A heart rate of 90 beats/minute or more for a long period of time without exceeding 100 beats/minute is not dangerous, but if it is 100 beats/minute or more for a long period of time it is more dangerous. Heart rate is the number of times a normal person’s heart beats per minute in a quiet state, also called the quiet heart rate. Generally normal people are 60-100 beats/minute, but if it is long-term 90-100 beats/minute, it is also within the normal range, and can not be said to be dangerous. Adults with a quiet heart rate of more than 100 beats / minute, medically known as sinus tachycardia, which requires attention. Commonly seen after agitation, excitement, drinking alcohol, smoking, drinking strong tea or coffee, or in fever, infection, shock, hypoxia, anemia, hyperthyroidism, heart failure and other pathological conditions, or in the application of adrenaline, atropine, ephedrine and other drugs. If the heart rate is still above 100 beats per minute without relief after lifestyle modification, you should consult a doctor to clarify the cause of the disease.