Underactive Thyroid

A lady member (age 50) of our running group suffers from an underactive thyroid being treated with medication. She has been running with us starting as a total beginner for 2 years and is finding that now as her fitness and general well being has improved and her pace increased once she hits 7/8 miles all energy goes.
Does this mean that her medication requires adjusting?
Her own theory is that because her metabolism is slow then after a certain amount of exercise her body can no longer provide her with the energy that she needs to sustain a better pace over a longer distance. We are currently training for the Glasgow 1/2 Marathon in September.
This lady has done so well and this weekend after our training session she was so upset because having completed about 7 miles of a 9 mile run in pretty warm conditions she was totally exhausted. She does take fluids on her runs so felt that she was hydrated enough. After the session she recovered quickly having had something to eat and a lucozade (non sport) drink.
Any help or you own experiences would be appreciated.


  • Ann

    This is a hard one. I am by no means an expert BTW and I know nothing about thyroid problems.

    Other areas to may be look at is fuel/diet in general. Is she eating enough and of the right type of food. This can have a tremendous affect on running and also on her endurance. Not enough fuel before you start running will run-you-dry so to speak especially with 7-8 miles+ runs. I know at one point I was struggling getting over the barrier of around that mileage or perhaps a little more ie 10 miles. It could well be that she needs a little more time and more runs of that length to build up also. Perhaps she is relatively new to that additional length of run?

    That sort of mileage is serious stuff and not something you can just do without alot of training and certainly not with ease to begin with. If you say she is hydrating correctly and enough, fine but it also may be that she should take on some fuel whilst running ie food/carbs. Unsure if she is drinking water whilst running also?

    I would say to speak to a doc or specialist about the thyroid side of things too. They surely will know whether this condition will affect running etc.

    Sorry I can't be more help.

  • Can't comment on thyroid excpet to say it's common to many people who run.

    Lots of runners (and walkers) have a 'time' or 'mileage' limit, at which they run out of energy. At it's simplest one of the goals of training is to increase that limit.

    What happens if she takes a glucose tablet just before the point when she normally runs out of energy?
  • Hi Ann,
    I've been thinking for a while about how to reply to this. My Mum and I both have underactive thyroids, so I do know a bit about it. Problem is that it can become very easy to blame everything on not being balanced. It is probably worth this lady getting a thyroid function test at the doctors, but not to be surprised if it comes out normal. Once you are balanced your metabolism should go back to normal, and your thyroid shouldn't affect you. I guess it is a bit like being short sighted, once you have the correct glasses you should be totally 'normal' again.

    There have been a few threads where people have become stuck at some distance or another. Maybe try to search for them to get some other ideas of how to help. I find if I try to trick myself it can help. The way I do it is to go on a different route and then I don't notice how far I'm running. Or if you are running in a big group, get a really interesting conversation going at around 6 miles, that might distract her from the length of the run! :-)
  • As Miss Piggy says, what your club member experiences sounds as if it's unlikely to be related to her thyroid condition or the treatment (which is simply a supplement of one of the naturally-occurring thyroid hormones) and I'd look at training issues.
  • Hi Ann
    I have Hashimoto's which is the autoimmune version of hypothyroidism. As the amount of training I do has increased so my need for supplementation has also increased (for info I currently take 275mcg/day T4 and 40 mcg/day T3).

    For me it seems to be the intensity of exercise that matters. While I was training for FLM and doing lots of miles at steady pace, I was OK. Since then I have being doing speedwork (and heavier weights too) and I've needed adjustment. I went through a period of crashing after exercise when I would get so so cold I was shivering violently and my teeth were chattering.

    I've read everything on exercise physiology and thyroid disease I can find (there isn't much), but the concensus seems to be that in a person with a healthy thyroid exercising at high rates of VO2max triggers an increase in TSH presumably to stimulate the thyroid to replace what is being used. People with thyroid disease don't have that response.

    If your friend had her supplement balanced and has since increased her activity level significantly, it is perfectly possible that she may need more supplementation. I'd suggest that if she has any other hypo symptoms in addition to the runnning problem, then she probably needs to re-visit her dosage. If the running is the only problem, I'd be more inclined to think it is a training / nutrition / hydration problem.

    I did all my medication adjustments myself because I found NHS doctors (no disrespect to any reading) particularly unhelpful with thyroid disease. I got the "You're taking 100 mcg of thyroxine so you must be fine" line and the symptoms which a year ago had DEFINITELY been caused by thyroid were now 'vague and unspecific'.

    I'd also advise caution in relation to test results. Most people don't have a thyroid test when they are healthy so don't know what their 'normal' level is. The ranges are very wide and unfortunately doctors seem to label you 'normal' if your results are anywhere in the range.

    I now see a thyroid specialist privately - if you want details, email me and I'll send them (- he does clinics all over the country including Glasgow - he is Glaswegian himself). I hope she is able to overcome this obstacle and good luck in the Glasgow Half.
  • Thank you all for you repsonses I will pass them on and keep them all on file for futre reference. I will let you know how things go.
  • Hi Shirl,

    Me again as not sure if you will get my other post on another thread...........I've posted you a message reference being recently dignosed with an under active thyroid and am desperately looking for information (any)about this subject in relation to exercise.

    I am a keen runner and wish to remain so, but life has been hard the past 18 months getting motivated. I now know why, but I know that I am still not right. The doctor is testing me out with 28mg and I have to got back in 3 months for a further blood test. I know I have to put my trust in his hands for the next three months to see how I go, but am still eating for six instead of the one person I am! Why can't my brain register I am full?

    Anyway that's just me nagging, any information is greatly received - many thanks in advance - Lizzy
  • Hello Shirl,

    Your contribution was really helpful... and rather scary. I was diagnosed 6 months ago and am now on 100mcg. It doesn't feel like enough. How did you feel about making your medical adjustments yourself? My doctor told me to give up running. I find this unacceptable. I would really appreciate the contact details of your specialist doctor in Glasgow - although I'm in London.

    My problem is tired and aching muscles and inability to recover for ages after running or a gym session. I didn't take part in the British 10k today because I can hardly walk, climb or descend the stairs, sit down or stand up. This is after an hour in the gym 4 days ago.

    I'm signed up for the Amsterdam Marathon in October and a charity cycle to Paris from London in September.  At the moment the only training I'm doing is taking pain killers. An Internet search for 'underactive thyroid and sports / running' brings up absolutely nothing.

  • Tania - Shirls post was dated 2003 and I haven't seen her around the forums for a while (hope you're ok Shirl - you're missed). I'm hypothyroid, have run a couple of marathons and am currently training for an Ironman. Your doc is talking pants telling you to give up running - find a different GP, they all have different ideas - if your TSH is at the high end of the 'normal range' - 0.5 - 5 is what the labs use where I am - then it's worth checking yoru iron levels and also B12, if you have autoimmune hypothyroidism then you might also have perniscious anaemia - and the symptoms (i.e tiredness, lack of energy etc) are similar enough to be masked. Good luck.
    If you think you can or you think you can't you're probably right.
  • Thank you Little Miss Piggy. I noticed Shirl's post date but I thought I would try anyway. I've also started a thread on the subject.I've been checked for pernicious anaemia and that is negative although I was on iron tabs for a while. I do have tiredness and lethargy but running and cycling have been part of my life too long for those little symptoms to have any sway. However, aching muscles are a different matter. If I walk like a 90-year-old then running is simply not going to happen. It does seem to me that more sportspeople with underactive thyroid need to speak up. So far obesity seems to have a monopoly on the condition. Good luck with your ironman. X Tania
  • HI sorehip! I have just been diagnosed with hypothyroidism on an incidental blood test...but i have no symptoms! In fact i did an ironman last August....does anyone know whether doing an Ironman can actually CAUSE hypothyroidism. Also could i have the details of the glaswegian doctor?

    Thanks so much!

  • Hi everyone I have just been diagnosed with underactive thyroid. The doctor has put me on 25mcg for 2 weeks then it will upped to 50mcg. I do feel a bit tired but I have still been doing 10k runs but slow 9 min miles way off what I would normally do. So as to not push myself to much. I'm supposed to be doing the VLM this year. The doctor has advised me not to do it but I want to. I though I could jog a bit then walk a bit and so on. I feel I can manage this. What do people think should I still do it or not? I've waited 8 years to get in & can not defer it as its through my club. Should I not do it or do it any advice please


  • BookyBooky ✭✭✭
    There's no reason for you not to do the VLM if you physically can - being hypothyroid and maintaining activity won't cause any problems, although you may not perform at your best. There's no harm to be done, so if you can manage it, then why not? image
  • Hi Wayne
    I too am hypothyroid - and have read widely on this as its caused me huge problems.
    What especially worries me about your post is
    i) you say that you are running way slower than you used to and are feeling tired (mind you this is a hard training month) - but this in itself suggests that your endocrine system isn't firing right yet.
    ii) your Dr has started you on incremental doses. This is what Drs always used to do but there is research now emerging which suggests starting at the full dose is better for fit relatively young people. It might be worth having a google - you'll find lots of articles like this http://archinte.ama-assn.org/cgi/reprint/165/15/1714.pdf (cut and paste into browser - I can't get the link feature to work - sorry)
    Anyway I was started on the full dose (100 mcg) straight away.

    The risk for you is that under-treated hypothyroidism and intense exercise risks cardiac problems. And the training for a marathon plus the marathon itself is a big physiological ask for anyone let alone for someone who is not stabilised on their treatment. It can take time to get the levels right especially for athletes as exercise and weight both impact on the right level of levothyroxine for you.

    I really think that any responsible running club would not want one of their members running when it could cause them long term harm.

    Hi Andrew McLaren - I feel that all the marathon training, marathon and 1/2M's that I completed 10 years ago - really pushing myself way beyond sense - eventually contributed to my hypothyroidism and current complete inability to exercise and hardly even walk, despite thyroid treatment. I say this because the brain fog & hair loss that I got whilst overtraining was exactly the same as that which I got during 2010 when my hypothyroidism was undiagnosed. Yet the endocrine system is so complex that many other factors come into play as well and it doesn't get easier as you age! Eg Other hormones including progesterone, which even men need in order to facilitate T4 to T3 conversion come into play, apparently.
  • Just thought Wayne - has anyone told you that it takes up to 3 months for the thyroxine to get into your system at the right level? So that's why its not working 'overnight' for you. And speaking of overnight, taking thyroxine last thing at night has been well proven (since 2007) to be more effective than in the morning which is when most drs tell you to take it. I switched over to night time and also let it dissolve in my mouth and really noticed a difference.
  • Yes, I did on another thread he posted on!
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