title: Fatigue at sea in Swedish shipping-a field study.
abstract: BACKGROUND
  Today many merchant ships sail with only two nautical officers, working a shift schedule of 6 hr on and 6 hr off. There are concerns that such a shift schedule is related to fatigue. However, little data exist from onboard studies of seafarers.
  
  
  METHODS
  Data were collected on board 13 ships. Fifteen participants worked on a 6-on, 6-off watch system and another 15 on a 4-on, 8-off watch system. Electrooculography, actigraphy, diaries, and reaction time tests were used to measure the effects of shift system on fatigue and sleep.
  
  
  CONCLUSIONS
  Sleepiness was higher during the night shift in the 6-on, 6-off system. Moreover, sleepiness increased more during the watch in the 6-on, 6-off system compared to the 4-on, 8-off system. There was a trend toward shorter sleep episodes in the 6-on, 6-off system and sleep was more often split into two episodes.
authors.affiliation: Department of Shipping and Marine Technology, Chalmers University of Technology, Göteborg, Sweden. margareta.lutzhoft@chalmers.se <margareta.lutzhoft@chalmers.se>
authors.forename: Margareta
authors.initials: M
authors.lastname: Lützhöft
authors.forename: Anna
authors.initials: A
authors.lastname: Dahlgren
authors.forename: Albert
authors.initials: A
authors.lastname: Kircher
authors.forename: Birgitta
authors.initials: B
authors.lastname: Thorslund
authors.forename: Mats
authors.initials: M
authors.lastname: Gillberg
mesh_terms: D000328:Adult; D005221:Fatigue; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012767:Ships; D012890:Sleep; D013548:Sweden; D013997:Time Factors; D014851:Wakefulness; D014940:Work Schedule Tolerance / Q000502:physiology*