Field exercise vs laboratory eucapnic voluntary hyperventilation to identify airway hyperresponsiveness in elite cold weather athletes

Abstract

Study objective: For the 2002 Winter Olympic Games, athletes were required to submit objective evidence of asthma or exercise-induced bronchoconstriction (EIB) for approval to inhale a β2-agonist. Eucapnic voluntary hyper-ventilation (EVH) was recommended as a laboratory challenge that would identify airway hyperresponsiveness (AHR) consistent with EIB. The objective was to compare the change in FEV1 provoked by EVH with that provoked by exercise in cold weather athletes. Design: Spirometry was measured before and for 15 min after challenges. The two challenges were performed in random order at least 24 h apart. Setting: EVH was performed in the laboratory at 19°C, and exercise took place in the field in the cold (2°C, 45% relative humidity). Participants: Thirty-eight athletes (25 female subjects; median age, 16 years). Interventions: For the EVH, athletes inhaled dry air containing 5% carbon dioxide for 6 min at a target ventilation equivalent to 30 times baseline FEV1. Exercise was performed by cross-country skiing, ice skating, or running for 6 to 8 min. Measurements and results: AHR consistent with EIB was defined as ≥ 10% fall in FEV1 from baseline after challenge. Eleven athletes were exercise positive (EX+) [FEV 1 fall, 20.5 ± 7.3%], and 17 athletes were EVH positive (FEV1 fall, 14.5 ± 4.5%) [mean ± SD]. Of 19 subjects with AHR, 58% were identified by exercise and 89% were identified by EVH. EVH identified 9 of 11 subjects who were EX+ and a further 8 subjects with potential for EIB. The average ventilation during EVH was 28 times FEV 1. Conclusion: Performing EVH for 6 min in the laboratory had a greater chance of identifying AHR in these athletes compared with 6 to 8 min of field exercise in the cold. The EVH test will be useful to evaluate elite summer sports athletes whose widely different forms of exercise provide an "equipment" challenge to any laboratory.