I would like my HRM to also be able to also read my body temp. Im sure the body surface temp is different from our internal temperature, however I'd imagine there is a way to account for that and have a reading of how hot we are running???
Unfortunately there is no strong correlation between skin temperature in general, and core temperature. There are some locations on the body where you can come close to core temperature but there isn't a commercially available sensor solution for that right now.