0347 Sleep Behaviour and Shift Work Tolerance in New Paramedics Beginning Shift Work

Abstract Introduction In experienced shift workers, researchers have evaluated levels of shift work tolerance (SWT) and sleep behaviours. SWT refers to not experiencing negative consequences associated with shift work, whereas sleep behaviours, describe strategies workers may use to cope with shift work. Neither sleep behaviours nor SWT have been longitudinally investigated in new emergency personnel. The current study aimed to track changes in sleep behaviour during the first 12-months of shift work, and secondly to explore whether changes in sleep behaviour were associated with SWT after 12-months of work. Methods One-hundred and five recruit paramedics were investigated at baseline (before shift work), and after 6- and 12-months of shift work. Paramedics’ sleep and mental health were evaluated at each timepoint via questionnaires. Participants also completed a 14-day shift work (via work diaries) and sleep (via sleep diaries and actigraphy) monitoring period at each timepoint. Sleep opportunity (SO), regularity, and behaviours in relation to nightshift were investigated. SWT at 12-months was categorised based on symptoms of depression, anxiety, insomnia, and sleep quality and efficiency on rest days. Results Linear mixed models found SO increased on day shifts and rest days, and sleep regularity declined from baseline to 6- and 12-months of shift work. There were no changes in SO on rest days, day shifts, or nightshifts between 6- and 12-months of shift work. Latent profile analyses identified levels of SWT as high (n=52), medium (n=27), and low (n=9) after 12-months of shift work. These profiles were primarily distinguished by levels of insomnia, depression, and anxiety. Increasingly irregular sleep between 6- and 12-months of shift work, and prioritising major sleep episodes (i.e., ≥3hrs) rather than naps at 6-months predicted classification as high SWT. Conclusion Our findings suggest after 12-months of shift work, different levels of SWT exist in paramedics, distinguished by their severity of insomnia, depression, and anxiety symptoms. Though sleep behaviours across the whole cohort did not change between 6- and 12-months, those whose sleep became less regular were more likely to have high SWT. Likewise, prioritising major sleep episodes at 6-months was associated with better SWT after 12-months of shift work. Support (if any)