Effects of a herbal drink on cycling endurance performance

In this study, we examined the effects of acute ingestion of a herbal drink (H) or a coloured water placebo (P) on physiological responses and performance during cycling exercise. Eight healthy and trained male young cyclists (age: 16.0±0.5years) exercised on a cycle ergometer at 72.0±0.8% of the maximal oxygen consumption (VO2max) until exhaustion in a room maintained at 23.9±0.2 oC and 64.2±1.6% relative humidity on two occasions, 1-week apart. During each exercise bout, subjects received 3ml.kg-1 body weight of H or P every 20 minutes in a doubleblind randomised study design. There was no significant difference between H and P trials in the total work time to exhaustion (84.5±5.1 and 82.3±5.6 min respectively). Changes in heart rate, oxygen consumption, plasma glucose concentrations, plasma lactate concentrations, rectal temperature, respiratory exchange ratio and energy expenditure were similar with both type of drinks. Loss of plasma volume was also similar with both drinks. Herbal drink elicited similar physiological responses, thermoregularity responses and exercise performances during endurance cycling when compared to the placebo ingestion. Thus, it can be concluded that the ingredient in the herbal drink did not provide any added advantage to cycling endurance performance. In both the herbal (H) drink and placebo (P) trials, time taken for exhaustion to occur were similar, and they were 84.5 ± 5.1 min and 82.3 ± 5.6 min respectively (p>0.05). The total volume of fluid consumed during exercise was also similar in both drinks, 751.0± 49.6 ml and 727.6 ± 42.7 ml in the H and P trials respectively. As a result of exercise, subjectsâ body weight decreased 0.7 ± 0.2 kg (2.6 ± 0.5%) and 0.8 ± 0.2 kg (2.8 ± 0.5%) in the H and P trials respectively, and these values were corrected for the fluid ingested during cycling. The decrease in body weight as expressed both in kg and percentage change of body weight with P did not differ statistically from H. Similar hemoglobin concentrations and hematocrit were noted at each time point during the H trial when compared with P trial. The percentage change of plasma volume relative to the preexercise level is shown in Figure 1. Plasma volume declined significantly (p