Underactive thyroid

Hi all,

I potentially have an underactive thyroid (TSH 4.5 [0.4-4], free T4 11.8 [9-21]).  I have a lot of symptoms but the NHS don't recommend treating until TSH reaches 10.  I'm scheduled for a recheck in 6weeks or so.

I'm planning on a lot of long distance runs at the weekends to try and build endurance, as this has been a weak area for me with my running.  I read elsewhere in the forum that intense training can skew your blood results, causing a lower TSH.  If I do my runs at a low HR (I'm trying the Hadd approach) would this still potentially interfere with results? 

I'm so tired - I'm sure I'm hypothyroid and I want the doc to listen!!  I also feel the need to run long distances because I'm so frightened of putting on more weight.  I'm carrying about 10lbs more than I need to just now and finding it so difficult to lose them.

Does anyone have any experience of how training can affect blood results?  I find the internet awash with information about low thyroid but not much specifically for runners.

Thanks in advance image


  • Yes please. I'm going for blood tests in a week or so with my thyroid in the frame as responsible for a few issues. I have a race the day before so if anyone has any info I'd be grateful! How's that for timing?

  • I don't know that there is any evidence to support it but my experience is that during a period of hard training (I'm talking 10 - 20 hours a week) my TSH is suppressed. Within two weeks - say when recovering from an event and taking it easy - my TSH will rise again.

    Unless your lab has different values we usually treat anything over 5 as hypo (in the USA it's 3) and if you're symptomatic to be honest I would expect you to be given at least 25mcg of levothyroxine to see if it made you feel better. May be worth seeing another doc in your practice - I had to change GP to find one who treated me more according to how I felt than to the numbers. I feel very rough if my TSH gets near 3 and usually run very low - TSH of .5 - 2 - as long as my T4 isn't too high.

    If you think you can or you think you can't you're probably right.
  • Little Miss are you based in England? We are fighting this issue at the moment with my daughter TSH 4.8, was 3.7 eight months ago with low T4 loads of symptoms that she has been to docs with over last few months now depression hair loss as well as obvious ones. I had my thyroid removed due to cancer 20+ years ago but doc still says wouldn't treat as thyroid until TSH is 10 yet it looks like textbook symptoms to me.

  • I am in indeed savi. Have a look here: http://www.thyroiduk.org.uk/tuk/about_the_thyroid/hypothyroidism.html

    It would appear that in the USA they hav now lowered the treatment threshold to a TSH of 2.5 - I would seriously consider a different GP or push for a referral to an endocrinologist.

    If you think you can or you think you can't you're probably right.
  • Hi Little Miss,

    Thanks very much for the reply.  I'm not training anywhere near as hard as that so I should be fine!  

    After another 11hours of sleep last night, though, I'm going to ask if they'll trial me on a low dose of levothyroxine and see if that helps.  I don't have time to be sleeping so much!  

    Savi and Nicky - I hope you both get the answers you're looking for, be it an all-clear or a diagnosis!

  • My tiredness was incredible before I was diagnosed and started on thyroxine - I could get up in the mroning of a weekend, have breakfast, then need to go back to bed for a nap. Just about managed to stay at work but would have to go to bed when I arrived home and have a nap before having the energy to get some dinner before going back to bed, by the time I saw the doctor even breathng was an effort - and I was only just under 5 - which is why I now run very low to feel well.

    Rubbishrunner - I only put those hours in as an indication of what I know affects my results, it could be that less than that could lower it too but I don't have any experience of that. Hope your doc is helpful.

    If you think you can or you think you can't you're probably right.
  • Thanks for the link Little Miss it confirms lots of what I thought. She has a repeat test in about 5 weeks so hoping for something a bit more definite. 

    Good luck to everyone 

  • You have sub clinical hypothyroidism . Ask your GP to also check thyroid autoantibodies next time. If they are very high you should be started on 25-50mcg of levothyroxine


  • I managed to speak with the GP and he (eventually!) agreed to trial me on 25mcg of L-thyroxine.  He's suggested repeat bloods in a couple of months and he'll check antibodies then too.

    He said if my thyroid had normalised then he'd probably stop treatment in case it's been a temporary thing but I'll see about that nearer the time image  Especially if there are antibodies present!

    Thanks for the help everyone.

  • Good result RR.

    If you think you can or you think you can't you're probably right.
  • That sounds hopeful RR fingers crossed you start to feel better

  • Update - repeat bloods recently and now TSH 2.6 but free T4 11.2 which is lower!  Also think I have a positive antibody test result but was getting the results from the receptionist rather than the doc so need to get that confirmed.  My ferritin's also plummeted - I've been doing a lot of 50 mile weeks so suspect that's part of it.  Going to push for 50mcg thryoxine daily as well as upping my iron and decreasing my miles and see how I go.

    So far, I don't feel a massive improvement - fingers crossed for the next 6 weeks! Hope everyone else is doing okay image

  • My ferritin is always low too RR - even when taking a multi vit including iron daily (not at the same time as the thyroxine as that can affect absorption). Hope you feel better soon.

    If you think you can or you think you can't you're probably right.
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