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    Significant difference in BP between left and right arm
    aprilofvt posted:
    Hello. I am a 34 yo F in good health though I do not eat or drink as much as I should. I have never been a smoker or drug user nor do I drink alcohol. Heart disease is not a remarkable issue in my family; lung issues in older age are more common.

    21 months ago I was bit by a tick and began seeing a dr for treatment several months later. I was surprised that my BP, which is normally an the lower end of normal, was 130/80. The dr suggested stress.

    Each time I saw her, this was my BP and I wondered if it was Lyme related. However, when I saw my primary for my phyisical, I was delighted to hear my BP was at 105/75; I was so happy to hear is was back to normal. My primary said I was probably more stressed going to the Lyme appts.

    Bring us to my next specialist appt. yesterday. My BP was 130/78 (left arm). I said--how odd! It was much lower at my primary. The nurse suggested taking my BP on my other arm...low and behold: 102/70 on my right arm (and my right arm was used at the primary!) She double checked and used a mechanical cuff. Indeed, my systolic BP in my left arm is 25 to 30 pts higher than my right.

    I did some reading and found recent research that indicates that a such a large difference can indicate vascular disease. My dr did not seem worried but ordered blood tests when I expressed my concern.

    What more should I know about this? How should I proceed?
    cardiostarusa1 responded:

    Usually, but not always, there is only a small difference between blood pressure (BP, systolic and diastolic) readings in both arms.

    It is reported that if the technique for taking the BP readings is good (accurate as possible), it's likely that the respective readings accurately reflect the pressure in each arm, BUT the higher reading reflects the "true" BP.

    If/when there is a clinically significant/substantial difference in BP between one arm and the other (such as hypertension in one arm), this may/can be due to factors and conditions, such as coarctation (narrowing, congenital) of the aorta, aortic dissection (tear in the wall of the aorta), atherosclerosis (plaque buildup), and thrombosis/embolism (blood clot) in an artery in the arm.

    Also, the right and left subclavian artery supplies oxygenated blood to the arms, and in a condition known as subclavian artery stenosis (SAS, most often acquired in life), BP will be lower in the arm with the narrowed subclavian (typically one artery is affected) artery, thus accordingly causing reduced blood flow through it.

    BP begins to rise as one awakens, peaks in the late afternoon or evening, and then drops off gradually, becoming the lowest when sleeping. Normal resting blood BP in adults is under 120/80 with 115/75 or 110/70 considered as being optimal/ideal.

    Taking BP measurements when at rest/relaxed will help yield more consistent readings. If one has had a peaceful night's sleep, then measurements are best taken as soon as one awakes in the morning, as at this time of the day, the body will be at its lowest functioning levels, both physically and mentally, and therefore the factors that affect BP will be minimized. One should try to take the BP at the same time(s) every day.

    PLUS, there was a study, in which University of Virginia researchers tested 100 individuals two times, once while they perched on a doctor's table, feet dangling, and then again as they sat in a chair with both feet resting on the floor and their back and arms supported.

    Systolic BP, the top number, dropped by 13 points on average while sitting in the chair. Why's this? According to study author Melly Turner, RN, if your arm, back, and legs are not supported, then you're exerting energy while being tested.

    The prestigious American Heart Association has been recommending the chair method, but harried medical staff often don't employ it. Sit quietly in a proper chair for 5 minutes before having the BP checked, and be sure the arm being used rests on a flat surface.

    Best of luck down the road of life. LIve long and prosper.

    Take care,


    WebMD community (since 8/99)



    Be well-informed

    Blood Pressure Differences Between Arms Could Signal Heart Risk

    "Doctors should, for adults, especially adult smokers and diabetics, at some point check the BP in both arms. If there is a difference it should be looked into further."


    Mayo Clinic

    Get the most out of home blood pressure monitoring



    "Be a questioning patient. TALK to your DOCTOR and ASK QUESTIONS. Studies show that patients who ask the most questions, and are most assertive, get the best results. Be vigilant and speak up!"

    - Charles Inlander, People's Medical Society

    . .

    It's your there.
    aprilofvt replied to cardiostarusa1's response:
    I checked in with my primary office. They are telling me the BO difference between arms isn't a big deal unless they are 50 points or more apart.

    I don't understand this. I read on the AHA page that a difference of 10 o more shoud be looked into. Mine are 25-30 apart and yes, both were then sitting down, similar posture.
    cardiostarusa1 replied to aprilofvt's response:
    "My dr did not seem worried but ordered blood tests when I expressed my concern."

    "They are telling me the BP difference between arms isn't a big deal unless......"

    "I don't understand this. I read on the AHA page that a difference of 10 or more shoud be looked into."

    Well, it's your body, so do feel free to seek, in-person, additional professional medical opinions, even if it turns out being just for getting some peace of mind in the matter.

    Take good care,




    It's your there.

    . .

    WebMD/WebMD forums does not provide medical advise, diagnosis or treatment.

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