Send to:

Choose Destination
See comment in PubMed Commons below
Neurosci Biobehav Rev. 2014 Nov;47:122-53. doi: 10.1016/j.neubiorev.2014.08.001. Epub 2014 Aug 10.

The energy allocation function of sleep: a unifying theory of sleep, torpor, and continuous wakefulness.

Author information

  • 1Ohio Sleep Medicine Institute, 4975 Bradenton Ave., Dublin, OH 43017, United States. Electronic address:


The energy allocation (EA) model defines behavioral strategies that optimize the temporal utilization of energy to maximize reproductive success. This model proposes that all species of the animal kingdom share a universal sleep function that shunts waking energy utilization toward sleep-dependent biological investment. For endotherms, REM sleep evolved to enhance energy appropriation for somatic and CNS-related processes by eliminating thermoregulatory defenses and skeletal muscle tone. Alternating REM with NREM sleep conserves energy by decreasing the need for core body temperature defense. Three EA phenotypes are proposed: sleep-wake cycling, torpor, and continuous (or predominant) wakefulness. Each phenotype carries inherent costs and benefits. Sleep-wake cycling downregulates specific biological processes in waking and upregulates them in sleep, thereby decreasing energy demands imposed by wakefulness, reducing cellular infrastructure requirements, and resulting in overall energy conservation. Torpor achieves the greatest energy savings, but critical biological operations are compromised. Continuous wakefulness maximizes niche exploitation, but endures the greatest energy demands. The EA model advances a new construct for understanding sleep-wake organization in ontogenetic and phylogenetic domains.

Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.


Energy allocation; Hibernation; Life history theory; NREM sleep; REM sleep; Sleep deprivation; Sleep function; Sleep homeostasis; Thermoregulation; Torpor

[PubMed - indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Write to the Help Desk