0261 MOOD MEDIATES THE RELATIONSHIP BETWEEN GLUCOSE AND PERFORMANCE DURING SLEEP LOSS

Abstract

Sleep loss disrupts how the body utilizes glucose, and glucose bioavailability influences attention and cognitive self-control. Recent results from our lab demonstrated that 15 grams of glucose in solution sustained psychomotor vigilance during 40 hours of continuous wakefulness. The time course of this effect, relative performance sustainment for seven hours, went beyond expectations for direct neuronal nutrition. Mood, glucose, and performance are also mechanistically tied in various literatures. Therefore, we tested a mediation model of supplemental glucose on performance during sleep loss via self-reported mood. 20 college students stayed awake for 40 hours. Cognitive performance and mood were quantified while rested, then every three hours across the sleep deprivation period. Participants received 15 grams of glucose solution or an equivalent sucralose placebo at hours 18 and 36. Participant mood and cognitive function were analyzed by group across time using a bootstrapping mediation model. As observed in previous results, participants in the sucralose condition committed an average of 2.83 more lapses than the glucose condition 7 hours post-dose, 22 hours into continuous wakefulness (path C, p < .05). However, sucralose participants also reported 10.17 more subjective fatigue units than glucose participants at the same time point (path A), while their subjective fatigue score predicted their lapse rate (path B). When paths A and B are added to the original path C, the effect disappears (path C’ = .99), indicating a near complete mediation of that effect by subjective fatigue, z = 2.26, p < .05, K2=.40. Strategic glucose supplementation can temporarily sustain performance during total sleep deprivation within certain parameters. Specifically, performance sustainment is achieved via prevention of negative mood development (subjective fatigue). Glucose prevents the development of negative mood, which optimizes conditions for positive motivation. Positive motivation provides a small but measurable boost in performance as quantified by continuous engagement with the psychomotor vigilance task. Additional analyses to understand the magnitude and reach of this effect are underway. This work was completed as part of contract N62645-14-P-2046 under direction of the Naval Medical Research Unit - Dayton.