A Laboratory Comparison of Clockwise and Counter-Clockwise Rapidly Rotating Shift Schedules, Part I. Sleep
FEDERAL AVIATION ADMINISTRATION OKLAHOMA CITY OK CIVIL AEROMEDICAL INST
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Many air traffic control specialists work relatively unique counter-clockwise, rapidly rotating shift schedules. Researchers recommend, however, that if rotating schedules are to be used, they should rotate in a clockwise, rather than a counterclockwise direction. Unfortunately, few studies have examined clockwise and counter-clockwise, rapidly rotating shifts. This study was designed to partially remedy this lack by examining the effects of both types of schedules on sleep duration, timing, and quality. Participants n 28 worked a week of day shifts 0800-1600, followed by two weeks of either a Clockwise n 14 or Counter-Clockwise n 14 shiftwork schedule, including early morning 0600-1400, afternoon 1400-2200, and midnight shifts 2200-0600. Participants recorded sleep data in daily logbooks and wore wrist activity sensors to provide an objective source of sleepwake data. Both groups reported less sleep before the early morning shifts Msub Clockwise 5.1h Msub counter-clockwise 5.5h than before the afternoon shifts Msub Clockwise 7.5h Msub counter-Clockwise 7.9h. The Clockwise group reported an average of 7.2h of sleep during the night before the midnight shifts and a nap during the day of 0.9h. In addition to a nighttime sleep of 6.0h, the Counter-Clockwise group also took a nap before the midnight shifts of 2.2h. Objective sleep data and subjective sleep quality ratings are also reported. While these data indicate that a longer concentrated sleep period is obtained prior to the midnight shift on the Clockwise rotation schedule, they do not fully support the hypothesis that a clockwise rotation will result in less sleep disruption.
- Anatomy and Physiology