Abstract: Firefighters have to handle dangerous situations such as hazardous chemical accidents, firefighting, and rescue operations. They often wear protective clothing for extended periods and work in high-temperature environments, which can lead to heat stress such as heatstroke and heat exhaustion. This study focuses on two personal cooling systems-liquid cooling garments (LCG) and phase change materials cooling vests (PCM),and conducts experimental research on their effectiveness in reducing the thermal physiological response of human movement wearing airtight chemical protective clothing in a high-temperature environment of 35 ℃. The results indicated that ,comparing with only wearing chemical pratective clathing， both LCG and PCM are effective in reducing skin temperature, core temperature, heart rate, etc., thereby improving human thermal comfort. However, LCG offers better improvement in thermal comfort.

Key words: cooling garments, chemical protective clothing, thermoregulation, thermal comfort