Atherosclerosis is a disease in which plaque builds up inside your arteries. Plaque is a sticky substance made up of fat, cholesterol, calcium, and other substances found in the blood. Over time, plaque hardens and narrows your arteries. That limits the flow of oxygen-rich blood to your body.Atherosclerosis can lead to serious problems, includingCoronary artery disease. These arteries supply blood to your heart. When they are blocked, you can suffer angina or a heart attack.Carotid artery disease. These arteries supply blood to your brain. When they are blocked you can suffer a stroke.Peripheral arterial disease. These arteries are in your arms, legs and pelvis. When they are blocked, you can suffer from numbness, pain and sometimes infections.Atherosclerosis usually doesn't cause symptoms until it severely narrows or totally blocks an artery. Many people don't know they have it until they have a medical emergency.A physical exam, imaging, and other diagnostic tests can tell if you have it. Medicines can slow the progress of plaque buildup. Your doctor may also recommend procedures such as angioplasty to open the arteries, or surgery on the coronary or carotid arteries. Lifestyle changes can also help. These include following a healthy diet, getting regular exercise, maintaining a healthy weight, quitting smoking, and managing stress. NIH: National Heart, Lung, and Blood Institute