title: Conditioned pain modulation is not decreased after partial sleep restriction.
abstract: BACKGROUND
  Sleep problems have been identified as a risk factor for several chronic pain conditions. Reduced sleep has been related to increased pain perception and it has been hypothesized that reduced pain inhibition may explain this. The aim of this study was to determine if sleep restriction (SR) affects heat pain perception and conditioned pain modulation (CPM).
  
  
  METHODS
  In a paired cross-over design with two conditions (2 nights habitual sleep (HS) vs. 2 nights 50% SR) CPM was tested in 22 healthy individuals (14 women, 8 men). The test stimulus (TS) was 2-min contact heat stimulation (47  ± 1.3  °C) to the volar forearm. TS was delivered before and during a 7 °C cold pressor test (conditioning stimulus, CS) to the contralateral hand.
  
  
  RESULTS
  TS was perceived as more painful after SR compared to after HS (p < 0.001). A stronger inhibitory CPM was found after SR versus after HS (p < 0.001).
  
  
  CONCLUSIONS
  The results indicate that SR leads to increased heat pain perception, but not reduced inhibitory CPM. This contradicts general assumptions on the relation between SR and the CPM effect.
authors.affiliation: Department of Work Psychology and Physiology, National Institute of Occupational Health, Oslo, Norway.
authors.forename: D
authors.initials: D
authors.lastname: Matre
authors.affiliation: Department of Work Psychology and Physiology, National Institute of Occupational Health, Oslo, Norway.
authors.forename: M R
authors.initials: MR
authors.lastname: Andersen
authors.affiliation: Department of Work Psychology and Physiology, National Institute of Occupational Health, Oslo, Norway.
authors.forename: S
authors.initials: S
authors.lastname: Knardahl
authors.affiliation: Department of Work Psychology and Physiology, National Institute of Occupational Health, Oslo, Norway.|Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway.|Section for Clinical Neurophysiology, Department of Neurology, Oslo University Hospital - Ullevål, Norway.
authors.forename: K B
authors.initials: KB
authors.lastname: Nilsen
mesh_terms: D000293:Adolescent; D000328:Adult; D001794:Blood Pressure; D003080:Cold Temperature; D003213:Conditioning, Psychological; D018592:Cross-Over Studies; D005260:Female; D005542:Forearm; D006358:Hot Temperature; D006801:Humans; D008297:Male; D010146:Pain / Q000503:physiopathology / Q000523:psychology*; D010147:Pain Measurement; D058748:Pain Perception; D012892:Sleep Deprivation / Q000150:complications*; D055815:Young Adult