What is High Cholesterol?

Cholesterol is a waxy substance that’s essential for building healthy cells in your body. However, having high cholesterol can pose significant health risks, primarily increasing your chances of developing heart disease.

When you have high cholesterol, fatty deposits can accumulate in your blood vessels. Over time, these deposits can grow larger, narrowing your arteries and making it harder for blood to flow freely. These deposits can also suddenly rupture and form blood clots, leading to serious events like heart attacks or strokes.

High cholesterol can be inherited, but it’s frequently linked to lifestyle choices that are within your control. This makes high cholesterol largely preventable and manageable. Adopting a heart-healthy diet, engaging in regular physical activity, and sometimes using medication can effectively help lower high cholesterol levels.

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Symptoms of High Cholesterol

One of the challenges with high cholesterol is that it typically doesn’t present any noticeable symptoms. You often won’t know you have high cholesterol unless you get tested. This is why regular cholesterol screenings are so important.

When to Get Your Cholesterol Checked

Health organizations like the National Heart, Lung, and Blood Institute (NHLBI) recommend starting cholesterol screenings at a young age. For children and adolescents, the first cholesterol check should occur between 9 and 11 years old, and then be repeated every five years thereafter.

For adults, the recommendations vary slightly by age and gender. The NHLBI suggests cholesterol screenings every one to two years for men aged 45 to 65 and for women aged 55 to 65. For individuals older than 65, annual cholesterol tests are generally recommended.

However, these are general guidelines. Your doctor might advise more frequent cholesterol testing if your initial results are outside the desirable range or if you have other risk factors. These risk factors include a family history of high cholesterol or heart disease, as well as conditions like diabetes or high blood pressure.

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Causes of High Cholesterol

Cholesterol travels through your bloodstream carried by proteins. This combination of cholesterol and proteins is called a lipoprotein. Different types of lipoproteins carry different kinds of cholesterol. The key types to understand are:

Low-Density Lipoprotein (LDL) Cholesterol: Often referred to as “bad” cholesterol, LDL’s primary role is to transport cholesterol throughout your body. However, when there’s too much LDL cholesterol, it can accumulate in the artery walls, contributing to the hardening and narrowing of arteries.
High-Density Lipoprotein (HDL) Cholesterol: Known as “good” cholesterol, HDL performs the vital function of picking up excess cholesterol from your body and transporting it back to your liver for processing and removal.

A standard cholesterol test, known as a lipid profile, typically also measures triglycerides. Triglycerides are another type of fat in the blood. Elevated triglyceride levels, along with high LDL cholesterol, can further increase your risk of heart disease.

Several factors can contribute to unhealthy cholesterol levels. Some are within your control, such as:

Inactivity: A sedentary lifestyle can negatively impact your cholesterol levels.
Obesity: Being overweight or obese is linked to higher LDL cholesterol and lower HDL cholesterol.
Unhealthy Diet: Diets high in saturated and trans fats are major contributors to high cholesterol.

Other factors that can influence cholesterol levels are beyond your direct control, including:

Genetics: Your genetic makeup can influence how your body manages cholesterol. Some people are genetically predisposed to having higher cholesterol levels, regardless of their lifestyle.

Certain medical conditions can also lead to unhealthy cholesterol levels. These include:

Chronic Kidney Disease
Diabetes
HIV/AIDS
Hypothyroidism (underactive thyroid)
Lupus

Furthermore, some medications used to treat various health issues can sometimes have the side effect of raising cholesterol levels. These medications might be used for conditions such as:

Acne
Cancer
High Blood Pressure
HIV/AIDS
Irregular Heart Rhythms
Organ Transplants

Risk Factors for High Cholesterol

Several factors can increase your likelihood of developing high cholesterol. Understanding these risk factors can help you take proactive steps to manage your health.

Poor Diet: Consuming a diet that’s rich in saturated fats and trans fats is a primary dietary risk factor for high cholesterol. Saturated fats are abundant in fatty meats and full-fat dairy products. Trans fats are often found in processed foods, packaged snacks, and many commercially baked goods.
Obesity: Having a body mass index (BMI) of 30 or higher significantly increases your risk of high cholesterol. Excess weight can impact how your body produces and processes cholesterol.
Lack of Physical Activity: Regular exercise is crucial for maintaining healthy cholesterol levels. Physical activity helps to boost your HDL (“good”) cholesterol and lower LDL (“bad”) cholesterol. A sedentary lifestyle contributes to an unfavorable cholesterol profile.
Smoking: Cigarette smoking has a detrimental effect on cholesterol levels. It can lower your HDL cholesterol, which is the protective “good” cholesterol. Quitting smoking is one of the most beneficial lifestyle changes you can make for your heart health and overall well-being.
Excessive Alcohol Consumption: Drinking too much alcohol can raise your total cholesterol level and triglyceride levels. Moderation is key when it comes to alcohol intake.
Age: While high cholesterol can occur at any age, it becomes more prevalent as people get older. As you age, your liver becomes less efficient at removing LDL cholesterol from your bloodstream, contributing to a natural increase in cholesterol levels with age. Even children can have high cholesterol, highlighting the importance of early screening, especially for those with family history.

Complications of High Cholesterol

High cholesterol, if left unmanaged, can lead to serious health complications primarily related to the development of atherosclerosis.

Development of Atherosclerosis

When there’s an excess of cholesterol in your blood, it can combine with other substances to form plaque. This plaque accumulates on the inner walls of your arteries, a process known as atherosclerosis. As plaque builds up, it causes the arteries to narrow and harden.

This narrowing and hardening of the arteries due to plaque buildup can significantly reduce blood flow. Furthermore, if plaque becomes unstable, it can rupture. A ruptured plaque can trigger the formation of a blood clot at the site of rupture. Both the plaque itself and the resulting blood clot can severely impede or completely block blood flow through the artery.

Atherosclerosis caused by high cholesterol can lead to a range of serious complications, including:

Chest Pain (Angina): When the arteries supplying blood to your heart muscle (coronary arteries) are affected by atherosclerosis, it can lead to chest pain, also known as angina. Angina is a common symptom of coronary artery disease. You might experience chest tightness, pressure, or squeezing, especially during physical exertion or emotional stress.
Heart Attack (Myocardial Infarction): A heart attack occurs when blood flow to a part of your heart is completely blocked. This often happens when plaque in a coronary artery ruptures, and a blood clot forms, obstructing blood flow. If blood flow is not restored quickly, the part of the heart muscle deprived of oxygen begins to die, leading to permanent damage.
Stroke (Cerebrovascular Accident): Similar to a heart attack, a stroke happens when blood flow to a part of your brain is interrupted. This can be caused by a blood clot that blocks an artery leading to the brain or by a ruptured blood vessel in the brain. High cholesterol and atherosclerosis are significant risk factors for stroke.

Prevention of High Cholesterol

The good news is that adopting heart-healthy lifestyle changes can not only help lower high cholesterol but also prevent it from developing in the first place. Preventive measures are largely the same as those used to manage existing high cholesterol. To help prevent high cholesterol, focus on the following:

Adopt a Heart-Healthy Diet: Emphasize fruits, vegetables, and whole grains in your diet. Limit your intake of saturated fats, found in red meat and full-fat dairy, and avoid trans fats, often present in processed and fried foods. Choose lean protein sources and healthy fats in moderation, such as those found in avocados, nuts, and olive oil. A low-salt diet is also beneficial for overall cardiovascular health.
Maintain a Healthy Weight: If you are overweight or obese, losing even a small amount of weight can help improve your cholesterol levels. Aim for gradual and sustainable weight loss through a combination of diet and exercise.
Engage in Regular Exercise: Aim for at least 30 minutes of moderate-intensity exercise on most days of the week. Regular physical activity helps to raise HDL cholesterol and lower LDL cholesterol. Find activities you enjoy to make exercise a consistent part of your routine.
Quit Smoking: If you smoke, quitting is one of the most impactful steps you can take for your heart health and cholesterol levels. Smoking significantly lowers HDL cholesterol and increases the risk of heart disease.
Drink Alcohol in Moderation (if at all): If you choose to drink alcohol, do so in moderation. For healthy adults, this means up to one drink a day for women and up to two drinks a day for men. Excessive alcohol intake can negatively affect cholesterol and triglyceride levels.
Manage Stress: Chronic stress can contribute to unhealthy cholesterol levels and other heart disease risk factors. Find healthy ways to manage stress, such as exercise, meditation, yoga, or spending time on hobbies and relaxation techniques.

By Mayo Clinic Staff. Meet our medical editors.