If patients have difficulty in their hearts after drinking coffee, it is often because some substances in coffee cause sympathetic nerves to be activated, and the sympathetic nerves will be overexcited after an increase in heart rate, leading to an increase in myocardial oxygen consumption. Insufficient oxygen and blood supply to the heart muscle will cause coronary artery ischemia, and prolonged ischemia will result in severe contraction of the coronary arteries, and patients will have symptoms such as chest tightness, shortness of breath, palpitations, and pain in the precordial region. In addition, patients who drink a lot of coffee, there will also be activation of the renin-angiotensin-aldosterone system, causing an increase in blood pressure, increasing the afterload on the heart, which will lead to further insufficiency of blood supply to the heart, and the heart will feel uncomfortable.