CAD reduces blood flow, which means less oxygen is getting to the heart. This may cause mild to severe chest pains or pressure, sometimes called angina. These feelings can spread to the arms or jaw. This can happen during stressful times, during physical activities such as work or exercise, or even at rest. If the flow of blood in a heart artery is blocked, a heart attack can occur. Anyone who experiences chest pain or signs of a heart attack should seek medical help as soon as possible.