In adults, a heart rate controlled by the sinus node with a frequency of more than 100 beats per minute is called sinus tachycardia. T-wave changes can be seen in conditions such as myocardial ischemia, ventricular hypertrophy, or emphysema. Sinus tachycardia T-wave changes are classified as physiological or pathological. Physiological is mostly related to increased sympathetic excitability, which is common after exercise, coffee, strong tea, quarrel, emotional excitement, excessive tension, staying up late, fatigue, etc. Some people may experience hyperventilation, sympathetic excitation, compensatory increase in heart rate, and the ECG may show T-wave changes, which may be normal when the ECG is reviewed in a stable state. Some patients may also have coronary artery disease, myocarditis and other heart diseases. If I have obvious symptoms of chest tightness and shortness of breath, especially after climbing stairs or activities, further examination must be conducted to clarify the cause.