Angina is primarily caused by what?

Angina is primarily caused by poor blood circulation to the heart, which is often the result of narrowed or blocked coronary arteries due to atherosclerosis. When an artery is constricted, it restricts blood flow to the heart muscle, leading to chest pain or discomfort known as angina. This condition typically occurs during physical exertion or stress when the heart requires more oxygen than the compromised blood supply can deliver.

The other options involve factors that can influence heart health but do not directly cause angina in the same manner. Regular exercise is generally beneficial for cardiovascular health and can help improve circulation. High blood pressure does contribute to heart disease but is not a primary cause of angina itself. Infection in the heart muscles, while serious, typically leads to different conditions such as myocarditis, and is not a direct cause of angina. Thus, understanding the root cause of angina as poor blood circulation emphasizes the importance of maintaining healthy coronary arteries to prevent this condition.