Extended workdays: Effects of 8-hour and 12-hour rotating shift schedules on performance, subjective alertness, sleep patterns, and psychosocial variables

Abstract A newly instituted 3-4 day/12-h rotating shift schedule was compared to the previous 5-7 day/8-h schedule using standard laboratory-type measures of performance and alertness, and a questionnaire on sleep patterns and other personal habits. After seven months adaptation to the new schedule, there were decrements in the laboratory-type tests of performance/alertness which could be attributed to the extra 4 h of work per day. There were also reductions in sleep, and disruptions of other personal activities during 12-h workdays. However, increases in self-reported stress were attenuated by the shortened workweek. These results are discussed in terms of trade-offs between longer workdays and shorter workweeks.