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Thyroid UK
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Crazy temperature problems

Hi everyone, hoping I can get some ideas about what's going on with my thermostat.

As background, I've fairly recently starting self medicating with lowish dose T3, but the following has been going on since before I started:

When I exercise, I always get way too hot, way too quickly - but my temperature is always low afterwards.

To give an example, the other day I got home from a half hour walk dripping in sweat and boiling hot (I do walk quickly, but I'm quite fit, I only had a thin top on and it was after dark so the outside temp was cool), but I took my temp and it was 34.6 °C.

Last night I was sat here feeling really chilly, (which is unusual for me, as even though my 'normal' temp without meds is 35.5 - 36 °C I usually feel quite warm) so I took my temp and it was 37 °C (!!). I've only ever been that hot when running a fever, (when I was a kid my mum knew I was ill when my temperature got up to 'normal').

Does anyone have a clue whats going on?

Firstly, why do I get so hot SO easily? Is it lack of T3? Like I said at the top, it was the same before I started taking anything, and I know I'm not on a high enough dose...

Second, why am I internally freezing when I feel like I've been to the sun (and look like I've been in the shower :\ ). I read somewhere that that can happen with low cortisol, where adrenaline compensates and causes the sweating. But I have crazy-high cortisol (can high cortisol do that?)

.... But then why am I cold when hot?

This thing is a flamin minefield and I have a brain made of play-doh. I've probably missed something important out... so you'll have to ask.

ps. Sorry if I seem like a random newbie asking for advice without inputting anything myself first. In my defence I've been reading this forum for ages and usually get the info I need from searching. You guys know everything :)

5 Replies

It all sounds like hypo symptoms, to me. And, all hypo symptoms are caused by low T3.


Welcome to our forum Ninjacazz

You haven't given any background on your profile. You don't say whether you have hypothyroidism, hashimotos - when you were diagnosed.

I assume you stopped levothyroxine and are now on T3 - a low dose?

If hypo we need T4 (levothyroxine) to convert to sufficient T3. T3 is the active hormone required in all of our receptor cells. If we exercise before being on an optimum of hormones it depletes the T3 in our cells and we don't feel so good. Our body's thermostat doesn't work propery if undermedicated.You may not be on a sufficient dose of T3.

You need an updated blood test and post the details on a new post.


I figured it was probably an under-medication thing. Thanks :)

I am hypo, but not Hashi's. I've been 'borderline' (T4 12ish (scale 12-24) and TSH just in range) for at least 10 years, but thats 'normal' in the medical world.

I slipped under the range nearly 6 months ago. Tried low dose levo briefly just to see what would happen late last year (self-med), but it made me feel worse (I know it takes some time to get working). Did the same with T3, just for a few days, and it made me feel better, again just an experiment. Left it alone after that for ages as I was scared of doing the wrong thing... Saw a few private Dr's with no luck.

Found a good endo a few months ago, who told me not to take thyroid meds as she thinks that my thyroid problem is caused by high cortisol, or something related to it. She got my GP to prescribe duloxetine for my anxiety and to help the pain, but it made me ill, so I cant take it.

A few weeks ago I got sick of putting up with unstoppable weight gain and pain... everywhere, so I started low dose T3. Pain loads better, stopped gaining weight (I think). I wanted to keep the T3 low, so as not to suppress my own thyroid too much if it can indeed be fixed at some point... but my body is clearly adapting and I keep feeling like I need more :\. Which I did expect, to be honest. The amount of research I've done into this... if I had put that time into my uni course I had to quit due to brain fog I'd be a geological genius. Ha.

Oh and I chose T3 over T4 due to the shorter half life, its easier to adjust (though a pain to multi-dose), and as my high cortisol would likely cause a rT3 nightmare.

I'll get on the profile thing.

1 like

Start off. Y getting a good thermometer and taking your basal (on waking) temperature. It's important to do it before getting out of bed and visits to the bathroom a huge no as losing body fluids brings your temperature down.

It is recommended you use a Mercury thermometer but they were stopped years ago (health and safety) I get a digital from a high street chemist but I founds that it was bleeping too soon. My temperature was nowhere near its maximum so I leave it in until it turns itself off as it detects no more change. I've tested it against a Mercury thermometer and it pretty accurate doing what I've suggested then let us know the average.


Hi silverfox,

I've been taking my waking temp for months now, and throughout the day. Before starting T3 my waking temp was always the highest of the day, usually 36.3-36.5. Since starting the T3, morning temps are more usually towards 36.5, but the main difference is that daytime temps have now come up to match it instead of dropping. Before the T3, average temps over the day were around 35.6-36.1, and now more 36.1-36.6, but variable. I'm following Dr Rind's metabolic temperature protocol.


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