The effect of Siberian ginseng (Eleutherococcus senticosus) on substrate utilization and performance during prolonged cycling

It has been suggested that Eleutherococcus senticosus (ES), also known as S iberian ginseng or ciwuija, increases fat utilization in humans. The purpos e of this study was to examine the physiological responses to supplementati on with ES in endurance cyclists. Using a randomized, double-blind crossove r design, 9 highly-trained men (28 +/- 12 years, (V)over dotO(2max) 57.3 +/ - 2.0 ml.kg(-1).min(-1)) cycled for 120 min at approximate to 60% (V) over dotO(2max) followed by a simulated 10-km time trial. Diet was controlled, a nd ES (1,200 mg.day(-1)) or a placebo (P) were administered for 7 days prio r to each of the two trials. Oxygen consumption, respiratory exchange ratio , and heart rate were recorded every 30 min, and rating of perceived exerti on, plasma [lactate], and plasma [glucose] were recorded every 20 min durin g the 120 min of steady state cycling. There were no significant difference s (p > .05) between the ES and P groups at any steady-state time interval o r during the cycling time trial (ES = 18.10 +/- 0.42, P = 17.83 +/- 0.47 mi n). In contrast with previous reports, the results of this study suggest th at ES supplementation does not alter steady-state substrate utilization or 10-km cycling performance time.