Work and sleep - what's stress got to do with it?

Sammanfattning: Work may affect sleep by reducing the time available for recovery and, via work stress, by reducing sleep quality. Further, people experiencing sleep disturbance may be less resistant to work stress. These processes may lead to the development of a vicious cycle between work and sleep, in which stress has a central role.Knowledge of the prospective relations between work, stress and sleep is limited, particularly from studies examining relationships from sleep to work stress and large-scale studies using objective measures of sleep.Consequently, this thesis aims to analyse the prospective relations, including directions of effects, between work-related factors, in particular work stress, and self-rated and objective measures of sleep.The first two studies used the Swedish Longitudinal Occupational Survey of Health, with biennial self-rated measures of work-related factors (demands, control, support, stress, physical factors, scheduling) and sleep. We used structural equation models to analyse the direction of effects between work-related factors and sleep. The next two studies used the Swedish Retirement Study, a prospective study using self-reports and actigraphy, which followed people into retirement. We used multilevel modelling to analyse within-individual changes in sleep duration, timing and quality over three waves across retirement.We observed prospective reciprocal relations between work stressors (demands, control and support), perceived stress and self-rated sleep quality. Work was associated with earlier timing of sleep and sleep deprivation of 30 minutes per night. Improvements in self-rated sleep quality after retirement were not accompanied by improvements in actigraph-measured sleep quality.In conclusion, this thesis has demonstrated that work, stress and sleep form a vicious cycle. Interventions targeting sleep disturbance could improve people’s experience of their work environments. Likewise, interventions aiming to lower stress and increase the flexibility of work could reduce the impact of work on sleep, and thereby on health, contributing to a decent and sustainable working life.