Interaction Effect of Workload and Circadian Rhythm in Air Traffic Controllers’ Fatigue

Objective To investigate interaction effect of workload and circadian rhythm in air traffic controllers’ fatigue. Methods At one busy international airport, air traffic controllers for the terminal area were recruited in this study. The volunteers were asked to fill out the questionnaire of the Stanford Sleepiness Scale about their fatigue feelings before, in the middle, and after their work. The questionnaire survey followed up with four-period groups including morning, afternoon, the first half of the night, and the second half of the night. The statistical results of the questionnaires showed that the fatigue levels of air traffic controllers increased very significantly during work periods; the levels were also influenced by circadian rhythm. The covariance analysis results showed that there was a very significant interaction effect of workload and circadian rhythm. Conclusions There existed a very significant interaction effect of workload and circadian rhythm in air traffic controllers’ fatigue. These results require more objective data to verify and will prompt to consider the effect in the assignment of workload and human resource for fatigue management.