Measuring blood pressure

Because high blood pressure rarely has any warning signs, you might easily be unaware you have it, at least until trouble strikes. That's why it's important to have your blood pressure checked periodically.

Whether you are at the doctor's office or checking your own blood pressure, it's important to take certain steps to get accurate readings.

• Don't drink a caffeinated beverage or smoke during the 30 minutes before the test.  Sit quietly for five minutes before the test begins. 
• During the measurement, sit in a chair with your feet on the floor and your arm supported so your elbow is at about heart level. 
• The inflatable part of the cuff should completely cover at least 80% of your upper arm, and the cuff should be placed on bare skin, not over a shirt. 
• Don't talk during the measurement. 
• Have your blood pressure measured twice, with a brief break in between. If the readings are different by 5 points or more, have it done a third time. 

It's a good idea to have your blood pressure measured in both arms at least once, since the reading in one arm may be higher (usually the right, since there's more direct blood flow from the heart on that side). The higher number should be used to make treatment decisions. 

For more on getting your blood pressure under control, buy Controlling Your Blood Pressure, a Special Health Report from Harvard Medical School.

Image: OscarWong/Getty Image