Effect of noise on fatigue: correlation between the subjective and objective indicators

Introduction: Fatigue is the exhaustion of the body or spirit that can be caused by stress, excessive work, drug use, physical or mental illness. Fatigue is a factor in reducing productivity and incidents. Therefore, measuring fatigue is important. The aim of this study was to determine the fatigue measurement based on subjective and objective indices. Method: A cross-sectional study was performed on 120 male and female students. By simulating the real environment of each person in the 50 and 70dB pressure levels for 40 minutes, before and after exposure to noise, the amount of mental fatigue was measured using the subjective index Visual Analog Scale (VAS) and the objective index continuous performance test (CPT). The results were analyzed using paired t-test and Spearman correlation coefficient in SPSS 20 software. Results: Measurement results with both self-declaration scale and continuous performance test showed that mental exhaustion was increased significantly after exposure to the mentioned pressure level, but the results of two methods were not consistent with each other. Conclusion: Considering that the VAS self-declaration scale is a subjective method, it seems that the mismatch of the two methods is more related to the ineffectiveness of this scale. Therefore, it is suggested that re-examination has to be done with more precise methods such as electroencephalogram.