title: Working night shifts affects surgeons' biological rhythm.
abstract: BACKGROUND
  Chronic sleep deprivation combined with work during the night is known to affect performance and compromise residents' own safety. The aim of this study was to examine markers of circadian rhythm and the sleep-wake cycle in surgeons working night shifts.
  
  
  METHODS
  Surgeons were monitored prospectively for 4 days: pre call, on call, post call day 1 (PC1), and post call day 2 (PC2). The urinary metabolite of melatonin and cortisol in saliva were measured to assess the circadian rhythm. Sleep and activity were measured by actigraphy. Subjective measures were assessed by the Karolinska Sleepiness Scale and Visual Analog Scale of fatigue, general well-being, and sleep quality.
  
  
  RESULTS
  For both metabolite of melatonin and cortisol, a significant difference (P < .05) was found in the measurement period between on call and pre call values. There was increased sleep time during the day on call and on PC1. For all subjective measures, a marked deterioration was seen on PC1.
  
  
  CONCLUSIONS
  Surgeons' circadian rhythm was affected by working night shifts.
authors: Department of Surgery, Herlev Hospital, University of Copenhagen, Herlev Ringvej 75, 2730 Herlev, Denmark. Electronic address: iamirian@gmail.com.
authors: Ilda
authors: I
authors: Amirian
authors: Department of Surgery, Herlev Hospital, University of Copenhagen, Herlev Ringvej 75, 2730 Herlev, Denmark.
authors: Lærke T
authors: LT
authors: Andersen
authors: Department of Surgery, Herlev Hospital, University of Copenhagen, Herlev Ringvej 75, 2730 Herlev, Denmark.
authors: Jacob
authors: J
authors: Rosenberg
authors: Department of Surgery, Herlev Hospital, University of Copenhagen, Herlev Ringvej 75, 2730 Herlev, Denmark.
authors: Ismail
authors: I
authors: Gögenur
mesh_terms: D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D007396:Internship and Residency; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012890:Sleep / Q000502:physiology*; D012892:Sleep Deprivation; D013043:Specialties, Surgical; D014940:Work Schedule Tolerance
keywords: Circadian rhythm; Cortisol; Melatonin; Night shift; Sleep deprivation; Surgeon