Coronary heart disease (CHD) is usually caused by a build-up of fatty deposits (atheroma) on the walls of the arteries around the heart (coronary arteries).

The build-up of atheroma makes the arteries narrower, restricting the flow of blood to the heart muscle. This process is called atherosclerosis.

Your risk of developing atherosclerosis is significantly increased if you:

• smoke
• have high blood pressure (hypertension)
• have high cholesterol
• have high levels of lipoprotein (a)
• do not exercise regularly
• have diabetes

Other risk factors for developing atherosclerosis include:

• being obese or overweight
• having a family history of CHD

Smoking is a major risk factor for coronary heart disease. Both nicotine and carbon monoxide (from the smoke) put a strain on the heart by making it work faster. They also increase your risk of blood clots.

Other chemicals in cigarette smoke can damage the lining of your coronary arteries, leading to furring of the arteries. Smoking significantly increases your risk of developing heart disease.

Read about how to quit smoking on NHS Better Health.

High blood pressure (hypertension) puts a strain on your heart and can lead to CHD.

Read more about high blood pressure.

Find further information on understanding your blood pressure on the Blood Pressure UK website.

Cholesterol is a fat made by the liver from the saturated fat in your diet. It's essential for healthy cells, but too much in the blood can lead to CHD.

Read more about high cholesterol.

Like cholesterol, lipoprotein (a), also known as LP(a), is a combination of fat and protein made by the liver. It's a known risk factor for cardiovascular disease and atherosclerosis.

The level of LP(a) in your blood is inherited from your parents. It's not routinely measured, but screening is recommended for people with a moderate or high risk of developing cardiovascular disease.

Find more information about high lipoprotein (a) on the Heart UK website.

If you're inactive, fatty deposits can build up in your arteries.

If the arteries that supply blood to your heart become blocked, it can lead to a heart attack. If the arteries that supply blood to your brain are affected it can cause a stroke.

Read about the physical activity guidelines for adults aged 19 to 64.

A high blood sugar level may lead to diabetes, which can more than double your risk of developing CHD.

Diabetes can lead to CHD because it may cause the lining of blood vessels to become thicker, which can restrict blood flow.

A thrombosis is a blood clot in a vein or artery.

If a thrombosis develops in a coronary artery it prevents the blood supply from reaching the heart muscle. This usually leads to a heart attack.