Daily Multidimensional Fatigue Scale and Physiological Indicators to minimize Subjective Bias in assessing Fatigue Levels

Abstract

Fatigue is a human factor that can diminish task efficiency and serve as a potential cause of safety incidents. The specific aim is to investigate the removal of subjective bias in fatigue assessment with the daily multidimensional fatigue inventory (DMFI), covering acute, cumulative, physical, and mental fatigue. Additionally, the goal is to investigate the elimination of residual subjective bias after DMFI using physiological indicators, the Psychomotor Cognition Test (PCT), salivary CRP, blood lactate, and salivary cortisol, related to each type of fatigue. The DMFI significantly classified daily fatigue into 5 levels (p<0.001). As the level of fatigue increased, the reaction time of PCT slows down, and the success rate decreased. PCT alone was not sufficient for classifying fatigue levels. However, PCT could possibly serve as a tool for data refinement, eliminating some subjective bias in self-reported fatigue levels. The levels of blood lactate showed a positive correlation with the increase in fatigue levels. Especially in groups with high levels of physical activity, the concentration of blood lactate can be utilized as a tool to eliminate subjective bias, and it was found to be useful in classifying fatigue into binary or 3 levels. Salivary CRP, representing cumulative fatigue, had some utility as a tool to track subjective bias in participants, specifically in office work where cumulative fatigue levels were relatively low. Salivary cortisol, representing mental fatigue, was found to be unsuitable as an indicator for tracking fatigue levels in mentally healthy participants. The accumulated data here will be utilized for the training of a deep learning-based fatigue level classifier.

Keywords: Fatigue, Lactate, Firefighter

DOI: 10.54941/ahfe1005175