Sleep, sleepiness and health complaints in police officers: the effects of a flexible shift system.

The aim of the study was to study the effects of a flexible shift system (based on self-determined work hours) with respect to sleep/wake complaints and subjective health. The comparison group was a rapidly rotating shift system, with frequently occurring quick returns. A secondary aim was to examine the relation between work hour characteristics indicating compressed or difficult rosters (e.g. number of workdays in a row, frequency of quick returns and long work shifts) and subjective sleep and sleepiness, within the flexible shift system group. The sample of the analysis included 533 randomly selected police officers, of which 26% were females. The participants answered a questionnaire. The results showed that the flexible shift system group did not differ with respect to sleep/wake complaints and subjective health. However, the flexible shift group obtained more sleep in connection with the shifts, probably because of longer rest time between shifts. Thus, they worked less quick returns and long work shifts. The association between work hour characteristics and sleep/wake complaints was weak in the flexible shift group. Instead, sleep/wake problems were mainly associated with the attitude to work hours.