What Is Blood Pressure (BP)?
Blood pressure, abbreviated BP, is the pressure of the blood against the arterial walls.
Blood pressure results from the force of the heart that pumps the blood into the arteries, and the force of the arteries as they resist the blood flow.
Why Are Two Values in the Blood Pressure Reading?
Blood pressure is expressed with two values, separated by a slash and with a unit (mm Hg), for example 125/85 mm Hg; pronounced “125 over 85 millimeters of mercury” (according to height of a column in a blood pressure monitor).
- The first (higher) value (125) represents blood pressure during the heart contraction (systole in Greek) and is called systolic blood pressure
- The second (lower) value (85) represents blood pressure during the heart relaxation (diastole in Greek) and is called diastolic blood pressure
What is Normal Blood Pressure Range?
For an adult (18 years or older), any blood pressure between 120/80 and 90/60, measured in the sitting position on the upper arm, is considered as normal.
It was found out that people with blood pressure within this range are at least risk to suffer from heart attack, stroke or other circulatory disorders (1), so it is often called optimal, ideal or healthy blood pressure range.
Standing up for a while, exercising, stress and even appointment with a doctor can increase blood pressure for more than 10 mm Hg within few minutes, so an average value from several blood pressure measurements rather than one single measurement should be considered as actual blood pressure.
Blood pressure tends to increase with age, so many doctors consider readings as high as 150/85 in old people as normal. However, many health institutions claim that blood pressure above 120/80 should be always considered as increased risk to develop a circulation-related disorder (1).
Blood Pressure Chart for Adults
- First value 91-119 AND second value 61-79 are considered as normal BP. Examples: 115/75 , 110/65.
- First value 120-139 OR second value 80-90 are considered as pre-high blood pressure or pre-hypertension. Examples: 135/85 , 115/85. Individuals in this group are at increased risk to develop high BP later in life.
- First value 140 or above OR second value above 90 are considered as high BP or hypertension. Examples: 150/85 , 135/95. A person with high blood pressure often does not have any symptoms.
- First value 90 or less OR second value 60 or less are considered as low BP or hypotension. Examples: 95/55 , 85/65.
Blood pressure chart (below): Find your top BP value on the vertical scale and read toward right, and your bottom BP value on the horizontal scale and read up; where two meat is your blood pressure.
Special blood pressure chart for children exists.
Article reviewed by Dr. Greg. Last updated on November 7, 2012