Sleep deprivation and energy metabolism: to sleep, perchance to eat?
Section of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Chicago, Chicago, Illinois, USA.
PURPOSE OF REVIEW: Many people currently sleep only 5-6 h per night. Epidemiological studies have demonstrated that self-reported short sleep is associated with an increased incidence of obesity and diabetes, highlighting the importance of this trend for public health. This finding has triggered renewed research into the mechanisms that link the regulation of mammalian sleep and metabolism. RECENT FINDINGS: In rodents, periods of starvation are accompanied by increased vigilance and sleep loss, presumably to help maximize food finding and energetic survival, whereas sleep deprivation results in increased energy expenditure and weight loss, consistent with a role of sleep in energy conservation and tissue maintenance. Information about the corresponding processes in humans is limited. Available data indicate that despite the presence of qualitative and quantitative differences, human sleep and metabolism also share reciprocal connections. SUMMARY: Evolution in an environment with limited resources has established bidirectional links between sleep and energy homeostasis, the molecular mechanisms of which are emerging rapidly. Epidemiological data suggest that the unique ability of humans to restrict their sleep voluntarily in an environment that promotes physical inactivity and overeating may have a negative impact on metabolic health. Randomized intervention trials are needed to confirm the validity of this hypothesis.