293 Shift Work Shift work can be defined as a work schedule outside the daytime hours of 7 AM to 6 PM. The circadian rhythms are interrupted because employees, naturally diurnal beings, are required to work during a nocturnal time frame. Shift work often is referred to as night shift, graveyard shift, or lobster shift. Shifts are either fixed schedules or rotating schedules, which at times include a three-shift rotation. More than 20 percent of the U.S. population works in some form of shift work. Approximately 20 percent of shift workers are unable to tolerate diurnal sleep and nocturnal activity, which often leads to health consequences for mental and physical well-being, typically referred to as maladaptation syndrome. Symptoms include sleep disorders, gastrointestinal disturbances, eating problems, alcohol or drug abuse, depression, personality changes, decreased socialization and relation- ship difficulties, and higher rates of accidents. There are several challenges for both the employees working shifts, as well as for the employer. Shift work has been associated with cardiovascular disease, gastrointestinal disorders, obesity, diabetes, and obstructive sleep apnea. The quality and quantity of sleep is often less. In addi- tion, family and social relations are impacted. Employers incur costs associated with increased absenteeism, turnover, production errors, and safety incidents. In October, 2007, a working group of scientists from 10 countries assessed the carcinogenicity of shift work. Based on their conclusions, the International Agency for Research on Cancer (IARC) and the American Cancer Society have decided to list shift work that involves circadian disruption as probably carcinogenic to humans, which is a Group 2A classification. The primary objective of a program targeted at shift work is to ensure the health and safety of employees scheduled to work outside daytime hours. The occupational health unit can mini- mize any negative consequences caused from shift work by developing primary and secondary prevention strategies. Primary Prevention ● Review work schedules to determine rotation schedule and frequency of shift changes. Stud- ies have indicated that employees tolerate a forward rotation better (i.e., rotating from days to evening or nights) than a reverse rotation. Ideal shift rotation length remains controversial however, a rapid rotation of every 2 days often is tolerated better than rotating shifts every 7 to 14 days. Longer rotation schedules of a month or more allow for accommodation how- ever, even employees who work a permanent night shift need to adjust after having days off. ● Educate management, supervisors, employees, and families regarding circadian rhythms, signs and symptoms of shift work stress, and possible health consequences of shift work and adaptation strategies. ● Advocate safe work environments and worker protection, including rotation schedules, adequate lighting, ventilation, noise controls, temperature controls, and availability of nutri- tious food. Definition and Purpose Program Objectives and Elements