Sleep Patterns, Mood, Psychomotor Vigilance Performance, and Command Resilience of Watchstanders on the Five and Dime Watchbill
Technical rept. Jun-Dec 2014
NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF OPERATIONS RESEARCH
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This study assesses crew rest and sleep patterns, psychomotor vigilance performance, work demands and rest opportunities, organization commitment, and psychological safety and command resilience of Sailors in the Reactor Department on USS Nimitz CVN 68 N 77 working the 5hrs-on10hrs-off 510 watchstanding schedule. Although crewmembers on the 510 received approximately seven hours of sleep per day, they reported experiencing excessive fatigue and dissatisfaction with the schedule. This contradiction is best explained by examining sleep and rest periods over a 72-hour period, during which a crewmember sleeps at three distinctly different time periods each day. On the first day of the cycle, the Sailor typically receives an early-terminated 4-hour sleep episode followed by two periods of sustained wakefulness, 22 and 20 hours. During these periods, daytime napping only partially ameliorates the fatigue and sleep debt accrued during these periods of sustained wakefulness. Given this pattern, it is not surprising that at the end of the underway phase, the crewmembers moods had worsened significantly compared to moods at the beginning of the underway period. Psychomotor vigilance performance in the 510 is comparable to the performance of Sailors on the 6hrs-on6hrs-off 66 schedule. It is significantly degraded compared to Sailors on the modified 6hrs-on18hrs-off 618 and the 3hrs-on9hrs-off 39 schedules. Specifically, the 510 had 21.4 slower PVT reaction times, and 71.5 more lapses plus false starts than the 39. Our findings suggest that the 510 watch, combined with other work duties, leads to poor sleep hygiene. Crewmembers on the 510 suffer from sustained wakefulness because of extended workdays and circadian-misaligned sleep times. In general, the self-reported survey results suggest low degrees of resilience, psychological commitment to the organization, and psychological safety.
- Personnel Management and Labor Relations
- Anatomy and Physiology
- Medicine and Medical Research