COMPARISON OF 8 AND 12 HOUR SHIFTS - IMPACTS ON HEALTH, WELL-BEING, AND ALERTNESS DURING THE SHIFT

Objectives - The generally agreed view is that there is no ideal shift system, and that most systems will have both advantages and disadvant ages. As such, attention has been placed on trying to identify good an d bad features of shift systems, with a view to minimising the possibl e ill health as a consequence of shiftwork. The present study focuses on the duration of the shift and looks at the implications for individ ual health, wellbeing, and alertness during the shift of extending the shift from the traditional eight hours to 12. Methods - Two groups of chemical workers, one working 12 hour shifts and the other working ei ght hour shifts, took part. All completed a modified version of the st andard shiftwork index (SSI), a set of self reported questionnaires re lated to health and wellbeing. Results - The two groups did not differ on most outcome measures, although the differences that did exist sug gested advantages for the 12 hour shift workers over the eight hour sh ift workers; with the notable exception of rated alertness at certain times of day. Conclusions - The results are explained in terms of the design of the 12 hour shift system and the specific sequencing of shif ts that seem to minimise the potential for the build up of fatigue. Al though the current data moderately favour 12 hour shifts, a cautionary note is sounded with regard to the implications of the alertness rati ngs for performance and safety.