Change from an 8-hour shift to a 12-hour shift, attitudes, sleep, sleepiness and performance

Objectives The present study sought to evaluate the effect of a change from a rotating 3-shift (8-hour) to a 2-shift shift (12 hour) schedule on sleep , sleepiness, performance, perceived health, and well-being. Methods Thirty-two shift workers at a chemical plant (control room operator s) responded to a questionnaire a few months before a change was made in th eir shift schedule and 10 months after the change. Fourteen workers also fi lled out a diary, carried activity loggers, and carried out reaction-time t ests (beginning and end of shift). Fourteen day workers served as a referen ce group for the questionnaires and 9 were intensively studied during a wee k with workdays and a free weekend. Results The questionnaire data showed that the shift change increased satis faction with workhours, sleep, and time for social activities. Health, perc eived accident risk, and reaction-time performance were not negatively affe cted. Alertness improved and subjective recovery time after night work decr eased. The quick changes in the 8-hour schedule greatly increased sleep pro blems and fatigue. Sleepiness integrated across the entire shift cycle show ed that the shift workers were less alert than the day workers, across work days and days off (although alertness increased with the 12-hour shift). Conclusions The change from 8-hour to 12-hour shifts was positive in most r espects, possibly due to the shorter sequences of the workdays, the longer sequences of consecutive days off, the fewer types of shifts (easier planni ng), and the elimination of quick changes. The results may differ in groups with a higher work load.