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 performance 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.