Examining courses of sleep quality and sleepiness in full 2 weeks on/2 weeks off offshore day shift rotations

V. Riethmeister*, U. Bültmann, M. R. De Boer, M. Gordijn, S. Brouwer

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review


To better understand sleep quality and sleepiness problems offshore, we examined courses of sleep quality and sleepiness in full 2-weeks on/2-weeks off offshore day shift rotations by comparing pre-offshore (1 week), offshore (2 weeks) and post-offshore (1 week) work periods. A longitudinal observational study was conducted among N=42 offshore workers. Sleep quality was measured subjectively with two daily questions and objectively with actigraphy, measuring: time in bed (TIB), total sleep time (TST), sleep latency (SL) and sleep efficiency percentage (SE%). Sleepiness was measured twice a day (morning and evening) with the Karolinska Sleepiness Scale. Changes in sleep and sleepiness parameters during the pre/post and offshore work periods were investigated using (generalized) linear mixed models. In the pre-offshore work period, courses of SE% significantly decreased (p=.038). During offshore work periods, the courses of evening sleepiness scores significantly increased (p<.001) and significantly decreased during post-offshore work periods (p=.004). During offshore work periods, TIB (p<.001) and TST (p<.001) were significantly shorter, SE% was significantly higher (p=.002), perceived sleep quality was significantly lower (p<.001) and level of rest after wake was significantly worse (p<.001) than during the pre- and post-offshore work periods. Morning sleepiness was significantly higher during offshore work periods (p=.015) and evening sleepiness was significantly higher in the post-offshore work period (p=.005) compared to the other periods. No significant changes in SL were observed. Courses of sleep quality and sleepiness parameters significantly changed during full 2-weeks on/2-weeks off offshore day shift rotation periods. These changes should be considered in offshore fatigue risk management programmes.

Original languageEnglish
Pages (from-to)759-772
Number of pages14
JournalChronobiology International
Issue number6: Special Issue
Early online date16 May 2018
Publication statusPublished - Jun 2018

Bibliographical note

Volume 35 Issue 6: Special Issue: 23rd International Symposium on Shiftwork and Working Time: Toward a Global Consensus


  • Actigraphy
  • Fatigue
  • Fatigue Risk management
  • Occupational Health
  • Occupational Safety


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