A heart rate of 120 beats per minute is a manifestation of a high heart rate, but if it is physiologically high, it generally has little effect; while pathologically high, if not treated in time, it may result in a drop in blood pressure, loss of consciousness, sudden death, and so on. 1. Physiological high: such as emotional tension, irritability, after strenuous exercise, may lead to heart rate increase, this type of high heart rate, generally have no effect on the body, when the causative factors are removed, the heart rate can return to normal. 2. Pathologic high heart rate: (1) Decrease in blood pressure: a persistently high heart rate may lead to a rapid decrease in blood pressure, and the patient may feel panic, shortness of breath, chest tightness, and in severe cases, shock may be caused. (2) Loss of consciousness: A persistently high heart rate may be caused by tachycardia, ventricular flutter or ventricular atrial fibrillation, which may lead to a decrease in the heart’s ejection volume, resulting in an increase in the heart rate, and the patient may suddenly fall into a coma, with a complete loss of consciousness. (3) Sudden death: A persistently high heart rate and an increase in myocardial oxygen consumption may suddenly induce sudden death, which is life-threatening and requires emergency resuscitation. If the heart rate is persistently high and currently reaches 120 beats/minute, it is recommended to consult a doctor as soon as possible and analyze the cause through ECG and cardiac ultrasound before combining with the doctor’s recommendations for targeted treatment.