6 tips for the most accurate blood pressure readings

There's a good chance you have high blood pressure and don't even know it. One in five Americans with hypertension are unaware of the problem, according to estimates from the Centers for Disease Control and Prevention. That's because high blood pressure usually harms the body without causing obvious symptoms—until it triggers a heart attack or stroke, that is.  

That’s why you need to get your blood pressure regularly measured by a health care provider. That means at least every two years, and more often if you're over age 50 or have other risk factors. Some people should consider measuring at home, too. That includes:

• Anyone who has been diagnosed with high blood pressure.
• Older people, whose blood pressure can vary considerably.
  
• People with “white-coat hypertension,” or blood pressure that spikes in a doctor’s office or hospital due to anxiety.
  
• People with diabetes, since high blood pressure poses special risks to them.
  

See our Ratings of blood pressure monitors and read our Best Buy Drugs report on  how to treat high blood pressure.

How to get accurate blood pressure readings

1. Try to take your blood pressure at the same time each day.

Levels are usually lowest in the morning, and then rise steadily through the day.

2. Avoid exercise, tobacco, and caffeine for at least an hour before.

All can make blood pressure spike temporarily (though it's unclear if they have a lasting effect on blood pressure.)

3. Go the bathroom.

A full bladder can raise systolic pressure by 10 to 15 mmHg. One of the main blood pressure medications, diuretics, lower blood pressure in part by causing your kidneys to remove more sodium and water from the body (in other words, go to the bathroom a lot), which helps to relax the blood vessel walls. (See our Best Buy Drugs advice on drugs for high blood pressure.)

4. Rest for 5 minutes before the reading.

Feet should be flat on the floor, legs uncrossed, and cuff at heart level; those can each affect systolic pressure by 2 to 10 mmHg.

5. Put the cuff on bare skin.

Putting it over clothes can raise systolic pressure by up to 40 mmHg.  

6. Remain quiet during the test.

Talking can raise systolic pressure by 10 to 15 mmHg.

Use our calculator to determine your risk of having a heart attack or stroke in the next 10 years. Use our tool to see which heart disease tests make sense for you.