The energy generators inside our cells reach a sizzling 50°C
While it might make sense to think that most of the reactions that take place in our body happen at body temperature, that's not the case.
There's folk I know who seem to thnk they're experts on how the immune system works, and who offer terrible unsolicited advice any time someone has a cold, or the flu, or whatever. It almost always relates to crap based off their own health-freak bias founded in ignorance.
This should be a good article to start with to tackle such bollocks.