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High Cholesterol (Hypercholesterolemia)

To understand high blood cholesterol, it helps to learn about cholesterol. Cholesterol is a waxy, fat-like substance that’s found in all cells of the body.




Atherosclerotic plaque due to high cholesterol levels

Figure A shows a normal coronary artery with normal blood flow. The inset image shows a cross-section of a normal coronary artery. Figure B shows a coronary artery narrowed by plaque. The buildup of plaque limits the flow of oxygen-rich blood through the artery. The inset image shows a cross-section of the plaque-narrowed artery. 

What Is High Blood Cholesterol?





Over time, plaque hardens and narrows your coronary arteries. This limits the flow of oxygen-rich blood to the heart.


If the flow of oxygen-rich blood to your heart muscle is reduced or blocked, angina (an-JI-nuh or AN-juh-nuh) or a heart attack may occur.

Angina is chest pain or discomfort. It may feel like pressure or squeezing in your chest. The pain also may occur in your shoulders, arms, neck, jaw, or back. Angina pain may even feel like indigestion.

A heart attack occurs if the flow of oxygen-rich blood to a section of heart muscle is cut off. If blood flow isn’t restored quickly, the section of heart muscle begins to die. Without quick treatment, a heart attack can lead to serious problems or death.

Plaque also can build up in other arteries in your body, such as the arteries that bring oxygen-rich blood to your brain and limbs. This can lead to problems such as carotid artery disease, stroke, and peripheral artery disease.

Symptoms of High Cholesterol

High blood cholesterol usually has no signs or symptoms. Thus, many people don't know that their cholesterol levels are too high.

If you're 20 years old or older, have your cholesterol levels checked at least once every 5 years. Talk with your doctor about how often you should be tested.


Lowering your cholesterol may slow, reduce, or even stop the buildup of plaque in your arteries. It also may reduce the risk of plaque rupturing and causing dangerous blood clots.

Reference: The National Heart, Blood, and Lung Institute

Last updated May 3, 2017