Popular asthma control drugs β2-agonists such as Albuterol, Formoterol, Terbutaline, etc. that are used as inhalers by millions of asthmatics around the world could have power and stamina enhancing properties in sportspersons, finds a new study. The analysis titled, “Can β2-agonists have an ergogenic effect on strength, sprint, or power performance? Systematic review and meta-analysis of RCTs” was published in the latest issue of the British Journal of Sports Medicine.
The researchers belonging to Faculty of Teacher Education, Art, and Sport, Western Norway University of Applied Sciences, Sogndal, Vestlandet, Norway and Norwegian University of Sport and Physical Education, Oslo, Norway, gathered study data from several randomized controlled trials to check the effects of the asthma drugs on sportspersons’ performance.
Sportspersons and β2-agonists
The team explains that asthma is one of the most frequent chronic diseases prevalent around the world and among all age groups. Athletes, they explained, need increased ventilation while performing and thus are at a higher risk of asthma. They added that athletes participating in the Olympic Games are most commonly diagnosed with asthma. The athletes with asthma are commonly prescribed inhaled glucocorticoids with inhaled β2-agonists before a performance to prevent the risk of asthmatic attacks during their performance. β2-agonists help asthmatics by opening up of the lung airways and helping them breathe better.
Due to the controversy regarding performance-enhancing effects of β2-agonists, the International Olympic Committee’s (IOC) Medical Commission banned their use prior to competing in 1972. The World Anti-Doping Agency (WADA) that controls the use of substances and drugs before performance also updated their list, and the latest list on 1st January continues to include β2-agonists. The researchers wrote that the WADA prohibits, “all use of β2-agonists except inhaled salbutamol (maximum 1600 μg over 24hours in divided doses not to exceed 800 μg over 12hours starting from any dose), inhaled formoterol (maximum delivered dose of 54 μg over 24hours) and inhaled salmeterol (maximum 200 μg over 24 hours).”
Studies testing performance enhancing activity of β2-agonists
Several studies have shown that asthmatic sportspersons outperform their counterparts who do not have asthma. Studies have thus looked at its effects on performance among sportspersons. A joint Task Force of the European Respiratory Society (ERS) and the European Academy of Allergy and Clinical Immunology (EAACI), however, states that there is no evidence that the physical performance of athletes could be improved using anti-asthma drugs.
The purpose of this study was to look at all available evidence and assess the effects of β2-agonists on “anaerobic performance in healthy non-asthmatic subjects.”
What was done?
This was a systematic review and meta-analysis looking at the existing evidence. For this study, the team of researchers looked through related studies in four databases, including PubMed, Embase, SPORTDiscus, and Web of Science. They included only the randomized controlled trials, which are considered to be gold standards in research. Studies published until December 2019 were included in this analysis. These studies were those that looked at the effect of β2-agonists on “maximal physical performance lasting 1min or shorter”.
For the analysis, the team used statistical tools such as the standardised difference in mean (SDM) with 95% confidence intervals (95% CI).
What was found?
For this analysis, the team included 34 suitable studies. There were 44 different studies. These were either randomized trials that compared β2-agonists with other controls or with placebo. A total of 323 participants were included from crossover trials. These trials involve all participants being included in the active drug treatment arm (here β2-agonists) by turns. The analysis also included 149 participants who were part of parallel trials where they were compared with control or placebo groups.
Results showed that β2- agonists improved anaerobic performance of healthy non-asthmatic adults by 5% (standardized difference in mean 0.29, 95% CI 0.16 to 0.42). This enhancement of effect was, however, was related to the route by which the β2-agonists were administered. Further, they noted;
- For approved β2- agonists the SDM was 0.14 (95% CI 0.00 to 0.28)
- For prohibited β2-agonists the SDM was 0.46 (95% CI 0.24 to 0.68)
- For inhaled administration of the β2- agonists the SDM was 0.16 (95% CI 0.02 to 0.30)
- For oral administration of the β2- agonists the SDM was 0.51 (95% CI 0.25 to 0.77)
- For acute treatment with the β2- agonists the SDM was 0.20 (95% CI 0.07 to 0.33)
- For treatment for multiple weeks with the β2- agonists the SDM was 0.50 (95% CI 0.20 to 0.80)
- β2-agonists improved performance in strength by SDM 0.35, 95% CI 0.15 to 0.55. A 6 percent improvement in weight lifting exercises was seen.
- β2-agonists improved performance in sprints by SDM 0.17, 95% CI 0.06 to 0.29. A 3 percent improvement in sprint exercises was seen.
The study authors wrote that this study proves from the available evidence that “non-asthmatic subjects can improve sprint and strength performance by using β2-agonists”. They added that it is not clear if WADA approved doses of β2-agonists could improve performance. Further oral administration enhances performance more than the inhaled administration of the β2-agonists. They wrote in conclusion, “Our results support that the use of β2-agonists should be controlled and restricted to athletes with documented asthma.”
- Riiser A, Stensrud T, Stang J, et al, Can β2-agonists have an ergogenic effect on strength, sprint or power performance? Systematic review and meta-analysis of RCTs, British Journal of Sports Medicine Published Online First: 03 August 2020. doi: 10.1136/bjsports-2019-100708, https://bjsm.bmj.com/content/early/2020/07/15/bjsports-2019-100708