Approximately 1 in every 3 American adults has hypertension, or high blood pressure. Hypertension is defined as a blood pressure of 140/90 mm Hg or higher. The risk for stroke, heart attack and kidney failure rises in proportion to the severity of hypertension, and even mildly elevated blood pressure may damage your organs. The Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure has classified hypertension into stages of severity to help guide treatment and categorize health risks.
A blood pressure lower than 120/80 is defined as normal. If your systolic blood pressure (the first number in your measurement) is consistently between 120 and 140, or your diastolic pressure (the bottom number) is between 80 and 90, you have pre-hypertension. This condition significantly increases your risk for developing true hypertension. Furthermore, some people with pre-hypertension already have organ damage due to elevated blood pressure. A study published in the May 2010 issue of "Hypertension" showed that 17 percent of people with pre-hypertension exhibit signs of chronic kidney disease. People with pre-hypertension are encouraged to maintain a healthy body weight, adopt a low-fat diet that is rich in fruits and vegetables, reduce daily sodium intake to less than 2,400 mg -- about 1 teaspoon of salt -- get 30 minutes of aerobic exercise on most days of the week and limit alcohol consumption to 1 or 2 drinks daily.
Stage I Hypertension
Stage I hypertension is defined as a systolic blood pressure between 140 and 159 or a diastolic pressure between 90 and 99. In comparison to pre-hypertension, stage I hypertension is associated with a higher risk for kidney disease, heart valve disease and other blood pressure-related conditions. People with stage I hypertension are urged to make the same lifestyle changes recommended for individuals with pre-hypertension. In addition, medications are recommended to lower your blood pressure. Some people with stage I hypertension may achieve adequate blood pressure control with a single drug, such as a diuretic, but many need more than one medication.
Stage II Hypertension
If your systolic blood pressure is 160 or higher, or your diastolic pressure is 100 or higher, you have stage II hypertension. People with sustained stage II blood pressures are significantly more likely to experience a stroke, heart attack, kidney failure or eye damage than individuals with lower blood pressures. Your Framingham cardiac risk score -- a gauge of your overall cardiovascular risk -- predicts a 1 in 10 chance of dying within 10 years if your blood pressure is not controlled. As with milder stages of hypertension, people with stage II hypertension should adopt a lifestyle that includes weight control, exercise and a healthy diet. More intensive medical therapy is indicated for stage II hypertension, so your doctor may prescribe 2 or more medications to bring your blood pressure down.
Although it is not separately classified as a stage of hypertension by the Joint National Committee, hypertensive crisis -- a systolic pressure above 180 or a diastolic pressure above 120 -- is a category of hypertension that warrants urgent and aggressive medical treatment. Such blood pressures dramatically heighten your risk for a stroke, heart attack or other organ damage. If a hypertensive crisis is associated with signs or symptoms of organ damage -- such as chest pain, bleeding into the eyes or paralysis -- immediate hospitalization is required. Otherwise, outpatient treatment with close monitoring may be possible.
According to the Centers for Disease Control and Prevention, hypertension contributes to 1 of every 7 deaths in the U.S. Despite its impact on Americans’ health, 30 percent of people with hypertension are not receiving treatment. Many people are not even aware they have hypertension, and only half of people who have been diagnosed have their blood pressure adequately controlled. The Joint National Committee recommends a blood pressure measurement at least every 2 years for people with normal blood pressures and every year for people with pre-hypertension. If you have stage I or stage II hypertension, follow your doctor’s recommendations.
- Morbidity and Mortality Weekly Report: Vital Signs -- Prevalence, Treatment and Control of Hypertension –- United States, 1999-2002 and 2005-2008
- Hypertension: Prevalence of Chronic Kidney Disease in Persons with Undiagnosed or Pre-hypertension in the U.S.
- Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure (JNC7)
- The American Journal of Cardiology: Stages of Systemic Hypertension and Blood Pressure as Correlates of Computed Tomography-Assessed Aortic Valve Calcium (from the Multi-ethnic Study of Atherosclerosis)
- Deutsches Ärtzeblatt International: End Organ Damage in Hypertension
- Cardiology in Review: Hypertensive Crisis (abstract)
- Creatas Images/Creatas/Getty Images