10.15: Atherosclerosis

Arteriosclerosis and atherosclerosis describe hardened, narrowed arteries that can progress silently and lead to serious cardiovascular disease.

Master this section and you'll be able to:

• Differentiate arteriosclerosis from atherosclerosis based on causes and effects on arteries.
• Describe how atherosclerotic plaque develops and leads to conditions like angina, heart attack, and stroke.
• Identify key modifiable risk factors and strategies that slow arterial hardening.

Arteriosclerosis and Atherosclerosis: How Hardened Arteries Differ

You may have seen the terms arteriosclerosis and atherosclerosis and wondered if they mean the same thing.

Arteriosclerosis

Arteriosclerosis is the general term for “hardening of the arteries,” referring to any condition in which artery walls become thickened, stiff, or less elastic. This hardening often increases with age as vessels naturally become less elastic and more rigid. This alone can cause arteriosclerosis, even if plaque is not involved.​ Arteriosclerosis can happen faster if a person has conditions such as:

• High Blood Pressure (Hypertension): The pressure damages artery walls, causing them to thicken and stiffen over time, especially in small arteries.​

• Diabetes: High blood sugar damages blood vessel walls, leading to hardening, especially in smaller arteries.​

• Autoimmune Diseases: Conditions like lupus or rheumatoid arthritis cause ongoing inflammation which can harm artery walls and make them stiffer.​

Atherosclerosis

Atherosclerosis is one specific type of arteriosclerosis. It develops when fatty deposits, or plaques, accumulate inside the arterial wall. These plaques contain cholesterol, fats, immune cells, and connective tissue that gradually narrow the vessel and restrict blood flow. The term comes from the Greek athero, meaning “gruel,” because a cut plaque reveals a thick, yellow, cholesterol-rich material, and sclerosis, meaning “hard.”

In short, arteriosclerosis is the umbrella term for hardened arteries, while atherosclerosis is the most common form caused by plaque buildup. All atherosclerosis is arteriosclerosis, but not all arteriosclerosis is atherosclerosis.
 

Arteriosclerosis vs. Atherosclerosis

Feature	Arteriosclerosis	Atherosclerosis
Definition	General hardening and stiffening of arterial walls	Specific type of arteriosclerosis caused by plaque buildup inside arteries
Cause	Aging, loss of elasticity, or various vessel changes	Accumulation of cholesterol, fats, immune cells, and connective tissue forming plaques
Location of Change	Thickening or stiffening of the arterial wall	Plaque forms within the inner lining (intima) of the artery
Effect on Blood Flow	May reduce elasticity and increase resistance	Narrows the vessel lumen and restricts blood flow
Relationship	Broad category	Most common form within that category

For the rest of this section we will focus on Atherosclerosis.

Atherosclerosis: When the Arterial Highway Starts to Narrow

Imagine your blood vessels as smooth, flexible highways built for easy blood flow. Over time, however, those highways can begin to narrow and stiffen as sticky, fatty material slowly collects on the inner walls. This long-term process, called atherosclerosis, forms plaques made of fats, cholesterol, immune cells, and connective tissue. As plaques enlarge, they reduce the open space inside the artery and make the vessel less elastic, forcing the heart to work harder to move blood forward.

Atherosclerosis progresses silently for years and is a major cause of peripheral artery disease. As plaque buildup continues, the arterial lining thickens, scars, and loses elasticity. The condition becomes dangerous when a plaque ruptures and a blood clot (thrombus) forms, which can block the artery at that spot. A clot can also break loose and travel as an embolus until it gets stuck in a smaller vessel, cutting off oxygen to tissues and causing many heart attacks and strokes. 

Understanding how this process develops helps you connect daily choices with long-term cardiovascular health.

Figure \(\PageIndex{1}\): Atherosclerotic Plaque Formation in Arteries. (a) A healthy artery shows a wide, open lumen that supports smooth blood flow, while an atherosclerotic artery contains a fatty plaque that narrows the passage and disrupts flow. (b) A histological section of an artery highlights the pale plaque material embedded in the vessel wall, illustrating how plaque buildup thickens and stiffens the artery.

As you know, arteries deliver oxygen-rich blood to every organ, so the effects of atherosclerosis depend on which arteries are narrowed or blocked. When it affects the coronary arteries, it becomes coronary artery disease, which can lead to angina or a heart attack. When it affects arteries supplying the brain, it becomes cerebrovascular disease, which can lead to a stroke.

Coronary Arteries and Angina

If the heart muscle does not receive enough oxygen during activity, a person may feel angina pectoris, a pressure or discomfort that can appear as chest pain, nausea, numbness, or even jaw pain. Exercise increases the heart’s need for oxygen, but narrowed arteries cannot keep up. Rest usually relieves the symptoms.

Atherosclerotic plaques can suddenly rupture or completely block flow. When a coronary artery becomes fully blocked, part of the heart muscle loses oxygen and begins to die. This is a heart attack, and severe damage can stop the heart from contracting altogether.

Brain Arteries and Stroke

Blockage of an artery supplying the brain causes an ischemic stroke. Ischemic means lacking adequate blood flow. When a tissue becomes ischemic, it is not receiving enough oxygen and nutrients because its blood supply has been reduced or blocked. Without enough oxygen, cells cannot make energy normally, and the tissue begins to malfunction. If ischemia lasts too long, the affected cells can die.

A hemorrhagic stroke occurs when a weakened artery wall (often from high blood pressure) forms an aneurysm that ruptures. An aneurysm is a bulging or ballooning of a weakened section of an artery. Over time, pressure from the blood flowing through the vessel causes the weakened wall to stretch outward, much like a worn spot on a garden hose. Most aneurysms form silently with no symptoms. The danger is that the stretched wall can rupture, leading to sudden, life-threatening internal bleeding, or it can form a clot that blocks blood flow downstream.

In both cases, oxygen delivery to brain tissue stops, leading to symptoms such as sudden weakness or numbness, difficulty speaking, vision loss, a sudden severe headache, dizziness, or collapse. Rapid medical care is critical.

A Long, Quiet Disease

Atherosclerosis develops slowly over decades. Arteries can narrow to one-quarter of their original diameter before symptoms appear, and for some people, the first sign is a catastrophic event. Despite this, the age-adjusted U.S. death rate from heart disease has dropped dramatically since the 1950s, thanks to lower smoking rates, dietary changes, and better treatment of hypertension and heart disease.

Artery Care 101: Practical Ways to Reduce Plaque and Stiffness

Although aging naturally stiffens arteries, many of the factors that accelerate arteriosclerosis and atherosclerosis can be changed. The overall goal is to protect the endothelium, slow plaque formation, and keep vessels flexible so blood can move freely. It is never too early to start.

• Maintain Healthy Blood Pressure. Keeping systemic arterial pressure within a normal range reduces mechanical stress on vessel walls. Regular monitoring, managing sodium intake, staying active, and following treatment plans all help prevent hypertension, one of the strongest drivers of arterial damage.

• Improve Lipid Profile. Lowering LDL cholesterol and raising HDL slows plaque formation. Emphasize: limiting saturated and trans fats; choose unsaturated fats (olive oil, nuts, fish); increase fiber (vegetables, fruits, whole grains); have your blood checked regularly.

• Engage in Regular Physical Activity. Aerobic activity (walking, swimming, cycling) improves endothelial function, decreases LDL, and increases vessel elasticity. Even short, regular bouts of activity help counteract plaque progression.

• Avoid Smoking and Secondhand Smoke. Tobacco damages the endothelium, encourages plaque formation, stiffens arteries, and accelerates all types of cardiovascular disease. Avoiding smoking is one of the most effective ways to prevent atherosclerosis.

• Maintain Healthy Body Weight. Excess adiposity increases inflammation, raises LDL, and contributes to hypertension and diabetes. Gradual, sustainable weight management improves cardiovascular health and reduces plaque progression.

• Control Blood Glucose. Chronically high blood glucose damages blood vessels and accelerates atherosclerosis. Students with diabetes or prediabetes should monitor glucose, follow medical guidance, and maintain consistent physical activity.

• Manage Stress. Chronic stress can raise blood pressure and promote harmful behaviors. Relaxation techniques, sleep hygiene, and social support help regulate sympathetic drive and reduce vascular strain.