Asia Pacific Environmental and Occupational Health Journal

Objective: The purpose of this study is to determine the relationship between heat stress index with the physiological changes and work productivity of aluminium manufacturing workers at Kuala Selangor, Selangor.

Method: The study design was cross-sectional. A total of 112 fulltime male workers were selected as the study respondents. The workers’ name list was obtained from the human resources department. The respondents were selected from the list name by simple random sampling. Variables measured were the environmental temperature (heat stress index), core body temperature, heart rate and blood pressure of the respondents. QUESTempo34 WBGT Thermal Environment Monitor was used to measure the environmental temperature, while the body temperature was measured using OMRON Digital Body Temperature device. Blood pressure and heart rate were measured using OMRON T3 Blood Pressure and Heart Rate Monitor. Face to face interview using questionnaire was used to determine the respondents’ socioeconomic background, employment information, health complaints and worker’s coping mechanisms.

Result: Heat stress index (WBGTin values) (oC) of respondents in the smelting department was significantly higher than workers in the powder coating and extrusion departments (p<0.001). The most commonly reported of heat-related symptoms, were heavy sweating and thirst. Majority of respondents stated that they took more time to complete task when exposed to the heat. Common coping mechanisms for the heat were to drink water and to get away from high temperature for a while. There was a significant correlation between heat stress index (WBGTin values) and work productivity of the respondents. However, physiological parameters such as body temperature, blood pressure, and heart rate have no significant correlation with the heat stress index (WBGTin values) in the workplace.

Conclusion: This study showed the heat stress index (WBGT in value) at the smelting section was the highest compared to the other sections in the factory and the exposure to high temperature exceeded the ACGIH threshold limit value standard (27.5oC) for heavy workload.

Keywords: heat exposure, environmental temperature, physiological changes, productivity