Can extreme hard physical exercise effect your thyroid hormones?

I've been on thyroxine since 2006, started at 50 mcg a day and am currently on 300 mcg daily. As I'm in the army my work consists of a quite physical hard exercise on a daily routine. Never used to bother me, but for the last 2 moths my muscles and joints would be in a lot of pain every time after any exercise. In a way it feels like my muscles don't recover and the pain just get worse.

25 Replies

  • Hi that's a large dose you have to take!!!! I took 150 levo until just before Christmas when the joint pain and weight loss was so bad I couldn't stand it anymore!!!!! I am a fitness instructor so like you do a lot of exercise and have done for years! Since only taking 25 levo my pain and stiffness is all away but thyroid levels are terrible!! Still feel better than on the medication and I have to blame that, just need to prove it to an endo when my appointment comes through!!!! Hope it eases for you soon it's horrible!!!

  • It may be that you are no longer converting thyroxine very well. One of the most common reasons for this is low iron or low ferritin (stored iron). You don't have to be anaemic to have low iron. If your ferritin is below 70 you may well benefit from taking an iron supplement.

    Other tests that are advisable are folate, vitamin B12 and vitamin D. You also might consider taking vitamin c, magnesium and zinc as these can also be helpful.

    Have you had recent thyroid blood tests? If so, please ask your doctor for the results with reference ranges. It can be helpful to know what your levels are when you feel well and when you don't. It might help you to find the right dose of thyroid medication if it ever needs adjusting.

    300mcg isn't particularly high for someone as active as yourself. It is unusual to see such high doses mentioned these days because doctors seem scared to prescribe them. Many people are under medicated.

    Sorry I can't be more help. It would be easier with your blood test results if you have them.

    I hope you find the solution soon.

    Carolyn x

  • Hi yes, had a blood test done 2 weeks ago, TSH was 9 something which was a bit high, also tested for iron, b 12, D , diabetes, but was all OK. My current symptoms hard to explain how I feel, don't feel tired as I normally do with underactive thyroid, but more muscle fituge. . And the more exercise I do the worse it gets. So instead of getting fitter or healthier it feels like I do more damage

  • TSH of 9 is very high for someone on no meds. For you, on 300mcg, something is very out of whack and the likelihood is you have thyroid hormone resistance and you're not converting T4 to T3. If the damn labs did their job and tested FT4 and FT3 it would be easier to see what's going on with you. I think you should request referral to an endocrinologist.

    It's very difficult to get NDT prescribed and becoming more difficult to get T3 but I would think you should at least get T3.

  • I agree with Clutter. Something is not right. Did they also test your T4 and t3?

    A referral to an Endocrinologist might be a good idea. The might be something else going on such as a pituitary problem causing your TSH to be high (which could cause the muscle fatigue if your T3 is to high) or Thyroid hormone resistance.

    I hope your doctor investigates thoroughly to find the cause of your symptoms so you can feel better.

    Carolyn x

  • They only looked at my TSH, don't think they look at the T3. I'll mention it tomorrow when I see them, thanks

  • T4 monotherapy didn't cut it for me and I was severely vitD and slightly folate deficient. I've lost and can't gain weight, and most loss is muscle mass.

    In addition to supplements you may need to add T3 to your T4. That and supplementing minerals and vitamins has made an enormous difference to me although I still lack stamina and energy.

  • I've been trying to get t3 and t4 treated separately, but the doctors keep on assisting that I don't need t3 as t4 will convert to t3. And it doesn't help every time I see a doctor it's always a different one

  • You don't need T3 if you're converting. Why do they find it so difficult to comprehend that conversion doesn't always happen?

  • Hi Tweed, thought it was only me with these symptoms. So you recon it might be the levo that gives the symptoms? I have tried going without the levothyroxine but trying to get the docs to put me on desiccated thyroid/armour thyroid to try is like talking to a brick wall. I know you can get it threw the NHS, but for some reason they don't like prescribing it.

  • Lots of exercise also depletes the adrenals, which makes it harder to use and convert T4. You might want to look at some adrenal support supplements - constant muscle soreness is a classic symptom of over training (ie not allowing the body enough time to recover).

  • Its vital you get the actual results and referance ranges for the tests that have been done as "normal "means zilch

    if your male then 300mg would be typical but most women are only on 175mcg of thyroxine

    hence if your tsh is 9 i would suspect you are not converting thyroxine t4 into the t3 your cells need and that ferritin is thus low or you have thyroid hormone resistance or adrenal problems

  • What you say make sense, I've got another doctors appointment on Monday and will try to explain to them points I pick up on this site. But it just feels as if they don't really listen to me, just because I look healthy. And it doesn't help every time I see a doctor, it's always a different one.

  • Welcome to the battlefield. I think you will get better advice here than at you GP or endo's appointment. Go to your doctors with the info. you have found here.Don't talk down to him but explain you think it's a conversion issue.You may find a GP is more open to being educated than a dyed in the wool endo.Do you have to make appointments to see the doctor if so even if you have to wait longer do try to see the same one. Personal I have found T4 gives more problems than it solves. Good luck.

  • There are other alternatives which may suit you better than levo. Unfortunately your Endo/GP may not prescribe. There is dessicated thyroid hormones which contain all of the thyroid gland hormones we don't produce (T4,T3,T2,T1 and calcitonin) and there is liothyronine (T3) which is the active hormone we need for our bodies to function properly. Many of us for whom levo doesn't work have found benefit by changing. These are some links:-

  • Unfortunately, you're probably going to have to do a lot of the analysis yourself and take it to the doctors.

    Quite a few people on here have said that vitamins B12 and D, folate and ferritin should be into the upper part of the range; that's definitely helped me. If your results are at the lower end, it might be worth trying some supplements. If you do, make a note of what you're taking and let the doctors know so that they can see the difference in test results and understand that you're taking some responsibility for your health.

    As for blood tests, get copies of your results and compare them over time to try to spot a pattern. Have a look at the four above plus TSH, FT4 and FT3. If your doctor is reluctant to test for FT3, suggest that you would like to eliminate that as a problem. It might be worth having a look at antibodies too.

    I think that the key is to work with doctors. You're more likely to get somewhere if you put forward a reasoned argument along the lines of "looking at ... , is it worth considering/investigating ...".

    Good luck!

  • Yes, read the article below.

    I've had to give up my running as I was physically exhausted within an hour or so later, even after consuming adequate amounts of food.

    You are probably producing too much reverse 3 because the physical activity increases adrenal fatigue. Even though i'm on optimal thyroxine I still get tired after moderate exercise.

    Unfortunately this is the down side to taking thyroxine over NDT because NDT containes T3, T2 and T1 and it's less likely you will produce reverse T3 on this type of medication.

    Unfortunately you are unlikely to be given this medication by GP's in this country (it's worth asking though) The only option is to fund it yourself.

    I found taking magnesium helped with the aches and pains.

  • I'll give anything a go! Don't mind funding it myself, but getting the prescription is where I'm stuck.

  • Hi swart, I was on 300mcg thyroxine for 35 years. The last 15 years I expreienced worse and worse recovery after execise and in the end I was unable to do any. Pain and fatigue was too bad. Helvella (one of the administrators here) said something to me that made sense---If you need 300mcg there may have been a conversion problem threre from the beginning. It seems that most common dose for somebody without a thyroid is between 150-200mcg, so if you need almost double, it may point to that. I am now on natural dessicated thyroid and T3 and I am doing better, but I have still a long way to go. Don't wait to long to make changes and all the advice here has been very good.


  • Thanks for the advice, I'm at that stage where the pain and fatigue are quite bad. I've been trying to get on desiccated thyroid for a while now, but so far no luck. I'll make sure to mention all of the advise I got from this site at my next appointment. Never new there was that many that suffered from this, whish you speedy recovery!

  • if you are lucky you will find somebody to prescribe on NHS if not you can get a list of private Drs from this site. many have to self medicate and if you find that you have to, there are many including me, that can point you in the right direction.

    The eye opener for me was the book Stop the thyroid madeness.


  • Swart, do you hail from SA by chance? Dont waste time trying to educate your gp, rather help yourself. I can point you in the direction of a private gp who will prescribe ndt. But why spend that kind of money when you can buy it online for less. Many here have trodden the path before you- the awakening, the belief your nhsgp will help u when you educate them, the battle, the injustice of the system, the realisation you have to take control yourself, regret that you wasted precious energy fighting for what you are entitled to when you should've started self med at the outset.

  • Yes bru, all the way from SA. I have tried buying it online but need a prescription, and the military doctors won't give me one so I can self med. And non of the NHS gp's will see me as because I'm in the army. Feels like I'm chasing my own tail...

  • Welcome fellow Saffa. Will pm you

  • This is the amount of thyroid gland hormone which used to be prescribed before the blood tests were invented.

    If you’re new to the use of thyroid hormone, and you’re up to a dose that should be working for you, but you’re not benefiting from it, be sure to let your doctor and your pharmacist know. The dosage range that’s safe and effective for most patients is between 2-to-4 grains (120-to-240 mg) of desiccated thyroid. The equivalent dosage range for T4 is 200-to-400 mcg (0.2-to-0.4 mg). If you’re not improving within this dosage range, you may have thyroid hormone resistance, or the potency of the tablets or capsules you’re using may be lower than what’s stated on the label.

    Also the following is a critique about the ineffectiveness of T4 for many.

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