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The effect of salbutamol on performance in elite non-asthmatic athletes

University of British Columbia

The effect of salbutamol on performance was studied in 7 male non-asthmatic elite (VO₂max ≥ 60 ml/kg/min) athletes. The subjects entered the study just prior to their competitive season. Salbutamol (2 puffs=200 µg) or placebo was administered by metered-dose inhaler, through a spacer device, 20 minutes prior to testing in a double-blind, randomized crossover design. Pulmonary functions including maximum flow volume curves were performed on the first two visits, at 5 intervals (pre-medication, 20 minutes post-medication, and 5, 10, and 20 minutes post-exercise). The first two sessions combined these pulmonary function measures with an exercise bout consisting of a continuously ramped cycle ergometer ride to exhaustion to determine maximal oxygen uptake (VO₂max), peak power, and maximal heart rate. Pulse oximetry was used to measure the oxygen saturation of hemoglobin. The next sessions involved performing a 45 minute ride at 70% of VO₂max, followed by a timed sprint to exhaustion. Lastly, a Wingate anaerobic test was used to measure total work and peak power. There was a non-significant decrease in VO₂max from a mean of 63.5 ml/kg/min (± 3.2) for the placebo (P) trial, to a mean of 62.6 (± 3.3) with salbutamol (S). No difference was found in peak power (P= 438 Watts ±26.3, S= 438 ±27.9) or maximum heart rate (P=191 beats/min ±5.4, S=191 ±6.0). The performance related variables of endurance sprint time (P=104 seconds ±22.8, S= 97 ±31.4), and Wingate peak power (P= 10.12 Watts/kg ±0.57, S= 9.97 ±0.60) showed a non-significant decrease, while the total work performed on the Wingate test (P= 19.30 kJ ±2.09, S= 19.61 ±1.54) displayed a non-significant increase. The data failed to show significance despite using statistical analysis with a level of significance of p<0.20 to maximize the power of the tests. There was a statistically significant (p<0.05) increase in post medication (pre-exercise) forced expiratory volume (FEV₁) of 4.5% with salbutamol. This baseline increase persisted post-exercise, but there was no interaction effect of salbutamol and placebo over time. This represents an expected effect in non-asthmatic individuals, and although statistical significance was achieved, the magnitude of difference is not considered to be clinically significant. It was concluded that a therapeutic dose of aerosol salbutamol does not have an ergogenic effect in elite non-asthmatic athletes and it is therefore recommended that inhaled salbutamol continue to be permitted in international competition for individuals with exercise induced asthma.

Text

2010-09-28

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http://hdl.handle.net/2429/28769

Physical Education

University of British Columbia

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