The effect of formoterol inhalation on endurance performance in hypobaric conditions

Introduction: Inhaled 92-agonists are important therapeutic agents for the treatment of exercise-induced asthma in athletes but are restricted by international antidoping regulations. Purpose: To investigate whether 18 mu g of inhaled formoterol affects endurance performance during running at high altitudes until exhaustion among 20 nonasthmatic male athletes aged 21-35 yr. Methods: In a randomized, double-blind, placebo-controlled crossover study, the athletes performed one screening test and two similar performance tests. Each performance test consisted of 20 min of warm-up and a running test until exhaustion, which lasted 210-300 sin hypobaric conditions equal to 2000 m above sea level. Maximal oxygen consumption (VO2max) and peak ventilation (V-Epeak) were measured during running, and pulmonary function was measured before and after exercise. The screening test was used to determine running speed on days 2 and 3, with inhaled formoterol or placebo in a randomized manner before exercise. VO2, V-E, arterial oxyhemoglobin saturation (SPO2), and heart rate (HR) were measured during exercise, and maximum plasma lactate concentration was measured after exercise. Results: Inhaled formoterol did not improve running time to exhaustion, VO2, V-E, SPO2, or HR (P > 0.05) in hypobaric conditions compared with placebo, although formoterol significantly improved lung function (FEV1 and FEF50) 15 and 30 min before exercise and 3, 6, 10, and 15 min after exercise. Conclusions: Inhaled fotmoterol did not improve endurance performance in healthy nonasthmatic athletes at hypobaric conditions equal to 2000 m above sea level. Inhaled formoterol can thus be used by asthmatic athletes in sports under extreme conditions.