2022 Volume 57 Issue 1 Pages 3-11
One of the management issues related to occupational safety and health at plant factory with sunlight is the risk of heatstroke in the summer. The estimated wet-bulb globe temperature (WBGT) value in a greenhouse calculated from past environmental data at a plant factory in Mie was generally controlled within the range of 20°C to 25°C, but this increased between July to September, reaching a maximum of about 35°C. In this study, electrocardiogram, tympanic temperature, oxygen consumption, and work speed were measured in three healthy adult male farmers after engaging in tomato cultivation work for 30 min under hot environmental conditions in summer and under suitable growth temperature conditions in autumn. WBGT values were 34.3±0.5°C under hot environmental conditions and 21.9±1.5°C under suitable growth temperature conditions. Heart rate increased with work and decreased with rest under both conditions. The degree of increase in heart rate was greater in all participants and did not return to resting values under hot environmental conditions. The workload under hot environmental conditions was classified as “hard work” based on the increase in heart rate and %HRR, even though energy expenditure was not high, and it was found that work speed decreased. Therefore, it is necessary to evaluate the physical strength and work load of each worker and implement a farm management system that includes countermeasure technologies that take into account the thermal environment.
