High Blood Pressure (Hypertension)

  • What Is It?
  • Symptoms
  • Diagnosis
  • Treatment
  • When To Call A Professional
  • Prognosis
  • Prevention
  • What Is It?

    Blood pressure has two components:

    • Systolic pressure, the higher number, represents the pressure that the heart must generate to pump blood to the rest of the body.
    • Diastolic pressure, the lower number, refers to the pressure in the blood vessels between heartbeats.

    Usually systolic pressure increases as we age. However, after age 60, diastolic pressure usually begins to decline because of stiffening of the body’s blood vessels.

    Blood pressure is measured in millimeters of mercury (mmHg). High blood pressure, or hypertension, is defined as systolic blood pressure of 140 mmHg or greater, or diastolic blood pressure of 90 mmHg or greater. This is because the risk of various health complications is increased when the blood-pressure levels are higher than this.

    High blood pressure can cause damage to many organs, including the brain, heart and kidneys, as well as arteries throughout the body. If you have high blood pressure that has not been diagnosed, or that is not being treated adequately, you are at greater risk of having a heart attack, stroke, kidney failure and blindness.


    High blood pressure can cause symptoms such as headaches, dizziness, fatigue and ringing in the ears. However, it often causes no symptoms.


    Because the diagnosis of hypertension depends on blood-pressure readings, careful measurement of blood pressure is essential. You should avoid smoking or drinking caffeine (coffee, tea, cola soft drinks) for at least 30 minutes before you have your blood pressure taken, and you should be seated for at least five minutes before. Two readings should be taken and averaged. If your blood pressure is high, your doctor should examine your eyes, heart and nervous system (to look for brain damage. He or she also should perform various tests to see if the hypertension has caused organ damage, including blood tests to check kidney function, and an electrocardiogram (EKG) to look for thickening of the heart muscle, reduced blood flow to your heart or irregular heart rhythms.

    Your doctor will diagnose you with hypertension if your blood pressure measures more than 140/90 mmHg on three consecutive visits over several months.


    To preventing hypertension, you should:

    • Get regular aerobic exercise.
    • Limit your intake of salt.
    • Eat a diet rich in fruits and vegetables and low in saturated fats.
    • Avoid smoking.
    • Maintain a desirable body weight.

    It is also important to try to modify all of the risk factors for coronary artery disease that are under your control. In addition to the above actions, you should:

    • Quit smoking.
    • Reduce your high blood LDL cholesterol (the “bad” cholesterol).

    There is the real possibility that you can cure your hypertension just with lifestyle modification, and won’t require blood pressure medicines.


    Both doctors and patients usually prefer to control blood pressure with lifestyle changes, but sometimes antihypertensive medication is needed to provide adequate control. Antihypertensive medications include diuretics, beta-blockers, ACE inhibitors, angiotensin receptor blockers, calcium channel blockers and alpha-blockers. Doctors tend to be more aggressive in using antihypertensive medications in people with diabetes, kidney disease or heart problems, because such people are at extra risk of developing problems from hypertension.

    When To Call A Professional

    Adults generally should have their blood pressure measured at least every few years. If your blood pressure is more than 130/85 mmHg, then you should schedule regular appointments with your doctor for blood-pressure monitoring and for advice about modifying your lifestyle to prevent problems in the future.


    The prognosis of high blood pressure depends on how long you’ve had it, how severe it is, and if you have other conditions such as diabetes that increase the risk of disease of the heart, brain, eyes and kidneys. When hypertension is treated adequately, the prognosis is much better. Remember that hypertension can lead to a poor prognosis even if you do not have any symptoms, and that both lifestyle changes and medicines can control your hypertension and greatly improve your prognosis.

    Johns Hopkins patient information

    Last revised:

    Diseases and Conditions Center

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