EFFECTS ON HEALTH OF A CHANGE FROM A DELAYING TO AN ADVANCING SHIFT SYSTEM

Objectives-Shift work can lead to a range of problems for some people that seem to result from the disturbance of the circadian system, and can broadly be classified as: disturbances of sleep, impaired physical and psychological health, and disturbed social and domestic life. The main attempt to try to reduce these problems has focused on the desig n of the shift system, and the identification of the most problematic features of the shift system. One such feature is believed to be the d irection of shift rotation. Systems that advance are thought to be mor e problematic than those that delay. The present study examines the ch ange in the direction of shift rotation from a delaying to an advancin g system on health and wellbeing. Methods-Self reported measures of to lerance to shift work were taken two months before and six months afte r the change. These included sleep difficulties, gastrointestinal prob lems, psychological ill health, chronic fatigue, social and domestic d isruption, job satisfaction, and satisfaction with the shift system. R esults-The change from a delaying to an advancing system resulted in a n increase in sleep difficulties between successive afternoon shifts, but a decrease in social disruption. There was little evidence of impa ired health on the advancing compared with the delaying system. Conclu sions-The increase in sleep difficulties was thought to result from th e undesired adaptation of the circadian system to night work, as a res ult of the afternoon shifts now following a series of night shifts, wh ereas previously they followed a series of morning shifts. The decreas e in social disruption was thought to result from the specific sequenc e of the shifts and the discontinuous nature of the shift system, in p articular, the long weekend off every third week. Lack of reported hea lth related differences are explained in terms of the relatively unhar mful nature of the shift system in question, and the relatively short time span over which the study was conducted.