High cholesterol has no symptoms. A blood test is the only way to detect if you have it.

Cholesterol is carried through your blood, attached to proteins. This combination of proteins and cholesterol is called a lipoprotein. There are different types of cholesterol, based on what the lipoprotein carries. They are:

• Low-density lipoprotein (LDL). LDL, or "bad" cholesterol, transports cholesterol particles throughout your body. LDL cholesterol builds up in the walls of your arteries, making them hard and narrow.
• High-density lipoprotein (HDL). HDL, or "good" cholesterol, picks up excess cholesterol and takes it back to your liver.

A lipid profile also typically measures triglycerides, a type of fat in the blood. Having a high triglyceride level can also increase your risk of heart disease.

Factors you can control — such as inactivity, obesity and an unhealthy diet — contribute to high cholesterol and low HDL cholesterol. Factors beyond your control might play a role, too. For example, your genetic makeup might keep cells from removing LDL cholesterol from your blood efficiently or cause your liver to produce too much cholesterol.

Factors that can increase your risk of bad cholesterol include:

• Poor diet. Eating saturated fat, found in animal products, and trans fats, found in some commercially baked cookies and crackers and microwave popcorn, can raise your cholesterol level. Foods that are high in cholesterol, such as red meat and full-fat dairy products, will also increase your cholesterol.
• Obesity. Having a body mass index (BMI) of 30 or greater puts you at risk of high cholesterol.
• Lack of exercise. Exercise helps boost your body's HDL, or "good," cholesterol while increasing the size of the particles that make up your LDL, or "bad," cholesterol, which makes it less harmful.
• Smoking. Cigarette smoking damages the walls of your blood vessels, making them more prone to accumulate fatty deposits. Smoking might also lower your level of HDL, or "good," cholesterol.
• Age. Because your body's chemistry changes as you age, your risk of high cholesterol climbs. For instance, as you age, your liver becomes less able to remove LDL cholesterol.
• Diabetes. High blood sugar contributes to higher levels of a dangerous cholesterol called very-low-density lipoprotein (VLDL) and lower HDL cholesterol. High blood sugar also damages the lining of your arteries.

High cholesterol can cause a dangerous accumulation of cholesterol and other deposits on the walls of your arteries (atherosclerosis). These deposits (plaques) can reduce blood flow through your arteries, which can cause complications, such as:

• Chest pain. If the arteries that supply your heart with blood (coronary arteries) are affected, you might have chest pain (angina) and other symptoms of coronary artery disease.
• Heart attack. If plaques tear or rupture, a blood clot can form at the plaque-rupture site — blocking the flow of blood or breaking free and plugging an artery downstream. If blood flow to part of your heart stops, you'll have a heart attack.
• Stroke. Similar to a heart attack, a stroke occurs when a blood clot blocks blood flow to part of your brain.