Ketone monoester attenuates declines in cognitive performance and oxygen saturation during acute severe hypoxic exposure under resting conditions

In a single-blind randomized crossover study, 16 male military personnel performed cognitive tests at rest in room air, normoxia and hypoxia (6096 m, 9.7 percent O2, 20 minutes) after ketone monoester (650 mg/kg, split dose) or taste-matched placebo. Ketone monoester raised blood beta-hydroxybutyrate above 4 mM at 30 minutes and lowered blood glucose by about 20 mg/dL. The decline in cognitive efficiency during hypoxia was attenuated, with 6.8 more correct responses per minute than placebo (p = 0.018), and oxygen saturation was higher (76.8 vs 70.4 percent, p = 0.049).