since a while i use the Estimated Body Temperature Data Field
i know it’s experimental, you have experience with it?
are you interested in comparing the data, possibly with data from a ramp test?
what I have noticed so far, in strenuous units I reach almost 39 degrees Celsius, can that be possible, does the body have a limit?
here a picture from my last Ramp Test:
Did not know there was such a thing 
Does it involve a new wireless sensor I haven’t heard about that measures your internal temperature? How does it… wait, no, I’d rather not know.
it works with every HR chest strap and the result looks not so bad, for my feeling, but would be interesting to compare with others 
Anyway, there will come a special sensor bythis company soon, but it looks like, it is very expensive:
yesterday, after a rather hot ride, my Edge 1030 flashed a little notice that I was “25% adapted” to the heat. I have no idea where THAT came from. It made me feel better for wilting, though.
You guys don’t ride with ANT+ enabled rectal thermometers? Amateurs.
So far I would not have noticed that the heat has too much influence on my body temperature
I always try to look at things a bit scientifically, even though I’m not a scientist, and I’m more of an amateur, but too nerdy
Haven’t played with the Garmin body temp app. Don’t know how they estimate core temp from HR, but I can’t imagine it’s super accurate at an individual level.
Garmin has the Tempe sensor which I’ve used for skin-temp readings indoors. Hook it to my HR band on the side of my chest. Can definitely see the massive difference from fan vs no-fan (like 32deg vs 26deg readings) and different clothing layers. But unfortunately it won’t connect to a Garmin that already has on-board temperature sensor, like most of the Edge units, so I haven’t used it out on the road.
Skin temp isn’t core temp, but it’s one part of the temperature gradient that’s relevant for how performance is limited by thermoregulation. Core temp basically reaches a limit that the body is unwilling to exceed, so performance and further heat generation will be throttled. A bigger gradient (greater difference in temp) from core to skin and the surrounding environment allows the body to shed heat faster, therefore perform more work at a higher rate of heat generation to match the rate of cooling.
Hence why fans to increase skin cooling are so critical for indoor performance.
here is now a hands on of the CORE i mentioned in this thread:
