Low leisure-time physical activity, but not shift-work, contributes to the development of sleep complaints in Swedish health care workers

Problem: Regular physical activity (PA) can prevent sleep complaints and improve sleep among people with sleep disorders, whereas nocturnal shift work is linked with a higher risk of sleep problems. The present study examines the prospective contribution of PA and nocturnal shift work to the development of subjective sleep complaints. Methods: Data is based on 1406 health care workers (M = 45.67 years, 88% women). Physical activity and sleep complaints were assessed via self-reports twice across a 2-year period. To address the issue of reverse causation, only participants without initial sleep difficulties were included in the prospective analyses. Results: Moderate-to-vigorous PA (MVPA) was associated with a lower risk of developing difficulties falling asleep at the 2-year follow-up. Both light PA and MVPA were associated with a lower risk of developing feeling of exhaustion upon waking. The prospective association between PA and these two sleep complaints persisted after controlling for covariates. No significant prospective association was found between PA and night time awakenings. Shift work was not related to any of the sleep complaints. Conclusions: The findings suggest that regular PA contributes to the prevention of new sleep complaints, independent of whether participants engage in nocturnal shift work. Promoting PA can be a promising strategy to prevent sleep problems, both in shift-workers and non-shift-workers. (C) 2017 Elsevier Ltd. All rights reserved.