Detecting High-Risk Fatigue: Tracking with Alertness and Physiological Metric Pattern

Abstract

Fatigue is a recognized factor contributing to safety incidents and reduced task performance. However, classifying fatigue levels among workers in the workplace is a challenging task due to its subjective nature. This study aimed to establish universal criteria for identifying high-risk levels of fatigue. Industrial settings commonly use risk management checklists for this purpose. This study analyzed the correlation between fatigue levels and physiological indicators associated with fatigue, including alertness levels. The alertness levels were measured by the psychomotor cognition test (PCT), and the physiological indicators included salivary C-reactive protein related to cumulative fatigue, blood lactate concentration related to physical fatigue, and salivary cortisol associated with mental fatigue. Subjective fatigue levels were categorized into five levels, with Level 1 representing optimal mental and physical conditions and Level 5 indicating severe fatigue. Results showed that the mean reaction time in PCT at Level 5 significantly increased, and the success rate sharply decreased, demonstrating a significant difference compared to Levels 1 and 2 (p<0.01). Blood lactate levels were exhibited a positive correlation with fatigue levels, sharply increasing from Level 4. Blood lactate levels in Levels 4 and 5 were significantly higher than those of Levels 1 and 2 (p<0.01). Salivary C-reactive protein (CRP) levels were also showed a rapid increase from Level 4, significantly higher than those of Levels 1 and 2 (p<0.001). Salivary cortisol concentration at Level 5, however, was relatively lower compared to those of Levels 1-4. In conclusion, cumulative fatigue and high-risk levels of fatigue due to excessive workload are reflected in vigilance tests and physiological indicators. These indicators can be valuable in reducing subjective biases when assessing fatigue levels. The study suggests that profiling vigilance tests and physiological indicators associated with fatigue can be employed to screen for high-risk fatigue levels.

Keywords: Fatigue, Alertness, CRP, Lactate, Cortisol

DOI: 10.54941/ahfe1005178