Efeitos analíticos e perceptuais da exposição ao calor em trabalhadores de fundição de metal

Abstract

This thesis investigated the human physiological response to occupational heat stress in a sample of 30 male operators from the melting sector of a metal foundry located in Southwestern Paraná, Brazil. The study aimed to verify the correlations and statistical effects of high thermo-environmental temperatures (measured by the WBGT) on the variations of non-invasive hormonal biomarkers, namely salivary cortisol (morning and evening) and 24-hour urinary catecholamines. The methodology integrated field data collection of thermo-environmental and laboratory parameters, alongside subjective fatigue assessments (Yoshitake Questionnaire, QY), employing Linear Regressions and Cluster Analysis. Although the linear models demonstrated a low coefficient of determination (R²), consistent with high biological variability, the in-depth data analysis revealed crucial findings for occupational safety: the presence of extreme values (outliers) in hormonal profiles, indicating exacerbated physiological responses and a risk of thermal overload in specific individuals. Additionally, the multiple regression model for catecholamines suggested that temperature variables (globe and wet-bulb) act in a joint and additive manner in the intensification of sympathetic activity. The Cluster Analysis validated these findings, identifying a higher-risk group which, besides reporting intense fatigue, concentrated the hormonal outliers. It is concluded that heat stress in foundry environments triggers relevant endocrine stress responses, and the study highlights the importance of utilizing atypical biomarker values as a primary monitoring tool and developing personalized prevention strategies in hazardous environments.