Cooler break areas: Reducing heat stress among construction workers in Japan

This study explores the break environment conditions provided to construction workers in hot and humid climates and assesses the impact of the thermal conditions in rest areas on the physiological and psychological responses of the workers. It was conducted during summer in Japan with 26 male rebar workers across five construction sites by monitoring variables such as ambient temperature, humidity, step count, pulse rate, blood pressure, forehead skin temperature, and fatigue level. Workers worked for approximately 8-9 h per day, with scheduled 15-30-min short breaks at 10:00 and 15:00, in addition to a 1-h break at lunchtime. While the work sites exhibited temperatures ranging from 30.0 to 38.4 degrees C and relative humidity between 47.0 and 87.2 %, the thermal conditions in the rest areas varied, with temperatures from 26.9 to 35.8 degrees C and relative humidity from 45.4 to 83.4 %. We found that break periods in cooler areas led to lower pulse rates and prevented excessive pulse pressure decreases after exercise. Additionally, the combination of a cooler environment during breaks with a cooling jacket led to lower maximum forehead skin temperatures during the subsequent work periods. However, workers tended to report higher tiredness levels when break areas were cooler. Therefore, while providing cool rest areas is beneficial for worker recovery and preventing heat-related illnesses, the potential negative effects on workers' perception of tiredness should be considered.