A Comparison of the Effects of a Carbohydrate Mouth Rinse on Cycling Performance in Depleted and Non-depleted Glycogen States

Abstract

Performance improvements have been reported when mouth rinsing with a carbohydrate (CHO) solution during short duration, high intensity endurance exercise. Limited research has been conducted in this area when endogenous CHO stores are depleted. PURPOSE: The purpose of this study was to assess the effects of a CHO mouth rinse on endurance-trained cyclists during a 30-kilometer time trial in depleted vs. non-depleted glycogen states. METHODS: 5 endurance-trained men (28±7 years; 179.32±8.15 cm; 68.65±8.16 kg; 54.00±5.95 mL/kg/min VO2 max) participated in a repeated measures crossover study using a CHO mouth rinse (6.4% maltodextrin) or placebo. RESULTS: Subjects completed the time trial faster (p=0.033) in the non-depleted state, despite reporting lower RPE (p=0.010). There was no significant treatment effect, but subjects completed the time trial 20 seconds faster in the depleted CHO mouth rinse condition. Power output was significantly higher (p=0.010) in non-depleted than depleted conditions; no significant treatment effect was observed. RER was significantly higher (p=0.001) in the non-depleted state; no significant differences were observed between mouth rinses. A mouth rinse segment interaction (p=0.028) was observed for heart rate in the last 6k for the CHO mouth rinse condition, indicating a possible increase in effort over the last segment of the time trial. CONCLUSION: CHO mouth rinse may be a valuable tool for performance enhancement in suboptimal nutrition states. Further, the results supported current knowledge regarding performance in depleted and non-depleted glycogen states.