The only way to find out if you have high blood pressure is to have your blood pressure checked. Your doctor or another qualified health professional should check it at least once every two years and more often if it's high. Blood pressure is measured by a quick, painless test using a medical instrument called a sphygmomanometer (SFIG'mo-mah-NOM'eh-ter).

A rubber cuff is wrapped around your upper arm and inflated. This compresses a large artery in the arm, momentarily stopping the blood flow.

Next, air in the cuff is released, and the person measuring the blood pressure listens with a stethoscope. When the blood starts to pulse through the artery, it makes a sound. Sounds continue to be heard until pressure in the artery exceeds the pressure in the cuff.

While the person listens and watches the sphygmomanometer gauge, he or she records two measurements. Systolic pressure is the pressure of the blood flow when the heart beats (the pressure when the first sound is heard). Diastolic pressure is the pressure between heartbeats (the pressure when the last sound is heard). Blood pressure is measured in millimeters of mercury, which is abbreviated mm Hg.

A typical blood pressure reading for an adult might be 118/78 mm Hg, but readings vary depending on age and other factors. Normal blood pressure is defined by a range of values, so don't be alarmed if your own reading is somewhat higher or lower. The important point is that the harder it is for blood to flow, the higher the numbers will be.

Are there larger and smaller blood pressure cuffs for overweight people and children?

Children and adults with smaller or larger than average-sized arms may need special-sized cuffs. These are available in some pharmacies and from medical supply companies. They may also be ordered directly from companies that sell blood pressure cuffs. Ask your doctor or pharmacist for help.

Related AHA publications:

• Understanding and Controlling Your High Blood Pressure brochure (also in Spanish)
• High Blood Pressure in African Americans brochure
• High Blood Pressure and Stroke brochure
• "How Can I Reduce High Blood Pressure?" printable sheet in Answers By Heart kit (also in Spanish kit)
• "What Is High Blood Pressure Medicine?", "Why Should I Limit Sodium?" and "How Can I Monitor My Cholesterol, Blood Pressure and Weight?" printable sheets in Answers By Heart kit
• Cholesterol, Blood Pressure and Weight Tracker (wallet card)