Inhaled Salbutamol and Endurance Cycling Performance in Non-Asthmatic Athletes

Abstract

Beta(2)-adrenergic agonists are important therapeutic agents for the prevention and treatment of (exercise-induced) asthma in athletes, but may have ergogenic effects. In this study we investigated whether inhalation of a supra-therapeutic dose of 800 microg salbutamol before exercise affects endurance performance during a cycling trial in non-asthmatic athletes. In a double-blind, randomized cross-over study, 16 athletes performed two trials, where they had to perform a certain amount of work as fast as possible on a cycle ergometer, 30 minutes after inhalation of 800 micro g salbutamol or placebo. Peak expiratory flow (PEF), forced vital capacity (FVC), and forced expiratory volume in 1 second (FEV(1)) were measured before and after exercise and blood samples were obtained before and during exercise. Cycling performance time was 4010.2 +/- 327.7 s after placebo inhalation and 3927.6 +/- 231.3 s after inhalation salbutamol (p < 0.05). Although salbutamol inhalation increased plasma free fatty acids, glycerol and lactate concentrations and decreased plasma potassium concentrations at rest, no differences between placebo and salbutamol in these variables were found during exercise. PEF and FEV(1) were increased after salbutamol inhalation at rest compared with placebo, but the difference between placebo and salbutamol after exercise was no longer significant. Inhalation of a supratherapeutic dose of 800 micro g salbutamol improved endurance cycling performance by 1.9 +/- 1.8 % in non-asthmatic athletes, which indicates that this route of administration does not exclude the possibility of an ergogenic effect of beta(2)-adrenergic agents in athletes. The increase in performance was not explained by changes in plasma concentrations of free fatty acids, glycerol, lactate, and potassium during exercise or by changes in ventilatory parameters at rest and after exercise. Therefore, the mechanism of the increase in performance remains to be determined.

Salbutamol intake and substrate oxidation during submaximal exercise

“…The authors reported that salbutamol did not affect VO 2 , respiratory exchange ratio, or plasma FFA but blood lactate appeared significantly increased during this exercise. It must be, however, noticed that findings on the effects of salbutamol on FFA and on lactate during exercise are inconsistent, other studies reporting no change or significant increase in these parameters after salbutamol administration at higher intensities (Van Baak et al 2000, 2004Collomp et al 2000aCollomp et al , b, 2002Collomp et al , 2005.…”

“…Cycling performance was significantly improved with salbutamol, with concomitant higher exercise lactate and free fatty acid (FFA) concentrations during the last part of exercise. However, Van Baak et al tested the effects of both acute salbutamol intake (4 mg) (Van Baak et al 2000) and of a supra-therapeutic salbutamol inhalation dose (800 lg) (Van Baak et al 2004) and also reported improvement in performance without any significant change in FFA during exercise performed, respectively at 70% W max and during another trial where the subjects had to perform a certain amount of work as fast as possible on a cycle ergometer. Blood lactate concentrations appear either increased in the first study (Van Baak et al 2000) aforementioned (70% W max ) or unchanged in the 2nd study mentioned (Van Baak et al 2004).…”

High-dose inhaled terbutaline increases muscle strength and enhances maximal sprint performance in trained men

“…While several studies have investigated effects of clinical therapeutic inhalation of beta 2 -agonists (2-4 puffs) on submaximal, supramaximal, and time-trial performance (Sporer et al 2008;van Baak et al 2004;McKenzie et al 1983;Carlsen et al 1997;Signorile et al 1992), effects of supratherapeutic high-dose inhalation of beta 2 -agonists are inadequately explored. To our knowledge, only one study by Elers et al (2012b), has investigated the effects of high-dose inhalation of salbutamol (40 × 200 µg) on incremental exercise performance, whereas no studies exist investigating the effects of high-dose inhaled beta 2 -agonist on muscle strength and supramaximal exercise performance.…”

The Impact of Exercise-Induced Bronchoconstriction on Athletic Performance: A Systematic Review

“…In contrast, some researchers have observed performance benefit; Van Baak et al [55] reported that 800 µg salbutamol significantly improved time-trial performance in well-trained amateur non-asthmatic male cyclists and triathletes (n = 16) by 1.9 ± 1.8% (P<0.05). However, lung function increased significantly following administration of salbutamol versus placebo suggesting some of the subjects may have had undiagnosed airway obstruction.…”