Whether sinus tachycardia is serious or not needs to be determined by the specific cause and cannot be generalized. Sinus tachycardia is a relatively common and relatively safe problem of arrhythmia in which the heart beats too fast at a frequency of 101-160 beats per minute. If it is caused by non-pathological factors such as lack of sleep, excessive mental stress, tension, anxiety, long-term consumption of strong tea and coffee, it is usually not a serious problem and will usually be relieved after adjusting life and rest and removing the triggers. If the symptoms are accompanied by precordial pain, chest tightness, shortness of breath, dizziness, pale and lusterless skin, and fear of heat and sweating, they may be caused by heart diseases such as coronary heart disease, dilated cardiomyopathy, or anemia, hyperthyroidism, etc. The symptoms are relatively serious and require medication or surgery depending on the cause. If pathological sinus tachycardia occurs, it is recommended to go to the cardiology department for cardiac ultrasound and other examinations, and also to the endocrinology department for blood routine and thyroid function examinations to clarify the cause and then treat the symptoms.