The study of Relationship between Mental Work Load and Sleep Quality in Video Display Terminals Users

Background & objectives: One of the factors affecting the performance of video display terminal users is their mental work load. Since low sleep quality causes fault and decreased accuracy in work, this study aimed to evaluate the relationship between mental work load and sleep quality in video display terminals users. Methods: This descriptive cross-sectional study was performed on 191 video display terminal users. National Aeronautics and Space Administration Task Load Index questionnaire (NASA TLX) which is a six-dimensional tool and measures mental, physical, temporal, performance, Frustration and Effort demands, was used in the study. For evaluation of sleep quality, Pittsburgh Sleep Quality questionnaire was used. Data were analyzed by descriptive statistics, independent T-test, one way ANOVA, Pearson correlation coefficient and regression analysis in SPSS version 20 software. Results: Mean score of sleep quality and mean of overall mental work load were 6.29±2.67 and 66.61±17.69, respectively. Pearson correlation coefficient showed no significant relationship between mental work load and sleep quality (p=0.34, r=-0.06). Independent       T-test showed that there was a significant difference in sleep quality between males and females (p=0.001). 39.2% of participants demonstrated good sleep quality, 4/52% relatively low quality and 4/8% low sleep quality. NASA-TLX showed that the lowest and highest scores of six scales were related to physical demand (16.27±22.43) and mental demand (78.57±21.31), respectively. Conclusion: In this study, there was no significant relationship between mental work load and sleep quality. Since mental work load was high in video display terminal users, use of effective programs to reduce the mental work load seems to be essential for these users.