The causes of high heart rate are categorized as physiological and pathological. Physiologic factors include exercise, diet, and emotions. Pathological factors include cardiac diseases such as myocardial ischemia, arrhythmia, etc.; endocrine diseases such as hyperthyroidism, diabetes mellitus, etc., the regulation of body fluids; other factors include anaemia or hypoxia of organs and tissues when in shock, fever, or taking drugs such as atropine. 1. Physiological factors: common in healthy people such as exercise, smoking, alcohol, tea or coffee, emotional changes, etc., causing sympathetic excitation and accelerated heart rate. It can be relieved after resting or removing the triggers. 2. Heart disease: Organic heart disease such as myocardial ischemia, congestive heart failure, due to the heart’s function is reduced, other organs of the body ischemia and hypoxia, resulting in a reflexive increase in heart rate. Arrhythmia patients, such as atrial fibrillation, atrial flutter, etc., due to conduction abnormalities, itself can cause rapid heart rate. 3. Endocrine diseases: such as hyperthyroidism and diabetes. Hyperthyroidism patients, thyroid hormone synthesis and secretion increased, the role of the heart, the heart rate high. Long-term diabetes leads to coronary heart disease, myocardial ischemia and hypoxia, heart rate compensatory acceleration. Insulin overdose, resulting in hypoglycemia, when the sympathetic nerve excitation, high heart rate. 4. Other factors: including anemia or shock when organs and tissues hypoxia heart rate. In addition, fever or taking certain drugs such as adrenaline, atropine will also speed up the heart rate. There are many other causes of high heart rate, it is recommended to determine the treatment program under the guidance of a physician to avoid blindly using their own medication.