Are You Wrong About Your Blood Pressure?

Doctor taking woman's blood pressure

It’s important to have an accurate blood pressure reading so that you have a clearer picture of your risk for heart disease and stroke. But many things can affect a blood pressure reading, including how you sit and what you wear. In honor of National High Blood Pressure Education Month, learn the right way to have your blood pressure measured and tips for keeping track of it at home.

One in three Americans, or about 75 million people, has high blood pressure, and nearly half of them do not have it under control.1 In fact, about one in six people with high blood pressure do not know it.2
High blood pressure raises your risk for heart disease and stroke—the leading causes of death for Americans.

What Affects a Blood Pressure Reading?

Many things can affect a blood pressure reading, including:

  • Nervousness at having your blood pressure taken. This is called “white coat syndrome.” As many as one in three people who have a high blood pressure reading at the doctor’s office have normal blood pressure readings outside of it.3
  • What you ate, drank, or did before your reading. If you smoked, drank alcohol or a caffeinated beverage, or exercised within 30 minutes of having your blood pressure measured, your reading might be falsely high.4
  • How you are sitting.5 Crossing your legs and letting your arm droop at your side rather than rest on a table at chest height can make your blood pressure go up.

A reading that underestimates your blood pressure might give you a false sense of security about your health. But a reading that overestimates your blood pressure might lead to treatment you don’t really need.

Man checking his blood pressure

Your arm should be supported and at chest height to help ensure an accurate blood pressure reading.

The Correct Way to Measure Blood Pressure

Learn the correct way to have your blood pressure taken, whether you’re monitoring it at home or at the doctor’s office. Use this checklist:

  • Don’t eat or drink anything in the half hour before you take your blood pressure.
  • Empty your bladder before your reading.
  • Sit in a comfortable chair with your back supported for at least 5 minutes before your reading.
  • Put both feet flat on the ground, and keep your legs uncrossed.
  • Rest your arm with the cuff on a table at chest height.
  • Make sure the blood pressure cuff is snug but not too tight. The cuff should be against your bare skin, not over clothing.
  • Do not talk while your blood pressure is being measured.

If you are keeping track of your blood pressure at home, try these additional tips6:

  • Use a chart, notebook, or app to keep track of your readings.
  • Always take your blood pressure at the same time every day.
  • Take at least two readings, 1 or 2 minutes apart.

Lowering Your Blood Pressure

You can lower your risk for heart disease and stroke by lowering your blood pressure levels.

  • Reduce how much sodium (salt) you eat. Sodium raises blood pressure. Most sodium is found in processed and prepackaged foods. Eat less sodium by cooking at home. Use lots of fresh vegetables and season with spices and lemon juice instead of salt. Learn more about how salt affects your blood pressure. pdf icon[663 KB]
  • Stay physically active. Exercise helps the most important muscle in your body: your heart. By getting enough physical activity each week, you keep your heart and blood vessels healthy and your blood pressure lower. Most adults should aim for at least 150 minutes of moderate physical activity each week. Moderate activities include bicycling or taking a brisk walk.
  • Quit smoking. Cigarette smoking causes your blood vessels to thicken and narrow. This raises your blood pressure—and your risk for heart disease.7 If you smoke, learn ways to quit. If you don’t smoke, don’t start.
  • Take your medicines as directed. If you have medicines for high blood pressure, take them the way your doctor has prescribed. About one in four adults older than 65 with Medicare Part D do not take their prescribed blood pressure medicines. This puts them at risk for stroke and heart problems.8 Watch a video on blood pressure medicine to learn more.external icon
  1. CDC. (2017). High blood pressure.
  2. Benjamin EJ, Blaha MJ, Chiuve SE, et al. Heart disease and stroke statistics—2017 update: A report from the American Heart Associationexternal icon. Circulation 2017;135(10):e146–e603. doi: 10.1161/CIR.0000000000000485.
  3. Gorostidi M, Vinyoles E, Banegas JR, de la Sierra A. (2015). Prevalence of white-coat and masked hypertension in national and international registriesexternal icon. Hypertens Res 2015;38(1):1–7. doi:10.1038/hr.2014.149.
  4. American Heart Association. (n.d.). Blood pressure measurement instructions. pdf icon[142 KB]external icon
  5. American Medical Association, Johns Hopkins University School of Medicine. (2015). Technique quick check: Common problems that account for inaccurate blood pressure measurement. pdf icon[103 KB]external icon
  6. Murakami L, Rakotz M. (2015). Improving health outcomes: Blood pressure. In: Daniel D, Prall M, editors. Self-measured blood pressure monitoring program: Engaging patients in self-measurement, 1st edition. American Medical Association and the Johns Hopkins University School of Medicine.
  7. CDC. (2017). Tips From Former Smokers™ campaign: Smoking and heart disease and stroke.
  8. CDC. (2016). Vital signs—Blood pressure control.