Pernicious Anaemia Society

Slow resting heart rate

Does anyone have a low resting heart rate along with a history of low b12.

Mine runs at low 50's while I rest on the bed then climbs to 70-80 while i move around.

I tend to feel much more tired at times when it's slow.

After I shower on a morning it climbs to 100-110 when I get dried but as soon as I lay down it drops back down to high 50's-60ish.

Does anyone else have a similar experience?

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My resting heart rate runs in the high 50s but I have always been led to believe that that is good. Now I have been diagnosed with low B12 I am wondering what heart rate is good. Sometimes my rate goes up to 180ish for no reason


When you are active your cells need more oxygen so muscles etc work so your body responds by speeding up the rate of delivery and your heart beat goes up - so changes in heart rate are to be expected. I'm by no means an expert but I don't think the changes that you describe are really that out of the ordinary - possibly a bit higher than might be normal for the activities described - but if you had anaemia when you were diagnosed then that means that your red blood cells aren't going to be as efficient as normal in the rate at which it picks up blood from your lungs and then passes it to your cells so the body is likely to compensate for this by pumping blood faster round your body.

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My blood is pretty much corrected now with the exception of my MCH which is still above range.

The tachycardia was much worse at the start of my b12 journey.

My heart just feels a bit slow for someone so sedate and does seem to run slow at times when I feel particularly tired such as today.


if you are really concerned about this then please talk to your GP about it - I'm not a medical professional and this forum isn't a substitute for professional medical advice.

it is possible that what is going on isn't wholly related to the haematological effects of B12 and some may be down to the neurological and neuropsychiatric effects - particularly as the mechanism that controls heart rate is part of the autonomic system - those processes that you do without conscious or with only semi-conscious thought.

I have noticed that I feel really out of it if my blood-sox (measure of the amount of oxygen in your blood) falls below 97 - though it isn't really a problem until it falls into the low 90s if not below 90.


Hi I'm going for an ECG and other tests because I've been having funny experiences where my blood pressure has been dropping very low and I feel faint and yet when the GP checks it it's normal . I not sure if it's connected to pA as my brother had a heart attack at the age of 49. It is all such a mystery. Have you had your blood pressure checked by the GP


Very occasionally but I do check it at home. It's not something gp's or even hospital doctors check routinely these days from my experience which seems crazy.

You'd think they'd test it every time you saw them. Especially at hospital appointments when feeling weak or dizzy is one of your issues. I don't get dizzy just fatigued and a while ago I felt odd when I stood up although that's not really an issue now. I had to stand still for a few seconds and bow my head to compose myself before walking after standing up.

My Bp is generally ok except for the odd high reading inbetween normal ones but I put that down to machine innacuracy when the one directly before it and after it is totally ok.


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