Optimization of night and shiftwork plans among policemen in Kuwait: a field experiment.

A pilot survey was designed to define incidence, rotation period, rotation direction and cycle of shiftwork plans in the production and service units in Kuwait. Preliminary results from the Ministry of Interior showed that four different shift plans are widely used. Forty policemen, ten from each shift plan, volunteered to fill in a diary for a period of two or more cycles. The diary was comprised of a set of questions planned to reveal disturbances in sleep duration, sleep quality, food intake and appetite. The daily questionnaire also covered psychosomatic complaints and subjective judgement of recovery. A control group, on permanent day work, volunteered to fill in the diary for the same period. The results indicated that one of the four shift plans was quite satisfactory and least harmful to the policemen. Two plans were associated with excessive strain during working days, but the number of free days was sufficient to achieve complete recovery. The fourth plan was associated with excessive strain during working days and recovery was not achieved after 24 h of rest at the end of the shift cycle.