title: Fatigue in military aviation shift workers: survey results for selected occupational groups.
abstract: BACKGROUND
  Shift workers are particularly vulnerable to increased sleepiness, chronic fatigue, and decreased performance, which can adversely impact productivity and safety in military flight operations. This study examined the association of specific risk factors including work context and shift system details (squadron: remotely piloted aircraft [RPAI vs. manned aircraft [MA]), work/rest guidelines (career field: crewmember vs. maintainer), and participation in deployed operations (environment: home base vs. deployed) on subjective fatigue using standardized and validated fatigue questionnaires.
  
  
  METHODS
  A cross-sectional survey of 172 U.S. Air Force (USAF) personnel was conducted from October 2004 to May 2005. The study sample was recruited from four different USAF occupational groups involved in some form of shift work to include irregular, rotational, or fixed shifts.
  
  
  RESULTS
  Participants reported a mean (SD) of 6.6 (1.8) hours of sleep per day with no differences by squadron, career field, or environment. Mean daily sleep did not correlate with scores on the fatigue questionnaires. Mean scores on the fatigue questionnaires were associated with squadron (mean fatigue score: RPA > MA), but not with career field or environment. There were no significant interaction effects, nor were there significant effects based on the covariates age, gender, and rank.
  
  
  CONCLUSIONS
  Work context, shift system details, or both appeared to best explain the observed differences in fatigue between USAF shift worker populations. Crewmember work/rest guidelines did not appear to be useful for mitigating fatigue associated with shift work. Shift work is intrinsically fatiguing, regardless of whether the shift worker is at home base or deployed.
authors.affiliation: 311th Human Systems Wing, Brooks City-Base, TX 78235-5105, USA. anthony.tvaryanas@brooks.af.mil
authors.forename: Anthony P
authors.initials: AP
authors.lastname: Tvaryanas
authors.forename: William T
authors.initials: WT
authors.lastname: Thompson
mesh_terms: D000328:Adult; D000337:Aerospace Medicine; D021081:Chronobiology Disorders / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D005221:Fatigue / Q000453:epidemiology*; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D008889:Military Personnel; D015999:Multivariate Analysis; D011795:Surveys and Questionnaires