To determine whether you have high blood pressure or hypertension, a medical professional will take a blood pressure reading.
How you prepare for the test, the position of your arm, and other factors can change a blood pressure reading by 10% or more.
This factor could be enough to hide high blood pressure, start you on medication that you don’t really need, or cause your doctor to incorrectly adjust your medication.
Many patients with high blood pressure have their own blood pressure monitoring equipment that they use at home. Obviously, it would be helpful to know how to accurately read your own blood pressure. It is also beneficial for optimal medical care if you keep a daily monitoring journal/notebook to note your blood pressure to show your doctor at your future appointments.
The American Medical Association (AMA) worked with Johns Hopkins University on a program to improve blood pressure control. Part of that effort involved promoting protocols to help accurately measure blood pressure. The AMA produced a one-page graphic entitled, “7 Simple Tips To Ensure an Accurate Blood Pressure Measurement,” which has helped inform physicians, medical professionals and patients that are monitoring their blood pressure at home:
- Putting the cuff over clothing, rather than a bare arm, can add 10-40 mm Hg to a measurement.
- Having a full bladder can tack on 10-15 mm Hg.
- Talking or having a conversation: an additional 10-15 mm Hg.
- Failing to support the arm at heart level can add 10 mm Hg.
- An unsupported back can increase a measurement by 5-10 mm Hg. That same range applies to feet left dangling from an exam table or high chair.
- Crossing legs means an extra 2-8 mm Hg.
In addition here are some other things you can do to ensure a correct reading:
- Don’t drink a caffeinated beverage or smoke during the 30 minutes before measuring.
- Sit quietly for five minutes before measuring.
- Measure your blood pressure twice, with a brief break in between. If the readings are different by 5 points or more, do it a third time.
Note: it’s a good idea to measure your blood pressure in both arms at least once, since the reading in one arm (usually the right) may be higher than that in the left. A 2014 study in The American Journal of Medicine found average arm-to-arm differences in systolic blood pressure of about 5 points.