The biggest change is the addition of a new category called prehypertension, which identifies people at higher risk for high blood pressure, heart disease and stroke.
| Category | Systolic Blood Pressure (mm Hg) | Diastolic Blood Pressure (mm Hg) | |
| Normal | Less than 120 | and | Less than 80 |
| Prehypertension | 120-139 | or | 80-89 |
| Hypertension | |||
| Stage 1 | 140-159 | or | 90-99 |
| Stage 2 | 160 or higher | or | 100 or higher |
To classify your blood pressure, your doctor averages two or more readings. For example, if you have 135/85 mm Hg on one occasion and 145/95 mm Hg on another, your doctor will say you have an average blood pressure of 140/90 mm Hg, which is stage 1 hypertension.
When systolic and diastolic pressures fall into different categories, the JNC advises doctors to rate the blood pressure by the highest category. For example, 150/85 mm Hg is classified as stage 1 hypertension, not as prehypertension.
Systolic hypertension is defined as a systolic pressure of 140 mm Hg or higher and a diastolic pressure below 90 mm Hg.
People in the normal category — those with a blood pressure below 120/80 mm Hg — have the lowest risk of developing cardiovascular disease. People in the prehypertension category have a greatly increased risk of developing hypertension. These people require lifestyle changes to reduce their risk. People with stage 1 hypertension generally require medication, although aggressive lifestyle changes (in diet and fitness) can sometimes help people avoid the need for medication.
