Carbohydrate Mouth Rinse and Hydration Strategies on Cycling Performance in 30 Km Time Trial: A Randomized, Crossover, Controlled Trial

The aim of this study was to investigate whether carbohydrate mouth rinse (CMR) improves physical performance of cyclists during a 30-km time trial test and its influence on water balance compared to other strategies of fluid intake. Eleven recreationally trained male cyclists completed a 30 km time trial cycle ergometer under three experimental interventions: (a) CMR, (b) drinking to replace all weight loss (DWL), and (c) drinking “ad libitum” (DAL). Time to complete the 30 km time trial, heart rate, average power, velocity, weight loss, urine color, urine density and pH were evaluated. Statistical analysis was performed using repeated measures analysis of variance (RM-ANOVA) and generalized estimating equations (GEE) with Bonferroni adjustment (p < 0.05). Time to complete the 30 km time trial was similar among CMR 54.5 ± 2.9 min, DWL 53.6 ± 3.9 min and DAL 54.5 ± 2.5 min (p = 0.13). CMR (1.7 ± 0.4%) elicited similar water loss compared to the DAL (1.4 ± 0.6%) intervention, but it was higher than the DWL intervention (0.6 ± 0.6%) (p < 0.01). CMR did not improve the performance of recreationally trained cyclists in a 30 km time trial test compared to other fluid intake strategies. Furthermore, CMR causes higher water loss compared to DWL intervention

The effect of carbohydrate mouth rinse on performance, biochemical and psychophysiological variables during a cycling time trial: a crossover randomized trial

Abstract Background The hypothesis of the central effect of carbohydrate mouth rinse (CMR) on performance improvement in a fed state has not been established, and its psychophysiological responses have not yet been described. The aim of this study was to evaluate the effect of CMR in athletes fed state on performance, biochemical and psychophysiological responses compared to ad libitum water intake. Methods Eleven trained male cyclists completed a randomized, crossover trial, which consisted of a 30 km cycle ergometer at self-selected intensity and in a fed state. Subjects were under random influence of the following interventions: CMR with a 6% unflavored maltodextrin solution; mouth rinsing with a placebo solution (PMR); drinking “ad libitum” (DAL). The time for completion of the test (min), heart rate (bpm) and power (watts), rating of perceived exertion (RPE), affective response, blood glucose (mg/dL) and lactate (mmol/DL), were evaluated before, during and immediately after the test, while insulin (uIL/mL), cortisol (μg/dL) and creatine kinase (U/L) levels were measured before, immediately after the test and 30 min after the test. Results Time for completion of the 30 km trial did not differ significantly among CMR, PMR and DAL interventions (means = 54.5 ± 2.9, 54.7 ± 2.9 and 54.5 ± 2.5 min, respectively; p = 0.82). RPE and affective response were higher in DAL intervention (p < 0.01). Glucose, insulin, cortisol and creatine kinase responses showed no significant difference among interventions. Conclusions In a fed state, CMR has not caused metabolic changes, and it has not improved physical performance compared to ad libitum water intake, but demonstrated a possible central effect. ReBec registration number: RBR-4vpwkg. Available in http://www.ensaiosclinicos.gov.br/rg/?q=RBR-4vpwkg