The Impacts of Rotating Shiftwork on Worker Fatigue Levels and Associated Adaptations: A Naturalistic Study Across Offshore Platforms in the Gulf of Mexico

Background: Shift rotation is a popular means of aiding offshore oil and gas extraction (OGE) workers in mitigating the health and safety impacts of night shift work. However, they can disrupt workers’ circadian rhythms, resulting in poor sleep quality, fatigue, and performance postrotation. Objective: To determine the impacts of forward (day-to-night) and backward (night-to-day) rotations on offshore OGE workers’ sleepiness, fatigue, performance levels, and subsequent circadian adaptation over time. Methods: 70 oil and gas workers from two offshore platforms in the Gulf of Mexico were followed for seven days, starting the day before the shift rotation. Subjective and performance-based measures of fatigue, as well as actigraphy, were collected daily from day and night workers undergoing shift rotation and compared to those on their fixed shift schedules. Results: Forward rotations negatively affected perceived sleepiness, sleep efficiency, total sleep time (measured by actigraphy), and increased reaction time on the Psychomotor Vigilance Task compared to workers assigned to fixed day shifts. The only observed impact of the backward rotation on fixed night shift workers was decreased total sleep time. Discussion: Workers assigned to the forward rotations took longer to adapt to the shift rotation, providing insights into how fatigue risk management strategies can be tailored to better address the needs of vulnerable shift workers. Application: The findings indicate that rotating shift work is detrimental to offshore workers, and it is recommended that the amount of rotating shift work during a worker’s offshore assignment be minimized, especially when transitioning from day to night.