Way to be vague :-p

If you boys wanna ride with 10cm of wire shoved up your cornhole, more power to you. I did it enough in grad school that I can say that's one Garmin metric I have no interest in.

Rectal temp (Tre) is a measure of pelvic temp (similar to using a thermister pill). It does not directly measure mean core temp, which is in the heart where the blood mixes. Esophageal temp (Tes) is a noninvasive measure of heart temp. Tre runs about 0.5C higher than Tes during leg exercise due to warming of the pelvic cavity by blood from the leg muscles. Also, increases and decreases in Tre are slower (due to the surrounding larger pelvic mass) than Tes, although the increases correlate well. The differences between Tre and Tes only become important during increasing and decreasing heart temp, not during equilibrium states like rest and steady submaximal exercise. This article might have good references on the 1960-80 original studies: Physiological Measurements 2012 June;33(6):915-24.

Interesting. That's pretty compelling. And a big difference.

Here's the pubmed link for anyone else interested
https://www.ncbi.nlm.nih.gov/pubmed/22551669

Lead and senior authors don't have anything since:
https://www.ncbi.nlm.nih.gov/...cauthor_uid=22551669
https://www.ncbi.nlm.nih.gov/...cauthor_uid=22551669

Looks like there is data on this going back to the 1950s but in pretty obscure journals.
https://www.ncbi.nlm.nih.gov/pubmed/?term=14824287

I don't think most studies take this into account.

If this is your area, you should put together a review article. I'm an associate editor for one of the ACSM journals (CSMR). If this can be summarized or meta-analyzed, it would land in one of our journals (probably ESSR).

Andy

It's something I've looked at for winter OW swimming (none wetsuit) but could only find the disposable capsules. Prefer to go off feel and how the body reacts to the cold but for additional safety some kind of core temperature monitoring device would be useful.