A heartbeat over 100 beats per minute with a fever may or may not be dangerous, depending on the person. A normal person’s heart rate is between 60 and 100 beats per minute. A heart rate of more than 100 beats per minute during a fever is due to an increase in basal metabolism caused by an increase in body temperature, which leads to an increase in the heart rate, and generally does not cause significant symptoms of palpitations and discomfort, which is less dangerous. In addition, it is necessary to be alert to whether it is a manifestation of myocarditis, if it is myocarditis, the risk is relatively high. In myocarditis, increased heart rate is accompanied by chest tightness, palpitations, fatigue, dizziness, chest pain and even dyspnea. This condition needs to be treated as soon as possible. At the same time, rapid heart rate is also dangerous for patients who already have a heart condition such as ischemic heart disease. In summary, it is recommended to consult a doctor for standardized diagnosis and treatment when necessary.