A Longitudinal Assessment of Sleep in Surface Warfare Officers During Training and Fleet Assignments: Preliminary Results

Abstract

Several previous studies have assessed fatigue on USN warships, especially of enlisted Sailors. Our study, however, is focused explicitly on Surface Warfare Officers (SWOs) (N=34) during training and after returning to the fleet. The average daily sleep duration was 6.83±0.44 hours (62% of the SWOs sleeping <7 hours/day). The average daily sleep duration was higher when SWOs were in training compared to their fleet assignment (p=0.068). SWOs slept 0.82 hours/day more on weekends compared to weekdays in fleet settings and 0.42 hours/day when in training. Sleep efficiency during the major sleep episodes was lower in fleet settings (p<0.001), heart rate was higher (p=0.020), and HRV was lower (p<0.001). These preliminary results suggest that chronic sleep deprivation is prevalent in SWOs, especially in fleet settings. The depressed HRV during fleet assignments may be explained by the high stress levels during these periods in conjunction with the increased sleep deprivation.