Angina is a form of chest pain or discomfort caused by a temporary restriction of blood and oxygen to the heart muscle. This condition is classified as stable or unstable. Stable angina is more common, and it occurs due to factors that increase the heart's need for oxygen, such as exercise or stress. This type of angina is relieved by rest. Unstable angina is an unexpected pain or discomfort that doesn't follow a pattern and can occur at rest. Although women and men experience some of the same symptoms of angina, women are more likely to experience the pain and discomfort in different areas as well as certain non-typical symptoms.