You should have your blood pressure checked regularly, particularly if you have a history of prehypertension or hypertension. When your blood pressure is measured, the reading will be categorized into one of three groups:
1. Normal blood pressure. If your systolic blood pressure is less than 120 mm Hg and diastolic pressure is less than 80 mm Hg, your blood pressure is normal.
2. Prehypertension. You fall into this category if you have a systolic pressure of 120 to 139 mm Hg or a diastolic pressure of 80 to 89 mm Hg. About 30 percent of adult Americans have prehypertension, which increases their risk of progressing to full-blown hypertension and developing hypertension-related complications such as heart attacks and strokes.
Generally, physicians will recommend lifestyle changes to control prehypertension. A recent study in the journal Stroke, however, suggested that blood pressure medication might cut the risk of stroke in people with prehypertension.
3. Hypertension. If your systolic blood pressure is 140 mm Hg or higher or your diastolic blood pressure is 90 mm Hg or higher, you have hypertension. Readings in the 140–159/90–99 mm Hg range indicate stage 1 hypertension; if blood pressure is higher—160/100 mm Hg or above—you have stage 2 hypertension.
Your doctor may talk about three other types of hypertension:
Isolated systolic hypertension. In this condition, systolic blood pressure is high (140 mm Hg or higher), but diastolic blood pressure is less than 90 mm Hg. About 65 percent of people over age 60 have isolated systolic hypertension.
White-coat hypertension. This form of hypertension is diagnosed when blood pressure is high only when measured by a doctor or nurse. It is normal, however, when taken at home. The risk associated with white coat hypertension is less than that of regular hypertension but greater than that of normal blood pressure.
Masked hypertension. In this case, blood pressure is normal at the doctor’s office but elevated when measured at home or at work. This condition is just as dangerous as regular hypertension.