An acceptable blood pressure reading depends partly on whether a person has any other diseases, or takes medication that may affect his reading. A medical professional must determine what is normal or acceptable for an individual.
Normal Blood Pressure
According to both the National Heart Lung and Blood Institute and the American Heart Association, normal blood pressure is a reading less than 120/ 80. The top number is the systolic pressure and is a measure of blood pressure while the heart is beating; the bottom number is the diastolic pressure and is a measure of blood pressure when the heart rests.
Hypertension
Hypertension, or high blood pressure, occurs when the systolic pressure is greater than 120/80. It becomes more serious when the numbers go above 140/90. At 180/110, a hypertensive crisis occurs and is an emergency; it does not matter whether both or just one of the numbers is too high.
Hypotension
Hypotension, or low blood pressure, is a reading less than 90/60. Only if the pressure gets really low, causing hypotensive shock is there an emergency. Low blood pressure may make a person feel dizzy or faint.
