Strategies to Augment Ketosis: Ketone Conferred Resiliency Against Sleep Restriction

Only 1 in 3 U.S. Army Active Component Soldiers are estimated to get the target =7-hr of sleep on duty days, and \~14% have a sleep disorder. Insufficient sleep has profound effects on human performance that include deficits in working memory, creativity, innovative thinking, strategic planning, mood disturbances, lapses in attention and vigilance, and impaired physical performance. In a classic dose-response sleep study performed at Walter Reed Army Institute of Research, it was demonstrated that limiting sleep to 3-hr per night for 7-days resulted in a steady deterioration on a psychomotor vigilance task across the week of sleep restriction. Sleep restriction over 3-days has been shown to adversely affect marksmanship performance, including significantly longer time to make decisions, misidentifying friends versus foes, and believing performance did not change over time. Short-term sleep restriction is linked with impaired glucose metabolism and decreased whole body insulin sensitivity, and increases the risk of developing T2D. Military personnel have few good options to counteract physical and cognitive detriments attributed to insufficient sleep. Warfighters increasingly turn to caffeine and sugar-containing energy drinks to combat sleep loss and fatigue, especially during deployment. At best, these nutritional countermeasures provide a transient performance gain, and may trigger a 'rebound' hypoglycemia that exacerbates performance detriments that can increase the risk of obesity and related problems. Ketosis could improve tolerance to sleep restriction and sleep abnormalities through multiple mechanisms. We have reported that a 1-yr KD improved sleep quality and the proportion of people categorized as poor sleepers. Ketones are a preferred brain fuel that may enhance neurocognitive function. The ability to metabolize a lipid-derived substrate (ketones) capable of sustaining the brain's high energy demands during periods with limited access to carbohydrate was a central adaptation in human evolution, that is also associated with a remarkable protection from the adverse signs of hypoglycemia. At the low end of nutritional ketosis (0.5 mM), \~5% of whole brain energy metabolism is provided by ketones. At ketone concentrations of 1.5 mM (typical of KDs), ketones supply nearly 20%; at the higher end of nutritional ketosis 4-5 mM \[achievable with ketone esters (KE)\], half of the brain energy demands are met by ketones. Importantly in situations where brain glucose metabolism is impaired, uptake and utilization of ketones remain fully intact, suggesting a hierarchy of importance placed on ketones as the preferred fuel for human brains.