title: On-call duty effects on sleep-state physiological stability in male medical interns.
abstract: BACKGROUND
  On-call duty among medical interns is characterized by sleep deprivation and stressful working conditions, both of which alter cardiac autonomic modulation. We hypothesized that sleep stability decreased in medical interns during on-call duty. We used cardiopulmonary-coupling (CPC) analysis to test our hypothesis.
  
  
  METHODS
  We used electrocardiogram (ECG)-based CPC analysis to quantify physiological parameters of sleep stability in 13 medical interns during on-call and on-call duty-free periods. There were ten 33.5-h on-call duty shifts per month for interns, each followed by 2 on-call duty-free days, over 3 months. Measurements during sleep were collected before, during, and after an on-call shift. Measurements were repeated 3 months later during an on-call duty-free period.
  
  
  RESULTS
  The medical interns had significantly reduced stable sleep, and displayed increased latency to the first epoch of stable sleep during the on-call night shift, compared to the pre-call and on-call duty-free nights. Interns also had significantly increased rapid-eye-movement (REM) sleep during the on-call night shift, compared to the pre-call and on-call duty-free nights.
  
  
  CONCLUSIONS
  Medical interns suffer disrupted sleep stability and continuity during on-call night shifts. The ECG-based CPC analysis provides a straightforward means to quantify sleep quality and stability in medical staff performing shift work under stressful conditions.
authors.affiliation: Department of Psychiatry, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Yu-Hsuan
authors.initials: YH
authors.lastname: Lin
authors.forename: Yen-Cheng
authors.initials: YC
authors.lastname: Ho
authors.forename: Sheng-Hsuan
authors.initials: SH
authors.lastname: Lin
authors.forename: Yao-Hsien
authors.initials: YH
authors.lastname: Yeh
authors.forename: Chia-Yih
authors.initials: CY
authors.lastname: Liu
authors.forename: Terry B J
authors.initials: TB
authors.lastname: Kuo
authors.forename: Cheryl C H
authors.initials: CC
authors.lastname: Yang
authors.forename: Albert C
authors.initials: AC
authors.lastname: Yang
mesh_terms: D000328:Adult; D001341:Autonomic Nervous System / Q000502:physiology / Q000503:physiopathology; D004562:Electrocardiography; D006801:Humans; D007396:Internship and Residency; D008297:Male; D012890:Sleep / Q000502:physiology*; D012892:Sleep Deprivation / Q000503:physiopathology; D013337:Students, Medical; D014940:Work Schedule Tolerance / Q000502:physiology*