a blood pressure monitor

Visit a doctor’s office for almost anything that ails you and the chances are good you will have your blood pressure measured. That’s because it is an essential diagnostic procedure to detect hypertension, a common condition that puts people at risk of heart and kidney disease.

Considering that millions of people have their blood pressure checked every day, it is surprising that this measurement can be so tricky. Mistakes are far more common than most people realize, and the consequences of inaccuracies can be serious.

Falsely Positive Blood Pressure Readings:

A false positive, that is, a reading higher than the true blood pressure, could lead to unnecessary medication. Drugs can be expensive and may have unpleasant side effects such as dizziness, fatigue, impotence, cough or swollen feet.

Falsely Negative Blood Pressure Readings:

A false negative, a reading lower than the actual blood pressure, could lead to undertreatment. This puts people at risk of heart attacks, strokes or kidney disease.

Blood Pressure Cuff:

What causes such errors? According to experts writing in the Journal of Human Hypertension (July, 1997), a common source of error in measuring blood pressure is using the wrong size cuff. A cuff that is too small for a large arm can result in a blood pressure reading higher than it should be. When was the last time a nurse or doctor actually measured your arm circumference and then selected a blood pressure cuff that was designed for your sized arm? Most of the time you will be measured with the device that is handy.

Too Much Talking Going On:

Another potential problem is talking. Not infrequently a nurse or physician taking blood pressure will strike up a conversation, thinking that it may put the patient at ease. On the contrary, talking during blood pressure measurement can easily raise the reading 10 to 20 points.

When we first heard about this phenomenon we were skeptical. How could seemingly casual conversation affect blood pressure? Research by J.J. Lynch, however, has revealed that when someone talks while having her blood pressure measured can have a profound impact on the outcome. In some cases blood pressure can go far higher than 20 points and could result in a false diagnosis of hypertension.

Arm Position Is Important:

The official position of the American Heart Association is that the “Patient’s arm should be supported at heart level.” If your arm is allowed to hang down lower than heart level the reading is likely to be falsely elevated. If, for some odd reason, your arm is allowed to rest above heart level the reading could be falsely lowered.

You might think this fundamental recommendation from the AHA would always be followed. You would be wrong. It never fails to amaze us that most chairs in exam rooms do not have an arm rest at heart level. Unless the nurse or doctor actually supports your arm at the correct level while measuring your blood pressure, chances are good that your arm will be lower than appropriate and that will falsely elevate the reading.

Another problem that is rarely considered by health professionals is a cold examining room. If you are wearing one of those flimsy little paper gowns, feeling chilly and exposed may increase blood pressure more than 10 points.

White Coat Hypertension:

And speaking of uneasiness, “white coat hypertension” affects up to one patient in five. These are people whose blood pressure skyrockets when the doctor walks into the room. Some people with normal blood pressure may have office readings as high as 180/110.

Many doctors and nurses have a hard time accepting this concept. After all, how could their mere presence cause a patient’s blood pressure to spike? Health professionals like to think of themselves as kind, compassionate healers, not scary threats to a patient’s well being. Nevertheless, many people become very anxious the minute a doctor knocks on the exam room door.

Anyone who is susceptible to this phenomenon should be measuring blood pressure at home. There are affordable, easy-to-use digital machines that allow people to keep a diary of their readings over the course of several weeks or months. This permits the physician to get a broader understanding of their blood pressure in a variety of settings. The home machine should always be checked against the equipment in the doctor’s office to make sure it is accurate.

Anyone who would like additional details about proper blood pressure measurement, white coat hypertension and drugs used to treat high blood pressure may find our Guide to Blood Pressure helpful. It has a detailed list of dos and don’ts of measuring and managing blood pressure. Here is a link to all our guides.

The People’s Pharmacy Perspective:

Measuring blood pressure is harder than it looks. Getting it right requires good technique and careful monitoring over time. This facilitates the best possible treatment for those who need it and protects others from unnecessary medication.

Share your own experience with blood pressure measurement below and please vote on this article at the top of the page.

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  1. Carol

    I too, when taking my BP at home take 3 readings the first us high (158/75) and with each reading comes down at least 15-20 points systolic (top number). Can’t figure this out, am on metoprolol, norvasc and losartan

  2. Victor

    I believe that bp measurements made using either a mercury manometer or dial gage are fairly inaccurate because not all medical personnel are adept at reading a moving scale at exactly the right moment of pressure drop. Also, they have to remember two different numbers to document while they may be distracted by the patient talking to them or by some other distraction.

    I spent 32 years working as a measurement instruments technician. My work involved all types of transducer measurements and recording, including pressure measurements. Electronic pressure measurement devices are highly accurate, repeatable, and not subject to differences in personnel skill level. I say it is time for the medical profession to apply some modern technology to blood pressure measurement.

    • mary

      My husband was at the doctors his first reading was 158. The doctor was very concerned but my husband said wait. After they had talked my husband asked her to do another reading it was 101, this was 15 minutes later, he dropped 58 points in 15 minutes.

  3. Linda

    I have excruciating pain when having my blood pressure taken. I took simvastatin for about 20 years before learning that it causes painful body issues. I could hardly get up from a chair. My hips hurt when in bed and even walking (same for my husband). On medication my bp was 136…off was 180. After being off meds I don’t have the old pains except for the bp cuff causing UNBEARABLE pain. My doctor scoffs that simvastation causes muscle damage but I strongly disagree. He thinks everybody needs statins but if they cause body pain, I disagree. So I actually don’t know an accurate bp reading for which I take metoprolol, which makes me wonder if I am overmedicated. I am 76 yrs old.

  4. d

    Many people manually bchecking bp let the pressure out very fast. As a result it is difficult for them to get an accurate reading. The automated machines tend to be more accurate for me. I have had complaints from doctor’s of white coat syndrome, inaccurate machines, etc… But the stroke says i probably have high blood pressure.

    • Pixie

      I also have extreme pain when BP is measured and the auto BP cuffs are most painful so I have it measured on my forearm, which still hurts. Also, statins are bad drugs. Better try natural treatments. Find a naturopathic Doctor. They are MDs who do not drug with Big Pharma. I take a diuretic for edema every few days. That is one pill. I am 77 and avoid Doctors and meds like the plague. Never had a flu shot or pneumonia vaccine. I think that they are trying to get everyone on drugs.

  5. Fred
    South Carolina

    So when my doctor or any nurse manually takes my BP they get about 130/80 not bad for a 67 year old but when they use the automatic machines (the expensive doctors office one) we get 158/85. Almost always 20 points higher. Now I have VT’s Ventricular Tachycardia so I have no idea if that screws with the machine or not; but it happens every time.

    Last week, I took my BP with my home cheap BP automatic device and I got 148/87 but an hour later my doctor taking it by hand gets 130/81. It does not matter if its at a hospital or a doctors office with very expensive machines or the cheapo home types when they take it manually its 20 plus points lower.

  6. ann

    Am from Kenya Africa.Almost all digital bp machines I have used(many for am a nurse) give high readings compared to mercury manual,sometimes a difference of 20 points diastolic.
    I pointed this to my supervisor but the hospital does not have enough staff to manually check bp.
    I pains me to realize so many people are being treated for a condition they don’t have.
    What a shame

  7. Jean

    Using an automatic BP machine, sitting and arm height correct, I will take my BP 3 times, waiting a few minutes between takes. 1st time a bit high in the 140’s, 2nd reading in high 120’s, 3rd reading is always lower, in the high 110’s. Why the different readings when everything is the same and which of the 3 readings should I record on my chart?

  8. Joyce

    I have the same problem in having a much higher reading in the doctors office. Many times readings were done incorrectly. Standing, arms hanging down etc
    . etc. When I take it later at home or even in drugstore its much lower.

  9. BJ
    Dallas, TX

    At the senior assisted living where we live the staff member responsible for dispensing meds and taking BP has even had me standing in the hallway while she took my BP. So much for using proper protocol !

  10. Virginia
    Tulsa, OK

    When the assistant in the doctor’s office takes my BP it hurts so badly that I wonder if that, in itself, makes my BP skyrocket. They pump it up again, and still it hurts really, really badly. Anybody else have this problem?

  11. Toni

    My bp is always ridiculously high anytime I am at my doctor’s office. In fact, I start having palpitations as soon as he is puting the strap on! But at home with my Omron bp monitor I get normal readings. How do I overcome this phobia of my doctor taking my bp?

  12. ANDREW

    It’s a good idea to buy two monitors and compare the readings from each, if they’re similar they should be accurate. This also enables the B.P. in both arms to be measured simultaneously – there should be a difference of less than 10 for the systolic pressure.

    • Fred

      Does not matter how many machines I use. If its the automatic ones I get a reading of 20 points higher than taken manually!

  13. Mark
    Sydney - Australia

    I reckon these Automatic BPM are a real scam.

    3 years ago i didn’t feel well.

    1) I visited my local pharmacy and they suggested a blood pressure test using their OMRON BPM. It was high (around 140/90). They send me to my Dr.

    2) My Dr, using his own OMRON BPM, found my BP high… He gave me 1 pill (Coversyl).

    3) Months later my Dr gave me a second pill (Zanidip – I think).

    4) Months later my Dr gave me a third pill (Minipress).

    5) I bought my own OMRON … measured High (~ 140 / 90) STILL after all those pills!!!!

    6) I bout a second OMRON … for the office… still measure HIGH.

    Numerous side effects ….

    Along the way I stop one of the pills on my own will. NO CHANGE

    I requested to my Dr to be sent to a BP specialist. After 3 visits and numerous tests using MANUAL BPM and other computerised equipment + ECG, etc etc etc… over the 3 visits my BP was even below normal (~ 117/78) – measured numerous times over 3 visits.

    I have now stopped a second pill. Feel much better … less side effects….

    I will soon stop the 3rd and final pill.

    I reckon these FREE machines given to pharmacies in Australia, Free to Doctors and Free to Surgeries are a real scam… forcing Drs to prescribe pills and creating huge side effects (obviously that more pills will cure). Good Lord!!!!

  14. D.B.

    Just after I entered menopause, my doc felt I had high blood pressure – even though readings were taken as many have described above. (I was having lots of trouble sleeping at the time.) She put me on HCTZ. After a couple of days, I was feeling really awful. Dizzy, nauseated, shaky, no energy. After 4 days, my heart was racing – 120 beats/minute – and I was just relaxing in a recliner reading the newspaper.

    I called to report the side effects and was told by the nurse that these side effects were not listed under this medication. I let her know that they were listed in the info I got from the pharmacy. After talking with the doctor, the nurse said they’d switch me to a Beta Blocker, until I reminded her that I have asthma – so a Beta Blocker would not be a good idea for me! I think my electrolytes were completely out of balance. No one ever suggested a smaller dose or anything else.

    I recently worked with a functional medicine practitioner to figure out why I couldn’t lose weight and was still very fatigued. Since January I have lost about 25 pounds of fat and have healed my esophagus of Barrett’s and healed SIBO and have lots less inflammation, and guess what! My blood pressure is much better. Funny, though, the FM practitioner never takes my blood pressure the same way twice and often does it incorrectly, too! I still take my own blood pressure at home a couple times a week, just to keep my eye on it.

  15. Rufina

    My Omron is so inconsistent. It will start with a high reading, i.e., 133/70, and as I keep taking more readings, alternating between my two arms, the reading gets lower to about 113/70. Now that confuses me. 133 is considered hypertensive for my age, 48, but not 113. I do not use the battery-powered omron. I plug it to an outlet thinking it’ll be more consistent and accurate with stable flow of power. My arm is rested and supported at heart level when i do this. I need to take at least 6 readingd every single session just so i get a pair of readings closest to each other. I’m so frustrated with Omron now ; (

    • Sue

      That’s not hypertensive, it’s the lower number that’s relevant, yours is perfect and consistent.

  16. John
    Central oregon

    I was diagnosed with high blood pressure. The doctor then gave me a medicine to bring it down it was making me dizzy all the time. So I got my own blood pressure machines I got two of them one on my wrist and the other on my arm.
    According to the two little machines I do not have high blood pressure, and I record them on the app on my iPhone to show the doctor every time I go in.

  17. Deepa

    I just received my Omron BP monitor. My husband had a correct reading and so did my fil. I have normal BP but my reading and pulse rate declare that I should be having some heart problem. It is ridiculous especially because a normal BP test by doctor says normal. I wonder if the cuff is too large for my arm.

  18. Wayne

    While I have not investigated the details, I have found that readings taken shortly after exercize but feeling rested and with a nortmal pulse can be substantially lower than a hour later.

  19. Marie

    I also agree with Gw about the doctors office. There is no support given to the arms at all and the feet are dangling from the examining table. Can I ask a question here? When someone is taking blood pressure measurement twice, which one is the correct one. Thank you for this post and God bless you, Marie

  20. Alice

    Most doctors and nurses don’t even know where the brachial artery on the inside of the arm is either. Most doctors and nurses don’t consider the shape of the arm. There has only been a very few times that either a doctor or nurse has taken a blood pressure measurement that were vary close to mind. I also question about how good their hearing is as well. I started taking my blood pressure about 20 years ago because I didn’t trust the doctor’s readings. I think most doctors and nurses need to take training how to take blood pressure properly.

  21. Debbie
    Houston, TX

    I had my blood pressure checked at an endocrinologist’s office. When the young woman finished I asked her what the reading was. She told me it was 124. I asked her 124 over what? Her reply was it is just 124 that is all!

    I have been in many doctor’s offices that claim my bp normal, which is so far from the truth. I have a great deal of problems with my blood pressure and it hasn’t been normal in at least 20 years. Unfortunately this effects the medical care you get.

    My suggestion is to keep a detailed record of your bp in a notebook and bring it in with you. It is important to show that this isn’t a new event, that this has been ongoing.

  22. Laurel

    I am able to donate blood regularly, and they write down the blood pressure readings for me. I take these readings with me to the doctor’s office as proof that normally my readings are acceptable. The folks at the Red Cross do take the readings with my feet on the floor, arm on a table at nearly heart level, quietly, and with a large enough cuff. I trust their readings. The waiting areas are quiet.

    I do not know if they take drop-ins, but if you have one close and are concerned, it wouldn’t hurt to ask. They certainly have no vested interested in the results.

    • Jeri
      Spokane, WA

      Thank you for this interesting suggestion!

  23. Grace

    I was diagnosed with high BP 30 years ago and have been on medication ever since. A double mastectomy and removal of all lymph nodes in both arms has resulted in lymphedema in both arms — thus, I cannot have blood pressure (or blood work/infusions, etc.) done on my arms. While one person at our cancer center used to take BP near my calf, my primary care office has pretty much stopped monitoring my BP at all. No matter where I go to my — gastroenterologist, gynecologist, urologist, heart specialists, surgeons, neurologist, endocrinologist etc. — no one has ever heard of not using arms to check for BP, they either skip it altogether or several struggle together to come up with another place to put a cuff……..

  24. LOUIS

    In addition to no talking, I have found that no body movement–head, arms, legs and shifting around will result in a most accurate reading, whether at home or in the doctor’s office.
    differences of 10 to 40 points higher occur.

  25. SH

    My husband has HBP and has this Omron Blood Pressure monitor. Omron HEM-711AC Automatic Blood Pressure Monitor with IntelliSense. Every time he goes to the doctor his blood pressure readings are much lower than what he gets with the machine. Changing the batteries helped some, but the readings were still 15 to 20 points higher with the machine. We bought a regular Sphygmomanometer and a stethoscope and started doing it manually instead and his BP is much lower than any of the measurements the machine was taking. I highly advise anyone with a machine to take your BP manually occasionally to check the accuracy of the unit they are using. Ours was reading so high it was scary at times.

    • Alice

      I stopped using digital sphygmomanometers for the reasons you mentioned. The Main Artery Pressure (MAP) and the Pulse on these digital machines work together to determine the systolic and diastolic. You will find that the pulse that the machine gives is much higher then if you take your pulse manually using your finger and a watch with a second hand, especially if you take your blood pressure in the morning. The differences between the 2 pulse readings can be as little as +/-4 to cause the systolic and diastolic to be way off. I have been using a manual sphygmomanometer ever since I found out how these digital things work and the reason they are off.

  26. carol

    I always take my BP at home for the week prior to my doctor visit and give her the readings. As a registered nurse, I am appalled by what I see when the assistants take BP’s. You are sitting on the end of the exam table with your legs dangling and your arm is hanging down. They also never seem to put the cuff on tight enough to pick up an accurate reading. My brachial pulse is difficult to palpate so the cuff needs to be snug to pick up the pulse. I have had readings of 180/110 with the cuff is not even touching my skin but when the cuff is on snug the reading comes down to 120/80. The assistants also don’t allow for a 10 minute rest period after escorting you to the exam room. I bet over half of people on drugs for hypertension have normal blood pressure,

  27. gw
    So Cal

    This blog should be required reading for every nurse and pa that takes blood pressures on a daily basis. I too, have never had my bp taking correctly at a doctor’s office. The numbers are always much higher than what I get on my home device.
    Also, where is the real science/research that shows taking medication to lower bp does more good than harm? Should treatment be based on your home average or your doctor’s office first reading? It seems that millions of people are being over-prescribed meds based on faulty testing.
    It is really disturbing that such a simple test is so incompetently performed almost universally by medical “professionals.” It makes me worry about whether other medical testing is performed safely and correctly.

    • Allan

      Allan B

      This was the most informative article I have ever read, relating to b/p. The viewers comments, in some cases are similar to mine. I also purchased an automatic b/p machine and find that I need to take three readings before I get a stable reading. The viewers who suggested using or comparing the readings with a manual method is a great idea.

  28. Mary

    My blood pressure was always high when I went to the doctor’s office. My doctor, who knew that, took it again before I left the office, and it had invariably gone down considerably. Mary M.

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