Prehypertension is a conition where a person's blood pressure is elevated above normal but not to the level considered to be hypertension (high blood pressure). The seventh report of the Joint National Committee (JNC 7) proposed a new definition of blood pressure values below 140/90 mm Hg. Prehypertension is considered to be blood pressure readings with a systolic pressure from 120 to 139 mm Hg or a diastolic pressure from 80 to 89 mm Hg. Readings greater than or equal to 140/90 mm Hg are considered hypertension. Classification of blood pressure is based upon two or more readings at two or more separate occasions.