Fever is a relatively common phenomenon. In life, people with a low immune system can easily catch a cold and fever, so what degree of body temperature is considered a fever? Here is a look at the knowledge of fever. First, a healthy body temperature must be 37 ℃? We all know that the normal body temperature of the human body is 37℃, but this value is the average body temperature of the human body under normal circumstances, even if you are healthy and chubby, the body temperature is not constant. Gender differences, age, environmental changes, changes in diet and medication may cause fluctuations in normal body temperature; secondly, if you can’t read the thermometer accurately or take your temperature at different times of the day, the measurement results may be slightly affected; in addition, the normal body temperature value may also vary slightly depending on the measurement site. How many degrees is considered a fever? Usually, a fever is considered when the body temperature rises above 0.5°C above the normal body temperature. However, everyone’s normal body temperature is slightly different and is affected by many factors, such as time of day, season, environment, menstruation, etc. Therefore, to determine if you have a fever, it is best to compare it with your usual body temperature under the same conditions. If you do not know your original normal body temperature (assuming, in fact, that no one knows), then an axillary temperature of more than 37.2°C can be considered a fever. Third, why do you have a fever? Those bacteria, viruses and so on, love to burrow into the human body, they will produce something before or after death, called “exogenous pyrogens”, they will make the body hot. On the other hand, after they invade, the human body is not a diner and will immediately fight back by producing a bunch of cytokines to attack them, and many of these cytokines will also cause fever, called “endogenous pyrogens”. Some malignant tumors also produce these cytokines. This inside and outside, we get a fever.