Ketone Monoester Supplementation Effects on a Comprehensive Cognitive Test Battery Following Non-Exhaustive Exercise

Abstract Ketone monoester (KME) supplementation has been suggested to preserve or enhance cognitive performance, but its effects across cognitive domains during non-exhaustive exercise remain unclear. We aimed to investigate whether KME improves cognitive performance during moderate-intensity exercise in healthy young men. In a randomized, double-blind, placebo-controlled, crossover study, 9 recreationally active healthy males (mean ± SD: age: 26 ± 5 year, V̇O 2max : 47 ± 4 mL·kg −1 ·min −1 ) completed two experimental trials involving 90 min of cycling at 60% V̇O 2max . Participants consumed either KME or tasted-matched placebo (PLA) drinks around exercise (total 0.75 g·kg −1 ). A comprehensive cognitive test battery (CTB) of validated tests assessed memory, attention, inhibitory control, and visual processing before and after exercise (tests included delayed recall, spatial span, digit span, endogenous and exogenous covert shift of attention, Stroop task, psychomotor vigilance task, global form perception, and global motion perception). Post-exercise blood β-Hydroxybutyrate concentrations were higher in the KME (3.3 ± 0.5 mM) vs. PLA (~ 0.1 ± 0.0 mM; P < 0.01). Only global motion perception showed a time x condition interaction ( P = 0.044), whereby KME rescued the decay observed in PLA. Moderate-intensity exercise of 90 min did not affect other cognitive performance metrics ( P > 0.05) and KME did not enhance cognitive function relative to PLA in any other domain tested ( P > 0.05). KME supplementation during 90-min of moderate-intensity non-exhaustive exercise preserved global motion perception but did not improve other cognitive performance in healthy young males.