Effects of Shift Work on Cognitive Performance, Sleep Quality, and Sleepiness among Petrochemical Control Room Operators.

Reza Kazemi,Majid Motamedzade ,Ali Reza Soltanian ,Rostam Golmohamadi,Rashid Haidarimoghadam,Mohammad Reza Zoghipaydar

doi:10.5334/jcr.134

Reza Kazemi, Majid Motamedzade + Show 4 more

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https://doi.org/10.5334/jcr.134

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Abstract

Shift work is associated with both sleepiness and reduced performance. The aim of this study was to examine cognitive performance, sleepiness, and sleep quality among petrochemical control room shift workers. Sixty shift workers participated in this study. Cognitive performance was evaluated using a number of objective tests, including continuous performance test, n-back test, and simple reaction time test; sleepiness was measured using the subjective Karolinska Sleepiness Scale (KSS); and sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) questionnaire. ANCOVA, t-test, and repeated-measures ANOVA were applied for statistical analyses, and the significance level was set at p < 0.05. All variables related to cognitive performance, except for omission error, significantly decreased at the end of both day and night shifts (p < 0.0001). There were also significant differences between the day and night shifts in terms of the variables of omission error (p < 0.027) and commission error (p < 0.036). A significant difference was also observed between daily and nightly trends of sleepiness (p < 0.0001) so that sleepiness was higher for the night shift. Participants had low sleep quality on both day and night shifts, and there were significant differences between the day and night shifts in terms of subjective sleep quality and quantity (p < 0.01). Long working hours per shift result in fatigue, irregularities in the circadian rhythm and the cycle of sleep, induced cognitive performance decline at the end of both day and night shifts, and increased sleepiness in night shift. It, thus, seems necessary to take ergonomic measures such as planning for more appropriate shift work and reducing working hours.

Highlights

Shift work is usually referred to as dividing working hours among two or more occupational groups in order to cover the time needed for duty performance or for production process
The results of paired sample t-test (Table 1) showed that, except for the omission error among night shift participants, a significant difference was observed in all the other variables between before and after night shift measurements
The results obtained from Analysis of Covariance (ANCOVA) (Table 2) indicated that there was a significant difference between the two shifts in change of omission and commission

Summary

Introduction

Shift work is usually referred to as dividing working hours among two or more occupational groups in order to cover the time needed for duty performance or for production process. Evidence shows that some of the industryrelated accidents during the last few decades, such as Chernobyl, Three Mile Island, Bhopal, and chemical spill into Rhine and Valdez, have all occurred in the middle of the night, and, according to the investigations, the main cause of these accidents was reported to be shift work and human errors committed by control room operators [2, 3] Cognitive functions, such as working memory, attention, information processing speed, etc., play a vital role in the performance of many tasks; even temporary failure of cognitive and mental performance can lead to serious consequences for people, especially when accurate and immediate response is required [4].

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