American Nursing Association Take Action for Health Blood Pressure
Consumers and Patients
About Blood Pressure
Controlling Your Blood Pressure
Setting a BP Goal
A Guide for Talking with Your Health Care Provider
Myths v. Reality
The ANA's Take Action for Healthy BP Tour
Links to more Information

What is Blood Pressure?

The force of blood against the inside walls of your arteries, plus blood vessels' resistance to blood flow, create your blood pressure. When blood pressure stays too high over time, it's called high blood pressure.

Blood pressure is measured in millimeters of mercury (mm Hg) and is recorded as two numbers: the systolic and the diastolic. These numbers are expressed as a ratio. For example, a systolic pressure of 120 and a diastolic pressure of 80 results in a blood pressure reading of 120/80 mm Hg, or 120 over 80.

Systolic:
When the heart pumps blood to the organs, this is called the systolic pressure (the top number in a blood pressure reading).

Diastolic:
After pumping, the heart rests and pressure drops to its lowest point just before a new beat - this is called the diastolic pressure (the bottom number in a blood pressure reading).

Each time your heart beats, it pumps blood - containing oxygen - through about 60,000 miles of blood vessels including, arteries, veins and capillaries. The system is like a series of rivers and streams in your body, ranging from large to small in size.

Since high blood pressure usually has no symptoms, it could be damaging your important organs without your even knowing it.

If you have high blood pressure, your heart has to work harder to pump blood through the arteries to your important organs. It is like having to blow air through a thin straw, compared to a large pipe-it's much harder and takes more effort to blow the air against the pressure (or resistance) of the thin straw. This increased pressure poses the potential for serious health risks.

Normal blood pressure for most adults is less than 120/80 mm Hg, or less than 130/80 mm Hg for people with diabetes or chronic kidney disease. People who have blood pressure that is consistently 140/90 mm Hg or higher are candidates for prescription medication.