Activity & exercise

Hi, I'm still waiting on test results so not sure yet whether it is b12 deficiency but wanted to ask a question about exercise. Do you find that the more you do (not necessarily exercise but activity overall) the more b12 you need? Or your symptoms are more noticeable if you've over done it? Like you had to make the b12 'last' almost? I was doing a lot of exercise when I'd noticed that symptoms I'd had for a while started getting worse. I was training for a run and exercising 6 times a week. At first I just thought I was just overdoing it but after reducing the amount and intensity I was finding it harder & harder til I stopped all together. My symptoms continued to get worse and I'm not doing any exercise currently. I'm just wondering whether this could have made things feel worse quicker? If that makes sense? Thanks

19 Replies

  • Some people will tell you that you do use up more B12 when you exercise. Personally, I don't see how that could be the the case. Yes, B12 plays a part in the chemical processes involved in energy production. But it is a catalyst in these reactions - it doesn't get used up to any great extent.

    But we all have a limit as to how much exercise will make us fatigued. A few years before diagnosis I could happily walk five miles carrying 15 kilos of birding and photography gear. By the time I got diagnosed I could barely walk to the supermarket from the car park.

    Fatigue is the most obvious of my symptoms and I notice my limit gets reduced if I go more than 8 days without a jab. But the limit doesn't get any higher if I switch to jabs more frequently. I tried doing alternate day injections with that aim and it just didn't work. I've had to slowly build up my stamina over a long time.

  • Hi I have retired from work as a builder about six yrs ago and diagnosed with pernicious anemia 9yrs previous during that period I had 3monthly injections reduced to every 2mths I guess the heavy work made it necessary for me to have more frequent injections. This past winter I took on a building project for a friend quite heavy work and found I was getting foggy head and low energy on average over the six months every 4 to 5 weeks so decided to look into and self inject and found a vast improvement. It's my guess is you are burning up a lot of b12 and probably need to replemish more regularly. We are of course all different , all I can say it works fo me

  • Hi How much B12 are you getting and are they injections?

    Perhaps you need more. I think (I'm no expert and happy to be told I'm wrong) that the more you have wrong with you and the more you do the more B12 you need.

  • After my blood tests for MMA & IF I started using patches & sublinguals as I was struggling to function properly. Still waiting on results, bloods were taken 2 weeks ago. Doctor won't give me anything yet as he doesn't believe it to be b12 so he ordered the above tests to rule it out. My serum b12 was well within the normal range but I was taking supplements (albeit not high doses) I'm noticing a slight difference in that I'm not falling asleep during the day anymore but other symptom like dizziness, 'the sighs', pins & needles are no better.

  • I have 1mg every 8weeks at my doctors and 2mgs midway (4th week) both injected

  • Hi beginner1 I should add to my previous reply that I have put myself on SI. as I feel I can to some extent be in control of my intake as and when I need extra b12 when I finish any heavy work or exercise I intend to drop back to SI 1mg and see how that works.

  • The symptoms you describe could be caused by a wide variety of slow-onset problems. Justy off the top of my head - B12 deficiency, Vit D deficiency, iron deficiency, diabetes, hypothyroidiusm. All have fatigue as a symptom (as, I'm sure, do many other problesm) and all gradually get worse - just as you describe.

  • I've been trying to get a copy of my blood test results but the surgery are being awkward about it. They have agreed I can have them they are just taking their time. Dr told me all was normal so hopefully once I get the results things may be a little clearer. The reason I believe it to be b12 is cause I had an issue with it a few years ago, I was as low as 83 (not sure of measurements) I was given injections for a few months then told all was fine, they never looked into why it might have been that low. It won't have been due to diet so I guess something else must be going on.

  • Exercise uses up T3 - the ACTIVE thyroid hormone - so if the reading is low then you will be fatigued. I know we have touched on this topic before as I have been re-reading your earlier posts. I gave you a link a month ago clarifying that you are legally entitled to your test results. Having your results would be useful in sorting the root cause.

    Low thyroid certainly accompanies Low B12 - VitD - Ferritin - Folate and many other vitals. All of which if low can cause you to feel tired. Low thyroid can often develop after having babies. Low thyroid can reduce stomach acid too due to a lowered metabolism.

    Symptoms of Low B12 and Low thyroid do overlap. There are over 52,000 people on the Thyroid UK forum here on HU and from reading over the last 5 years - most have had very low B12 and the others too.

    However good the diet is - we are what we absorb - not what we eat :-)

    Do hope you soon have the treatment you deserve ....

  • Thank you. Yes, I've been pushing for my results so I can post them here and although they've agreed they have sent me a little round the houses and told me it was easier just to sign up for patient access then to be told it would take 3 weeks for my results to be available to view. I was hoping to have them before seeing my doctor next so I was clear on what I wanted to ask.


    Here's the link again. You should not have to push - they are your results and you are entitled to them. Waiting yet another 3 weeks on top of the 4 you have already waited is so unacceptable. I feel for you - especially as you are feeling unwell - why all the control when you are trying so hard to find wellness and taking responsibility.

  • It doesn't make sense to me, I'm trying to help myself and take responsibility for my health. Not just cause it sucks feeling like this but also cause I've got stuff to do whether I'm well or not and it's easier to do if you're feeling good. I feel like I'm being proactive but it appears my gp surgery doesn't like that.

  • Your surgery should be able to print your results and hand them over - instantly.

    Simple as pushing the print button.

    When I get mine I ask the receptionistfor a copy and she prints them and hands them over while I wait.

    Terrible service 😖.

  • I thought this too. I asked for them and the receptionist said ok, went on my notes then hesitated then said she couldn't print them out down here and to ring the practice manager. I'm guessingsomething was on my notes which is why they keep passing me round.

  • Hi KJP723. Hmm...sounds like you might be right 😖.

    However, GP's can only refuse access to your medical records if they believe that the release of information will cause serious harm to your physical or mental health...but I fail to see how seeing a copy of your own blood results will cause you serious harm!

    Indeed, far less harm, I would argue, than the harm cause by your GP failing to treat you 😡.

    You could make a formal written request under the Freedom of Information Act - your GP would then have to justify the reason for withholding access, in writing - and it,would ha e to be a good reason, backed up by a little thing called evidence! But this would take time (think the advised response time is 28 days - but up to forty days to comply.

    It's also worth noting that if you ever find anything in your medical records that you think is wrong (or inappropriate) you can apply to have this removed.

    See Marz has left you a link that will be useful 😀.

    If it was me, I'd keeping pushing to get's your legal right.

    I think I'd apply, in writing, under the Freedom of Information Act, for a full copy of all medical records (records of surgery visits, treatments, diagnosises, correspondence with other health professionals, all blood tests results) - for completeness you'd need to list everything you want (no excuses then for things to be left out).

    It would perhaps be enlightening to see what has been done (or not done) - and what your GP has recorded in your medical records that makes them apparently reluctant to release your blood test results to you.


    Good luck 👍

  • You deserve better :-) When you have little ones - and not so little - you need all the help you can get. I remember those days when I used to fall asleep in lay-byes on my way to appointments - and then again on arriving home before feeding the family - plus more paperwork ..... Am really appreciating retirement - and the years are flying by :-)

  • Phone up and tell them you are coming in tomorrow to collect them. If they haven't got them ready say you will wait , settle yourself leaning on their counter.

  • I've rung this afternoon and said this and they said they would have them ready in the morning. Can't believe I didn't do this sooner!!


  • There you go. Now don't forget the leaning on their counter bit, signifying I'm staying here until I get them.

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