If the patient feels uncomfortable after drinking coffee, it is often because certain substances in coffee lead to the activation of sympathetic nerves, and after the sympathetic nerves are overexcited, there will be an increase in heart rate, which leads to an increase in myocardial oxygen consumption. Insufficient supply of oxygen and blood to the heart muscle will cause coronary artery ischemia, prolonged ischemia will occur coronary artery contraction, patients will have chest tightness, shortness of breath, palpitations, precordial pain and other symptoms. In addition, a large number of patients drinking coffee, there will be renin-angiotensin-aldosterone system activation, causing increased blood pressure, increasing the afterload of the heart, which will lead to further blood supply to the heart is not complete, the heart will have a difficult feeling.