Detrimental Effects of Variable Work Shifts on Quality of Sleep, General Health and Work Performance

Objectives: The aim of this study was to explore the detrimental effects of working a varying pattern of 8-hour shifts on quality of sleep, general health and work performance. Subjects and Methods: The Arabic version of the Pittsburgh Sleep Quality Index (PSQI) and 2 self-administered questionnaires were used to assess quality of sleep, work perfor- mance and general health in a sample of 200 males on a schedule of varying 8-hour shifts at the Kuwait Oil Company. A matched sample of an equal number of workers on a fixed daytime shift as a control group was enrolled in the study. Results: Compared with men working on a straight daytime shift schedule, those working on 8-hour variable shifts exhibited higher rates of heavy smoking (p 0.003), coffee/tea consumption (p 0.0001), constipation (p 0.002), job stress (p 0.0001) and poor sexual performance (p 0.0001). Variable-shift workers reported persistent sleep disturbances in 3 dimensions of the global score of the PSQI (p 0.0001). They also had significantly more complaints of fatigue (p 0.005), poor level of work performance (p 0.005) and loss of concentration (p 0.005). Shift workers were significantly more prone to making errors and having accidents at work, and were more likely to report absence from work than the controls (p 0.0001 and p 0.005, respectively).Conclusion: These results suggest that the majority of workers on an 8-hour variable-shift schedule experienced various health problems, poor quality of sleep and an increased risk for errors and accidents at work as compared with those workers on a straight daytime shift schedule.There is a need to compare potential benefits of an alternative work shift schedule.