ABSTRACT
A new set of time signals, of activity and rest, such as those associated with shifting work schedules, can upset the normal rhythms. During daylight, the body is prepared for work; sleep is normal at night. There are three basic solutions that help to avoid serious complications that can result from doing shift work during the evening or the night, or at other unusual timings. The first solution is to insert just one odd work shift and then return to the normal schedule. The second solution is to adopt a permanent work arrangement at the "unusual" time. The third solution entails a limited number of work shifts at the odd time, followed by an interruption, and then continues again with a limited number of work shifts at the same or at timing. Two sets of criteria exist by which to judge the suitability of shift plans: one set focuses on the worker and the other, on the organization.
