Effects of Terbutaline Sulfate on Physiological and Biomechanical as Well as Perceived Exertion in Healthy Active Athletes: A Pilot Study

This study aimed to investigate the effects of beta2-agonist terbutaline sulfate (TER) at a supra-therapeutic dose (8 mg) on aerobic exercise performance. Twelve (6 females and 6 males) amateur athletes familiarized with all experimental procedures had their anthropometric data obtained on day 1. On days 2 and 3 either 8 mg of TER or a placebo (PLA) was administered orally (double-blind manner) to participants who had rested for 3 h prior to aerobic exercise performance 20 m multistage fitness test (MSFT)]. This test was used to predict maximal oxygen uptake (VO_2max) and velocity at which VO_2max occurs (vVO_2max). The Borg rating of perceived exertion (RPE), cardiovascular variables [heart rate (HR) and blood pressure (BP)] and blood glucose concentration [BGC] were obtained 15 min pre- and immediately post-MSFT. Significant mean group differences were reported between PLA and TER groups (p < 0.05), respectively, in the RPE (15.6 ± 1.2 vs. 17.3 ± 1.5 a.u.), maximum heart rate (HR_max: 191.2 ± 7.1 vs. 197.2 ± 8.6 bpm) and BGC (118.4 ± 18.3 vs. 141.2 ± 15.8 mg/dL) post-MSFT. The main effect of gender (male vs. female) in TER and PLA groups (p< 0.05) was observed, with higher estimated VO_2max, vVO_2max, HR_max and a lower mean HR pre-test in male than female athletes. For these reasons, the inclusion of TER in the Prohibited List should be re-discussed because of the lack of ergogenic effects.