President Fords historic trip and fall down the steps of Air Force One. 1  People & Blogs. 2  Standard YouTube License.
The bottom number, called the diastolic pressure, is the measurement as the heart relaxes between beats. Normal blood pressure is a systolic pressure of less than 120 millimeters of mercury (mm Hg) and a diastolic pressure of less than 80 mm Hg, or 120/80 mm Hg, according to the American Heart Association (AHA). Having a blood pressure greater than 140/90 mm Hg is considered high blood pressure or hypertension. A blood pressure level between normal and hypertension, is called prehypertension, meaning it is higher than normal, but not high enough to be considered hypertension.
One or both of these numbers can be too high. Normal blood pressure is when the top number (systolic blood pressure) is below 120 most of the time, and the bottom number (diastolic blood pressure) is below 80 most of the time (written as 120/80 mm Hg). If your blood pressure numbers are 120/80 or higher but below 140/90, it is called pre-hypertension.