High Blood Pressure (Hypertension)

Is Your Blood Pressure Too High?

Most people with high blood pressure do not experience any symptoms, which is why regular blood pressure checks are so important.

High blood pressure can only be diagnosed with repeated blood pressure measurements. The best way to tell if you have high blood pressure is to have your blood pressure measured by a health professional.

Sometimes individuals with severe or chronic high blood pressure experience headache, dizziness, fatigue, or blurry vision. These are danger signs, and medical help should be sought immediately. People with lesser degrees of blood pressure elevation may experience sleep disturbances, emotional upset, or a dry mouth.

Although blood pressure varies from person to person, there are accepted guidelines for what is considered optimal, normal, and high. Since high blood pressure is associated with cardiovascular and other diseases and even death, it is critically important to identify and treat it early. You can use the following chart to help determine whether your blood pressure is too high.

This classification, which comes from the sixth Joint National Committee’s report on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI), is referred to as the JNC VI Blood Pressure Classification System.


Where you stand

Systolic (mm Hg)


Diastolic (mm Hg)



















Stage 1




Stage 2

> or = 180


> or = 110

Stage 3

(Adapted from Table 2 from The Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure (JNC VI) NIH Publication #98-4080, November 1997; National Heart, Lung and Blood Institute National Institutes of Health)

  • If your systolic blood pressure readings are consistently greater than 140 mm Hg and/or your diastolic blood pressure readings are consistently greater than 90 mm Hg, your blood pressure is considered high.
  • When the systolic blood pressure and diastolic blood pressure fall into different categories, the higher category should apply. For example, a blood pressure of 165/94 mm Hg should be classified as stage 2 hypertension.
  • Although “optimal blood pressure” is defined as a blood pressure of less than 120/80 mm Hg, unusually low readings should also be evaluated.

Need to Know:

A single blood pressure reading may suggest high blood pressure, but your doctor should obtain a series of blood pressure readings. A variety of factors cause daily fluctuations in blood pressure, including:

  • Time of day
  • Hormone levels
  • Drugs
  • Pain or stress
  • Certain diseases
  • Cigarette smoking
  • Drinking caffeine-containing products (such as coffee, tea, or cola)

Based on your initial readings, your doctor will let you know whether you should return for further blood pressure checks and/or treatment.

In short, a diagnosis of hypertension is not based on a single blood pressure reading. High blood pressure can only be diagnosed on the basis of multiple blood pressure readings.

After the initial screening, your doctor should take two or more readings during each of two or more office visits.

Any person 18 years or older who is not acutely ill (for example, with a flu or cold) or taking medication to control hypertension can be diagnosed with high blood pressure for a sustained systolic pressure of 140 mm Hg or greater or a diastolic pressure of 90 mm Hg or greater.

Need to Know:

If your blood pressure is in the normal range, you should have it rechecked in two years. Those with high-normal blood pressure should have it rechecked in one year.

But if your blood pressure reading is above normal, you need to return for one or more blood pressure visits within the next one to two months. Anyone with a systolic blood pressure of 180 mm Hg or more, or a diastolic blood pressure of 110 mm Hg or more, should receive care immediately, or within one week at most.


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