What is high cholesterol?

We all need some cholesterol in our blood to stay healthy, but too much can lead to serious health problems such as heart attacks and strokes.

Anyone can have high cholesterol, even if you are young, slim, eat well and exercise. That’s because high cholesterol can be caused by different things, including your genes.

High cholesterol is very common, but most people don't know they have it because it doesn't usually have any symptoms. That's why everyone should have a cholesterol check.

Another type of blood fat called triglycerides can also become raised and lead to health problems, you can have these checked too

There are treatments available for high cholesterol, but it's usually possible to lower cholesterol naturally with healthy lifestyle changes.


What causes high cholesterol?

Find out

What happens if you have high cholesterol?

If there is too much cholesterol in your blood, this can be laid down in the walls of your arteries – the large blood vessels that carry blood around your body. 

Fatty areas known as plaques can form, and these become harder with time, making the arteries stiffer and narrower. This process is called atherosclerosis.

  • Narrowed arteries
    When the arteries become narrower, it’s harder for blood to flow through them. This puts a strain on your heart because it has to work harder to pump blood around your body. Eventually, the heart can become weak and can’t work as well as it should.
  • Blood clots
    Blood clots can form over the fatty, hardened parts of the arteries (plaques). The blood clots can block the artery completely, cutting off the blood flow. Bits of the blood clots can break away and become lodged in an artery or vein in another part of the body, which can cause a heart attack or stroke.

What can happen if you have atherosclerosis?

If your arteries become clogged up with blood fats (a process known as atherosclerosis) your blood can't flow around your body as easily. This can lead to a number of diseases of the heart and blood vessels. 

These are known together as cardiovascular disease or CVD – cardio refers to the heart, and vascular refers to the blood vessels.

  • Coronary heart disease (coronary artery disease)
    This is where the arteries have become clogged up and stiff. The blood can’t flow around the body and back to the heart easily, and blood clots can form. This can lead to chest pain, heart failure, heart attacks and strokes. This is the most common type of heart disease.
  • Angina (chest pain)
    This is a dull, heavy or tight pain in the chest which can spread to the left arm, neck, jaw or back. It happens when the arteries leading to the heart have become narrowed and the heart can't get enough blood. The pain is caused by a lack of oxygen. It can be brought on by exercise or activity, as the heart needs more oxygen during physical activity.
  • Heart attack
    This is a medical emergency. It happens when an artery leading to the heart becomes completely blocked, often by a blood clot, cutting off the blood supply. Part of the heart muscle quickly dies, but if it’s treated quickly, the blockage can be removed.

    If you think you or someone you are with is having a heart attack, call 999 straight away. The signs of a heart attack include:
    • a crushing pain in the chest
    • sweating
    • shortness of breath
    • feeling or being sick
    • feeling weak or faint
    • suddenly feeling very anxious.
  • Heart failure
    This is not the same as a heart attack. Heart failure usually happens when the arteries are clogged up and the heart has to work too hard to force blood around the body. To start with, the heart muscle gets bigger to cope with the extra effort, but eventually it becomes too weak and can’t push blood around your body.

    It doesn’t mean your heart is about to stop working, but it can cause serious problems, including breathing problems because the blood can’t flow around your lungs easily.
  • Stroke
    This is a medical emergency. It happens when an artery in or leading to the brain becomes blocked, cutting off the blood supply. Part of the brain can’t get enough oxygen and dies. This can cause disabilities, but getting treatment straight away can lower the risk of long-term problems.

    If you notice the signs of a stroke, in yourself or someone else, call 999 straight away. The signs include:
    • the face droops on one side
    • slurred speech or being unable to talk or smile 
    • weakness in the arms or not being able to lift them.
  • Mini strokes (TIAs)
    Blocked blood vessels can also cause mini strokes known as TIAs (transient ischaemic attack). These cause signs of a stroke that are temporary and pass within 24 hours, usually after a few minutes. Mini strokes are a warning sign that you could have a full stroke.

    See your doctor straight away if you think you have had a TIA so that you can get treatment and support to prevent a full stroke.
  • Peripheral arterial disease (PAD)
    This is when one or more of the arteries leading to the legs and feet become blocked or narrowed, so not enough blood can reach them. This can make your feet feel cold and painful, especially when walking. It can be hard to walk, and the worst-case scenario is that the foot needs to be amputated.
  • Vascular dementia
    There are different types of dementia, and vascular dementia is the second most common type. It can cause problems with memory, thinking and talking. It’s caused by problems with the blood supply to the brain – either by a stroke or mini strokes, or because the blood vessels in the brain have become too narrow.

What is high HDL cholesterol?


Lowering your cholesterol 

The good news is that there are treatments and lifestyle changes that can lower your cholesterol and triglycerides, and these changes all add up. By lowering your blood fats, you'll lower your risk of illnesses or help stop them from getting worse.  

If you have any questions or concerns about your cholesterol level and how to lower it, feel free to contact our helpline. 

Email our helpline 


Watch the webinar: cholesterol and blood lipids

Learn how to manage your blood lipids with help from our panel of experts. Learn about:

  • living with familial hypercholesterolaemia
  • high cholesterol in children and young people
  • genetic testing
  • optimal management 
  • Lp(a), triglycerides and other blood fat conditions
  • managing your risk - what difference you can make.

Are you a healthcare professional? Visit our HCP section


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