Cholesterol is a fatty chemical which is part of the outer lining of cells in the body. Plaque accumulation can be accelerated by smoking, high blood pressure, elevated cholesterol, and diabetes. Ultimately, atherosclerosis causes significant narrowing of the coronary arteries. During exercise or excitement, the narrowed coronary arteries cannot increase the blood supply to meet the increased oxygen demand of the heart muscle. Chest pain that occurs with exercise is called exertional angina.
Exertional angina is reversible, and subsides with rest.
Occasionally, for unknown reasons, the surface of the cholesterol plaque can become sticky, causing blood clotting. Unlike exertional angina, death of the heart muscle from a heart attack is permanent. Chest pain or pressure is a common symptom of heart attack. Interestingly, heart attacks do not usually happen during exercise, although exercise is commonly associated with exertional angina. One quarter of all heart attacks are silent, without chest pain.