low body temperature

[LadyBothwell]

Hello, I have pernicious anaemia (15+ years), I had a B12 injection on Thursday. I've always "felt the cold" my feet are permanently like ice, but having had a head cold a few weeks back and with the current "news" Ive been taking my temperature over the last few weeks and noted that it is never very high, this morning for example it is 34.7 (armpit). I also have problems absorbing iron and have iron infusions every 6 months so am wondering if this is a sign iron is low. I've recently increased my B12 from every 8 to every 4 weeks so wondered if that might deplete the iron more quickly.

[suztango]

Do you have an under active thyroid? Low body temperature is a classic symptom. If you have one auto immune issue, then you are likely to have another eg hypothyroidism (hashimotos)

[LadyBothwell in reply to suztango]

thanks, I was tested for thyroid and diabetes a few months back, and results normal

[suztango in reply to LadyBothwell]

What time of day did you do the test? (TSH and the thyroid hormones vary throughout the day eg TSH is highest in the early hours and lowest at around lunchtime. So testing should be before 9am and fasting.)

Also, did you get TSH, FT4, FT3 and the thyroid antibodies tested? fT3 is the ONLY active thyroid hormone. And the one to tell you if you're normal or not. Optimum levels for FT3 are high in range.

[LadyBothwell in reply to suztango]

thank you, I don't remember what time of day it was, in the morning definitely. TSH 1.58 miu/L 0.35 0 5.5) and serum free T4 15.9 (11.5 0 22.7). I don't see anything starting with an F on the results but there is a note against Thyroid Function test saying requested I recall them saying that was "normal" along with the diabetes and the rheumatoid factor (UK based) at the follow up.

[suztango in reply to LadyBothwell]

If they checked Total F4 then that test tells you nothing. FT4 (the free storage thyroid hormone) needs to get converted to FT3 (free active thyroid hormone). Total T4 is both free and non free components.

If your test was done in the morning but nearer lunchtime, this could be why your TSH is towards the lower end.

Also, there is a central thyroid condition where TSH is low, but also are FT4 and FT3. Its so important to get all three done at the same time.

[LadyBothwell in reply to suztango]

ok, I don't have any other symptoms of Hypothyroidism at least according to Dr Google! I read somewhere on here but now cant find it that if B12 starts working it can use up other resources hence my question about using more iron . I have a blood test for iron and transferrin levels next week so I guess I will find out more then

[Sleepybunny in reply to LadyBothwell]

Hi,

I suggest putting any thyroid results on Thyroid UK forum on HU.

There are other thyroid tests a GP could order .

thyroiduk.org/tuk/testing/t...

thyroiduk.org/tuk/testing/i...

[deniseinmilden]

I've always had low B12 and whenever I've landed up in hospital I've had a job to get out again because my temperature is always significantly lower than it should be and have had to resort to running up the stairs, having a hot drink, lots of blankets, etc to fake a normal temperature! I used to get hypothermia really easily too.

Since I started daily jabs nearly 5 years ago I have gradually become a normal temperature and only go super cold if I get too tired.

I get iron anaemic too but that doesn't seem to make as much difference as the B12.

Definitely worth checking your iron and making sure you have plenty of folate, potassium, magnesium, and vitamin D too.

[Sunshine1932]

Perhaps you need more b12. I was ALWAYS cold and I could never warm up from my feet to nose.

It is a horrible feeling but now I inject every other day it's gone.

I'm not saying you need to inject every other day but maybe more is needed.

I also have Raynauds and had that since a teenager but the b12 coldness is totally different. It gets you cold to the bones. Plus my temperature was always normal no matter how cold I was.

I wouldn't go looking for a disease that isnt there, just treat the symptom as you have been.

Good luck x

[Buttercup1283]

Funny u should say about temperature, mine has been low the last month or so but my iron levels are high. Normal thyroid and have hypoglycaemia (low blood sugar). I can’t fast for tests unfortunately. I was wondering too why my temp was low. My b12 and folate was low but I’ve been working on improving those

[Gambit62 Administrator]

LadyBothwell, when I first read your post my reaction, like suztango was the possibility of hypothyroidism (about 40% of patients with PA subsequently develop hashimotos), however your TSH and free T4 aren't highlighting this as an issue.

A general blood panel looks at a range of measures that are generally good indicators of particularly problems. It isn't meant to rule things out but is intended to find obvious problems or suggest areas where more exploration is warranted. Its not really intended to be something that categorically rules out problems. If the test throws up other problems then it would be appropriate to follow up with other tests confirming the problem. If nothing obvious crops up then it might be appropriate to start delving into things that didn't come up as obvious.

Temperature does vary through the day - think first thing in the morning is a point at which it is expected to be at its lowest anyway ... and people do vary as to what temperatures suit them - I tend to operate at lower temperatures and once my temperature gets up to the high 36s I start to find it quite difficult to function. where you read the temperature can also affect the results and can also affect the accuracy of a reading.

B12 doesn't interact directly with iron absorption - more that having a problem absorbing iron means you are more likely to have an iron absorption problem. Occasionally after you have been B12 deficient for a while a process that requires both B12 and iron might start working better again using up iron and depleting levels (could possibly happen if you had anaemia) but this would be temporary.

I'm not really that up on the effects of iron deficiency. cold isn't listed by the NHS as a symptom but people do vary and it isn't always possible to list every possibility as a result.

It is going to be quite difficult to know what is going on and see if things have changed if you don't have historic data to look at and it may well be that what you are seeing is quite normal for you.

[LadyBothwell in reply to Gambit62]

thank you, yes Im thinking it might be normal for me, I don't take my temperature often but Im pretty sure it never gets above 36.2 and it is now 36.16 it must have been the time of day I took it at the weekend. Probably wont monitor it as its easy to go down the rabbit hole of worrying unnecessarily. Im pretty sure its my iron, the timing is a bit early but the symptoms are there.