High cholesterol usually causes emergency events like such as strokes or heart attacks due to plaque build up in your arteries. It can also cause heart disease and other complications.

Cholesterol is a waxy, fat-like substance that your liver produces. It’s vital for the formation of cell membranes, vitamin D, and certain hormones. Cholesterol doesn’t dissolve in water, so it can’t travel through your body by itself.

Particles known as lipoproteins help transport cholesterol through the bloodstream. There are two major forms of lipoproteins.

Low-density lipoproteins (LDLs), also known as “bad cholesterol,” can build up in the arteries and lead to serious health problems, such as heart attack or stroke.

Eating too many foods that contain high amounts of fat increases the level of LDL cholesterol in your blood. This is known as high cholesterol, also called hypercholesterolemia or hyperlipidemia.

High-density lipoproteins (HDLs), sometimes called “good cholesterol,” help return the LDL cholesterol to the liver for elimination.

If your levels of LDL cholesterol are too high, or levels of HDL cholesterol are too low, fatty deposits build up in your blood vessels. These deposits will make it difficult for enough blood to flow through your arteries. This could cause problems throughout your body, particularly in your heart and brain, or it could be fatal.

High cholesterol typically doesn’t cause any symptoms. In most cases, it only causes emergency events. For instance, a heart attack or stroke can result from the damage caused by high cholesterol.

These events typically don’t occur until high cholesterol leads to the formation of plaque in your arteries. Plaque can narrow arteries so less blood can pass through. The formation of plaque changes the makeup of your arterial lining. This could lead to serious complications.

A blood test is the only way to know if your cholesterol is too high. This means having a total blood cholesterol level above 200 milligrams per deciliter (mg/dL). Ask a doctor to give you a cholesterol test after you turn 20. Then get your cholesterol rechecked every 4 to 6 years.

A doctor may also suggest you have your cholesterol checked more frequently if you have a family history of high cholesterol. They might also suggest it if you demonstrate the following risk factors:

  • have high blood pressure
  • are overweight
  • smoke

Genetic conditions that cause high cholesterol

There’s a condition passed through genes that causes high cholesterol called familial hypercholesterolemia. People with this condition have cholesterol levels of 300 mg/dL or higher. They may develop xanthoma, which can appear as a yellow patch above your skin, or a lump underneath your skin.

Coronary artery (heart) disease (CAD)

Coronary artery disease (CAD) is a type of heart disease. It occurs when plaque buildup causes the main arteries that supply your heart with blood to be narrowed or hardened.

Symptoms of heart disease may be different for men and women. However, heart disease remains the number one killer of both sexes in the United States. The most common symptoms include:

Stroke

The buildup of plaque caused by high cholesterol can put you at serious risk of having the blood supply to an important part of your brain reduced or cut off. This is what happens when a stroke occurs.

A stroke is a medical emergency. It’s important to act fast and get medical treatment if you or anyone you know experiences the symptoms of a stroke. These symptoms include:

Heart attack

The arteries that supply the heart with blood can slowly narrow due to the buildup of plaque. This process, called atherosclerosis, happens slowly over time and has no symptoms. Eventually, a piece of the plaque can break off. When this happens, a blood clot forms around the plaque. It can block blood flow to the heart muscle and deprive it of oxygen and nutrients.

This deprivation is called ischemia. When the heart becomes damaged, or part of the heart begins to die due to the lack of oxygen, it’s called a heart attack. The medical term for a heart attack is myocardial infarction.

According to the American Heart Association, someone in the United States has a heart attack roughly every 39 seconds.

Symptoms of a heart attack include:

  • tightness, squeezing, fullness, pain, or aching in your chest or arms
  • difficulty breathing
  • anxiety or a feeling of impending doom
  • dizziness
  • nausea, indigestion, or heartburn
  • excessive fatigue

A heart attack is a medical emergency. Damage to the heart could be irreversible, or even fatal, if treatment doesn’t begin in the first several hours after a heart attack.

It’s important to act fast and get medical treatment if you or anyone you know experiences the symptoms of a heart attack.

Peripheral arterial disease (PAD)

Peripheral artery disease (PAD) can occur when plaque builds up in the walls of the arteries. This will block the flow of blood in the arteries that supply blood to your kidneys, arms, stomach, legs, and feet.

Symptoms of early PAD may include:

  • cramping
  • achiness
  • fatigue
  • pain in your legs during activity or exercise, called intermittent claudication
  • discomfort in your legs and feet

As PAD progresses, symptoms occur more frequently and even occur when you’re at rest. Later symptoms that may occur because of reduced blood flow include:

  • thinning, paleness, or shininess on the skin of your legs and feet
  • tissue death caused by lack of blood supply, called gangrene
  • ulcers on your legs and feet that don’t heal or heal very slowly
  • leg pain that doesn’t go away when at rest
  • burning in your toes
  • leg cramps
  • thick toenails
  • toes that turn blue
  • reduced hair growth on your legs
  • decrease in the temperature of your lower leg or foot, compared to the other leg

People with PAD have a higher risk of having a heart attack, stroke, or limb amputations.

High cholesterol is very easy to diagnose with a blood test called a lipid panel. A doctor will take a sample of blood and send it to a laboratory for analysis. The doctor will ask that you don’t eat or drink anything for at least 12 hours prior to the test.

A lipid panel measures your total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides. The Centers for Disease Control and Prevention (CDC) says these are the desirable levels:

  • LDL cholesterol: less than 100 mg/dL
  • HDL cholesterol: 40 mg/dL or higher
  • triglycerides: less than 150 mg/dL

Your total cholesterol is generally considered “borderline high” if it’s between 200 and 239 mg/dL. It’s considered “high” if it’s above 240 mg/dL.

Your LDL cholesterol is generally considered “borderline high” if it’s between 130 and 159 mg/dL. It’s considered “high” if it’s above 160 mg/dL.

Your HDL cholesterol is generally considered “poor” if it’s below 40 mg/dL.

The American Heart Association recommends having your cholesterol levels checked every 4 to 6 years if you’re a healthy adult over the age of 20. You may need to have your cholesterol checked more often if you’re at an increased risk of high cholesterol.

You may also need more frequent cholesterol checks if you have a family history of cholesterol problems or heart attacks at a young age, especially if they’ve affected your parents or grandparents.

Because high cholesterol doesn’t cause symptoms in the early stages, it’s important to make good lifestyle choices. Eat a healthy diet, maintain an exercise routine, and regularly monitor your cholesterol levels by getting them checked at the doctor’s office.