There's a reason why your doctor takes your blood pressure nearly every time you step into their office: It's a quick and painless way to get a snapshot of your heart health. But that doesn't mean it's the best way.
That's because blood pressure can change based on a variety of factors, including pain, temperature, physical exertion and even doctor's visits.
So how do you avoid these potentially false positives and false negatives? Do DIY testing.
If you can't imagine yourself sitting at your kitchen table manually pumping up a blood pressure cuff, don't worry. The newest crop of over-the-counter monitors are wireless, digital and easier than ever to use. Here's what you need to know before buying one.
How do wireless blood pressure monitors work?
Every time your heart beats, it pumps blood throughout your circulatory system, putting pressure on the walls of your blood vessels. Blood pressure monitors typically measure the force of this pressure in millimeters of mercury (mmHg) using something called a sphygmomanometer.
A sphygmomanometer inflates a rubber cuff that's wrapped around your finger, wrist or upper arm until no blood can flow through the brachial or radial artery. When the air is slowly released from the cuff, blood starts to flow through the artery again, creating a pounding sound that can be detected with a stethoscope or an algorithm.
Your systolic blood pressure is the pressure reading noted when this pounding sound first starts. Your diastolic blood pressure occurs when it stops.
Digital wireless blood pressure monitors will display your results on the main unit, in an accompanying smartphone app -- where you can view graphs and trends and sync the data with additional apps such as Apple Health -- or both.
The measurement is written as two numbers. The top is your systolic blood pressure (the pressure when your heart beats). The bottom is your diastolic blood pressure (the pressure between beats). A healthy blood pressure range is from 90/60 to 120/80 mmHg.
Who are wireless blood pressure monitors for?
The American Heart Association (AHA) and other health organizations recommend that people with high blood pressure measure it at home, a practice known as self-measured blood pressure (SMBP) monitoring or home blood pressure monitoring (HBPM).
Blood pressure naturally rises and falls throughout the day but chronically high readings (at least 130/80 mmHg) can be a sign that your heart is strained and working too hard, a condition known as hypertension. High blood pressure often has no obvious signs or symptoms, which is why it's known as the "silent killer." Over time it can increase your risk of heart attack, stroke and heart and kidney failure.
SMBP can help rule out "white coat hypertension," in which a person's blood pressure is high in the doctor's office but normal in daily life, and masked hypertension, in which a person's blood pressure is normal in the doctor's office but elevated in daily life.
"Taking blood pressure as part of every routine office visit is, at best, not necessary, and at worst, may lead to inferences about a person's hypertension status that are incorrect," says Yale Medicine cardiologist Erica S. Spatz, MD. "Ideally we would be using home blood pressure readings to screen for and monitor hypertension. These readings are more indicative of a person's true hypertension status and better associated with the outcomes we care about, namely heart disease, stroke and kidney disease."
It can also inspire a stronger sense of responsibility for your health and better control over your situation. Research shows that adults with hypertension who monitor their blood pressure at home (with or without additional support) are more likely to successfully lower their readings compared with usual care.
But you don't have to have hypertension to benefit from using wireless blood pressure monitors. They can also detect hypotension, or chronically low blood pressure (below 90/60 mmHg, though this can vary from person to person). In some people, hypotension can cause no problems. In others, it can signify that something more serious, like heart failure or severe infection, is going on, especially if it's accompanied by symptoms such as dizziness, fainting or nausea.
"In the elderly or in people who are frail, we are particularly concerned about falls," says Spatz. "So it's important to assess for low blood pressures, especially with standing."
Whether you have high or low blood pressure, SMBP monitoring can help both you and your doctor catch issues early and track whether any medication or lifestyle interventions are working, all while cutting back on office visits.
What if I don't have high or low blood pressure?
People who are otherwise healthy but at an increased risk of developing hypertension and cardiovascular disease, such as people with a family history of early hypertension or women with a history of preeclampsia during pregnancy, can also benefit from SMBP tests. "Monitoring home blood pressure from time to time can provide an early window into elevated blood pressures, giving higher-risk people the feedback they need to avert the onset of hypertension," says Spatz.
Totally healthy? Occasional SMBP can still be helpful. "Knowing how your blood pressure responds to periods of stress or lack of sleep can provide important mind-body connections, and may motivate you to take a more holistic approach to your cardiovascular health," says Spatz.
Just one caveat: Some people are unable to get an accurate blood pressure reading using these devices because of illness, birth defects or conditions such as an irregular heartbeat, so talk to your doctor about whether SMBP is right for you.
What to look for in a wireless blood pressure monitor
Wireless blood pressure monitors are widely available without a prescription, but it pays to be choosy.
The AHA only recommends the use of upper-arm cuff oscillometric devices that have successfully passed validation protocols, according to a 2019 scientific statement in medical journal Hypertension. (Oscillometric devices automatically detect and analyze pulse waves versus relying on someone to listen with a stethoscope.)
Wrist-based monitors, although convenient, aren't recommended. Studies show they're more likely to produce inaccurate readings, both because they're highly sensitive to body position (leading to people using them wrong) and because arteries at the wrist tend to be narrower and not as deep beneath the skin.
Both the British and Irish Hypertension Society and Dabl Educational Trust websites maintain a list of validated blood-pressure monitors, including wireless upper-arm cuff oscillometric devices. You can also take your device to your doctor's office and compare its readings to those taken by your physician. (If you're buying a monitor for a senior, a pregnant person or a child, make sure it's validated for this specific use as well.)
After accuracy, the size of the cuff is of utmost importance. Cuffs that are too large or too small can produce inaccurate readings. The AHA recommends the following circumference-based sizing guidelines, but you can also have a doctor or pharmacist help fit you for one.
Arm Cuff Sizing Guidelines
|Arm Circumference||Usual Cuff Size|
|22–26 cm||Small adult|
|35–44 cm||Large adult|
typical range in price from approximately $30 to $100, though a higher price tag doesn't necessarily equate to higher quality. If you're willing to spend a little more for extra bells and whistles (your insurance may help you with the cost), keep an eye out for these helpful features:
- An automatic monitor. Look for a device that lets you initiate a reading with the press of a button.
- Customizable readings. Some devices will take three consecutive readings and automatically calculate the average, according to AHA recommendations.
- A digital readout. Whether it's displayed on the device or in an accompanying app, the measurement should be clear and easy for you to read.
- Shareability. If you're managing an existing condition, devices that store your readings, along with the dates and times they were taken, and easily allow you to export or share them with your doctor are best.
How to use a wireless blood pressure monitor
"Checking your blood pressure at home should not be burdensome," says Spatz. "I recommend that patients with stable hypertension take out the cuff the week prior to their appointment and measure twice a day so we can use these measurements to guide our management. Unless we are making active changes to the treatment plan, patients can put away the cuff until the next visit."
You should talk to your doctor about what routine is right for you, but in general, here are some best practices:
- Measure your blood pressure twice a day. Ideally at the same time each day. Take the first measurement in the morning after you go to the bathroom but before you eat, exercise, drink anything caffeinated or take medication. Take the second measurement before dinner or least 30 minutes after consuming food, alcohol, caffeine or tobacco. Again, use the bathroom first, as a full bladder can slightly increase your blood pressure.
- Get comfortable. You should be seated in a chair, back supported with your legs uncrossed and feet flat on the floor.
- Position your arm properly. Always use the same arm to take your blood pressure (If one arm tends to produce a higher reading, use that one). Rest it on a flat surface, such as a table, with your upper arm at heart level (prop it up with a pillow if it's too low). The cuff should be wrapped snugly, but not tight, around the bare skin of your upper arm, directly above the bend in your elbow.
- Sit quietly. Take five minutes to get calm and relaxed in this position. Try not to think about anything stressful.
- Take two to three readings. Keep your body in the same position and try not to talk while your device is taking a reading. If your device doesn't automatically record your result, write it down along with the time. Leave the cuff in place deflated, wait one to two minutes and then take another reading. Repeat this process a third time and then average the results. It's normal for your blood pressure to be about five points lower at home than at the doctor's office.
When to see a doctor about your blood pressure
"A blood pressure less than 120/80 mm Hg is ideal," says Spatz. But your doctor will discuss what an appropriate number for you is.
If you get a single reading higher or lower than that number, don't be alarmed. Take additional readings using the guidelines above.
If your measurements suddenly spike above 180/120 mm Hg, the AHA recommends waiting five minutes and testing again. If your blood pressure is still exceedingly high, contact your doctor immediately.
If your blood pressure remains higher than 180/20 mm Hg and you're experiencing symptoms such as chest pain, back pain, shortness of breath or a change in vision, call 911.
If your blood pressure is lower than normal and you're experiencing dizziness, lightheadedness, nausea or anything else out of the ordinary, contact your doctor.
"While monitoring blood pressure at home can be done independently with some simple guidelines about what is normal, it is still important to have a trusted doctor or nurse available to help to interpret the readings," says Spatz. "Blood pressure varies tremendously throughout the day, and there may be spikes or dips in the blood pressure which may or may not be clinically meaningful."
Note: The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.