Thermoregulatory responses of agricultural workers at house cultivation work under heat environmental conditions in summer

Abstract

The purpose of this study was to examine the thermoregulatory responses of agricultural workers at heat environmental house cultivation work in summer, and in the particularly this study screened it about a risk of the heat disorders in elderly agricultural workers.

The subjects were 25 house cultivation practitioner men, 59.6±6.7 years old in full-time agricultural workers. There were the work places to investigate in the glass type house, and type of the farming works were the making of floriculture and soil. The survey items were measured the environmental conditions, tympanic temperature, heart rate, the sweat rate, salt concentration, rehydration and thirst sensation.

WBGT was an average of 27.4 to 30.1°C. The sweat rate and salt loss quantity from sweat were 668.7±179.5 g/hr and 545±347 mg/hr. The elevation of tympanic temperature was 0.27±0.10°C/hr and the rehydration was 236.5±62.4 g/hr. Also, the dehydration rate at work was 2.15±0.72%. The thirst sensation reached 56.0±17.9% at the end of works. Furthermore, it was found that the positive correlations between the age and sweat rate, the dehydration rate, the quantity of elevation of body temperature, the salt loss of the sweat, and the negative correlation was found between age and the thirst sensation at the latter half of the work.

The results revealed that sweat rate, dehydration rate and elevation of body temperature were high because the rehydration rate was low with increase of feeling thirst with aging at the house cultivation work in summer. Therefore, to prevent heat disorders in the elderly agricultural workers at the house cultivation farming, it is necessary immediately instruct to sufficient supplementation of the rehydration including salt.