Severe heat stroke is mainly manifested in three types, divided into heat cramps, heat exhaustion and pyrexia. First, heat cramps mainly appear as muscle spasms, skeletal muscle spasms, such as twitching of the limbs, abdominal muscles and facial muscles, twitching time within a few minutes, and then relieved, but intermittent episodes, the body temperature is not very high, the body temperature is more than 38 degrees or more, rarely appear 40 degrees. Secondly, heat exhaustion, mainly manifested as general weakness, dizziness, nausea, vomiting, headache, and even postural hypotension and syncope after a large loss of body fluids. Third, pyrexia, the main manifestation is mainly high fever, body temperature will all exceed 40 degrees, there will be no sweating, mental abnormalities, mental abnormalities are mainly manifested as delirium or irritability, or even serious coma, convulsions, etc.