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 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 common, and the consequences of inaccuracies can be serious.

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.

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.

What causes such errors? According to experts writing in the British Medical Journal (April 14, 2001), one of the most common sources 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.

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 raise the reading 10 to 20 points.

Other problems include the wrong arm position or a cold examining room, especially if you are wearing one of those flimsy little paper gowns. Feeling chilly and exposed may increase blood pressure more than 10 points.

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. The experts writing in the British Medical Journal note that some people with normal blood pressure may have office readings as high as 180/110.

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. And should you want to know some secrets about common mistakes in treating hypertension, check out our book, Best Choices From The People’s Pharmacy.

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.

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  1. Betty
    Hamburg, NY

    If the blood pressure cuff is put on really tight, can that give a wrong reading?

  2. Jessica
    St. Petersburg

    I don’t think there is a right and/or wrong answer for how to take a individuals BP. For me it’s nearly impossible to even get a reading much-less a accurate reading, when my feet are on the floor but this is what the nurses and ma’s were taught to do. And the heart inst says is the right thing to do, so that leaves me in a really bad position when seeing anyone new or going to a clinic or the hospital! I found this blog trying to find out why the we are supposed to put are feet flat on the floor but no luck! Does anyone have the answer? Thanks…

  3. arul

    I am 40 yrs old male diagnosed hypertension 20 yrs back (140/90). Due to fear of side effects i avoided any medicine. Whenever I take reading in clinic or hospital my readings are always high (150/100). I did many efforts to control BP in so many natural ways (quitting smoke, cutting salt, exercise etc and so on) but in vain.
    I am afraid to go for any blood test(renal liver lipid profile). I don’t have any courage to face if something goes wrong (The fact of the effect longstanding hypertension is nightmare for me) I spend most my time worrying about this. Couple of years back I bought a Sphygmomanometer to test my self at home but it was not easy. But recently I got a amron digital automated bp machine which is very easy to take reading my self.
    To my big surprise the readings are always normal 120/80. I became very much happy and there is no limit for my joy… I became very much obsessed with the new device and taking reading several times. It always shows normal reading only few times it goes over 130/85. But I didn’t get any chance try with others. I feel there is nothing wrong with my device because there is not much variation in my readings even if I take reading at short intervals. I am 100 percent confident that am taking readings in correct procedure.
    So I again went to health center to try the reading. But to my disappointment the reading is high. The people advised me to take medicine as early. I got very much upset and confused. Coming to this blog I am surprised to hear somewhat similar experience and feeling of me. Am I suffering from white coat hypertension?. Which is real? (doctor test or self test).
    Can any one figure out what is happening in my case?

    • Ron

      Do as I did. Take your Omron blood pressure monitor to the health center with you. Have the professional read your blood pressure and use your Omron. Alternate, perhaps two readings by each method. Once by the professional, once by Omron. Once again by professional, once again by Omron.

      I found my Omron to be very consistent with the doctors and nurses. The doctor was pleased to see this too, because now he has faith in my home measurements which I take with me to his office. It’s a good idea to retest the Omron against the professionals once every year or so. Best wishes. -Ron

  4. David

    My first readings are always higher than subsequent. Many have stated this but why? As an engineer I need a technical answer. All things being equal why should a digital machine give different readings? Yes of course I understand minor differences and conditions so please don’t brush me off with that. My inquiries to manufacture companies have resulted in basically that they don’t know. Without this basic technical understandings the machines are useless in my opinion. I can understand most technology but not gobbele-d-gook. If you have a clue, please let me know. Thank you!

  5. ejs

    First BP reading I always throw out as it is at least 10 pts high. 5 min later, 2nd reading is usually pretty accurate. I always sit for at least 10 min before taking readings.
    Yes, I have white shirt syndrome…. The medical staff just go nuts with me. My normal bp is 126/70 with the staff I always jump to 165/90…. Sad part is no one wants to believe me. I keep a graph on a spread sheet with a running average. works great.

    • Ron

      Take your blood pressure measuring device with you to the medical staff. Show them your measurements correlate well with theirs. They will place more confidence in your home measurements, and your graphs. This will help convince them you don’t need medication. – Ron

  6. BobK

    I believe that the first reading is normally higher. The problem is that ALL doctors and nurses take only one reading and then prescribe medication based upon that single reading. I don’t know if the doctors mentally subtract out some factor from the first reading they take or not but the fact remains that meds are prescribed by the readings. Mine BP was in the 140s (first reading) which may suggest meds but my subsequent readings are in the 120s which would not.
    Also NOW we are being told that as we grow older that higher readings are to be expected. Finally where is the test data that shows the damage down by higher pressure? I sure would like to what the statistics are regarding high BP and organ damage. OR is this a scheme by the drug companies to capture more of the audience so they can sell more BP medications???

  7. PLR

    Your monitor is working fine. I found this (and many other similar statements) when searching around:
    When a series of readings is taken, the first is typically the highest. A minimum of 2 readings should be taken at intervals of at least 1 minute, and the average of those readings should be used to represent the patient’s blood pressure. If there is >5 mm Hg difference between the first and second readings, additional (1 or 2) readings should be obtained, and then the average of these multiple readings is used.
    “Recommendations for Blood Pressure Measurement in Humans and Experimental Animals
    Part 1: Blood Pressure Measurement in Humans: A Statement for Professionals From the Subcommittee of Professional and Public Education of the American Heart Association Council on High Blood Pressure Research”-
    Hypertension. 2005;45:142–161.

  8. Soozi

    Agree with lc, doctors everywhere are reinforced for putting us all on medications.
    There is no reward for the doctor who explains limiting processed foods and sodium, including exercise, perhaps meditation, etc. However, prescribe medication for high BP and they will have billings for life!! Rechecks and renewals go on forever.
    There is hardly a reason why a doctor would help us resolve our bp naturally, because they have to pay their staff and themselves and feed their families. It’s frustrating to watch how it works and understandable, that they are caught in a quandary.
    Also agree with the wide range of ways BP is taken in the doc office. I have NEVER had my bp taken properly. Happily I monitor myself at home and modify my lifestyle when it gets a bit too high.

  9. JAS

    QUESTION: How often do doctor’s office staff calibrate these BP cuff devices?

  10. lc

    I agree with all the previous comments; here in Ontario Doctors are compensated more by the government if they can get people ON drugs, like for mild hypertension.
    My doctor was pressuring me to go on meds, but I kept telling her that since I have Parkinsonism, my blood pressure (measured at home) was low when the sinemet was ‘fresh’ in my system, then BP went high when the drug wore off. I also told her that hypotension was a problem with me, and that I didn’t want to take her meds for hypertension as I felt it put me at greater risk of low BP.
    She didn’t seem to like that. Then last spring, I was out in the nearby park, and I felt very weak, and could hardly make it home. I took my blood pressure and it was 66/35!!! Imagine what it would have been had I taken her meds? I called her office and spoke with the Nurse Practitioner who spoke with the MD and then called me back. The doctor’s advice was to drink more fluids and sit down if I feel light headed – genius, eh?
    Something is fundamentally wrong with the way medicine is being practiced today. No wonder people are flocking to ‘alternative’ health care providers. If I didn’t have PD I wouldn’t go near an MD.

  11. Diane

    I always have a high BP reading, to get to the clinic I have to walk down a alley, cross the street to get to the actual clinic door. I always request the MA to give me some time just to sit. (which they do) But I do talk. My pressure is 135, 145, or even 155 (do not remember the bottom pressure) and of course my Dr always suggest DRUGS which I decline.
    The home BP reader sounds good to me and will suggest it at next visit,

  12. JB

    As a retired Nurse, I am disgusted at the way Medical Assistants are being trained. I have not seen one yet that took a blood pressure reading the correct way.

    • Tammy

      Hello JB,
      I was reading the articles on this site about correct ways to take bp and I so agree with you. Every DR I have went to does not take my bp correctly, once I was even answering questions and she had my arm dangling I even said something to her and she looked at me like I was stupid.I am really getting terrible anxiety over my bp because i take home readings and the first one was 131/90 and 5 minutes later it was 120/80 then 5 more minutes it was 130/80 so I have no idea which one is correct. I am scared of my bp getting high and causing harm to me.i don’t know if I need bp meds or not. I don’t like taking it at the DR office because its no help in determining if it needs medication. its always high there. any advice would be so appreciated. Thank you.

  13. MD

    I agree with Margie 100%. I entered the exam room, sat quietly in the chair – back supported, feet on the floor, arm resting on the desk and the CNA insisted I “hop up” on the exam table to get my vitals taken. When I told her I would rather sit on a firm chair with my feet on the floor to get my BP taken, she told me I had to sit on the exam table because my arm must be higher than my heart when the BP is taken!!
    I lifted my arm to show how absurd that is and she insisted I sit on the table. So with feet dangling, arm dangling, as she walked around the room trying to find the thermometer, my BP was 165/98!
    When the doctor came in I asked her to take it manually while I was seated in the chair. She said her BP machine is “state of the art” and they don’t have manual BP cuffs in the office anymore. I refused all prescriptions for hypertension medications and have not been back since.
    My BP is normally in the 100/70 range so I knew these readings were inaccurate. Readings at other practitioner’s offices support the 100/70 range

  14. Integrity

    Thank you People’s Pharmacy for this & and all you information. I have observed & learned to trust your integrity. You watch out for Patients. When we get oppositional & conflict of interest direction from our Drs. I make sue to check your site. Thank you.

  15. Integrity

    As with many comments made by readers & People’s Pharmacy, I have had similar experiences. The worst being my “former” Dr. yelling at me for taking my blood pressure # at home & then once & last time wore my BP Monitor to Dr. Office. (to compare & calibrate with Dr./Nurses BP #s only.) I told her I never had worn it before. She yelled &; concluded I was a “Hypochondriac.” Refused to listen to or hear my logic. (& that I only seldom took BP measurements at home.)
    She told me to STOP TAKING MY BP AT HOME & STOP WEARING THE BP MONITOR. This same Dr. had recently diagnosed me as pre diabetes & mild kidney disease. Thus my then recent concern about BP. I had previously never had symptoms, Labs, or previous diagnosis of either. I suspected her RX BACLOFEN or the dosage for Spasms/pain (due to FQ TOXICITY over several years by previous Drs.) might have altered my Labs. (I have Kaiser thus access to my Labs & copies of Lab reports previously.)
    She/Dr. Denied that RX BACLOFEN could alter those Labs despite my additional very ADVERSE PHYSICAL EFFECTS. I was so WEAK I had a “Caregiver” with me in the office. (also as a witness) Caregiver confirmed my observations of Drs. Very inappropriate behavior & that “It appeared that she had her mind made up before she came into the room.”
    I only had taken 2 of the 10 mg. in 2 days. Then Neurologist suggested .5 mg. of Baclofen for 5 days. But still ADVERSE EFFECTS so I stopped the RX Baclofen. I CHANGED DRS. FILED A COMPLAINT with KAISER. (Kaiser “blew it off,” “white washed it.”
    I changed Drs. No RX Baclofen. Waited 2 months. My Labs 2 months later were all in NORMAL RANGE. Blood Pressure, insulin, kidneys & more were all normal. I had previously told & always tell all Drs. that I am “highly sensitive” to RXs. This is an example of patients needing to be aware & their own advocates. From BP Readings & more, many DRs. & Medical Practices DO NOT ACT IN PATIENTS BEST INTERESTS. THEY SIGNIFICANTLY CONTRIBUTE TO PATIENT HARM. I am now afraid to go to Drs. Have completely lost confidence, especially after seeing how many have altered/omitted my medical records. No attorneys will take cases that do not rise to $250,000.
    My advice: take your own BP readings. Compare w. Drs. Also Nurses & Drs have FAILED TO PUT ME IN A “GOWN” OR EXAM ME FOR 8 YEARS. I don’t know if this is MEDICARE FRAUD OR JUST PLAIN NEGLIGENCE.

    • Ron

      Sounds like your second doctor is the one to stay with. Smart of you to change doctors as you did.

  16. Rosie

    I always wonder if the hearing ability of the BP taker makes a difference? Many of us have a degree of hearing loss, so some nurses must also have hearing loss and I wonder if that matters in getting accurate readings?

  17. Donnie

    My doctor had a tech that put the cuff on so tight, that it caused pain and my arm to go numb, even before the reading was taken. Then she wondered why the BP number was high. I often have white coat hypertension, too. I monitor my BP at home, for that reason.

    • Yosako

      That’s more like undercuffing than white coat hypertension…if it’s “so tight it hurts” it’s likely that’s too small of a cuff, which causes a false high BP reading.
      Be sure your cuff is the proper size given your arm circumference.

  18. raw

    The current device are not accurate & medical assistant are not trained, who normally measure BP.
    This is your quote—just what I had to say. I refuse to let my BP be taken with the device that hangs on the wall and I have found many ‘nurses’ don’t even know how to manually take BP. When I tell them I want my BP taken manually they look at me like I asked them to preform surgery. I would be on medication if the doctors used the readings I have from their modern device—-when actually I have normal to low readings when taken manually.

  19. TomN

    I have the exact same experience taking home readings. The first one, even after five minutes of rest, is almost always higher than the second reading, often by 10 points or more systolic. The second is after a minute or two more of rest, and the third, after another minute or two, is usually a little higher than the second, but still significantly lower than the first. I usually average the second and third.

  20. Barbara

    Excellent comments from Margie. She covered what The Peoples’ Pharmacy left out in their comments.

  21. jla

    I monitor my readings at home, several times during the day, then I take the previous 30 days of reading to my appointments. I tell them why, too.
    I have had my pressure taken as soon as I enter the exam room, standing, then right after getting up on the table. I’ve had my pressure taken over sweaters and fleece shirts. I’ve had pressure taken with the cuff laying on the inside of my forearm and the monitoring portion just below the elbow joint. I’ve had my blood pressure taken with my arm dangling, held straight out with no support and even with my elbow lifted about eye level with their table digging into my arm.

  22. BobK

    For home BP measurements I purchased a top of the line brand that takes either a single or three measurements of my blood pressure. Each measurement is separated by a one minute interval or more. According to the User’s Manual this is the most accurate method of taking blood pressure measurements.
    What is strange is that each of the three measurements are different and some noticeably different. As an example the first reading could be 144, the second 127, and the third 129. The first is always consistently higher and by a significant amount. The second is always lower as is the third. Taking more measurements results in the lower reading.
    I had many discussions with the company technical staff and we went through all of the correct ways to take one’s BP. After a month or so of phone calls they suggested that I return the unit for calibration. However, the unit was found to be properly calibrated so the problem still existed and with no apparent solution.
    Listening to a doctor’s show on Sirius Radio they had a program hosted by a leading heart specialist. I called in and asked the doctor about my blood pressure readings. He immediately told me to ALWAYS throw out the first reading as it will be high and inaccurate. The second and third readings will be the accurate numbers.
    This exactly fit my numbers when taking my blood pressure. However, no other doctor supports this and doctors and nurses continue to take a single reading. So I’m not sure who to believe. Has anyone else experienced this variation in readings?

    • Ron

      I am seeing similar comments all through this site. My experience is the same. Not certain why, but it has been suggested that we are more rested the longer we sit there. To add another professional who supports your radio-show doctor, see: http://www.medic8.com/healthguide/blood-pressure/using-a-home-blood-pressure-monitor.html
      A couple of pages down you’ll find the following:
      “You will find that your first reading is higher then the second reading and the third. If you notice this, then carry on taking readings until they stop dropping and level out.”
      I have found it written that we should throw out the first, higher reading and average the second and third, as the first is actually considered inaccurate.

  23. SalW

    I often feel I am better off the longer I stay away from my doctor’s office to prevent “disease creep.” As Dr. Oz just recently revealed, he was taught in medical school how to treat disease but not how to prevent it. My geriatrician seems too consumed in lowering numbers no matter what the risk.
    At age 75, I have no cardiovascular disease and may have mild hypertension but, upon my recent physical, my blood pressure registered 144/77 with a portable cuff like we use at home, and I had not had my blood pressure medication in 28 hours. Without taking my pressure himself with the wall unit before I left, he quickly put me on Valsartan/HCT 320-12 mg. A false positive indeed! I didn’t consider this reading alarming in the first place.
    This new Diovan prescription caused me to be extremely short of breath and so fatigued with an afternoon systolic pressure in the 110’s that I would fall asleep in a chair. I took myself off this new med and went back to the Losartan I previously was taking with a return to a 139/70 average.
    This also happened at the same time that the Diovan scandal erupted in Japan for the company’s falsifying some records of their trials. So what other crucial facts did they distort? I understand this scandal has now spawned a criminal action against Novartis. The country’s Health Ministry lodged a complaint against Novartis, accusing its domestic unit of exaggerated advertising. My doctor reads very little about new studies and such and knew nothing of this problem with Diovan!
    Thanks to the Graedons who equip us with vital information to protect ourselves when no one else will do it for us!

  24. Margie

    The biggest mistake made with a blood pressure check in the doctors office is having you “hop up” on the exam table and immediately having your blood pressure taken. There you are, with your feet dangling and someone talking to you. You, of course,are already a bit anxious about getting to your appointment and seeing a doctor. If your blood pressure in this situation is higher than what you get at home, it is erroneous to term it “white coat hypertension”. It should be called a lapse of best practices.
    A proper reading is obtained when you are sitting for at least five minutes in a chair with your feet on the floor. You can speak up and request a proper blood pressure check. I do! I also have a print out of my home blood pressure results to hand my doctor.

  25. M

    In addition as to what is mentioned in British Journal or Lancet. I might add accurate BP are measured with doctor or nurse personal BP equipment as in old days. The current device are not accurate & medical assistant are not trained, who normally measure BP.
    Finally, at home with your own device which is used on daily basis with record keeping. You may stand up & take a reading and compare it with sitting. SUPINE position is the most accurate reading of BP.
    Thank you.

  26. Eva

    I have been told by nurses to keep both feet flat on the floor, and that the arm being used should be extented forward.
    Other nurses have taken my blood pressure with my feet dangling and with the arm dangling.
    Which is correct? Or does it matter?

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