Fast heartbeat can be caused by physiological factors, such as after strenuous exercise, high mental tension, etc.; it can also be caused by pathological factors, such as anemia, hyperthyroidism and so on. 1. After strenuous exercise, high mental tension: sympathetic excitation, so that the heart contraction, heart rate acceleration, accelerated conduction; similarly, tea, caffeine, and so on can lead to sympathetic excitation, heart rate acceleration; and is taking certain drugs, such as atropine, adrenaline, and so on. 2. Anemia: Anemia can lead to insufficient oxygen carried in the blood, the body to compensate for the increase in heart rate so that the heart ejection of blood increased. 3. Hyperthyroidism, the body is at a high metabolic level, the demand for oxygen increases, the heart rate increases, and cardiac output increases. 4. Pheochromocytoma, increased secretion of adrenaline, as if sympathetic excitation, accelerated heart rate. 5. Some diseases of the lungs and organic lesions of the heart itself may lead to accelerated heart rate. If you feel the accelerated heart rate to exclude physiological factors, or combined with other discomforts, you should go to the regular hospital as soon as possible for medical treatment.