Angina affects nearly 7 million people in the United States, according to the National Heart Lung and Blood Institute (NHLBI). Angina is a condition characterized by chest pain and pressure, and it affects men and women equally. Here is a guide to understanding angina:

Throughout your entire life, your heart continuously pumps blood throughout your body. In order to keep functioning, the heart receives oxygen from the coronary arteries, which work like a garden hose, transporting oxygen-rich blood to the heart. If this important artery is clogged, the heart becomes parched and damaged from not getting enough oxygen. Arteries clog when a fatty material called plaque adheres to the vessel walls and begins narrowing the vital passageway. Imagine a traffic jam in your heart that prevents necessary nutrients from passing through. Your heart’s struggle for oxygen causes angina — chest pain or pressure from this lack of oxygen.

There are four major types of angina, and each has its own set of symptoms. Doctors need to discern between the types, because the different diagnoses require different treatments. Stable angina occurs in fairly predictable intervals at the same level of severity. Stable angina can be a warning sign for an eventual heart attack. Unstable angina does not follow a pattern of occurrence or severity. Unstable angina requires emergency medical care, as the disease could point to a heart attack in the  immediate future. Variant (Prinzmetal’s) angina results in pain during periods of rest, typically between midnight and early morning. Variant angina can usually be relieved with medicine. Microvascular angina lasts longer and is more severe than other kinds of angina, and medicine may not alleviate the pain.

Each type of angina has its own specific symptoms, but there a number of common symptoms across the spectrum. All forms of angina are marked by chest pain or pressure, which can spread to the arms, neck, back and jaw. Occasionally, angina appears with indigestion and nausea. The left side of your body may also start to feel tight or heavy in the arms, elbows and wrists. Common symptoms of angina also include fatigue and shortness of breath. While angina can occur during periods of rest, pain is mostly triggered by physical exertion in a short period of time. If angina medicine and rest do not relieve chest pain within a few minutes, this could be the sign of a heart attack.

Angina is one symptom of a much larger heart problem — plaque build-up caused by coronary heart disease. The underlying causes of angina generally correspond to the causes of coronary heart disease that include: smoking, high amounts of fat and cholesterol in the body, high blood pressure or high blood sugar due to diabetes. Angina can also be a symptom of coronary microvascular disease — damage to the lining of tiny heart arteries.

Treatment for angina should alleviate the symptoms and prevent potential disaster. A combination of lifestyle changes and medications also combat ongoing chest pain. Doctors commonly prescribe nitrates to treat angina, as these medicines widen blood vessels and increase blood flow back to the heart. Other medications reduce the heart’s workload by lowering blood pressure, slowing the heart rate or preventing clots from forming. Lifestyle changes to mitigate angina include maintaining a heart-healthy diet and avoiding stressful situations. If the angina persists despite medical and behavioral intervention, the doctor may recommend an angioplasty or coronary artery bypass grafting (CABG). These various medical interventions may sound extreme, but they all aim to prevent a possibly dangerous heart attack.