Back to my original question, how do you know if such a device is worth getting?
Monitors are cheap and if not as accurate as one beng operated by a trained clinician should certainly show trends and allow you to take your BP under consistently controlled conditions - before caffeine and day to day stresses such as a rush to the GP surgery get a chance to skew the reading.
I have an Omron wrist mounted monitor (I understand that arm mounted ones are more accurate) bought many years ago after I was warned that my BP was creeping into the range that could be a cause for concern. Whether or not the monitor was 100% accurate, taking and recording daily (or at least regular) readings and seeing the way in which a few improvements in diet and lifestyle brought my BP down into the (very) healthy range as confirmed at the next GP visit.
I don’t use it regularly now but if my trousers start getting a bit tight, I start using the monitor and scales and jot down the results as part of the process of getting things back on track.
If you are able to, giving blood regularly gets you a free BP check by a trained nurse, a cuppa and biscuit. I used to donate platelets every two or three weeks and got a fairly thorough health check each time - a bit time consuming but very satisfying if you can do it.
A few years ago, after a couple of days feeling really cr@p with what I had self-diagnosed as acute man-flu, I decided to check my BP with the Omron. I can’t remember what the BP readings were but they looked “wrong” and my HR was in the 190s. After checking manually that the HR was seriously high, I made an emergency appointment to see my GP who looked a little sceptical but after a quick ECG was on the phone to A&E arranging me to be fast tracked through triage.
All very exciting and a bit worrying but after many tests including being fitted with 24 hour monitoring device (which I wore while out on a 40 mile bike ride) and eventually getting to see a consultant cardiologist, the conclusion was that heart, lungs and just about everything else were in good to very good nick but I had a susceptibility to atrial fibrillation (heart going like the clappers but out of synch) which can be triggered by excess caffeine. Caffeine intake now significantly lowered and no repeats. The anti-coagelents used in platelet donation may have been a factor but sadly despite the cardiologist telling them that there was no issue with me giving whole blood the Blood & Transplant Sevice won’t let me donate.
FWIW, it turns out that my mother has the same issue but since well into her 70s she was still wasting my inheritance on trekking trips in Nepal and Bhutan and now in her 80s is still clocking up getting on for 1000 miles a year walking including UK long distance footpaths and trekking in Europe, I’m reasonably optimistic about the prognosis.
What’s the worst that can happen if you use BP monitor at home? You will be £20 or so out of pocket and they don’t take up much space if eventually consigned to the kitchen drawer. On the plus side, if the readings give you concern, you can go and get your BP checked by a grownup at a GP surgery or walk in centre.