Ketone monoester attenuates oxygen desaturation during weighted ruck exercise under acute hypoxic exposure but does not impact cognitive performance

In a single-blind randomized crossover study, 16 males did cognitive assessments before and during hypoxic exposure in a normobaric altitude chamber (4572 m, 11.8 percent O2) with moderate weighted ruck exercise. They co-ingested 40 g of dextrose with a ketone monoester (573 mg/kg) or a calorie- and taste-matched placebo of about 50 g maltodextrin. Beta-hydroxybutyrate concentrations stayed above 3 mM with the monoester (P < 0.001). Cognitive tasks (code substitution, Stroop, and a shooting simulation) did not differ between trials.