How the reduction of working hours could influence health outcomes: a systematic review of published studies

Objectives The health effects of work-time arrangements have been largely studied for long working hours, whereas a lack of knowledge remains regarding the potential health impact of reduced work-time interventions. Therefore, we conducted this review in order to assess the relationships between work-time reduction and health outcomes. Design Systematic review of published studies. Medline, PsycINFO, Embase and Web of Science databases were searched from January 2000 up to November 2019. Outcomes The primary outcome was the impact of reduced working time with retained salary on health effects, interventional and observational studies providing a quantitative analysis of any health-related outcome were included. Studies with qualitative research methods were excluded. Results A total of 3876 published articles were identified and 7 studies were selected for the final analysis, all with a longitudinal interventional design. The sample size ranged from 63 participants to 580 workers, mostly from healthcare settings. Two studies assessed a work-time reduction to 6 hours per day; two studies evaluated a weekly work-time reduction of 25%; two studies evaluated simultaneously a reduced weekly work-time reduction proportionally to the amount of time worked and a 2.5 hours of physical activity programme per week instead of work time; one study assessed a reduced weekly work-time reduction from 39 to 30 hours per week. A positive relationship between reduced working hours and working life quality, sleep and stress was observed. It is unclear whether work time reduction determined an improvement in general health outcomes, such as self-perceived health and well-being. Conclusions These findings suggest that the reduction of working hours with retained salary could be an effective workplace intervention for the improvement of employees' well-being, especially regarding stress and sleep. Further studies in different contexts are needed to better evaluate the impact of work-time reduction on other health outcomes.