title: Daytime napping associated with increased symptom severity in fibromyalgia syndrome.
abstract: BACKGROUND
  Previous qualitative research has revealed that people with fibromyalgia use daytime napping as a coping strategy for managing symptoms against clinical advice. Yet there is no evidence to suggest whether daytime napping is beneficial or detrimental for people with fibromyalgia. The purpose of this study was to explore how people use daytime naps and to determine the links between daytime napping and symptom severity in fibromyalgia syndrome.
  
  
  METHODS
  A community based sample of 1044 adults who had been diagnosed with fibromyalgia syndrome by a clinician completed an online questionnaire. Associations between napping behavior, sleep quality and fibromyalgia symptoms were explored using Spearman correlations, with possible predictors of napping behaviour entered into a logistic regression model. Differences between participants who napped on a daily basis and those who napped less regularly, as well as nap duration were explored.
  
  
  RESULTS
  Daytime napping was significantly associated with increased pain, depression, anxiety, fatigue, memory difficulties and sleep problems. Sleep problems and fatigue explained the greatest amount of variance in napping behaviour, p < 0.010. Those who engaged in daytime naps for >30 minutes had higher memory difficulties (t = -3.45) and levels of depression (t = -2.50) than those who napped for shorter periods (<30 mins) (p < 0.010).
  
  
  CONCLUSIONS
  Frequent use and longer duration of daytime napping was linked with greater symptom severity in people with fibromyalgia. Given the common use of daytime napping in people with fibromyalgia evidence based guidelines on the use of daytime napping in people with chronic pain are urgently needed.
authors.affiliation: National Institute for Stroke and Applied Neuroscience, Auckland University of Technology, 90 Akoranga Drive, Private Bag 92006, Auckland, New Zealand. alice.theadom@aut.ac.nz.
authors.forename: Alice
authors.initials: A
authors.lastname: Theadom
authors.affiliation: Department of Psychology, University of Surrey, Surrey, UK. MCropley@surrey.ac.uk.
authors.forename: Mark
authors.initials: M
authors.lastname: Cropley
authors.affiliation: Chronobiology Unit, Groningen institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands. thomas@kantermann.de.|Institute for Occupational, Social and Environmental Medicine, Clinical Centre Ludwig-Maximilians University Munich, Ziemssenstrasse 1, 80336, Munich, Germany. thomas@kantermann.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kantermann
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002940:Circadian Rhythm; D003863:Depression; D005260:Female; D005356:Fibromyalgia / Q000503:physiopathology* / Q000523:psychology*; D006801:Humans; D008297:Male; D008568:Memory; D008875:Middle Aged; D012720:Severity of Illness Index; D012890:Sleep / Q000502:physiology*; D055815:Young Adult