Effects of Carbohydrate Mouth Rinse on Human Capacity and Performance-A Systematic Review and Meta-Analysis of 90 Controlled Trials.

Objective: The aim of the current systematic review and meta-analysis was to examine the acute effects of carbohydrate (CHO) mouth rinse on exercise capacity and performance in humans of any health and fitness status. Methods: We registered our systematic review with PROSPERO (CRD42018085308). Eligibility criteria included adult humans > 18 years old at any health and fitness status undertaking any CHO mouth rinse prior and during of any type of acute exercise session. Results: We included 90 crossover design-controlled trials. We found improvements in distance covered (Hedges' g = 0.17; 95% CI 0.03 to 0.30, p = 0.02; τ2 = 0.00; I2 = 0%; Q(14) = 9.61, p > 0.05), performance time (Hedges' g = -0.15; 95% CI -0.25 to -0.05, p < 0.01; τ2 = 0.008; I2 = 9.3%; Q(34) = 76.48, p < 0.01), speed performance (Hedges' g = 0.17; 95% CI 0.05 to 0.30, p < 0.01; τ2 ≈ 0; I2 = 0%; Q(23) = 22.73, p > 0.05), workload (Hedges' g = 0.25; 95% CI 0.08 to 0.41, p < 0.01, τ2 = 0; I2 = 0%; (Q(9) = 7.37, p > 0.05) and maximum voluntary contraction (MVC) (Hedges' g = 0.18, 95% CI 0.02 to 0.34, p = 0.03; τ2 = 0; I2 = 0%; (Q(10) = 7.73, p > 0.05). No effect of CHO mouth rinse on muscular endurance, maximum power output, or maximum oxygen consumption (VO2max) was found (p > 0.05). Conclusions: The available evidence suggests that CHO mouth rinse can produce a small, outcome-dependent ergogenic effect in distance covered, performance time and speed performance as well as small improvements in workload, with less robust evidence for MVC-evidence that mainly applies to male participants. The practical importance of these findings is likely to vary according to the exercise context and competitive context.