Affect of exercise on Thyroid levels

[dizzy864]

Hi everyone.

I, realised back in March that my long suffering with nerve pain had got considerably better. I don't know why it suddenly reduced. I'm just really pleased that it did! I decided to get my health and weight under control as I am now able to exercise. I started doing three or four walks a week. I started very gradually and have been surprised how rapidly I have been able to build up. The walks have got longer - now 6 to 8 km and faster too. At the same time, I started doing stretches and aerobic exercised in doors once or twice a day. I've improved my diet too. I am really thrilled with the result. I've lost 9 lbs and 3 inches off of both my waist and hips. More importantly I am so much fitter.

A couple of weeks ago, I had to do my annual thyroid test. I booked it for 09.25 - the earliest I can ever get at my surgery. I remembered to stop vitamins with Biotin the week before and I split my levo from the evening to the morning before and stopped lio 12 hours before. 40 minutes before the test I got a phone call telling me it had been postponed to 11.30! I refused - I really can't go an extra two and a half hours without eating in the morning! I was offered the following morning - refused as this would mess up my thyroid med schedule and make the test meaningless! I rebooked it for two weeks later. ( 12/ 6 /24 ) Incidentally this is the third time my test has been cancelled at short notice. it's so annoying.

I have been on the same meds for four years now. 125mcg liquid levo plus 47.5mcg lio. I know the T3 result is going to be over range again and the TSH has been suppressed for years. I know that I should not be having blood tests due to high dose lio, but my surgery insists.

I thought because of the exercise I've been doing since March my results would be lower than normal. I thought exercise uses up T3. Actually they've jumped up instead.

22/5/23 free T4 21.6 ( 11.0 - 23.0 ) 12/6/24 free T4 23.4 ( 11.0 - 23.0 )

free T3 8.24 ( 3.1 - 6.8 ) free T3 9.84 ( 3.1 - 6.8 )

I know due to it's half life I should not take lio for 72 hours befor the blood draw but this is obviously not possible. I go 12 hours without lio, which means missing a tablet as I take lio every 8 hours. I can't tollerate taking the missing tablet earlier.

I do not feel over medicated. I am thrilled that after several years of total inactivity due to various health issues, I can at last exercise. I have to have a conversation with a random gp from my surgery sometime in the next couple of weeks. My surgery is staffed almost entirely by newly qualified locums!! The only senior doctor there that I could ask to speak to used to be my assigned gp. I fought him for years over my thyroid problems. He knew nothing and was convinced he was right. I suffered for years with him and will not go back to him!! We no longer have assigned gps so never speak to the same person twice!

I'm expecting the locum to insist I reduce my meds. I really do not want to do so. Is there an explanation for the increase in my results? I'm concerned as my free T4 has never been above range. It was 20 in 2022, so is climbing steadily. Is the big rise just an anomoly? Should I consider asking for a re test?

Any explanation or advise would be very welcome.

[Teddyandolive]

perhaps an over simplification here dizzy, but weight loss would presumably lead to a requirement to reduce thyroid hormone dose?

[dizzy864 in reply to Teddyandolive]

Hi, weight loss could explain the increase this year. However jup until March this year I ve been steadily gaining weight due to being too tired to exercise. By the same reckoning my results should have gone down year on year for the previous three years as my weight increased. That was not the case. When I ve been over medicated in the past, the first sign is I feel hyper. This is definitely not the case now.

[HealthStarDust]

I know due to it's half life I should not take lio for 72 hours befor the blood draw but this is obviously not possible.

72 hours? I don’t think I’ve ever seen that advise for blood tests when taking T3. It’s about 8-12 I thought.

[dizzy864 in reply to HealthStarDust]

Yes, the advice is 8 to 12 hours before draw. But that is only because that is the most anyone on T3 can go without it. Unless you re one of the people who is able to take it in one daily dose. Levo is stopped for 24 hours before blood draw because it has a 24 hour half life. By the same reckoning lio should be stopped for 72 hours as it has a 72 hour half life. I wasn't suggesting anyone stop lio for 72 hours as that would be Impossible. The point I was making was that my T3 results will always be over range and there's nothing I can do about it.

[Noelnoel in reply to dizzy864]

What you’ve achieved is amazing and it’s exciting that you’re now able to exercise but it sounds a bit frenetic. Albeit slowly, you’ve gone from nothing to between 21 and 40 miles/wk, plus indoor aerobics twice a day with stretches, that sounds awfully like overmedication. Without that much activity, imagine how much higher your labs would’ve been. You’d probably feel quite jittery too. This burst of energy might just be the jitters expressing itself through exercise

I’m not a medic so it’s just a thought. Could be utter nonsense

[dizzy864 in reply to Noelnoel]

Hi, I wish I could walk 21 to 40 miles a week! I said 6 to 8km three or 4 times a week. That's 24 to 32 km a week. That's 15 to 20 miles. My stretches etc have built up to 10 to 12 minutes once or twice a day. It's taken 3 months to get to that. I don't think it's excessive. I ve always been extremely active. I used to do at least an hour six days a week on an exercise bike. I did this for many years until February 2020 when I caught COVID then had long COVID for well over two years. Then other health issues.

[Noelnoel in reply to dizzy864]

Sorry, my miscalculation. Don’t know how I arrived at those numbers

Don’t you think it’s a possibility that you are overmedicated.

Those numbers are high. You could try not exercising for a while to see if you start to feel jittery, maybe headachey, tremors, sweating, anxious, insomnia or any number of overmedicated symptoms. I mention those only because they’re what I get when I’m over

[dizzy864 in reply to Noelnoel]

I don't think so. I usually notice feeling hyper - or my husband tells me! And I struggle to get to sleep. Neither is the case at the moment.

[HealthStarDust in reply to dizzy864]

I’ve been overmedicated a few times, and in some of the times I did not get the same pattern of overmedicated symptoms I would expect.

What ever the cause, your numbers are high hence you are currently overmedicated. But, perhaps your body can handle it. Perhaps not enough of it gets to your cells? Everyone is different.

[dizzy864 in reply to HealthStarDust]

Yes, I have absorption problems which throws out the results. Liquid levo helped but hasn't solved my problems. I ve always needed results at the very top. A few years ago it got worse and T3 needs to be above range for me to function. This is the first time T4 has been above range. I reduced lio very slightly last night. I feel really rough this morning. I will stick with it a bit longer and see how it goes.

[Noelnoel in reply to dizzy864]

Reducing lio will lower FT3 but will likely raise FT4. By how much did you reduce it

[dizzy864 in reply to Noelnoel]

By 2.5 much it's 1/8 of a tablet. It's really the lowest amount I can do

[dizzy864 in reply to Noelnoel]

Does that mean I'm completely stuffed?? I reduced my night dose of lio by 2.5 mcg ( 1/8 of a tablet ) three nights ago. I'm feeling terrible today. My blood pressure has shot up - I think that explains my constant headache. I had a lot of difficulty this morning trying to swallow my tablets. I'm freezing cold in spite of it being warm and sunny outside. I feel hung over, lethargic and really tired. I'm struggling to get to sleep at night. I'm up to the loo more frequently than normal. I'm constipated. I reduced lio in the hope that my T4 would drop into range. If doing so is not going to achieve this then I really don't know what I should be doing. I expect T3 to be above range but not quite as high as it is now.

[tattybogle in reply to dizzy864]

if the fT4 level is what you are trying to lower , then the levo dose is what you should be reducing .

(This ought to lower the fT4 (and probably the fT3 will reduce a little too )

reducing your T3 dose is only likely to reduce fT3 level , it would not be expected to reduce your fT4 level.

also , when you make any changes to dose , you need to give it a good 6 wks to allow the body to adjust itself to the changed levels before you make any judgements abut how you feel on the new dose. many of us have found hat even a very small change in Levo dose can feel pretty lousy for the first 4/5 weeks , but if we stick with it for a few wks longer to allow body to adjust itself , we realise it is actually ok

[dizzy864 in reply to tattybogle]

I really don't want to reduce levo. I am so much better since starting liquid levo. I think reducing that would definitely make me worse. Plus I don't want the next 6 to 8 weeks of being ill all through the nice weather. Even a tiny reduction has such a massive affect on me. I think because of the absorption problem some of my cells are already deprived of what they need whilst other cells are getting a bit too much.

[tattybogle in reply to dizzy864]

So ,when in doubt from looking at surprising blood tests . (and if don't have clear signs of under or overmedication) don't change anything for now ......wait another 3 mths and retest...... your next result may surprise you too .

[dizzy864 in reply to tattybogle]

I think that's very sensible!!

[Noelnoel in reply to tattybogle]

Extremely sensible

[Noelnoel in reply to dizzy864]

That seems an extreme response to a tiny reduction but no, it doesn’t mean you’re stuffed

I don’t feel qualified to advise further except to say that had it been me I would’ve tried a small levo reduction. That would’ve taken FT4 to within range at least and in a less abrupt manner because of its half life and depending on whether or not you have any conversion going on, FT3 might’ve declined a little

I see greygoose is around. She has a wealth of experience and knowledge and is much better placed than me to advise

[dizzy864 in reply to Noelnoel]

I ve been so much better since I started on liquid levo so I really don't want to reduce that.

[Noelnoel in reply to dizzy864]

Ok

Wishing you the best of luck

[HealthStarDust in reply to dizzy864]

Very good luck to you.

[dizzy864 in reply to HealthStarDust]

Thank you

[Noelnoel in reply to dizzy864]

I understand that you’re not feeling overmedicated at the moment but I just wondered whether that could be because you’re very active now. Could it be that if you stopped exercising you might then start to feel the effects of too much thyroid replacement. I’m not saying that is the case, only that it’s a distinct possibility

I also understand that you’re enjoying doing and feeling well and are concerned your GP will want a dose reduction but on the other hand it could be that you’re one of those who needs high levels of T3

It would be worth having a word with  DippyDame , she’s on high levels of T3 because she has a form of resistance . She’ll ask you all the right questions which might help you understand what could be happening for you. You’ll then be able to put forward a case to your GP for continuing as you are or making a gradual shift to T3 only

Good luck

[dizzy864 in reply to Noelnoel]

Hi, Thanks for replying. I have no way of knowing what the effect of stopping exercise would be. After four years of inactivity, I really don't want to find out! I have an additional problem. My blood pressure has always been on the low side. Eighteen months ago, it suddenly became high. The gp that I saw insisted that I reduce lio as he believed my being over medicated was to blame. I did reduce lio very slightly and immediately, my blood pressure went up higher than it had ever been. ( up from the mid 150s to the high 170s ). I put my lio back up and it returned to it's previous levels. Doing exercise and getting my weight down a bit, has lowered my blood pressure to low 140s. After one dose reduction, my blood pressure is up to 157 - the highest it's been since beginning of May.

I did suggest a switch to T3 only three years ago. The endo I saw would not agree to it.

I wondered about increasing liquid levo and reducing lio. When I went on liquid levo, I reduced lio down from 60mcg to 47.5mcg ( 20% ). I also feel a lot better although still not completely well.

[Noelnoel in reply to dizzy864]

I have no way of knowing what the effect of stopping exercise would be. After four years of inactivity, I really don't want to find out!

I understand, I’d be very reluctant too but I imagine a maximum of two weeks would not be enough to sabotage your efforts but long enough to allow you to feel the effects of being less active

Other than this I don’t know what to suggest. I hope a more knowledgeable and experienced member come along with some some suggestions you’d be willing to try

Have you contacted DippyDame ?

[dizzy864 in reply to Noelnoel]

Hi, yes I have messaged dippy dame

[Noelnoel in reply to dizzy864]

Would be interested to hear what she says if you don’t mind sharing it

[Noelnoel in reply to dizzy864]

Did you get a response

[dizzy864 in reply to Noelnoel]

No, not yet.

[dizzy864 in reply to Noelnoel]

I reduced lio last night by a very small amount. I feel really rough this morning but will stick with it a bit longer. I still don't think I m over medicated but T4 has never been above range before. Because I don't absorb meds properly, I am always on the edge of being hypo / hyper. It's a balancing act all the time. More meds makes something's better and others worse. Unfortunately reducing meds has the same affect.

[HealthStarDust in reply to dizzy864]

I believe your half lives are wrong. Levo is about 6-8 weeks, and T3 a matter of hours.

[dizzy864 in reply to HealthStarDust]

Sorry all I can say is I think you are very wrong! Levo is 24 hours, and lio has a much longer half life of 72 hours. At least thats what I have read.

[HealthStarDust in reply to dizzy864]

You are wrong. I woud not point it out so profusely if I did not think it to be dangerous to believe, particularly if new users stumbled upon it.

If only the half life of levothyroxine was 24 hours as it would be much easier to adjust dose as required!

See  tattybogle below.

[helvella Administrator Thyroid UK in reply to dizzy864]

Liothyronine has a much shorter half-life than levothyroxine.

How it is determined - and the state of the person - have a big impact, but

Single Dose T3 Administration: Kinetics and Effects on Biochemical and Physiologic Parameters

Studies reported by Nicoloff and colleagues in 1972 calculated a half-life of T3 that varied with thyroid status (8). The mean half-life was 0.63 days in 7 hyperthyroid patients, 1.0 day in 8 euthyroid individuals, and 1.38 days in 9 hypothyroid patients.

ncbi.nlm.nih.gov/pmc/articl...

Administration and Pharmacokinetics of Levothyroxine

The long terminal half-life of orally administered LT4, about 7.5 days, is consistent with once-daily dosing.

ncbi.nlm.nih.gov/books/NBK5...

[tattybogle in reply to HealthStarDust]

HealthStarDust, correct half lives are.

T4 approx 7 days

T3 approx 1.5 days (varies a bit)

too late for me to do links , but put this into search engine :

levothyroxine half life liothyronine

[dizzy864 in reply to tattybogle]

This is completely different to the article I read last month! I LL try and find it again but I didn't make a note of it.

[greygoose in reply to HealthStarDust]

T4 is about 7 days and T3 is about 24 hours.

[tattybogle in reply to dizzy864]

Levo has an approx 7 day half life dizzy , not 24hrs .

The 24 hrs testing advice for levo is not based on it's half life.

Levo (and T3) both show up as a steep increase in fT4 (or fT3) starting approx 1 hour after taking the dose (varies a bit depending on the individual's speed of gut absorption) ........ reaching their peak level briefly .. then falling gradually to more stable level, how long this takes will vary a bit , but by around 12hrs after taking a dose of T4 or T3 , the fT4 and fT3 will have 'more or less' reached this stable point.

So we usually want to avoid testing during this period (between taking dose and reaching a more stable ft4 / ft3 level) , because the levels are moving up and down so rapidly and we can't be sure what point we are testing.

[tattybogle in reply to tattybogle]

this stuff i've collected may be of interest re. your exercise question :

it's mostly about very intense exercise causing short term changes on thyroid hormone levels

healthunlocked.com/thyroidu... the-effect-of-acute-exercise-session-on-thyroid-hormone-economy-in-rats

healthunlocked.com/thyroidu... after-high-intensity-interval-exercise-ft4-ft3-up-from-normal-12-hours-later-both-down-from-normal.-both-return-to-normal-by-72hrs

[greygoose in reply to dizzy864]

Levo is stopped for 24 hours before blood draw because it has a 24 hour half life. By the same reckoning lio should be stopped for 72 hours as it has a 72 hour half life.

Pretty certain that's not correct. The half-life of T4 is about 7 days. For T3 it's about 24 hours.

[Xcskier in reply to greygoose]

I agree with greygoose. The 72 hours statistic is the time it takes TSH to rise back up to baseline after a single dose of T3.

[greygoose in reply to Xcskier]

Is it? I didn't think TSH moved that quickly. And I wasn't aware that it dropped after a dose of T3 because it doesn't respond that quickly.

[Xcskier in reply to greygoose]

Here's one paper I found. Subjects were euthryroid so it was a relatively large dose, but the study's strength was that thyroid hormones were measured over an extended period.

ncbi.nlm.nih.gov/pmc/articl...

[greygoose in reply to Xcskier]

OK, but what was the point? And would it be the same with hypos - why even try it euthyroid people who are not likely to be taking large doses of T3?

[tattybogle in reply to greygoose]

yes , it must surely be different with hypo's.

hypothalamus/pituitary's response to regularly getting needed small raise in hormone levels ... vs... healthy (young) men getting a sudden large T3 boost that was way over what their pituitary needed or expected.... seems logical (to me) that TSH might drop rapidly in that case , but might not in the case of a hypo regularly taking just the needed/ expected dose.

as though a hefty kick up the bum will rapidly shift TSH, but a gentle push won't .

[greygoose in reply to tattybogle]

Which is logical when you think about it. So, pretty much more useless research and I don't really know why we're talking about it! 🤣

[dizzy864 in reply to Xcskier]

Hi, thanks for that. It makes interesting reading. What I was more interested in is the effect of daily or regular exercise on thyroid levels. The surveys all seem to be a bout the effect of one bout of strenuous exercise on T3 in healthy, non thyroid patients. I m not sure how or if those results are relevant