When you have HIGH BLOOD PRESSURE your heart is working harder than it should to pump blood throughout your cardiovascular system.PULMONARY HYPERTENSION means that you have HIGH BLOOD PRESSURE in the arteries of your LUNGS. And the way it's measured is distinct from the way that blood pressure in the rest of your body is evaluated. In place of the systolic and diastolic numbers, such as 110 over 70, you are given only a single numerical value to assess this form of hypertension. Normal pulmonary blood pressure at rest is about 14 millimeters of mercury. If the amount of pressure your heart has to exert to pump blood into your lungs is measured as 25 millimeters of mercury when you are at rest or 30 while exercising, you are said to have PULMONARY HYPERTENSION. Many times, the cause of pulmonary hypertension remains a mystery and it is diagnosed as IDIOPATHIC, meaning there's no discoverable REASON for its development. But doctors do know that it's probably linked to a genetic predisposition and that it most commonly affects young people and women. Other times, pre-existing lung disease, such as COPD, or heart defects, sleep apnea, and blood clotting disorders may be the trigger. Older people are MORE likely to have this type of hypertension. Pulmonary hypertension occurs when cell damage in the lining of the small blood vessels in the lungs causes the vessels to contract and restrict the flow of blood. Symptoms aren't noticeable until the condition WORSENS. Then a person may experience SHORTNESS of breath, fatigue, dizziness, chest pressure, SWELLING in the ankles and feet, a speedy pulse and heart PALPITATIONS. Pulmonary hypertension is usually diagnosed with a physical exam, an echocardiography, a chest X-ray, or an electrocardiogram. To find out more about pulmonary hypertension, watch the other videos in this series.