Shift Working: the Arrangement of Hours on Night Work

Abstract

PROBLEMS of adaptation to shift-working routines may be increased by physiological disturbance when changing to night work is involved. It has been shown that performance on some kinds of work can be affected by inversion of normal time routines so that output at night is lowest in the early hours of the morning^1,2. This is believed to be associated with diurnal rhythms which persist with old periodicities into the new routines. Experiments have shown, however, that complete inversion of the environment is accompanied after a period by synchronization of diurnal rhythms with the new routines³. For this reason physiologists have sometimes suggested that, to facilitate adaptation and improve efficiency, night work should be permanent or for a long period^4,5.