The chest pain or discomfort that your doctor calls angina is caused when your heart cannot get the oxygen it needs. For example, the chest discomfort you get when you run too fast or too long, makes you get out of breath. It is the same with angina, except it is your heart that is not getting enough oxygen.
Your blood vessels carry blood to all parts of your body. Blood first passes through the blood vessels in your lungs and picks up oxygen to carry with it. When the blood vessels that feed your heart get smaller--or constrict--they can't carry as much blood and oxygen as your body needs.
Angina is often a warning sign of a more serious condition. Your doctor may give you medicine to open up the blood vessels around your heart, while others reduce the work your heart has to do. This lets more blood and oxygen flow to your heart and lessens the pain of angina attacks.
You can do things to help lower your risk if you have angina. Ask your doctor about ways you can help lower your blood pressure if it is high. If you smoke, you should quit, as smoking has been shown to increase the chance of high blood pressure and angina. Ask your doctor about exercise. Don't eat foods that are high in fat or cholesterol.