Bicarbonate Unlocks the Ergogenic Action of Ketone Monoester Intake in Endurance Exercise

Nine well-trained male cyclists completed a simulated race of 3 hours of submaximal cycling, a 15-minute time trial and an all-out sprint in a randomized crossover design, receiving 65 g ketone ester, sodium bicarbonate at 300 mg/kg, both together, or a control drink, with 60 g/h carbohydrate. Ketone ester raised blood D-beta-hydroxybutyrate to about 2 to 3 mM but lowered blood pH from 7.43 to 7.36 and bicarbonate from 25.5 to 20.5 mM. Adding bicarbonate raised blood bicarbonate to 31.1 mM and pH to 7.51, and gastrointestinal symptoms were similar between groups.