Causes of angina 

Angina occurs when the heart is not supplied with enough blood.

Like all of the body’s organs and tissues, your heart needs a constant supply of oxygen-rich blood to function normally.

Blood is supplied to the heart by two large blood vessels known as the coronary arteries. Angina most often occurs when the coronary arteries become narrow and hardened due to a condition called atherosclerosis.

When you are resting, the muscles of your heart only need a relatively small supply of blood. However, when you exercise or feel stressed, your heart muscles have to work harder and the demand for blood increases. If the coronary arteries are narrowed, the required amount of blood is unable to reach the heart in time, triggering the symptoms of angina.

In some cases, angina occurs when the blood supply is blocked by a piece of fatty deposit (plaque) that has broken away from the lining of the arteries. Plaque can build up in the arteries due to atherosclerosis.

Increased risk

Anything that causes the coronary arteries to narrow can increase your risk of angina. For example:

These risk factors can often be inter-related. They are explained below in more detail.

High blood pressure

Your arteries are designed to pump blood at a certain pressure. If that pressure is exceeded, the artery walls will be damaged. High blood pressure can be caused by:

  • being overweight
  • drinking excessive amounts of alcohol
  • smoking
  • stress
  • a lack of exercise

For reasons that are not fully understood, high blood pressure is more common among people of Afro-Caribbean and south Asian (Indian, Pakistani and Bangladeshi) origin. A tendency to develop high blood pressure also often runs in families.

Read more about preventing high blood pressure.

High-fat diet and cholesterol

Cholesterol is a type of fat that is essential for the functioning of the body. It helps produce hormones, protects nerve endings and makes up cell membranes (the walls that protect individual cells). There are two main types of cholesterol:

  • low density lipoprotein (LDL) - is mostly made up of fat, plus a small amount of protein; this type of cholesterol can block your arteries so it is often referred to as ‘bad cholesterol’
  • high density lipoprotein (HDL) - is mostly made up of protein, plus a small amount of fat; this type of cholesterol can help reduce a blockage in your arteries so it is often referred to as ‘good cholesterol’

Most of the cholesterol that the body needs is manufactured by the liver. However, eating foods that are high in saturated fat results in cholesterol being broken down into LDL (bad cholesterol).

Read more about lowering your cholesterol.

Lack of exercise

A lack of regular exercise can raise your blood pressure and increase your risk of developing type 2 diabetes. Both of these increase your risk of developing angina.


Smoking can damage the walls of your arteries. If your arteries are damaged by smoking, blood cells called platelets will form at the site of the damage in an attempt to repair it. This can cause your arteries to narrow.

Smoking also decreases your blood's ability to carry oxygen around your body, which increases the chances of a blood clot occurring.

Read more about stopping smoking.


If you have poorly controlled diabetes, the excess amount of glucose in your blood can damage the walls of your arteries.


Arteries tend to get narrower over time. Therefore, the older you are, the more likely it is that your arteries will have narrowed, increasing your risk of developing angina.

Family history

Heart disease can run in families, so if you have a first degree relative (mother, father, brother or sister) with a history of heart disease or angina, your risk of developing angina is increased.


Atherosclerosis is a thickening of the walls of the arteries. Find out how it affects the body, the risk factors involved, prevention and treatment.

Media last reviewed: 30/04/2013

Next review due: 30/04/2015

Lower your cholesterol

Foods you can eat and those you should avoid to help lower your cholesterol

Page last reviewed: 13/06/2013

Next review due: 13/06/2015