Key takeaways

High cholesterol, necessary for metabolism and cell production, becomes a health concern when levels are too high, leading to heart disease and stroke.
High cholesterol is caused by a diet high in saturated and trans fats, a sedentary lifestyle, smoking, being overweight, or having a genetic predisposition.
The effects of high cholesterol include stroke, heart attack, peripheral vascular disease (PVD), and kidney disease, all of which can have severe health consequences.
Lowering cholesterol levels can be achieved through diet changes, exercise, weight loss, quitting smoking, and possibly statin medications, with lifestyle changes often necessary alongside medication.

When you think of cholesterol, it might bring images of heart disease, fast food, and saturated fats to mind. But cholesterol is actually necessary for your health—for your metabolism, and for hormone and cell production. When there’s too much of it, however, it can become concerning.

“High cholesterol, also known as hypercholesterolemia, is the presence of excess cholesterol in the blood,” explains Lola Adeyemi, MD, a preventive and public health physician and the co-founder & COO of Magna Carta Health. Four levels make up your cholesterol numbers (or “lipid panel,” as it will appear on your bloodwork).

Low-density lipoprotein (LDL) is the “bad” cholesterol that can lead to buildup in your arteries. Less than 100 mg/dL is ideal. 160–189 mg/dL is considered high.
High-density lipoprotein (HDL) is “good” cholesterol and high numbers can actually protect against heart diseases. You want this at 60 mg/dL or more. Levels less than 40 mg/dL put you at higher risk for heart disease.
Triglycerides are the type of fat your body uses for energy, but too much increases your risk of health issues. Less than 150 mg/dL is ideal. 200 mg/dL or more is considered high.
Total cholesterol is the combination of LDL, HDL, and triglycerides. Ideally this number should be less than 200 mg/dL. A level of 240 mg/dL or more is considered high. The absolute total cholesterol number is not as important as the individual good and bad cholesterol numbers.

What causes high cholesterol?

Several things can cause high cholesterol including:

Eating a diet high in saturated and trans fats
Leading a sedentary lifestyle
Smoking tobacco (or exposure to tobacco smoke)
Being overweight or obese

Having a relative with high cholesterol can also increase your risk of having high cholesterol. Known as familial hypercholesterolemia, this is a genetic condition that changes how your body processes cholesterol.

High cholesterol doesn’t cause high blood pressure or diabetes. However, these two conditions do put you at an increased risk for heart disease and stroke, says Dr. Adeyemi. Heart disease and stroke are also caused by high cholesterol.

How do you know if you have high cholesterol?

The problem with high cholesterol is that it’s a silent condition. Meaning, you won’t feel any different as your levels spike. There aren’t really any symptoms until you have a heart attack or stroke, according Glenn Gaesser, Ph.D., professor of exercise physiology at the College of Health Solutions at Arizona State University. The only way to know if you have high cholesterol problems is by taking a blood test, usually during your annual physical.

4 effects of high cholesterol

There are several ways high cholesterol can affect your body. About 75% of the cholesterol you need is made by the liver and the other 25% is from the food you eat. Too much in your system—particularly LDL—can form fatty deposits, or plaques, in your blood vessels, explains Dr. Adeyemi. This is known as atherosclerosis. Complications of high cholesterol include:

1. Stroke

A stroke occurs when the blood flow to your brain becomes blocked, causing brain cells to die. This blockage may be a result of a growing plaque inside an artery of the neck or brain, or may come from pieces of plaque breaking off and traveling through the blood vessels to the brain. You can be at risk for stroke if you have high blood pressure, high cholesterol, diabetes, or if you smoke. Symptoms of a stroke depend on the type, but commonly include facial drooping on one side, slurred speech, confusion, severe headache, and dizziness. Treatment can include medications to help break up the blockage, or surgery to remove the clot.

2. Heart attack

Atherosclerosis can cause a heart attack when plaque buildup cuts off blood supply to the heart. Heart cells start to die and can cause chest tightness or pain, nausea, jaw pain, dizziness, and shortness of breath. You are at increased risk for heart attack if you have high cholesterol, high triglycerides, diabetes, or high blood pressure or if you smoke tobacco products. Treatment most often involves a cardiac catheterization (heart cath) with balloon angioplasty or stent placement, but may also involve open heart surgery with bypass of the blocked vessel. If the heart attack causes enough damage to the heart muscle, a pacemaker or defibrillator may be necessary.

3. Peripheral vascular disease

Peripheral vascular disease (PVD) is when blood vessels outside of your brain or heart become blocked or narrowed. Symptoms can include pain or weakness in your legs that goes away once you’ve rested. You have a higher risk of PVD if you have a family history of PVD or high cholesterol, are overweight, have a heart condition, or are over 65. Treatment can include medications or surgery.

4. Kidney disease

High total cholesterol or a lower HDL can put you at increased risk for kidney disease. This is usually a silent disease; however, when kidney disease becomes severe, symptoms may include blood or foam in the urine, swelling in your feet and ankles, or muscle cramps. Depending on how severe the condition is, you might need dialysis or a kidney transplant.

How can you lower cholesterol levels?

Luckily, there are some things you can do to lower your health risks of high cholesterol.

Diet changes: There’s more to cholesterol than what’s in your food. “Components of a healthy diet, especially fiber, can have modest effects on cholesterol levels,” explains Dr. Gaesser. “Fiber such as oatmeal or bran reduces the absorption of cholesterol into the bloodstream and can reduce LDL levels.”
Exercise: While it won’t really make big improvements to your total cholesterol, according to Dr. Gaesser, it can help raise your HDL and lower your LDL.
Lose weight: Even a 5% to 10% weight loss can have positive effects on high cholesterol.
Consider quitting smoking: Quitting smoking can raise your HDL and decrease the risk for other heart conditions.
Statin medications: Sometimes diet and exercise aren’t enough to make the necessary changes. In that case, medications called statins help decrease your cholesterol as well as lower your chances of having a heart attack or stroke.

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The takeaway: “Use of statins will not work effectively if your lifestyle is poor,” Dr. Adeyemi cautions. Statins and lifestyle changes often need to be done together to have the best results.