Short-Term(-)-Hydroxycitrate Ingestion Increases Fat Oxidation during Exercise in Athletes

Abstract

(-)-Hydroxycitrate (HCA) is known to inhibit increasing malonyl CoA concentration during endurance exercise. Furthermore, a short-term administration of HCA enhances endurance exercise performance in mice. Therefore we investigated the shortterm administration of HCA on the exercise performance of athletes. Subjects were administered 250mg of HCA or placebo as a control (CON) for 5d, after each time performing cycle ergometer exercise at 60% VO₂max for 60min followed by 80% VO₂max until exhaustion. Blood was collected and expired gas samples analyzed at rest and every 15min. The respiratory exchange ratio was significantly lower in the HCA trial than in the CON trial (p<0.05). Fat oxidation was significantly increased by short-term administration of HCA, and carbohydrate oxidation was significantly decreased (p<0.05) during exercise, presumably resulting in increasing the cycle ergometer exercise time to exhaustion after 1h of 60% VO₂max exercise (p<0.05). These results suggest that a short-term administration of HCA enhances endurance performance with increasing fat oxidation, which spares glycogen utilization during moderate intensity exercise in athletes.