There is no danger in having a fever with a rapid heart rate because the heart rate will return to normal when the body temperature returns to normal after timely administration of medication to reduce the fever and control the body temperature. When the body temperature increases, the body fluid regulation is damaged, so it will lead to a lack of water in the body, the heart metabolism will be accelerated, which will lead to an increase in the heart rate. The higher the temperature of the body during fever, the more serious the increase in heart rate, so fever and heart rate are directly proportional. Usually have a history of heart disease patients once the fever, should be timely for fever, always test the body temperature, to avoid the accelerated heartbeat on heart disease caused by certain triggers. The increase in heart rate during fever will not be more than 100 beats per minute, so it will not lead to life-threatening. Fever when the body is in a quiet state, drink more water to replenish water, can promote the body fluid metabolism.