Pyrexia belongs to a type of severe heat stroke, but also the most serious category, according to the type of different, different performance, the main performance of multiple organ function damage, serious cases can be life-threatening. 1. exertional pyrexia: mostly seen in young people, often occurring during heavy physical labor or strenuous exercise, may appear high fever, convulsions, sweating or no sweating, rapid heart rate or even coma symptoms, serious cases can be due to multi-organ failure and life-threatening. 2. Non-exertional pyrexia: this kind of condition is common in old and weak or chronically ill patients, when exposed to hot environment for a long time, it can be manifested as delirium, epilepsy and all kinds of behavioral abnormalities, and even high fever, coma and shock. Therefore, it is recommended to go to the hospital in time to avoid delaying the condition when the above mentioned manifestations occur.