Thyroid UK
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Any advice on how to take the most reliable basal temperature test?

Do your pulse readings fluctuate?

Hi All,

I bought a digital infra-red thermometer this week and it's a whole degree celcius different from my under-arm digital thermometer! How confusing!! Which one do I believe?!! I've also found that my morning temperature is highest on waking than after I've got up for an hour or so when it'll then read lower (goes against the grain doesn't it?!!!!) I'm suspicious this is because I'm nicely toasty and warm after being under my duvet, 2 blankets, winter PJs with bedsock all night!!! (lol!) Does anyone else find this?

I also find that my pulse can fluctuate when taken on waking, depending on how I'm feeling. If I'm feeling typically hypo thyroid it'll be low but often when I am feeling particularly hypo it feels like my body then goes into a compensatory mode where it feels like my adrenals step in and I then feel 'wired' and my pulse reads higher! Do you find this?

What's your preferred way of taking your basal temperature?

Do you find your pulse readings an accurate indicator of thyroid function - do your's fluctuate?

Best regards :-)

3 Replies

Temperature does vary by where measured, by time of day, and numerous other factors.

The Wiki article on human body temperature has quite a lot of information (though, as always, cross-check information elsewhere):



I have a Braun ThermoScan in-ear one that seems to be reviewed as one of the most accurate online - I use it for my kids too, though they are still regarded as being up to 0.5degC lower than old fashioned Mercury thermometers done under the armpit.

I've been tracking my temp since starting on 10mcg T3 daily in combination with a reduced mean dose of T4 to 142.5mcg from 175mcg. I'm up by around 0.7degC with my readings this morning at 37.1degC in one ear and 37.3degC in the other.

I've also been tracking my pulse since starting on T3 and find that it's up by around 10 on average - I'm typically high 60's now when sitting resting (Coffee'd up too) and had been high 50's pre T3.

For comparison info, I'm a reasonably fit 33yr old Male carrying around a bunch of extra weight at mid 18 stone - my ideal is around 14 stone.

1 like

Thank you Rod & TDR1980 for your valued replies, most grateful. Interesting TDR1980, because I've noticed my temperature differs between both my ears too - I wonder why?!


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