Jami

Hello I have to fill in the missing word and I'm completely stuck. The paragraph is talking about thermoregulation and the 'life-threatening condition' is heat stroke. The rest of it makes sense and was easy to fill in but this bit doesn't seem to make sense to me at all. I know you won't just tell me the answer but any clues would be really appreciated. "A life-threatening condition occurs when the core temperature reaches the…………………………. temperature"