The goal of this observational study is to explore the optimal target body temperature in first 24 hours and the relationship between body temperature and adverse outcomes of heat stroke. The main questions it aims to answer are: * the optimal target body temperature at 0.5 h, 2 h, and the lowest body temperature of heat stroke. * the best body temperature at the cutting point of stop cooling. * The relationship between the volume and speed of ice saline infusion and the cooling effect.