No Benefit of Ingestion of a Ketone Monoester Supplement on 10-km Running Performance

Eight endurance-trained runners performed, in a double-blind randomized crossover design, 1 hour of submaximal exercise at about 65 percent VO2max followed by a 10 km time trial. They drank a carbohydrate-electrolyte solution either alone or with 573 mg/kg of ketone monoester. The ketone monoester gave plasma beta-hydroxybutyrate of about 1.0 to 1.3 mM during exercise, while glucose, lactate, VO2, running economy, heart rate and perceived exertion were similar. The 10 km time trial did not differ (p = 0.483) between ketone monoester (mean 2402 s) and carbohydrate alone (mean 2422 s), and cognitive performance was also unchanged.