For patients with stable angina due to coronary artery disease, there are no obvious symptoms at night while sleeping; for unstable angina due to coronary artery disease, symptoms of pain may appear at night while sleeping. 1. Stable angina: When coronary artery blood flow is reduced in coronary artery disease, the blood supply to the heart muscle is relatively fixed. In the case of labor and emotional excitement, there is a sudden increase in cardiac load, resulting in an increase in cardiac oxygen consumption. The coronary blood supply is unable to meet the myocardium’s demand for blood causing angina pectoris. Therefore, stable angina is most common after exercise and is usually asymptomatic at night while sleeping. 2. Unstable angina: The rupture of unstable atherosclerotic plaques leads to spasmodic contraction of the coronary arteries, which reduces the supply of oxygen to the myocardium and aggravates ischemia. Resting or nocturnal angina can occur. When you suspect that you may have angina pectoris, you can go to the hospital for consultation and treatment under the guidance of the doctor after confirmation of the diagnosis.