Reducing the dose of combined caffeine and ephedrine preserves the ergogenic effect

Background: Ingestion of a combination of 5 mg . kg(-1) caffeine (C), and 1 mg . kg(-1) ephedrine (E) was reported to have an ergogenic effect on high intensity aerobic exercise performance, but 25% of the subjects experience d vomiting and nausea while engaging in hard exercise after the treatment. The present study was undertaken to investigate whether reduced levels of C + E would alleviate the problem and maintain the ergogenic effect. Mefhods : Twelve healthy untrained male subjects completed four randomized and doub le-blind, cycle ergometer trials to exhaustion at a power output equivalent to similar to 85% (V) over dotO(2)peak 1.5-2 hours after ingesting a place bo (P) or a mixture of C + E in the following doses: 5 mg . kg(-1) of C plu s 0.8 mg . kg(-1) of E (CLE); 4 mg . kg(-1) of C plus 1 mg . kg(-1) of E (L CE); or 4 mg . kg(-1) of C plus 0.8 mg . kg(-1) of E (LCLE). Trials were se parated by 1 wk. Venous blood samples were obtained and analyzed for caffei ne and ephedrine levels 1.5 h post-drug ingestion, (V) over dotO(2), (V) ov er dotCO(2), (V) over dotE, and RQ were measured every minute throughout th e exhaustion ride. Heart rate and perceived exertion (RPE) were also record ed every 5 min and at the end of the exercise session. Results: Plasma leve ls of C and E immediately before the exhaustion ride were (mean +/- SD): 38 .7 +/- 5.2 mu mol . L-1 C, 1.285 +/- 0.275 mu mol . L-1 E in the CLE trial; 33.2 +/- 5.8 mu mol . L-1 C, 1.462 +/- 0.283 mu mol . L-1 E in the LCE tri al; 33.0 +/- 2.9 mu mol . L-1 C, 1.229 +/- 0.202 mu mol . L-1 E in the LCLE trial. The times to exhaustion for the treatment trials (CLE = 27.5 +/- 12 .4 min, LCE = 27.6 +/- 10.9 min, LCLE = 28.2 +/- 9.3 min) were similar and were significantly greater than placebo (p = 17.0 +/- 3.0 min). The drugs d id not affect (V) over dotO(2), (V) over dotCO(2), or (V) over dotE. Heart rates were significantly higher for the drug trials while RPE was lower com pared with P, No incidents of nausea or vomiting occurred with the lowest d ose of the C + E, LCLE. Conclusions: A lower dose of C + E resulted in an e rgogenic effect similar in magnitude to that reported previously with a hig her dose, and with a reduced incidence of negative side effects.