Systolic blood pressure (BP) of less than 140 mm Hg and diastolic BP of less than 90 mm Hg were previously considered normal. However, there was some evidence that even BP in the high reference range was associated with an increased risk of cardiovascular disease. The Seventh Report of the Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure defined a new BP category "prehypertension" for systolic and diastolic BP: 120 to 139 mm Hg and 85 to 89 mm Hg, respectively. This new category is a continuum to hypertension and is a risk factor for cardiovascular disease. The progression of prehypertension to hypertension can be delayed or may be prevented by lifestyle changes.