Thyroid UK
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Body temperature

Hello all, first time here. I have *not* been diagnosed as hypothyroid but was interested to know what you would expect to happen to basal body temperature if starting to become hypothyroid?

Guess I may be in an unusual position as I've had blood tests done that confirm TSH and thyroid antibodies are both "high", but I don't have any subjective symptoms. (I'm diabetic, TSH is routinely tested). The decision at the moment is not to treat and repeat tests in 6 months because I don't have symptoms, but to go back sooner if they start to appear.

I've started monitoring temperature since then and generally basal is about 36 celsius, which I believe is considered low, but maybe that's just normal for me.

I'm trying to establish if there's a risk of hypothermia, as my temperature was 35.1 celsius after being out running on a warm day here. I'd expect that would go lower as the weather cools down in the coming months.

10 Replies

I had bookmarked this, see if it helps. If not, I think Stop the Thyroid Madness has an article or two on it. Broda Barnes is the one who invented this theory if you want to google him.


I've had temperature readings as low as 35.4C after cycling in fairly warm conditions. Everything I've read suggests that this is not normal, and indicative of hypothyroid. Two GPs have said they were not bothered by the low temperature, and an endocrinologist said it was "interesting". However, they have all been trying to persuade me to take less thyroxine, regardless of how cold I get!! The GPs I've seen can't understand why I bother to test my temperature when I'm cold or tired. But - I regard it as useful information, and will continue to do it whenever I think it's necessary to show what's happening. I'm afraid it's a difficult area and one that doctors today don't seem to concern themselves with.


Hi Temp is a guide but I am treated correctetly and my temp is always very low, always has been.



You may not be adequately converting T4 to T3 if you're only on the standard T4 treatment favoured here? May help to add T3/liiothyronine.


If you've had a high enough TSH plus antibodies -- then it's an inevitable march toward having Hashimoto's -- and your GP is daft?! Treating would prevent the progression and onset, and may help with symptoms you were not aware were attributable to the hypothyroidism, that your tests have revealed you have. Regarding low basal temp -- I had been first diagnosed in the US with temps sometimes as low as 34.5C. Temperature was the method of diagnosing before the problematic one-size-fits-all TSH. A low temp, I'd been told, can lead to low moods -- as it affects serotonin production. Another help for raising temps -- this is from my old integrated doctor in the US -- is to use a lightbox (as recommended for SAD)-- regardless of whether you're feeling low. The light is helpful BECAUSE it helps raise body temps -- and that is what helps mood as well.

Good luck!!


THanks but it does not really apply to me. Best wishes,



If you have low basal tempreture with no symptoms it could well be wilsons syndrome look it up it may be a light bulb moment for you


The fact that you have antibodies shows that their is an attack going on to your thyroid glad. You have hashimotos and a good book is!auth...

Also, email and ask for a copy of Dr Toft's Pulse Online article, wherein he states :

But if it persists then antibodies to thyroid peroxidase should be measured. If these are positive – indicative of underlying autoimmune thyroid disease – the patient should be considered to have the mildest form of hypothyroidism.

In the absence of symptoms some would simply recommend annual thyroid function tests until serum TSH is over 10mU/l or symptoms such as tiredness and weight gain develop. But a more pragmatic approach is to recognise that the thyroid failure is likely to become worse and try to nip things in the bud rather than risk loss to follow-up.

Treatment should be started with levothyroxine in a dose sufficient to restore serum TSH to the lower part of its reference range. Levothyroxine in a dose of 75-100µg daily will usually be enough.

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Why wait until serum TSH is >10 in the UK -when most of the developed world sets the upper limit at 3? The whole business is a fit up- with the 'range' being garnered, using sick and dying people samples, to set the guidelines too high. FRAUD !!


Hi all, thought it was worth a follow up on this in case someone else finds it useful.

It turns out the temperature monitor I was using was in fact inaccurate by 1 degree, so the monitor said I had a body temperature of 36 when it was in fact 37!

The "high" thyroid antibodies test is not conclusive in my case, as I said I already have an autoimmune condition: type 1 diabetes.

Now there was a problem, but hypothyroidism wasn't it. After the half marathon, I discovered I had been overtraining; once overtrained I didn't sleep properly for nearly 2 weeks. Some symptoms overlap with hypothyroidism, this is a good article on the subject:

I don't know if it is significant, but I had a follow up TSH test at a time after I realised I'd been overtraining and had taken 3 weeks off to rest. It was after this period of rest that my TSH came back to a normal level.

My TSH came back down to a normal level without treatment, I finished the half marathon in less than 2 hours, and more importantly raised money for the juvenile diabetes charity.


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