New Blood Pressure Guidelines

Normal blood pressure reading in an adult is

a. systolic less than 110 / diastolic less than 80 millimeters of mercury (mmHg)
b. systolic less than 120 / diastolic less than 80 mmHg
c. systolic 120-139 or diastolic 80-89 mmHg
d. systolic 140-159 or diastolic 90-99 mmHg


The correct answer is b. The seventh report of the Joint National Committee(JNC 7) proposed a new range for normal blood pressure (less than 120/80) and a new category of prehypertension. This recommendation was based on several studies, completed since the 6th JNC report in 1997, which showed a strong correlation between increasing blood pressure and an increase in heart attacks, cardiovascular disease, stroke, and kidney disease.

An analysis of data from the Framingham Heart Study demonstrated that relative to blood pressure less than 120/80 mmHg, prehypertension (120 to 129/80 to 84 mmHg) was associated with an increased risk of heart attacks (relative risk 3.5) and coronary artery disease (relative risk 1.7), but not stroke. In the Women's Health Initiative study involving over 60,785 postmenopausal women who were followed for 7.7 years, women with prehypertension, compared to normotensive individuals, had an increased risk of cardiovascular death, myocardial infarction and stroke. The risk of cardiovascular disease beginning at 115/75 mmHg doubles with each increment of 20/10 mmHg.

Data from the 1999 and 2000 National Health and Nutrition Examination Survey (NHANES III) suggested that the prevalence of prehypertension among adults in the United States was approximately 30 percent. The prevalence was markedly higher among men than women (39 and 23 percent, respectively). Lifestyle modifications and a closer monitoring is recommended for these patients. Medications may be necessary if other risk factors are present. According to JNC7, a blood pressure of systolic 140-159 mmHg or diastolic 90-99 is classified as stage I hypertension, and a medication should be started for these patients. Stage II hypertension is categorized as systolic more than 160 mmHg or diastolic more 100 mmHg. These patients will usually require two medications for control of the blood pressure in addition to making the lifestyle modifications.

For more information on lifestyle modifications and medication management see JNC 7 report.
Note that the European Recommendations have chosen to continue the same guidelines as the JNC 6 report.