This study investigated whether wearing phase change material (PCM) packs made of edible oils, such as coconut oil (CO) and palm oil (PO), after engaging in physical activities can alleviate heat strain in a hot and humid environment. Eleven healthy young males performed a treadmill exercise for 30 min. After the physical activity, the participants underwent resting recovery for 30 min with or without a cooling vest made of either CO-or PO-based PCM packs. Results showed that wearing PCM packs made of edible oils as a personal cooling device significantly reduced tympanic temperature, mean skin temperature, and heart rate during the recovery period. The CO-and PO-based PCM packs also improved perceptual thermal strain during recovery. Hence, PCMs made of edible oils can be used as a cooling device to reduce heat strain and improve comfort after physical work in a hot and humid environment. From the aspects of ergonomics and human factors, the use of CO-and PO-based PCM packs for personal cooling is a viable option for preventing heat-related disorders and maintaining productivity and workers' well-being. K E Y W O R D Sedible oils, heat strain alleviation, phase change material, post-cooling | INTRODUCTIONCore body temperature increases in proportion to metabolic heat production during physical activities, such as firefighting, industrial activities, military drills and operations, and sports, in a hot-humid climate. When this increase exceeds the permissible limit for work in a hot environment, that is, the core temperature exceeds 38.5°C, the human body experiences hyperthermia, which impairs work performance and threatens safety and health. Therefore, effective strategies for alleviating heat strain during and after physical work in a hot and humid environment