Everyone would like to have healthy, “normal” blood pressure. But what exactly does that mean? When your doctor takes your blood pressure, it’s expressed as a measurement with two numbers, with one number on top and one on the bottom, like a fraction. For example, 120/80. The top number refers to the amount of pressure in your arteries during contraction of your heart muscle. This is called systolic pressure. The bottom number refers to your blood pressure when your heart muscle is between beats. This is called diastolic pressure. Both numbers are important in determining the state of your heart. For a normal reading, your blood pressure needs to show a top number that’s between 90 and 120, and a bottom number that’s between 60 and 80. Note that blood pressure readings are expressed as millimeters of mercury. This unit is abbreviated as mm Hg. Blood pressure that is too low does not supply your body and heart with enough oxygenated blood. Low blood pressure is known as hypotension. Instead high pressure is known as hypertension. Now you measure your blood pressure with digital blood pressure monitor (sphygmomanometer).