Inhaled β2-agonists are important therapeutic agents for the treatment of exercise-induced asthma in athletes but are restricted by international antidoping regulations.
To investigate whether 18 μg of inhaled formoterol affects endurance performance during running at high altitudes until exhaustion among 20 nonasthmatic male athletes aged 21-35 yr.
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 s in hypobaric conditions equal to 2000 m above sea level. Maximal oxygen consumption (V˙O2max) 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. V˙O2, V˙E, arterial oxyhemoglobin saturation (SPO2), and heart rate (HR) were measured during exercise, and maximum plasma lactate concentration was measured after exercise.
Inhaled formoterol did not improve running time to exhaustion, V˙O2, 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.
Inhaled formoterol 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.
1Norwegian University of Sport and Physical Education, Oslo, NORWAY; 2Voksentoppen BKL, Rikshospitalet, Oslo, NORWAY; and 3Oslo Research Group of Asthma, Allergy in Children, Lung and the Environment, Oslo, NORWAY
Address for correspondence: Amund Riiser, Norwegian University of Sport and Physical Education, Postboks 4014 Ullevâl Stadion, 0806 Oslo, Norway; E-mail: email@example.com.
Submitted for publication February 2006.
Accepted for publication June 2006.