Failure of chronic Ginseng supplementation to affect work performance and energy metabolism in healthy adult females

Ginseng has long been used for various medicinal reasons in East Asia and has recently also become a popular nutritional supplement in Western countries. Although commonly alleged to increase work performance by enhancing the body resistance to stress and fatigue, human experimental research evidence to either support or refute these claims is limited and conflicting. Therefore, this randomized, double-blind, placebo-controlled study served to examine a group of healthy adult females who for eight weeks added 200 mg . day(-1) of a concentrated extract of Panax Ginseng C.A. Meyer (n=10) or placebo (n=9) to their otherwise supplement-free normal diet. Before and after the trial intervention, each subject performed a graded maximal cycle ergometry test to exhaustion and completed a standard habitual physical activity questionnaire. It was observed that chronic ginseng supplementation had no effect on maximal work performance (J) and resting, exercise, and recovery oxygen uptake (VO2, ml . kg(-1). min(-1)), respiratory exchange ratio (RER), minute ventilation (VE, L . min(-1)), heart rate (beats . min(-1)), and blood lactic acid (mmol . L(-1)) levels (p>0.05). Habitual physical activity scores of study participants were found to be similar between the placebo and ginseng treatment groups and at the beginning and end of the eight week trial period (p>0.05). The present data in healthy adult females indicate that chronic dietary supplementation with a standardized extract of Panax Ginseng C.A. Meyer does not result in an enhancement of work performance or a change in energy metabolism and improvement of the recovery response from maximal physical work.