Incidence of Sleep Loss and Wakefulness Degradation on a U.S. Coast Guard Cutter Under Exemplar Crewing Limits

摘要

The central objective of this study was to determine whether crew members are experiencing unacceptable fatigue levels while sailing under Exemplar crew reductions. This study was conducted aboard the CG Cutter MUNRO (WHEC-378 foot) during a patrol from Tokyo, Japan to Pearl Harbor, Hawaii. Daily evaluations of alertness and of the stability of the sleep/wake cycle were used to characterize fatigue levels throughout 30 consecutive days on patrol. Fourteen crew members participated in wakefulness maintenance tests consisting of the observation of the latency to sleep onset while volunteers attempted to maintain wakefulness. Forty-three volunteers also participated in daily sleep evaluations by wearing wrist worn activity monitors 24 hours per day. Activity monitor data were used to document daily sleep onset times, wake up times, and the stability of the sleep/wake cycle throughout the 30 day evaluation. Correlation analysis confirmed that participants experiencing frequent disruptions of the sleep/wake cycle also suffered reductions of sleep below six hours and a high incidence of failure to maintain wakefulness above six minutes, signifying reduced alertness. Watch schedules requiring frequent rotations from daytime to nighttime and early morning duty hours contributed to the consistent disruption of sleep/wake cycles. The combination of current watch schedules, reduced personnel, and high operational tempo are expected to exacerbate the fatigue symptoms documented in this patrol.