Sleep deficiency, operational fatigue and the interplay of compromising factors: Analysis to aid in fatigue management

The United States Navy is a high-reliability organization that must maintain optimum performance under challenging conditions. One key challenge for sailors is obtaining sufficient sleep, which can lead to fatigue and other outcomes that compromise operational readiness. Identifying sleep issues and their causes is critical for military leaders to care for their personnel, and to make informed, risk-based operational decisions. Though previous studies in shipboard environments have implicated factors responsible for insufficient sleep (e.g. poor sleep environment and work demands), there has been less research into characterizing the complex interplay among such factors in relation to sleep and work-related fatigue outcomes. This study seeks to address this gap. Data were drawn from the Afloat Safety Climate Assessment Survey of 7617 sailors from 73 ships. The survey included demographic characteristics and measures of crew endurance (e.g. sleep, occupational impairment due to fatigue). Descriptive analyses characterized the presence and severity of sleep issues across subpopulations and operational settings (e.g. the type of ship); structural equation modelling techniques characterized and quantified the statistical associations among factors. The results indicate that sleep deficits are widespread, holding across subpopulations and operational settings. Though sleep deficits varied across subpopulations, no group obtained an average of more than 7 hr of sleep per night. Fatigue-induced occupational functional impairment was directly related to sleep deficiency, and sleep environment and job-related factors were contributors to sleep deficiency. Moreover, job-related factors emerged as potentially more consequential. Lastly, factors may exist aboard a ship that could help promote better sleep.