Exogenous Ketosis Improves Sleep Efficiency and Counteracts the Decline in REM Sleep after Strenuous Exercise

Abstract

ABSTRACT Introduction Available evidence indicates that ketone bodies may improve sleep quality. Therefore, we determined whether ketone ester (KE) intake could counteract sleep disruptions induced by strenuous exercise. Methods Ten well-trained cyclists with good sleep quality participated in a randomized crossover design consisting of two experimental sessions each involving a morning endurance training and an evening high-intensity interval training ending 1 h before sleep, after which polysomnography was performed overnight. Postexercise and 30 min before sleeping time, subjects received either 25 g of KE (EXKE) or a placebo drink (EXCON). A third session without exercise but with placebo supplements (RCON) was added to evaluate the effect of exercise per se on sleep. Results Blood d-β-hydroxybutyrate concentrations transiently increased to ~3 mM postexercise and during the first part of the night in EXKE but not in EXCON or RCON. Exercise significantly reduced rapid eye movement sleep by 26% (P = 0.001 vs RCON) and increased wakefulness after sleep onset by 95% (P = 0.004 vs RCON). Interestingly, KE improved sleep efficiency by 3% (P = 0.040 vs EXCON) and counteracted the exercise-induced decrease in rapid eye movement sleep (P = 0.011 vs EXCON) and the increase in wakefulness after sleep onset (P = 0.009 vs EXCON). This was accompanied by a KE-induced increase in dopamine excretion (P = 0.033 vs EXCON), which plays a pivotal role in sleep regulation. In addition, exercise increased sleep spindle density by 36% (P = 0.005 vs RCON), suggesting an effect on neural plasticity processes during sleep. Conclusions These data indicate that KE ingestion improves sleep efficiency and quality after high-intensity exercise. We provide preliminary evidence that this might result from KE-induced increases in dopamine signaling.