Determination of Approximate Fatigue Occurring-time on the Basis of its Effective Factors on Industries Workers in Tabriz city

Abstract

Background and Purpose: In today industrial world, the experience of fatigue in the workplace has significantly increased and thus, the negative consenquences of fatigue, such as disability, absence from work, low performance, inadequate work quality, human errors, accidents and work-related fatalities, have also increased. As respect, there is no clear and perfect understanding of fatigue in the workplace and also, there is no accurate way to forecast the fatigue occurance time to avoid from negative concenquences of it, yet; the present study has investigated the relationships among fatigue and its related factors to provide a model to determine the approximate fatigue occurrence time. Materials and Methods: Data has collected from 338 workers of several manufacturing industries in Tabriz city by a self-reported questionnaire including a fatigue in time assessment check list, demographic informations, environmental factors, insomnia severity index, general health (GHQ-12), work load (NASA-TLX), job stress (HSE) and job satisfaction Andrews and withy. The software of SPSS and Amos have used to data analysis and designing of a fatigue model and also data has analyzed by K-S test, Repeated Measures, Varimax and Factor Analysis. Results: There is a weak relationship between fatigue and demographic factors in the study of fatigue and its related factors relationships. There are significant relationships among other factors including general health, depression, sleep quality, job stress (that consist of job demands, control, coworkers support, roll and change), job satisfaction and workload (including physical, mental, temporal demands, effort, performance and frustration) with fatigue in the times of the working day (P<0.05).

In the study of internal consistency reliability, the internal reliability of all groups was confirmed (α>0.7). Also, according to the results, the fitness of the final model was confirmed by the presented fitness indexes (CFI=1, TLI=1, RMSEA=0.000, X2/DF=4.825). Conclusion: According to the results and final designed fatigue model in this study, and with attention to the dividing of the working day into three periods, the third period (15:00 to 18:00) was identified as the most principle and probable fatigue occurrence time.