What's the Right Way to Measure Blood Pressure?

If you’ve ever tested your blood pressure at home, you’ve probably discovered that you don’t get a consistent number. Numbers can jump up or down 20, 30, or even 40 points in one day — sometimes in just a few minutes. It’s different at different times of the day, and no two days are the same.

If you monitor your blood pressure at home, you might also discover that many health care providers don’t follow the guidelines for properly taking blood pressure readings. Guidelines featured in a video by the American Academy of Family Physicians instruct home measurers to follow these steps:

  1. Don’t eat or use caffeine, alcohol, or tobacco products 30 minutes before measuring your blood pressure.
  2. Go to the bathroom and empty your bladder before measuring your blood pressure.
  3. Rest for 3 to 5 minutes before measuring your blood pressure. Do not talk.
  4. Sit in a comfortable position, with your legs and ankles uncrossed and your back supported.
  5. Place your left arm, raised to the level of your heart, on a table or a desk, and sit still.
  6. Wrap the cuff smoothly and snugly around the upper part of your bare arm. The cuff should fit snugly, but there should be enough room for you to slip one fingertip under the cuff.
  7. Check to see that the bottom edge of the cuff is 1 inch above the crease of your elbow.

How Do You Know if You Have High Blood Pressure?

Among the uncertainties about blood pressure, there is a reliable option in the quest to discover a number you can trust: It’s called ambulatory monitoring. If your physician advises this option, you’ll wear a device that measures your blood pressure at half-hour intervals for 24 hours. According to the United States Preventive Services Task force, a federally sponsored group that draws up medical guidelines, 12 to 48 hour monitoring is the preferred way to determine a diagnosis of high blood pressure.

In an effort to reduce deaths from cardiovascular disease, the NHLBI initiated a study called Sprint to answer the question, “Will lower blood pressure reduce the risk of heart and kidney disease, stroke, or age-related declines in memory and thinking?” Sprint researchers are following 9,000 adults with high blood pressure; half are expected to get their systolic blood pressure below 120, and the other half below 140. Study results should be out in 2017.

In the meantime, the optimal blood pressure number is still somewhat of a mystery.