• Due to excessive bot signups along with nefarious actors we are limiting forum registration. Keep checking back for the register link to appear. Please do not send emails or have someone post to the forum asking for a signup link. Until the current climate changes we do not see a change of this policy. To join the forum you must have a compelling reason. Letting us know what skills/knowledge you will bring to the community along with the intent of your stay here will help in getting you approved.

Rectum temperature much higher than under the tongue temperature

Callmestar

Member
Joined
Apr 3, 2019
Messages
580
I've had hypothyroid type symptoms for years and more recently had a high TSH of 8.6. I'd been taking my temperature via under the tongue and it was always low. Typical 36.0c/96.8f upon waking. This morning I thought I'd try tongue and then rectum after reading quite a bit about the rectum probably being more accurate.

My under the tongue temperature was 36.1c and my rectum temperature was 36.7c? Clearly a massive difference with one suggesting I'm very cold and hypo and the other suggesting I'm relatively normal.

Confused 🤷
 

xeliex

Member
Joined
Feb 10, 2016
Messages
473
Rectal temps typically are higher indeed around 0.5 degrees.
Go by the oral reading and keep trying to raise it a little.
My daytime oral temps are great but the mornings just don't change much despite thyroid meds.
 

haidut

Member
Joined
Mar 18, 2013
Messages
18,922
Location
USA / Europe
I've had hypothyroid type symptoms for years and more recently had a high TSH of 8.6. I'd been taking my temperature via under the tongue and it was always low. Typical 36.0c/96.8f upon waking. This morning I thought I'd try tongue and then rectum after reading quite a bit about the rectum probably being more accurate.

My under the tongue temperature was 36.1c and my rectum temperature was 36.7c? Clearly a massive difference with one suggesting I'm very cold and hypo and the other suggesting I'm relatively normal.

Confused 🤷

Serotonin, which is mostly produced in the gut, can raise rectal temps and rectal temp is in fact one of the methods of assessing serotonergic activity of substances in animal experiments. The difference in this case is small, so not saying it is due to serotonin, but for a larger discrepancy it may be applicable. That's why armpit (core) temps may be a better temps assessment than other areas. Rectal temps are mostly used on toddlers, as their serotonin is low and rectal temps are good surrogate of core temps as well.
 

Blaze

Member
Joined
Apr 25, 2020
Messages
447
I've had hypothyroid type symptoms for years and more recently had a high TSH of 8.6. I'd been taking my temperature via under the tongue and it was always low. Typical 36.0c/96.8f upon waking. This morning I thought I'd try tongue and then rectum after reading quite a bit about the rectum probably being more accurate.

My under the tongue temperature was 36.1c and my rectum temperature was 36.7c? Clearly a massive difference with one suggesting I'm very cold and hypo and the other suggesting I'm relatively normal.

Confused 🤷
Rectal temps have always been the most accurate way to measure and give a much better approximation of core temps. The only reason it is not used more is the discomfort factor. Patients will always prefer the oral temp method or the infrared temps taken by scanning the forehead.
 

Similar threads

Top