Angina pectoris is the most common symptom of coronary heart disease, and the clinical treatment strategies for angina pectoris are based on preventing the occurrence and development of angina pectoris. However, the severity of myocardial infarction is also lower in patients with recurrent angina pectoris. The branch circulation is richer, which shows that angina pectoris or myocardial ischemia can promote the formation of collateral circulation, which has a protective effect on patients with coronary heart disease. Exercise can induce myocardial ischemia, so many patients with coronary heart disease are afraid to exercise or doctors have warned patients Exercise, but exercise may increase the ability of myocardial self-protection by inducing reversible myocardial ischemia, promoting the formation of measurement branch circulation. One of the main arguments supported by this passage is:. ['Exercise is not necessarily harmful to patients with coronary heart disease.', 'As a patient with coronary heart disease, avoid exercise.', 'Exercise increases the likelihood of myocardial infarction.', 'Preventing angina pectoris is a good way to treat coronary heart disease.']