Sleep and Pain: A Bi-Directional Relation?

Objective This review gives an overview about the consequences of sleep deprivation (SD) on pain perception and discusses the bi-directional relation between sleep and pain. Methods A medline research (16.7.2010) for the terms "sleep" AND "pain" AND ("sleep deprivation" OR "sleep loss" OR "sleep restriction" OR sleep interruption") showed 177 hits. Only studies with control group or cross-over design that investigated sleep deprivation (total or partial form) as independent and pain as dependent variable were included. Results 7 studies fulfilled the inclusion criteria. SD leads in 5 of 6 studies to an increase of bodily complaints measured by self rating tests and a decrease of pain inhibition. 3 of 5 studies show a decrease of mechanical or thermal pain threshold after SD. Conclusions Not only can pain lead to sleep disruption, but SD can also reduce pain threshold. Sleep and pain might be mutually related, by shared neurotransmitter pathways. A further explanation is an influence of SD on opioid protein synthesis and/or opioid receptors. So when chronic pain and sleep disorder coexist, both conditions should be treated.