Shiftwork and different dimensions of fatigue

The purpose of the present study was to study the effects of shift work on different dimensions of perceived fatigue, as well as to study if fatigue changes over an entire shift cycle, using the Swedish Occupational Fatigue Inventory (SOFI). The participants, 48 men and 44 women, worked on a rotating three shift in a paper mill. Fatigue was rated at the end of each shift, using the SOFI, the Karolinska Sleepiness Scale, and the scale Accumulated Time with Sleepiness. Reaction time tests were also carried out at the end of each shift. The results showed that the reported fatigue was primarily expressed in terms of Sleepiness, and to some extent also in terms of Lack of energy and Lack of motivation. These dimensions also discriminated most between work shifts, where the highest levels of fatigue were reported during the night shifts. Longer reaction times coincided with increasing ratings of the mental aspects of fatigue. Sleepiness is well known in shiftwork. The present results add that Lack of energy and Lack of motivation also form part of the perceived fatigue after night shifts. In addition, fatigue tends to accumulate during night shifts. Relevance to industry A reliable and valid method to assess subjective aspects of fatigue may be important in ergonomics. This study indicated the validity of SOFI in relation to shiftwork. (C) 2000 Elsevier Science B.V. All rights reserved.