Hypertension

High blood pressure, also known as hypertension, is the most common cardiovascular disease. Hypertension is the leading cause of stroke and a major cause of heart attack. In the United States alone, approximately 73 million people have high blood pressure.

Blood pressure refers to the force of blood pushing against artery walls as it courses through the body. Like air in a tire or water in a hose, blood fills arteries to a certain capacity. Just as too much air pressure can damage a tire or too much water pushing through a garden hose can damage the hose, high blood pressure can threaten healthy arteries and lead to life-threatening conditions such as heart disease and stroke.

A blood pressure reading appears as two numbers. The first and higher of the two is a measure of systolic pressure, or the pressure in the arteries when the heart beats and fills them with blood. The second number measures diastolic pressure, or the pressure in the arteries when the heart rests between beats.

Normal blood pressure rises steadily from about 90/60 at birth to about 120/80 in a healthy adult. If someone were to take your blood pressure immediately after you’d delivered a speech or jogged five miles, the reading would undoubtedly seem high. This is not necessarily cause for alarm: It’s natural for blood pressure to rise and fall with changes in activity or emotional state.

It’s also normal for blood pressure to vary from person to person, even from one area of your body to another. But when blood pressure remains consistently high, talk with your doctor about treatment. Consistently high blood pressure forces the heart to work far beyond its capacity. Along with injuring blood vessels, hypertension can damage the brain, eyes, and kidneys.

People with blood pressure readings of 140/90 or higher, taken on at least 2 occasions, are said to have high blood pressure. If the pressure remains high, your doctor will probably begin treatment. People with blood pressure readings of 200/120 or higher need treatment immediately. People with diabetes are treated if their blood pressure rises above 130/80, since they already have a high risk of heart disease.

Researchers identified people with blood pressures slightly higher than 120/80 as a category at high risk for developing hypertension. This condition is called prehypertension and affects an estimated 50 million American men and women. Prehypertension is now known to increase the likelihood of damage to arteries and the heart, brain, and kidneys, so many doctors are now recommending early treatment.

Hypertension may also lead to heart failure, a common but disabling condition that can cause breathing problems. Patients who have very high blood pressure are said to have malignant hypertension, with a diastolic pressure usually exceeding 130 or a systolic pressure above 200. Malignant hypertension is a dangerous condition that may develop rapidly and cause organ damage quickly — it requires immediate medical attention.

High blood pressure is more likely in people who: have a family history of high blood pressure, heart disease, or diabetes, are older or overweight, not physically active, drink excessively, smoke, eat foods high in saturated fats or sodium, use certain medications such as NSAIDs, decongestants, and illicit drugs such as cocaine.

In as many as 95% of reported high blood pressure cases in the United States, the underlying cause cannot be determined. This type of high blood pressure is called essential hypertension.

When a direct cause for high blood pressure can be identified, the condition is described as secondary hypertension.