Abstract
The structure of many shiftwork systems currently in operation reflects tradition rather than design. Research into shiftwork, however, suggests that parameters related to objective physiological, psychological, and social criteria can be included in the design of shift systems, but that they nonetheless meet mathematical and other constraints. To illustrate the existing diversity of shift systems, the frequency distribution of some fundamental characteristics of 487 continuous shift plans in operation within the Federal Republic of Germany are shown. These characteristics include the number of consecutive night shifts, start and finish times of shifts, duration of shifts, distribution of leisure time, duration of the shift cycle, and the regularity of the shift system. They are discussed with respect to research evidence concerning the following criteria: physiological adaptation; performance and accidents; wellbeing (e.g., sleep, fatigue, and appetite); health (e.g., gastrointestinal and psychosomatic disorders); personal and social problems. Nine practical recommendations are suggested as design parameters for planning shift systems.
