Body Temperature and Hypothyroidism

Hi, following on from a recent question I asked, I have thought several times in my life that my thyroid may be dodgy but blood tests have never indicated as such. It came up again when I mentioned feeling cold all the time and also in a book I have on fibro it mentions checking out your temperature at rest (first thing in the morning). So...I've gone and purchased myself some of those new-fangled digi thermometers that measure in Celcius (Lordy, I have to do online conversions - I'm a Farenheit girl if you please!) In fact I bought two of the things as I was going to do an underarm one but not done that so far, only in the mouth.

But every time, my temperature has been no higher than 36.3 which s barely over 97 and one day it was below 97 degrees. Normal temp should be 98.6F although they do have a normal range but this looks well outside the normal range.

On the other thread it was suggested that GPs can diagnose hypothyroidism but if your blood tests have always come back normal - what next?

I have a friend who's had all sorts of problems with her thyroid & pitutary gland and has had to have all sorts of medication.

Thanks x

19 Replies

  • my thyroid levels have aways just been slightly under and dismissed for many years despite all the signs being there. - Until one very hot summer in the 1980's. I was constantly cold and wore an arran cardi. My rheumi sent me to see a specialist who ignored the blood results and said what is inignificant for others IS significant for you. After a short time on thyroine I couldn't believe the difference!



  • Thanks Sandra - going to mention it to my GP next time I see her.

  • Hi Kirby, go by the centigrade your thermometer is giving you. In C your temp. should read between 36.5 and 37.5 Normal is 37.0 +/- 0.5.

    The 36.3 is below normal, Basal body temp. is taken when hypothyroid is suspected. Lots of info on Thyroid U.K. part of the HU web site.

    Hope this helps.

  • Thanks Siskin. It only gives Celcius readings but yes, I worked out that 36.3 was below normal and today it was 36.1 and stayed that way throughout the day. Thanks for your help.

  • as a general rule mine is around 38* and have been told that was ok, but it wouldn't hurt to check it with your GP, or even a pharmacist may be able to advise,

    my thyroid test have always come back normal too, I just assumed the blood test or that was always accurate but I have never questioned it though xx

  • I did mean my was 37 but clicked the wrong number :( xx

  • Thanks fibro for your feedback. xx

  • A low basal body temperature (measure your body temperature first thing in the morning. If consistently below 36 degrees centigrade, suspect Hypothyroidism).

    There are several different types of thyroid function tests which may be carried out. Interpreting all the different tests is complicated as there are various conditions which can change the level of these hormones. A rough guide to the different types of tests and their interpretation is given below. However, your doctor consultant should explain individual test results.

    Usually the first test to check thyroid function measures the levels of TSH in your blood. In people with hypothyroidism (Underactive thyroid) the amount of TSH will usually be high. This is usually because the thyroid is not making enough T3 to stop the pituitary producing TSH. If the level of TSH is high, you will usually have further tests to check the levels of T3 and T4 in the blood.

    In people with Hyperthyroidism (Overactive thyroid) the level of TSH will usually be low. This is usually because the thyroid gland is making too much of its hormones. When levels of T3 and T4 are high, the pituitary is 'turned off' and the amount of TSH produced is less. If you are found to have low levels of TSH you may have some more blood tests to check the levels of T3 and T4 in the blood. These tests may help doctors to find a specific cause of the low TSH.

    Please check with your GP Kirby, they will explain the various tests to you as they can vary slightly. This will also reassure you. (((hug))) xxx

  • Many thanks, Libs. Have booked an appointment for next week, but to be frank I don't trust the digi thermometer. I thought it was below 37 degrees that it was suspected hypothyroidism as gleaned from some sites. But I just checked my sister's and hers also read 36.4 today whereas yesterday hers was showing 37.4. I think I need to get hold of a glass type - I've seen them on the internet or maybe I can see if one of the local pharmacies do one.

    Thanks xxx

  • You may have a faulty digital thermometer Kirby, the digital type tend to be more accurate than the old fashioned glass type. Might be worth trying another digital thermometer, just a thought?!

    If you still want the glass type, I am sure your local pharmacy would have one.

    I hope your appointment goes well, please let us know how you get on, take care. (((hug))) xxx

  • I bought two digi thermometers, Libs! They do vary by about 0.2 degrees.


  • They can vary Kirby, now you have two lol! I hope it all sorts out well for you my dear. xxx

  • Thanks! xxx

  • Hi Kirby, for basal body temp. you should take your temp. before getting out of bed, and before eating or drinking anything. Your digital thermometer should have a clinically verified guarantee written on the box or insert.

    Your basal temp. will flutuate so has to be repeated daily over several weeks. Temp. may also fluctuate if still having periods, as basal body temp. changes around the time of ovulation.

    I believe glass mercury thermometers are now illegal so you may have problem getting one from a pharmacy.

    All the best.

  • Thanks Siskin - I checked with pharmacist and she said basal body temp is different than temp when you're taking temp for a fever, so 36.1 is within the normal range. Glass thermometers are OK as long as they're not filled with mercury.

    Take care

  • Hope you soon get things sorted. Cheers.

  • I have had all this checked and mine is always ok, hope you get to the root of the problem soon xxxxx

  • Glad yours is all OK, Ozzygirl.

    Take care


  • Well at least once it is done you will know where you are working hun xxxxx

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