(BP) is the pressure exerted by circulating blood upon the walls of blood vessels. Blood pressure is usually expressed in terms of the systolic (maximum) pressure over diastolic (minimum) pressure and is measured in millimeters of mercury (mm Hg).
Normal blood pressure is 120/80 mm Hg. It will be relieving to hear that we have normal level but what do this numbers actually mean.
The top number, or systolic pressure
, reflects the amount of pressure during the heart’s pumping phase, or systole. As the heart contracts with each beat, pressure in the arteries temporarily increases as blood is forced through them.
The bottom number, or diastolic pressure
, represents the pressure during the resting phase between heartbeats, or diastole.
What is Systole?
Systole is the part of the cardiac cycle when the ventricles contract.
What is Diastole?
Diastole is the part of the cardiac cycle when the heart refills with blood following systole (contraction).
The cardiac cycle
refers to a complete heartbeat from its generation to the beginning of the next beat, and so includes the diastole, the systole, and the intervening pause.
When systolic and diastolic pressures fall into different categories of blood pressure
, Doctors rate overall blood pressure by the higher category. For example, 150/80 mm Hg is classified as stage 1 hypertension, not prehypertension.
To classify your blood pressure, a doctor averages two or more readings taken after you have been seated quietly for at least five minutes. For example, a patient with a measurement of 135/85 mm Hg on one occasion and 145/95 mm Hg on another has an average blood pressure of 140/90 mm Hg and is said to have stage 1 hypertension