Acute inhalation of salbutamol increases endurance performance in well-trained, non-astmatic athletes
The ß2-agonist salbutamol is one of the most widely used drugs to treat asthma. Its bronchodilatatory and systemic effects have also drawn the attention of the athletic community because of their potential ergogenicity. This study examined the effects of a single supratherapeutic dose (800 µg) salbutamol by inhalation on lung function and endurance performance. Sixteen well-trained male cyclists and triathletes (23±3 yr; 73±6 kg; 12.0±2.9 fat%; 11.2±3.4 hours of training per week; 416±40 Wmax) participated in this study. All participants were non-asthmatic, which was confirmed by an exercise provocation test. Exercise performance was measured by means of a time trial on a magnetically braked cycle ergometer (Lode Excalibur) in a double-blind, randomized, placebo controlled cross-over protocol. Each subject performed two time trial tests, which were separated by at least 4 and maximally 13 days. The following lung function parameters were measured using a Microspiro Hi-298 (Chest): peak expiratory flow (PEF), the one-second value of forced expiratory volume (FEV1), forced ventilatory capacity (FVC), and the percentage of FEV1/FVC.
After salbutamol treatment the time to complete the time trial was lower than after placebo (3928±231 vs. 4010±328 s). A one-tailed paired t-test proved this difference to be significant (p=0.0274). Salbutamol also significantly increased PEF, FEV1, and FEV1/FVC before exercise; PEF remained elevated after completion of the test (one minute post-exercise). This study shows that the expiratory flow of healthy subjects at rest and after completion of an endurance test is increased after the administration of salbutamol. The results of this study also suggest that a single supratherapeutic dose of 800 µg salbutamol increases endurance performance in well-trained, non-asthmatic athletes.
Ingestuurd per e-mail op 2/11/98; Confirmation number: 10528
The literature about this subject is somewhat contradictory concerning short lasting exercises, but regarding endurance exercises no effects have ever been found. However, the studies performed so far never used doses above 400 µg of inhaled salbutamol, as this is the maximal used dose in the general treatment of asthma. It is questionable whether athletes who consider the use of a ß2-agonist as an ergogenic aid would restrict themselves to such restraints.
O.M. de Hon(1), F. Hartgens(1), M.A. van Baak(2), L.J.R.M. Buisman(1), G. Rietjens(1)
1. Netherlands Centre for Doping affairs, Rotterdam
2. Maastricht University, Dept. of Human Biology, Maastricht, the Netherlands
