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Pernicious Anaemia Society
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Exercise or not?!

Hi all, so I've not quite got a diagnosis, am not yet on any treatment but am hopefully on my way to both. I wanted to ask, I've noticed a few folk on here saying that strenuous exercise can be a bad move if you're B12 deficient, is that right?

I certainly feel terrible if I try to properly exert myself and had previously thought I was just unfit and need to do more, but if it is actually bad for me, that seems a bit different! Can anyone advise about this at all?

Thank you

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I’ve continued to walk a lot as I’m lucky enough to ba able to and have always continued weekly Zumba no matter how tired I have felt before as doesn’t seem to make me any worse even when head is not quite my own . I know that isn’t particularly strenuous but with walking in particular improves my frame of mind . I think it just depends on what you feel able to do .

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I can only speak of my personal experience. Pre diagnosis I was struggling to exercise as I had no strength or energy.

Once diagnosed I was given injections every 2 months by my GP (no loading doses offered) and I was able to start exercising again but at a relatively low level. As I was running out of steam before the 2 months were up my GP agreed to try out monthly injections which gave me a definite improvement and might have been enough had I not been into long distance cycling. That said, I still felt that I wasn’t on top form and I would definitely have a dip if I exercised hard or had alcohol.

I decided to try out weekly si and I find that it suits me. No ups and downs in energy levels and I’m cycling as well as I ever have.

So my view is that if I get my si frequency right I can live a normal life which includes exercise.


Certainly noticed that any time I overdid things, I paid for it.

Just inished reading "Diagnosis and Treatment if CFS and ME", as well as another excellent book on B12 def and chronic illness:

"...exercise takes energy away from the immune system and, indeed, intensive exercise is a recognised immunosuppressant."

What struck me was that both mentioned the huge importance of not over exercising but staying gently within your own limits. It was also noted in both books that many athletes suffered B12 deficiency and/or MS, CFS/ME, Parkinson's etc. - which are illnesses that seem to have overlapping neurological symptoms.


Yep, I agree with the above comment - if I overdo it, boy do I suffer. But, I do like to walk and usually manage a 3 mile ramble most days. But it took me months to build up to it. I started with just short walks around the block at first. I would say take it easy and build up the exercise very slowly, listening to your body all the time. If it makes you tired, cut down, if you feel ok, do just a little more.


Thank you all, sounds very sensible!


Slow and steady, that was the key for me.

At first I could hardly do anything. I would take the dogs out for a short walk and that was me done for the day. As time passed the walks got longer. I took up swimming (mainly because there was no risk of falling over and, if I suddenly got exhausted I was only 50 m from the car.

Now I'm regularly doing over 10,000 steps a day and I'm getting back to my favourite exercise - archery.


I would advise listening to your body. If you feel great do what you can; if you feel bad, rest. I used to be a triathlete. Now I do what I can in between SI (which sadly isn't much). Good luck with it.


I was b12 deficient. After starting injections i would feel better and want to go for a walk, which i would do and the next day i would experience a "crash".

I was finally diagnosed with h pylori in August 2017 and realized this chronic infection will segregate your iron stores (ferritin) away from being available to your body. So even though it looked like i had plenty of iron stores, it wasnt available.


My serum iron and saturation percent were low and once i started taking iron in addition to b12 injections i no longer had the crash!

This is a super important consideration for menstrating women that seem to have a crash even without exercising as the worst of the crash can be 2 or 3 or 4 days after starting their cycle and therefore, in our foggy brained state, we fail to tie the two together.


Can I ask KimberinUS, have you been treated for H Pylori? I'm just waiting for test results for that. I have very low serum ferritin.


Yes, the following link is kinda how i was treated. Except i did it for 2 days instead of one due to concern that one day wouldnt work.


I was just retested Friday, 12 weeks since treatment, to see if it is gone. The research i have done says you should wait minimum of 8 weeks to be retested because the treatment can reduce it without actually killing all of it. Therefore you need to wait to give it a chance to proliferate again before testing. I meant to test sooner but i was in the middle of moving which required much of my time.


Just got results to see if h pylori gone and it is not.

Im doing a 14 day treatment this time.


Ah, good luck!


Wow, wish that I could even do anything. I struggle to walk around my flat. I finished loading injections a month ago and no symptoms have got any better. I feel absolutely awful. Am going back to docs this week. Last time I went, I left in tears after I was told that my bad breathlessness and vertigo was anxiety and they did not think my fast heart rate and low blood pressure was related to defiency . I am taking my mum with me to try to get help.


So sorry Meggydo , I hope things improve for you.


I found I was far too weary before diagnosis but tried to keep on taking gentle walks with my daughter and her sons as often as possible. After starting injections it was much easier though and I did have much more energy but if I overdo it or have a strenuous period I just have to stop and rest, perhaps for a day or two. At 73 I often think that could be a result of advancing age.

Photography has been a wonderful form of exercise, particularly landscape photography and it has also taken me to some fine scenery on the many strolls we now take with our cameras here and abroad. You always have plenty of excuses to stop and admire and record the view so not over tiring yourself. With the advent of digital cameras it is also a relatively inexpensive hobby.

Many years ago I heard a reading on the radio of something Mark Twain had written. He said, of exercise, he couldn't believe anything which made him feel tired could possibly do him any good. This seemed to me to be a reasonable argument and I have lived by it ever since. Mind you he also told of being prescribed by his doctor a quart of whisky a day for 3 months when complaining of feeling generally unwell which had worked extremely well as he had never felt better but one of his friends tried it and was dead within a month. Obviously what works for one can be deadly for another.

Moderation in all things, including moderation.

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