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Shift work tolerance and the importance of sleep quality: a study of police officers

The aim of this study was to examine how subjective shift work tolerance was related to general health variables, with the expectation of inter-individual differences in the nature of this relation. A total of 740 employees of the Dutch Police force completed a questionnaire, covering seven health-related domains: sleep quality, sleep duration, need for recovery, fatigue, physical health, mental health, and work–life balance. Based on subjective reports of shift work tolerance, participants were classified as intolerant, medium-tolerant, or tolerant workers. Analysis involved group comparisons, regression, and cluster analysis. Eighteen percentage of the shift workers were classified as intolerant. The intolerant and medium-tolerant workers expressed more severe complaints than the tolerant workers, for all seven health-related domains. Shift work tolerance was primarily related to sleep quality and subsequently to need for recovery, fatigue, and work–life balance. No indications were found for systematic inter-individual differences in the nature of this relationship. For all participants equally, the degree of shift work tolerance was related to the severity of health-related complaints. This study highlights the central role of sleep for tolerance to shift work and underlines the need for occupational medicine to take explicit account of sleep.