WORK SHIFT DURATION - A REVIEW COMPARING 8 HOUR AND 12 HOUR SHIFT SYSTEMS

Objectives-Shiftwork is now a major feature of working Life across a b road range of industries. The features of the shift systems operated c an impact on the wellbeing, performance, and sleep of shiftworkers. Th is paper reviews the current state of knowledge on one major character istic of shift rotas-namely, shift duration. Evidence comparing the re lative effects of eight hour and 12 hour shifts on fatigue and job per formance, safety, sleep, and physical and psychological health are con sidered. At the organisational level, factors such as the mode of syst em implementation, attitudes towards shift rotas, sickness absence and turnover, overtime, and moonlighting are discussed. Methods-Manual an d electronic searches of the shiftwork research literature were conduc ted to obtain information on comparisons between eight hour and 12 hou r shifts. Results-The research findings are largely equivocal. The bul k of the evidence suggests few differences between eight and 12 hour s hifts in the way they affect people. There may even be advantages to 1 2 hour shifts in terms of lower stress levels, better physical and psy chological wellbeing, improved durations and quality of off duty sleep as well as improvements in family relations. On the negative side, th e main concerns are fatigue and safety. It is noted that a 12 hour shi ft does not equate with being active for only 12 hours. Conclusions-Th ere can be considerable extension of the person's time awake either si de of the shift. However, the effects of longer term exposure to exten ded work days have been relatively uncharted in any systematic way. Lo ngitudinal comparative research into the chronic impact of the compres sed working week is needed.