Decreased psychomotor vigilance of female shift workers after working night shifts

PLoS One. 2019 Jul 5;14(7):e0219087. doi: 10.1371/journal.pone.0219087. eCollection 2019.

Abstract

Background: We compared psychomotor vigilance in female shift workers of the Bergmannsheil University Hospital in Bochum, Germany (N = 74, 94% nurses) after day and night shifts.

Methods: Participants performed a 3-minute Psychomotor Vigilance Task (PVT) test bout at the end of two consecutive day and three consecutive night shifts, respectively. Psychomotor vigilance was analyzed with respect to mean reaction time, percentage of lapses and false starts, and throughput as an overall performance score, combining reaction time and error frequencies. We also determined the reaction time coefficient of variation (RTCV) to assess relative reaction time variability after day and night shifts. Further, we examined the influence of shift type (night vs. day) by mixed linear models with associated 95% confidence intervals (CI), adjusted for age, chronotype, study day, season, and the presence of obstructive sleep apnea (OSA).

Results: At the end of a night shift, reaction times were increased (β = 7.64; 95% CI 0.94; 14.35) and the number of lapses higher compared to day shifts (exp(β) = 1.55; 95% CI 1.16-2.08). By contrast, we did not observe differences in the number of false starts between day and night shifts. Throughput was reduced after night shifts (β = -15.52; 95% CI -27.49; -3.46). Reaction times improved across consecutive day and night shifts, whereas the frequency of lapses decreased after the third night. RTCV remained unaffected by both, night shifts and consecutive shift blocks.

Discussion: Our results add to the growing body of literature demonstrating that night-shift work is associated with decreased psychomotor vigilance. As the analysis of RTCV suggests, performance deficits may selectively be driven by few slow reactions at the lower end of the reaction time distribution function. Comparing intra-individual PVT-performances over three consecutive night and two consecutive day shifts, we observed performance improvements after the third night shift. Although a training effect cannot be ruled out, this finding may suggest better adaptation to the night schedule if avoiding fast-changing shift schedules.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Female
  • Germany
  • Health Personnel / psychology*
  • Humans
  • Linear Models
  • Middle Aged
  • Psychomotor Performance / physiology*
  • Reaction Time
  • Shift Work Schedule / adverse effects*
  • Wakefulness / physiology*
  • Work Schedule Tolerance

Grant support

The study was funded by the German Social Accident Insurance (Deutsche Gesetzliche Unfallversicherung - DGUV, Project No.: FF-FP0321, URL: https://www.dguv.de/de/index.jsp. The grant was not awarded to any author listed on the manuscript. Further financial support was granted by the Berufsgenossenschaft für Gesundheitsdienst und Wohlfahrtspflege (no grant number available) and received by Sylvia Rabstein, Dirk Pallapies, and Thomas Brüning. (URL: https://www.bgw-online.de/DE/Home/home_node.html;jsessionid=E5C50466C326B9712F6DEBC23BD07C9C). Additional DGUV-funding for conducting the apnea screening was also granted to the Bergmannsheil Sleep Clinic (received by Prof. Jürgen Behr). No grant number is available for these extra funds. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We acknowledge support by the DFG Open Access Publication Funds of the Ruhr-Universität Bochum.