For a long time, normal blood pressure was defined as 120/80 mm Hg (systolic/diastolic). Recently, however, the American Heart Association revised its guidelines about what an optimal blood pressure range is, and when blood pressure is considered too high or too low.
While 120/80 used to be considered normal, the new guidelines define three levels of abnormal blood pressure values.
120-139 / 80-89 is now considered to be “prehypertension” (or “almost high blood pressure"), and doctors are watching blood pressures in this range more carefully than in the past
140/90 is the cutoff for Stage 1 Hypertension. Stage 1 Hypertension may or may not be treated with medicines, depending on lifestyle and other risk factors.
Systolic pressures above 160, or diastolic pressures above 100, patients are classified as having Stage 2 Hypertension, a serious condition that warrants immediate medical treatment