Thyroid UK
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Monitoring my temperature - interesting results

So, I decided to monitor my temperature for a month before going to my doctors or getting private testing on my thyroid. The results so far are quite interesting. The highest my temperature has been is 36.8 and that was just before my period (sorry for the detail) and today when I woke up and felt like I had a fever. Generally it is 35 point something but my lowest is 34.9 and that was in the evening after putting the kids to bed/moving around. But my feet were freezing and I thought I would just take my temperature. My evening temp is often lower than my morning one. Will have to see what the average is at the end of the month. Does a low temperature always mean thyroid though? I would google what other ailments can cause low temp but I don't like doing that as you can get all manner of illnesses cropping up and it's not worth the anxiety! lol

13 Replies

Hi Some people do have a naturally low Temp. , although often it is an indication of thyroid disease. My Temp. has always been about 35, a fever for me is a normal temp. It causes me trouble in hospital sometimes etc. My thyroid is stable and has been for some years.A few ailments can cause a low temp. but unusual. Are you sure yours is not normally low? As we normally do not take it unless ill?

Best wishes.



I have also done the temperature monitoring thing. In a normal circadian rythym, temperature is at its lowest temp around 2 hours before we wake and highest in the late afternoon or early evening with a variation of about .5 of a degree. Normal range varies from 36.4 to 37.1 and in women, it is highest after ovulation. Exercise and humidity also affect what would be a normal temp (up and down respectively). Your temp also depends how you take it. Under the tongue will give a result about .4 less than an internal method. The interesting thing with your temperature is that the circadian rythym seems back to front and your temps sound low overall. Thyriod is one of a few things that could be behind this so identifying any other symptoms, such as exessive sweating, would be helpful in narrowing it down. Good luck.


You can also get lower temps after being active because of poor adrenal function.

If you take your basal (in bed temp) that is an indicator for thyroid.

Then take 3 more readings 3 hours apart from the basal test ideally, and divide them by 3 to get your average daily temp. Do this for 5 or 6 days and if there is more than a 0.2 or 0.3 difference in the readings then this will indicate adrenal issues.

So I would do my basal, then do 10, 1pm and 4pm for my adrenals.

The other thyroid temp indicator is 3pm ish where your temp should be 37.0 or thereabouts.

I find that I can exercise for 30 mins and my temp will drop drastically for a few hours afterwards, this is adrenals.

Here's a temp chart you can print off, if you don't already have one.


thank you for the detail in this post. This is interesting... I'm in the process of taking my temperature (The Times , I forget!)


Off topic, but obviously there are some responders here who know a bit about monitoring temps.

I bought a digital forehead thermometer (for monitoring flushes/sweats/freezes) but found that I could be red-hot yet the reading remained the same. I wonder if anyone could recommend a SPECIFIC thermometer that is fast and convenient - and not too dear ;-) I haven't been able to find the old-fashioned glass/mercury ones.

Many thanks :-)


Hi clemenzina --- did a 7 day temp chart sometime ago--- the first two of the day before rising monitored the thyroid, all the rest were for the adrenals. The latter fluctuated a lot which indicated an adrenal problem. So perhaps it is the same with you. By the way, before rising, the very first temperature to take us under the arm then by mouth.


Thanks all

Sorry, I should have said the reason I was monitoring is because I have fibromyalgia and I believe there is an underlying cause so yes, I do have many symptoms of hypothyroidism, as they are so similar to fibro. The readings in the morning are all basal temps before I get out of bed, the evening ones vary in time. But all your advice is really useful, I will try taking them at intervals throughout the day, and averaging it out. And next time I exercise I will take my temp afterwards to see how low that is. MP x


There's quite a few reasons why we can have a higher or lower temperature - which is why medicine seems to claim to not take it very seriously. (not of course because it's cheap and DIY)

Most thyroid friendly doctors however (while understanding the need to screen for other causes) tend so far as I know to see it as an important indicator of likely hypothyroidism...

My own experience is that it's a solid indicator within those limits, especially if it's maintained over an extended period.

I was low for many years - but no, I couldn't get my GP to take any notice of it.....



Thanks Ian. Was yours low for years with accompanying symptoms? My doctor has tested my thyroid because of hair loss of my legs (on the bright side it's less time I have to spend beautifying myself!) but of course they came back normal. I don't believe hair loss on the legs is just 'one of those thing' and I don't seem to come across any info that says it is fibro related so I am now 'gathering my evidence' with a view to going back to the doctors - will be interesting to see if she thinks temperature is significant or not. I am contemplating bypassing the GP and paying for private tests but it's just a case of money and also because I think I shouldn't have to! MP


Hi Melody. Pardon the length, and you're probably familiar with much of this too - but it's a chance to set out a picture which may help some.

I had 15 years plus of steadily worsening hypothyroidism - plus various associated ills. By the time I figured what the problem was (the doctors never did) I was about five years in and my temperature was near the lower end of the range that gets quoted as indicative of hypothyroidism.

I had most of the classic symptoms too. Cold feet and hands, low energy, all sorts of aches and pains, blinding headaches, spotty back and upper arms, bleeding gums, bloaty yellowish complexion, gut irregularity and other troubles, multiple food sensitivities, weight gain, brain fog/cognitive impairment, auto immune problems and episodes of various sorts, visual disturbances, a chronic sinus infection which in the end required surgery to clear, susceptible to every bug going, gout, dangerously raised blood pressure, tinnitus etc etc.

Even today taking T3 and in pretty decent health my temperature tends to be a whisker low. It came up very quickly when my replacement finally started working - from just over 97 deg F to just over 98 deg F. Which is perhaps the best confirmation of all that the problem was hypothyroidism.

Try 'basal body temperature' with 'thyroid' together in google - it should bring up lots of hits. There are many sites that set out how to test it and how to respond to variations.

Dr. Broda Barnes was the guy who brought the test to widespread notice I gather. In this book which even today is one of the best and most straightforward descriptions of hypothyroidism and its causes.

The big development from his day is probably that many more (as in my own case) now seem to run into thyroid trouble as a result of possibly modern diet and environment induced auto-immune illness rather than the basic regional mineral shortages due to deficient soils and the like which traditionally were the prime cause.

This seems often to lead to secondary hypothyroidism - that's where we produce adequate amounts of hormone so the blood tests read as normal - but enzyme and related issues downstream compromise conversion and use of the hormone. This is the scenario that seems to lead to so many (again like myself) struggling for years to get diagnosed - because the stock blood test for primary hypothyroidism doesn't catch it, and its diagnosis is difficult.

The simplest test of all (but not always reliable either - in that issues like nutritional or adrenal deficiencies, hormone absorption problems and other issues can prevent our making use of trial hormone) may be for the doctor to prescribe some T3 hormone. With possibly some adrenal assistance if needed. They have a huge resistance to doing this. Scientific respectability requires diagnosis using tests first, and trial replacement is frowned on. Yet against that there don't seem to be reliable tests available for secondary hypothyroidism - it seems that by default the diagnosis seems often to be symptom and hormone trial based etc.

The result is not many get fobbed off with a 'normal' result for the stock blood tests.

Bear in mind as repeatedly written about here that some of us don't do well on stock blood values. I'm actually fine at a TSH of about 0.5 and don't like it much lower, but there's definitely reason based on reports to think that quite a few falling below mid range for blood hormone levels may not to be as well as they could be. Beyond that there also seem reportedly to be some (few?) that need to run with higher blood hormone levels/lower TSH than even the upper limits of the stock ranges to feel well.

Be aware too that as hinted at in the first post that some seem to oversell the use of the basal body temperature test - there are many other reasons why temperature can be low.

Good luck with it, and congrats for getting stuck in and taking responsibility for yourself. Your temperature sounds definitely low enough to beg some questions, and it sounds like you are on a good trail......



Typo: 'The result is that many get fobbed off with a 'normal' result for the stock blood tests.'

The problem it seems is basically that very few doctors indeed are prepared to take the time or have the skills needed to engage in the detective work needed to make a symptom and trial based diagnosis of hypothyroidism.

They also fight shy of the risk that such an approach may not deliver after a lot of time and work, and that it's not as watertight a defence as a third party lab test against accusations of making an error..



I find that I have a lower reading in the evening too!


Hi there. I have been hashi hypo for over 20 odd years and never felt well but last 6 had fybro, cfs and hypoglycemia eventually after many tests have been diagnosed with hypopituritsm and now taking high dose of steroids daily (taken now for 3 months) next step is thyroid meds (been on levo all this time) endo agree prob not been converting in cells so to prepare for my forthcoming visit have been doing temp test with interesting results. I take 1st dose steroid at 6am so take 1st temp (around 36) once up and moving about during day yhey fluctuate anything between 34.4 to 35.5 throughout the day the lowest being when I am do for another steroid which are for adrenal probs. So do this indicate that I still have adrenal probs or is it an indication of thyroid under medication?. Endo say I have secondary addisons due to hypopituritsm disorder.


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