Adaptive sleep behaviours and shift work tolerance during the transition to shift work

Objective: To evaluate whether recruit paramedics adapt their sleep behaviour during the first 12-months of shift work and to identify sleep behaviours that are associated with better shift work tolerance (SWT) after 12-months of shift work. Methods: Recruit paramedics (n = 105; Mage = 25.81 years; 51.38% female) were evaluated before (baseline), and after six- and 12-months of shift work. At each timepoint, participants completed questionnaires evaluating their mental health and sleep. Participants also underwent 14 days of sleep and shift monitoring (sleep/work diaries and actigraphy) at each timepoint to examine sleep behaviours, including sleep opportunity (SO), sleep regularity and number of sleep episodes. Results: Linear mixed models found SO increased (on day shifts and rest days), and sleep regularity decreased between baseline and follow-up timepoints. There were no changes in SO (on day shifts, nightshifts, and rest days) or sleep regularity between six- and 12-months of shift work. Latent profile analysis at 12-months follow-up identified high (n = 52), medium (n = 27), and low (n = 9) SWT levels (measured via depression, anxiety, insomnia, sleep quality and sleep efficiency) in paramedics. Reduced sleep regularity (i.e., more irregular sleep) between six- and 12-months of work and prioritising major sleep (rather than naps) at six-months predicted high SWT. Conclusions: These findings suggest clear SWT levels exist early in paramedics' careers whereby symptoms of depression, anxiety, and insomnia were the strongest contributors to SWT. New paramedics' sleep behaviours, including sleep regularity and prioritisation of longer sleep between nightshifts, may play an important role in influencing how paramedics tolerate shift work.