Pernicious Anaemia Society
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Is exercise advisable when B12 levels are still low?

This is my first post from Australia, after having been diagnosed with PA in January 2017.

This comes 18 months after completing chemo and radiation treatment for breast cancer. Looking at the PA symptoms I tick many of the boxes and yet I kept thinking they were post chemo and or tamoxifen side effects, so a new diagnosis surprised me but explained a lot. I have had a monthly injection for the past two months and another due next month. My fatigue, balance and mind are still struggling with little improvement. If I undertake light exercise it almost wipes me out. It is unclear why some people seem to receive regular injections initially and then monthly whereas others receive monthly? It is also unclear whether exercise should be limited until your levels improve or if exercise can in fact help you push through your fatigue?

My level was 130 when diagnosed. I live in Australia. Any suggestions re exercise and a more regular injection regime would be most helpful. I am 60.

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Hi Hidden with regard to exercise I can only speak from experience as I'm not a medically qualified person.

I find that my energy levels are self limiting so I tend to conserve it as much as I can although I do do 20 minutes a day on a "power assisted" bicycle because of my diabetes. Down through the years i have often felt embarrassed by my apparent "laziness" because "people" don't understand how debilitating P.A. is as there are no outward signs for them to see.

However, we are all different and what suits one person may not suit another. I had two daughters under seven when I was diagnosed with P.A. which was 13 years after gastric surgery by which time I was a walking "Zombie".

In the U.K. treatment for P.A. with neurological symptoms using hydroxocobamalin B12 is:

"The BNF advises that for Pernicious anaemia and other macrocytic anaemias patients presenting with neurological symptoms should receive 1000 μg i.m. on alternative days until there is no further improvement, then 1 mg every 2 months".

This means that here you would have an injection every other day for at least a fortnight or until symptoms have improved sufficiently before going on to a maintenance dose of every eight weeks.

What form of B12 is used in Australia? Cyanocobamalin, hydroxocobamalin or methylcobamalin?

It is vital that you have a good healthy level of Folate as this is essential to process the B12 you are having injected and this will get "used up" in doing so. If your Folate level has not been tested recently I suggest you ask your doctor for it to be done and at the same time request he treat your neurological symptoms by more frequent injections.

I do hope you have complete recovery from your breast cancer. I thank God that my wife got through it all nine years ago and I, after 45 years with P.A am still "clivealive" at 75.

I wish you well for the future.

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Thank you for responding so quickly "clivealive". The information you provided was most helpful. I have been receiving Hydroxocobamalin injections. My Doctor is reluctant to inject other than monthly at the moment. She believes that many of the neurological symptoms I am presenting can also be as a result of chemotherapy or tamoxifen and therefore she does not want to over treat me. She could well be correct however it appears that maybe I am about to start experiencing some of the same frustration others have felt when first diagnosed with PA.

I am so pleased your wife has fully recovered and that you appear to have a positive attitude towards your diagnosis.

Take care!

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One cannot be 'overtreated' with B12, fortunately, because there is no upper limit above which it becomes toxic to the body.

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You need to have light exercises- range of motion- yoga? - this stimulates the repair of the nerves for the muscles you are using. Only exercise the nerves you want to keep.

Are you supplementing with folic acid, B6 and B1 along with a daily multivitamin to support B12 in the repair of the nerves?

I self inject cyano weekly and try to maintain a high level of B12 above the upper limit for the blood test to maximize any repair. Further blood test tend to confuse GP who tend to want to withdraw B12 injections once you are in the "normal" range. You want >1500 pg/ml and explain this to your GP if they insist on further blood tests.

The repair is extremely slow. Any setback seems to undo in a day what took a month to progress.

Start a logbook of all your symptoms and assess the neurological ones on a daily basis with your own scoring system. Use the log to monitor your overall progress because in the short term you will feel like you are on a roller coaster ride.

Share your log with your Dr and ask for further suggestions as the Dr needs to buy in to this method of gathering evidence, in lieu of further blood tests, for more justification for more frequent injections.

You also have to have the serious and calm conversation with the Dr that as more symptoms appear you are not a total hypochondriac and the log book will help weed you the real symptoms that can measure how much B12 you need and how your nerve repair is progressing.

Symptoms like pain are counterintuitive in that the signal gets stronger as the nerve repairs and it takes about 3 days for the brain to recalibrate to the stronger signal. If this pain comes after the jab, try exercise & working through the pain telling yourself that it is the illusion of the nerve repair. And is a good symptom.

With exercise, this illusion of pain magically disappears after about a half hour as you build up confidence that it is really just an illusion.

The exercise helps to convince the brain that it needs to recalibrate.

Worry about the pain increases stress which seems to make the pain seem worse.

The getting started with the exercise is the hardest but once you get going it becomes easier.

Swimming is another good exercise


Thank you for your insightful overview Pvanderaa regarding good health and a calm mind. I agree it is important to sometimes stop and get things better into perspective in order to eliminate the panic. My Doctor currently appears less concerned about my PA diagnosis and feels that many of my symptoms are as a result of chemotherapy treatment and the breast cancer drug, Tamoxifen which I now take. All the side effects appear one of the same, which can be very frustrating in determining what is what. What I do know is some of these symptoms have become more severe and this needs to be addressed in time. The idea of a daily log is a great idea.

I will also look into folic acid, B6, B1 and daily multivitamins. I need to check how these work with Tamoxifen however certainly something I will look into.

Thank you for taking the time to provide so much information. It is greatly appreciated.


Yes, done in moderation exercise can do lots of good, whatever conditions one may have.

I used to be fairly active, walking for many miles a day carrying a lot of gear for bird watching and photography. When the PA struck I didn't have the energy to walk from the car park to the supermarket.

As my treatment continued things got better, I could take the hounds out for their walks, slowly. But I got worried a couple of times when the fatigue hit when we were half a mile from home - and I had to have several rests on the way back.

Then I hit on the idea of swimming. My poor balance didn't matter as I couldn't fall over in pool. If I got exhausted I could swim to the side and have a rest immediately. I was never more than 100 yards from car.

That really helped me get my energy levels back up. Nowhere near where they used to be (still wrecked after 90 min walking) but I do feel able to cope with day-to-day energy demands.


Hi fbirder! Swimming or water walking is a great idea! I have done that in the past and will revisit it again. Thank you for suggesting this.


Good question.

For myself, after a fairly short walk into town and back I tend to fall asleep, although energy level varies a lot from day to day. It's very disappointing in a way as I hoped my energy levels and stamina would improve substantially and quickly with B12.

However, what I remembered recently from being very ill in my twenties is that it takes time to heal and you do need to rest to allow recovery to take place. Like most people, I want to feel completely better at once, and continue with normal life.

Accepting that may not be possible - and that's ok - is important, resting whenever you need to (if your life/finance/support level permits) and pacing yourself with gentle exercise as people have explained above is a big step forward in itself.


I'm so glad you asked this question - it's something I wonder about a lot. When I was in the depths of my B12 deficiency, I was incredibly depressed about not having the energy to exercise. Before I got sick, I worked out twice a day, six days a week. When I was really sick, I couldn't walk a block. But, I did find that sometimes a light workout (like on an elliptical - somewhere I wouldn't get "stuck" too far from safety) really helped to clear my head. I think you just have to experiment and see what feels right -- and always do a little less than you think you can do, just to be safe.

I did read somewhere that sweating a lot can deplete B12. Not sure if that's true or not, but I tried to be mindful about doing activities that didn't make me sweat much, just to be safe. If someone else on the forum knows whether this is true, I'd love to hear your thoughts.

In regard to the frequency of shots, I'm not a doctor but it sounds like more frequent shots would help you a lot. My level was similar to yours when I was diagnosed and I was put on shots every two weeks. I struggled for months on that dosage and just kept getting worse. When I pushed for weekly shots, I finally started to get better. I learned that other people in my city were started on DAILY shots, which would have helped me a lot. I really regret not pushing harder for more shots early on. I wasted months of my life because a nurse said I couldn't metabolize B12 any faster than that, which is totally untrue. During this process, I learned that I'm my own best advocate. I also learned that they take the "neuro" symptoms a lot more seriously, so I always talk about those first.

All that said, I hope this helps! Good luck with everything!


I believe that you can actually get B12 over the counter in Australia - ie you don't need a prescription - though it's not well known that it isn't prescription only - even by pharmacists.

Some chemo drugs can affect your folate levels - not sure if that is true for the medications you have taken - and as folate is needed to process and use B12 it could be a factor.

Suggest you go back to your GP and ask for clarification on why they are so reluctant to treat the B12 deficeincy more aggressively - it could be concerns around correlations between B12 treatment and higher rates of cancer and larger tumours - however, this is a correlation and no causal link has actually been established. The higher rates of cancer could be explained by an undiagnosed cancer prior to diagnosis as B12 deficiency is known to be a cancer risk. The larger tumours are unfortunately likely to be down to B12 promoting the production of cancerous cells as well as healthy cells. B12 itself is not known to have any toxicity and is used in amounts 5000-10000x the amount you receive in a shot to treat cyanide poisoning as the treatment of preference because of the low toxicity - the main undesirable effect is the possibility of hypertension caused by the amount of fluid that is involved.

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