0177 Improving Watchstanding Schedules on US Navy Watchfloors

Abstract Introduction This project assessed the work/rest schedules of shift workers on information warfare enterprise (IWE) watchfloors. Our objectives were to document and evaluate the watchbills used, assess the watchstanders’ state, and develop fatigue mitigation recommendations tailored to the watchfloors. Methods Data were collected from two US Navy watchfloors (N=82 participants; 62.2% males, median age of 27 years (range 19 to 54 years, 85.4% enlisted). Using a quasi-experimental, longitudinal approach, participants wore ŌURA rings and completed questionnaires at the beginning and end of the study (Epworth Sleepiness Scale-ESS; Insomnia Severity Index-ISI; Profile of Mood States-POMS). The first watchfloor used a 4-section/12hr-shift watchbill; the other used a 6-section/8hr-shift watchbill. Watchstanders rotated between all shifts in their watchbill every 30 days. The sleep/wake patterns of watchstanders were modeled with the Sleep, Activity, Fatigue, and Task Effectiveness model implemented in the Fatigue Avoidance Scheduling Tool (SAFTE/FAST). Results Participants slept a median 6.7hrs/day with 62.3% sleeping 7hrs/day and 14.5% sleeping 6hrs/day. Approximately 89% of participants were classified as poor sleepers, 30.5% reported symptoms of excessive daytime sleepiness, 20.7% reported symptoms of insomnia, and 20.7% had all three conditions. Approximately 74% of participants scored worse than the 50th percentile of the normal adult population on total mood disturbance; 79.0% scored worse on tension-anxiety, 80.3% on vigor-activity, 72.8% on fatigue, and 80.3% on confusion-bewilderment subscales (all p 0.05; POMS). While the watchstanders preferred the 6-section/8hr-shift watchbill compared to the 4-section/12hr-shift watchbill, no differences were observed in any of the variables of interest (daytime alertness, insomnia symptoms, mood, daily sleep duration, napping, long sleep episode variables; all p0.10). Conclusion The 6-section/8hr-shift watchbill with shorter shifts and more duty sections is generally preferable to the 4-section/12hr-shift watchbill. Based on these findings, FAST model predictions, background literature on shiftwork, and other studies conducted by the NPS Crew Endurance Team, we developed fatigue mitigation guidelines and recommendations. Support (if any) This study was funded by the Naval Postgraduate School, Naval Research Program (NRP Project ID: NPS-23-N055-A).