Beta-2 Agonists Can Improve Athletes' Speed and Strength

By Lisa Rapaport

August 07, 2020

(Reuters Health) - Beta-2 agonists can improve speed and strength in athletes without asthma, according to a new study that also suggests this might be true for versions of these drugs that have not been banned by the World Anti-Doping Agency (WADA).

Researchers conducted a systematic review and meta-analysis and examined data from 34 studies covering 44 randomized controlled trials with a total of 472 participants. Overall, beta-2 agonists improved anaerobic exercise performance in people without asthma by 5% (standardized difference in mean (SDM) 0.29) compared with placebo.

"This shows that non asthmatic athletes can perform better in sports if they use beta-2 agonists illegally," said lead study author Amund Riiser, an associate professor at Western Norway University of Applied Sciences.

"Beta-2 agonists should not be prohibited in athletic completions, because they are a necessary treatment for athletes with asthma, but they should be regulated and controlled, and limited to those with an asthma diagnosis documented with objective tests" Riiser said by email.

WADA has banned all beta-2 agonists except certain doses of inhaled formoterol, salbutamol, and salmeterol.

When researchers looked at these approved forms of beta-2 agonists separately from banned versions of these drugs, the banned versions had a statistically significant increase in performance (SDM 0.46) but the approved versions did not (SDM 0.14).

This suggests that more research is needed to determine whether approved beta-2 agonists boost athletic performance, the study team concludes in the British Journal of Sports Medicine.

Oral beta-2 agonists had a bigger impact on performance (SDM 0.51) than inhaled formulations (SDM 0.14), the study also found.

The effect of beta-2 agonists was also more pronounced after multiple weeks of treatment (SDM 0.50) than after acute treatment (SDM 0.20).

One limitation of the study is that the smaller studies used in the analysis varied widely in design and methodology, the study team notes. It's also possible that results measured in a lab might not represent what would happen during live competition.

"I don't think this study will have a huge impact on clinician guidelines, as they would normally follow the respective national or international guidelines," said Morten Hostrup, an associate professor in the department of nutrition, exercise and sports at the University of Copenhagen.

"However, the study may have the ability to indirectly affect prescriptions of beta2-agonists to athletes in the future if WADA decides to change the beta2-agonist regulations," Hostrup, who wasn't involved in the study, said by email.

SOURCE: British Journal of Sports Medicine, online August 3, 2020.