Purpose of review: Carbohydrate during exercise has been demonstrated to improve exercise performance even when the exercise is of high intensity (>75% VO2max) and relatively short duration (approximately 1 h). It has become clear that the underlying mechanisms for the ergogenic effect during this type of activity are not metabolic but may reside in the central nervous system.
Recent findings: Carbohydrate mouth rinses have been shown to result in similar performance improvements. This would suggest that the beneficial effects of carbohydrate feeding during exercise are not confined to its conventional metabolic advantage but may also serve as a positive afferent signal capable of modifying motor output. These effects are specific to carbohydrate and are independent of taste. The receptors in the oral cavity have not (yet) been identified and the exact role of various brain areas is not clearly understood. Further research is warranted to fully understand the separate taste transduction pathways for simple and complex carbohydrates and how these differ between mammalian species, particularly in humans.
Summary: Carbohydrate is detected in oral cavity by unidentified receptors and this can be linked to improvements in exercise performance.