THE EFFECTS OF R-1,3-BUTANEDIOL WITH CARBOHYDRATE SUPPLEMENTATION ON CYCLING PERFORMANCE ABOVE THE LACTATE THRESHOLD

Abstract

ABSTRACT Introduction: The purpose of this study was to examine the effects of R-1,3-Butanediol combined with carbohydrate supplementation on cycling performance above the lactate threshold. Exogenous ketones have gained attention as a potential benefit for exercise performance, serving as an alternative fuel source during exercise. Methods: A randomized, crossover design was performed in which eleven trained endurance athletes completed two experimental trials: ketone-plus-carbohydrate (KET+CHO) and a carbohydrate-only (CHO) condition. Participants consumed the beverage 30 minutes and immediately before exercise. Participants cycled at an intensity of 15% above their lactate threshold until volitional exhaustion on a cycle ergometer. Time to fatigue (TTF) served as the primary performance outcome variable. Physiological variables, including blood lactate, blood beta-hydroxybutyrate (HB), and blood glucose, were measured before, during, and after exercise. Results: No significant differences were observed between conditions for TTF (p = 0.59). However, the percent difference in TTF was 21.1% greater in the KET+CHO condition compared to the CHO condition. Blood HB concentration was elevated following ketone supplementation, confirming nutritional ketosis. No significant differences in blood lactate or blood glucose were observed between conditions. Conclusions: These findings suggest that R-1,3-Butanediol combined with carbohydrate supplementation does not significantly improve cycling performance above the lactate threshold in trained endurance athletes. Nevertheless, the observed increase in TTF may indicate a potential performance benefit that warrants further investigation with larger sample sizes, alternative dosing strategies, and other physiological measurements.