Blood Pressure Numbers and Meanings

Every time we go to the doctor our blood pressure is checked. The doctor usually tells us the numbers, but how many of us really know what they mean? While some of us do know, there are quite a few who don't. But knowing and understanding our blood pressure is an important part of staying healthy and something we should all talk to our doctor about.

Blood Pressure Defined

• When we measure blood pressure, we are actually measuring how much force our blood is exerting on our arteries as it is pumped through the body. Constriction or tightening of the arteries will increase blood pressure.

How Pressure is Measured

• While blood pressure is often taken digitally now, older blood pressure cuffs were attached to a tube of mercury. The numbers in our blood pressure represent how many millimeters the mercury rose when our blood pressure was tested. This measurement is abbreviated as "mmHg."

Systolic

• A blood pressure measurement consists of two numbers. The first number is called the systolic pressure and measures blood pressure when the heart beats, or contracts to push blood through the body.

Diastolic

• The second number in a blood pressure reading is the diastolic pressure. Diastolic pressure measures the amount of pressure in between beats, when the heart is at rest.

The Numbers

• A blood pressure of 120/80 is considered to be perfect. Anything below 140/90 is acceptable and generally normal for adults. A reading of 140/90 is considered to be high.

Low Blood Pressure

• Low blood pressure is not defined by a certain set of systolic or diastolic numbers. A person is not considered to have low blood pressure unless and until they show physical signs of low amounts of blood flow.