High Cholesterol: What’s the Risk?

Medically Reviewed by James Beckerman, MD, FACC on March 23, 2016
5 min read

Just as oil buildup in a car can damage the engine, too much cholesterol can spell trouble over time. It will raise your risk of heart attack, stroke, and more, says New York cardiologist Nieca Goldberg, MD.

Since there’s no “check cholesterol” warning light built into your body, you’ll need to take action to find out if there’s a problem. All that takes is a simple blood test at your doctor’s office, and then you’ll know if your “bad” (LDL) level is too high, your “good” kind is too low, and if your triglycerides (another type of blood fat) are in check.

“Everyone needs to be on top of their numbers, because high cholesterol can double your risk of a heart attack,” says Goldberg, who’s the medical director of the Joan H. Tisch Center for Women’s Health at NYU Langone Medical Center.

Although cholesterol is often cast as a villain, you actually need some of it.

“It’s an essential fat that’s used to make cell membranes, hormones, and more,” says Jeffrey Michel, MD, a senior staff cardiologist at Baylor Scott & White Healthcare in Temple, Texas.

The problem is when there’s too much of this waxy substance, which is the case for a lot of people. About 1 in 8 Americans has high cholesterol.

It can happen for different reasons.

Your body, especially your liver, may make too much cholesterol because of your genes or lifestyle, such as being inactive and overweight. It also does that when you eat foods high in saturated fats, such as meat and full-fat dairy, or trans fats.

It’s part of the plaque that can narrow and harden your arteries. That can lead to a heart attack or stroke.

Plaque has a purpose that sounds innocent. Your body uses it to repair damage to the inner lining of your arteries. That damage can happen because of things like:

  • High cholesterol or triglycerides
  • Smoking
  • High blood pressure

When the damage happens, plaque ingredients -- LDL cholesterol, white blood cells, calcium, and waste from cells -- flock to the site. They team up to form plaque, which works like a rough patch.

The problem is, it hangs around. And over time, more and more builds up. Then it hardens, and your arteries narrow. That makes it harder for your blood to pass through.  Your blood pressure goes up.

There’s an immediate risk, too: blood clots.

Some plaque is vulnerable. These are a soft, fat-filled group of cells with a thin covering. If there’s stress -- like the wear and tear of high blood pressure -- this cap can burst open, like a pimple.

When that happens, your body thinks of it as a wound, Goldberg says. Blood platelets swoop in to try to fix it. They form a blood clot, and that can be a big problem.

Large blood clots can block part or all of the artery. That puts the brakes on blood flow there. As a result, the area doesn’t get enough oxygen -- and now it’s an emergency.

Blood clots cause heart attacks -- the heart muscle doesn’t get oxygen. They’re also a top cause of stroke. When the brain doesn’t get enough oxygen because of a blood clot, that’s an “ischemic” stroke. (The other type, “hemorrhagic” strokes, happen when a blood vessel bleeds in the brain.)

Plaque doesn’t always rupture, even if it’s vulnerable. Researchers are studying why.

Even if it doesn’t burst, a buildup of plaque can also cause:

Chest pain: Also called angina, this happens when your heart can’t get enough blood because of narrowed arteries. You may have pain when your heart works harder, such as during exercise or times of stress.
Peripheral artery disease: When plaque builds up in the coronary arteries (which supply blood to the heart muscle), that’s coronary artery disease. When it strikes arteries in your legs, stomach, arms, or head, it’s called peripheral artery disease. It can cause pain, cramping, and tiredness. If left untreated, you may get gangrene or need to get the affected area amputated.

This process doesn’t happen overnight. “It takes years for cholesterol to build up in the arterial walls,” Goldberg says.

But the clock starts to tick sooner than you may think.

“It can begin as early as childhood,” Goldberg says. Research shows that children can have changes in their blood vessels that leads to this buildup of plaque when they grow up. 

You probably wouldn’t know it’s happening unless you get a blood test. 
Because high cholesterol causes few symptoms, many people go years without knowing their numbers. “That’s dangerous, because the plaque buildup you have in your 20s, 30s, or 40s doesn’t go away,” Goldberg says. “It adds up over time, which may mean a heart attack or stroke in your 50s or 60s.”

The longer you have high cholesterol, the more likely you are to develop heart disease. In one study, people who had high levels for 11 years or more had double the risk than those who had them for 10 years or less.

Most people with high cholesterol don’t have any warning signs. The exception is people with a genetic disorder called hypercholesterolemia. “They can develop fatty deposits in their skin and eyes,” Michel says. But for most of the nearly 74 million Americans with high LDL cholesterol, it’s a stealthy condition.

The key is to start to whittle down high cholesterol as soon as you know that you have it. Although you may not be able to completely undo all of the damage, you may be able to partially reverse it (or “regress” it, as you doctor would say), or slow or stop it from getting worse.

Because it’s easy to let high cholesterol go unnoticed, nearly 1 in 3 people with high LDL numbers don’t have the condition under control. That puts them at risk.

It’s crucial that you speak to your doctor about getting your cholesterol checked, Michel says.

The American Heart Association recommends getting your cholesterol checked every 4 to 6 years starting at age 20. But if you are at risk for heart disease – for instance, if it runs in your family, or you smoke, or you’re overweight -- talk it over with your doctor. “He or she may recommend getting tested at a younger age, or more regular screenings,” Michel says.

Your target for total cholesterol is less than 180 mg/dL.
If your level is higher, your doctor will consider that in along with other risk factors, such as your family history, smoking habit, and weight, to prescribe a cholesterol-lowering plan. That usually includes lifestyle steps, such as regular exercise and eating a heart-healthy diet high in whole grains, vegetables, fruit, and healthy fats. You may also need to take a cholesterol-lowering medication.