ABSTRACT
The ergonomic problem with regard to shiftwork is that of enabling the individual to work at abnormal hours, an activity which runs both counter to his or her own biology (Homo sapiens being a diurnal species), and counter to the surrounding society which is structured to protect the sleep of day workers, but not that of night workers, and expects evenings and weekends to be free for social, religious, athletic, and cultural events. Moreover, shiftwork is not simply restricted to a very small group of people who can be carefully selected or self-selected to experience minimal problems. Neither is it restricted to the youngest and fittest of workers who can bid their way out of abnormal hours when they advance into their middle age. Employment trends, particularly in the manufacturing sector, now dictate that the “bidding out of shiftwork by seniority” option often no longer applies. For many middle-aged and late middle-aged workers the only option is between shiftwork and no work. Thus, approximately one fifth of all employees are engaged in some form of work that requires their presence outside of the “standard” 7am to 6pm working day on a regular basis, and can thus be regarded as “shiftworkers.”
