Introduction Working in shifts and/or at night requires, among other things, adjusting sleep times, meal times and time for socializing. These bio-psycho-socio adaptations, when combined with wakefulness (i.e., work and exposure to environmental stimuli) during usual sleep and rest periods, have been linked to a number of negative health, wellbeing and performance outcomes. While the understanding of these negative consequences is primarily based on inductive inferences, deductive inferences for a successful identification of vulnerable or tolerant people are currently rather inconclusive.

Objectives Determination of tolerance factors for shift and night work to reduce or avoid negative consequences for health, well-being, and performance

Methods Quantitative research studies

Results One challenge to mitigate or avoid the negative consequences of shift and night work is the disparity between the individuality of shift work regulations and the inter-individual differences between employees on a biological, psychological and sociological level.

Conclusion The understanding of shift work tolerance is preliminary. The studies available on this topic differ in many aspects of study methods such as definitions of exposure and outcome variables and confounders considered. Future studies need to specify the exact shift work schedule that is investigated, and there needs to be a concerted effort to come to a consensus on what ‘tolerance’ to shift work means. Prospective studies would increase our understanding of which individual factors are associated with the development of tolerance over time, especially if they collect participants’ complete occupational histories. Taking a paucity of evidence on these issues into account, the presentation will identify areas for future research with the goal of increasing evidence-based harm mitigation strategies for shift workers.