How to Read a Blood Pressure Monitor

How to interpret the three key metrics you see on your device—plus tips on getting accurate readings

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Person using a blood pressure monitor. Photo: Getty Images

Getting an accurate reading on a home blood pressure monitor requires a certain amount of effort. First off, you need an accurate device. Resources like CR’s blood pressure monitor ratings and the American Medical Association’s Validated Device Listing can help you find a good one. 

Then there are important steps to take, once you have your monitor, to make sure your readings are accurate. (Read more about that below.)

But what do the readings on a blood pressure monitor mean? We break down the three key metrics displayed on home blood pressure monitors.

Illustration by: Sharon Seidl

Which Measurement Is Most Important?

It’s most useful to track systolic blood pressure, and systolic pressure is the basis for most guidelines, says Willie Lawrence, MD, chairman of the oversight committee of the American Heart Association’s National Hypertension Control Initiative and medical director of the Center for Better Health and Cardiovascular Wellness in Benton Harbor, Mich.

Increases in systolic pressure are more consistently associated with increases in disease risk when compared with diastolic blood pressure, according to the latest guidelines on blood pressure targets

More on measuring blood pressure

Still, elevated diastolic pressure is also a risk factor for disease. If you have, for example, “normal” systolic pressure but “stage 1” diastolic hypertension, you would be diagnosed with stage 1 hypertension, according to current guidelines

As for your pulse reading, there’s no hard and fast ideal number for your heart rate. It’s considered an indicator of how efficiently your heart can pump blood through your body, so a lower heart rate while at rest is generally an indicator of better physical fitness. But Lawrence says there’s no definitive target for it the way there is for blood pressure. Still, when you track it over time, changes in your normal heart rate could help indicate a heart condition, according to the American Heart Association

Get an Accurate Reading

At-home blood pressure monitoring can give an important picture of your cardiovascular disease risk. But using the proper technique to get an accurate reading is crucial, Lawrence says. “Otherwise the blood pressures you get at home, they don’t mean anything.”

Procedures to follow include:

  • 30 minutes before you measure, don’t smoke, consume caffeine, or exercise.
  • Use the bathroom before you measure. Wear a short-sleeved shirt—you should not measure your blood pressure over your clothes.
  • Sit with your back straight and supported in a chair, with your feet flat on the floor. Your arm should be supported on a flat surface like a table or solid chair arm, with your upper arm at heart level. 
  • Sit quietly without talking (or texting) for 5 minutes before a measurement.
  • Measure at the same times twice every day; take two or three readings at a time, a minute apart.

Top-Scoring Blood Pressure Monitors

Catherine Roberts

As a science journalist, my goal is to empower consumers to make informed decisions about health products, practices, and treatments. I aim to investigate what works, what doesn't, and what may be causing actual harm when it comes to people's health. As a civilian, my passions include science fiction, running, Queens, and my cat. Follow me on Twitter: @catharob