Association of changes in work shifts and shift intensity with change in fatigue and disturbed sleep: a within-subject study

Objectives: The aim of this study was to examine whether changes in work shifts and shift intensity are related to changes in difficulties to fall asleep, fatigue, and sleep length.
Methods: Questionnaire responses of hospital employees (N=7727, 93% women) in 2008, 2012, 2014 and 2015 were linked to daily-based records of working hours during three months preceding each survey. We used conditional logistic regression and longitudinal fixed-effects analyses to investigate odds ratios (OR) and 95% confidence intervals (CI) for each 25% within-individual change in the proportion of working hour characteristics in relation to changes in fatigue, difficulties to fall asleep, and 24-hour sleep length.
Results: Change in night but not in morning or evening shifts was associated with parallel changes in odds for longer sleep length (OR 1.45, 95% CI 1.28–1.64) and fatigue during free days (OR 1.38, 95% CI 1.16–1.64). Similarly, short shift intervals and having >2 but not >4 consecutive night shifts were associated with increased odds of fatigue during work (OR 1.42, 95% CI 1.19–1.72 and OR 1.10, 95% CI 1.05–1.19, respectively) and difficulties to fall asleep. Among workers aged ≥50 years, the associations were the strongest between night shifts and longer sleep (OR 2.24, 95% CI 1.52–3.81) and between higher proportion of short shift intervals and fatigue during free days (OR 1.68, 95% CI 1.10–2.54).
Conclusions: Among shift workers with fatigue or sleep problems, decreasing the proportion of night shifts and quick returns and giving preference to quickly forward-rotating shift systems may reduce fatigue.

Source: Härmä, M., Karhula, K., Ropponen, A., Puttonen, S., Koskinen, A., Ojajärvi, A., ... et Kivimäki, M. (2018). Scand J Work Environ Health.

Abonnement courriel

Messages récents


Mots-Clés (Tags)