0143 Firefighters' Sleepiness and Total Sleep Time Varies Throughout Their Shift Schedule

Abstract

Abstract Introduction Most career firefighters in the US are allowed to rest and sleep, yet at the same time must be ready to respond to emergencies. We recently found that inter-daily rhythms in firefighter total sleep time (TST) and that the rhythms are related to their shift schedule. Considering the relationship between sleep duration and health outcomes, the purpose of this research is to assess the daily relationship between preceding TST and sleepiness throughout two popular fire department shift schedules. Methods Firefighters participated in a pre-experimental, longitudinal sleep study that assessed sleep over 18 days on the 24-hours on and 48-hours off (24/48) (n=22) and again 18 days, six-months after firefighters transitioned to the 48-hours on and 96-hours off (48/96) shift schedules (n=20). Daily TST was assessed using actigraphy and the Emergency Services Sleep Diary and daily sleepiness was assessed using the Epworth Sleepiness Scale (ESS), completed every afternoon at 1:00 PM. Results The results of the one-way repeated measures ANOVA for each schedule indicated a statistically significant difference in ESS scores among days within the 24/48 (F(2,42) = 8.56, p<0.01) and 48/49 shift schedule (F(5,95) = 7.40, p<0.05). Using pre-shift as baseline, differences of preceding TST and afternoon sleepiness were related in the 24/48 (r(64)= -.62, p ≤.001) and 48/96 (r(118)= -.54, p ≤.001) shift schedule. The greatest mean levels of sleepiness occurred on days in which firefighters commuted to and from the fire station. During non-workdays, mean afternoon sleepiness decreased as firefighters returned to baseline TST. Conclusion Firefighters experienced an inverse relationship between preceding TST and afternoon sleepiness. The least TST occurred on commute days; firefighters begin shift with insufficient sleep and drove home with insufficient sleep. Subsequently, firefighters experienced greatest levels of sleepiness during those afternoons. The findings of daily variation in TST and sleepiness highlight the importance for firefighters to prioritize sleep so that they begin shift well rested and commute home well rested. In addition, the implication of the results questions whether other acute health outcomes also vary within fire department shift schedules. Support (If Any)