Stager, J. M. (2009). Comparative and synergistic effects of caffeine and albuterol on the severity of exercise-induced bronchoconstriction. ACSM 56th Annual Meeting, Seattle, Washington. Presentation number 2544.

Previous research has demonstrated a beneficial effect of caffeine on preventing exercise-induced bronchoconstriction. This study aimed to extend previous published findings that have demonstrated a beneficial effect of caffeine on exercise-induced bronchoconstriction by evaluating the comparative and synergistic effects of caffeine and albuterol (b2-agonist) on the severity of exercise-induced bronchoconstriction. Asthmatics (N = 10) with exercise-induced bronchoconstriction served as Ss. One hour before an exercise challenge, each S was given 0, 3, 6, or 9 mg/kg of caffeine or placebo mixed in a flavored sugar drink. Fifteen minutes before the exercise bout, an inhaler containing either albuterol (180 µg) or placebo was administered to each S. Pulmonary function tests were conducted pre- and post-exercise (1, 5, 10, 15, and 30 minutes). The exercise challenge was running on a motorized treadmill to volitional exhaustion while breathing dry air from a gas tank.

Caffeine significantly reduced the mean maximum percentage fall in post-exercise FEV1 at 6 and 9 mg/kg when compared to the placebo and baseline conditions. There was no significant difference in the post-exercise percentage fall in FEV1 between albuterol (without caffeine) and the 9 mg/kg dose of caffeine. Interestingly, there was no significant difference in the post-exercise percentage fall in FEV1 between albuterol (without caffeine) and albuterol with 3, 6, or 9 mg/kg of caffeine. Similar changes noted for the post-exercise percentage fall in FEV1 were also observed for FVC, FEF25-75%, and PEF. It was determined that a dose-response relationship existed between the percentage fall in post-exercise FEV1 and caffeine dose administered (0, 3, 6, and 9 mg/kg) for all dependent variables.

Implication. Moderate (6 mg/kg) to high doses (9 mg/kg) of caffeine reduced the severity of exercise-induced bronchoconstriction in a dose-response manner. No significant difference existed between high doses of caffeine and albuterol which suggests that caffeine may represent an alternative to albuterol for reducing the severity of exercise-induced bronchoconstriction. [Albuterol is a banned substance that is supposed to have performance-enhancing qualities. Here it was shown to have similar effects to the non-banned caffeine.]

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