Blood Pressure Hijinx

February 5, 2024 2:19 PM

Are these sorts of BP reading swings normal?

My doc and I have been working on my BP for about a year now. All well and good. But, I’ve noticed something really damned weird about my BP readings sometimes, and I’m wondering if this is one of those “Oh, yeah, no worries, that happens” things, or a “Y’need to get to the hospital asap” things.

Note: The numbers I’m going to use are just for example’s sake, not my real numbers, in order to avoid derailing into “Dude, those numbers are fucked-up” territory.

Let’s assume I take my BP at the same time daily, and sitting in the same position. So, let’s say I get a BP of 138/65, which seems a bit high for me. So, without removing the cuff, I immediately run my BP again, and it comes up 114/60, which is seriously wtf? I take it again, and now it’s at 123/63.

I guess my simple question is, is it “normal” for BP readings taken literally within seconds of each other to vary so wildly?

FWIW, I’ve taken my cuff into my doc’s office and tested it against their cuff and they agree with each other.

posted by Thorzdad to Health & Fitness (9 answers total)

Blood pressure readings can vary quite a bit over a short period of time. Body position, standing-sitting, crossed legs can all impact it. A drop from 138 systolic to 114 in your example is perhaps larger than normal, but absent any other signs/symptoms I would not be super concerned.

Source: ICU nurse who has many times cycled a blood pressure reading to get one that I liked, or that fit expected trends. Cuff pressures can be pretty flukey.
posted by Pantengliopoli at 2:33 PM on February 5, 2024 [2 favorites]

My cuff does 3 readings pausing 30 seconds between each and then averages them. I don't recall seeing a huge jump up or down though.
posted by 922257033c4a0f3cecdbd819a46d626999d1af4a at 2:37 PM on February 5, 2024 [1 favorite]

This document from the AMA about measuring BP says:

Failure to wait at least one minute between measurements can impact the reliability of the blood pressure reading.
posted by lulu68 at 2:42 PM on February 5, 2024 [6 favorites]

It's normal. My fancy (Withings) BP cuff can automatically average 3 measurements taken a few minutes apart.

Previously, I'd measure 3x and throw out any obvious outlier and average the rest. Sometimes there's an obvious outlier, sometimes they are all similar.
posted by jpeacock at 2:44 PM on February 5, 2024 [2 favorites]

Totally normal, and my BP cuff also does the 3 measurements thing. I’m sure I’ve read that variations as high as 20pts could be expected. Ive definitely seen 10pt swings like you’ve described within the same couple of minutes at home, and I personally don't worry about a single funky reading.
posted by cgg at 4:03 PM on February 5, 2024

This likely isn’t it however, I suffer from “White Coat Syndrome” where when I first have my blood pressure taken, it’s always high just from the act of having it taken, and fine at the end of my visit once I acclimate to being at the Dr’s office. It’s consistent and apparently common enough that my Drs office at a large HMO doesn’t think anything of it.

It could be that even relaxed and breathing calmly this happens to me, it’s a psychological tic and probably self reinforcing.

I’d do it once, wait a bit and try again.
posted by bitdamaged at 5:59 PM on February 5, 2024

Just anecdata, but I take my blood pressure regularly and the first reading is almost always notably higher than the second two. I have brought this up with my doctor and she wasn't concerned.
posted by rhiannonstone at 9:10 PM on February 5, 2024

I see about a 10 pt swing regularly from 1 to 2 measurements (130/85 to 120/75, say), even without actively trying to calm myself or do breathing stuff. Try giving yourself a few minutes to stabilize after you sit down before taking the measurement.
posted by Lady Li at 11:55 PM on February 5, 2024 [1 favorite]

A word about varying readings. My brother was asked to monitor his BP and bought an inexpensive electronic machine to do it at home. When I used it the readings were way out from my own usual readings. It is therefore important to not only follow the guidelines about how to measure blood pressure but according to this article on Home Blood Pressure Monitoring from the Council for Cardiology Practice there is a list of recommended blood pressure monitors validated and approved for accuracy by The British Hypertension Society. Lots to choose from and worth checking out before deciding which machine to buy and be sure of accurate readings.
posted by jallypeeno at 8:05 AM on February 6, 2024