Different Types Of Carbohydrate Mouth Rinses Do Not Improve Performance In Cyclists

Carbohydrate (CHO) mouth rinsing has been suggested as a strategy to improve endurance performance by activating receptors in the mouth that stimulate brain areas linked to the reward system. Despite some evidence of potential benefits, results remain inconclusive, and few studies have examined the effects of different CHO types or the possible placebo effect of mouth rinsing. PURPOSE: The aim of the study was to investigate the effect of mouth rinsing with different types of carbohydrates on the performance of male amateur cyclists. An additional objective was to assess the potential placebo effect of carbohydrate mouth rinsing. METHODS: A randomized, double-blind, placebo-controlled, crossover study was conducted with 12 amateur cyclists who completed the test under four conditions: mouth rinse with maltodextrin, fructose, placebo (non-caloric juice), and a no-rinse condition. The testing protocol included an initial incremental test to determine maximum power, followed by four subsequent visits where participants completed a time trial protocol. Each session consisted of a 3-minute warm-up at 90 revolutions per minute (RPM), followed by a 30-minute time trial. The first 15 minutes consisted of constant cycling at 90 RPM and 65% of peak power output, followed by a 15-minute time trial in which volunteers exerted maximal effort. Power output, heart rate (HR), and rating of perceived exertion (RPE) were recorded. The differences in power output between groups were evaluated across the entire duration (30 minutes), specifically during the steady-state phase (first 15 minutes) and the time-trial phase (final 15 minutes). A one-way ANOVA was conducted to compare the mean power output and a two-way ANOVA was applied to assess group-time interaction effects on HR and RPE across different interventions. RESULTS: No significant differences were observed in total power output (MALT = 242.3 W; FRUCT = 238.9 W, PLA = 241.7 W, CON = 240.5 W; p = 0.996), and time-trial power (p = 0.989) across the various conditions. Additionally, neither rinsing with different types of carbohydrates nor the placebo condition influenced HR (p = 0.649) or RPE (p = 0.343). CONCLUSIONS: Carbohydrate mouth rinsing did not enhance male cyclists' performance in time trials or produce a placebo effect, suggesting limited ergogenic benefit.