Made an interesting observation today.
I was in my school office cubicle working on some assignment between 1pm to 3pm (on a miserable Saturday). For some reason, the air conditioning was turned way up high today, so the room was literally freezing. I froze my ass off the two hours I was there, glued to my seat.
At 3pm, I left the office and headed for home. It was a scorching hot afternoon, and I must have spent at least 20 minutes out in the open while on the way back (counting all the time I wasn't in the shelter or a bus or the train).
It is plausible that the freezing conditions in the office led to what appears to be a malfunctioning of my bodily sensation of heat, at least temporarily because, despite the killer heat, I went nowhere close to even feeling the sensation of perspiration (you know it when you feel it - that tingly feeling on your skin indicating that your sweat glands are working up). Which is very odd because I think I perspire reasonably easily and those same sunny conditions would've triggered my sweat glands any other day.
But this wasn't any other day. As a result, I traveled home with my sweat glands (or some other correlated organ) pretty much switched off.
What happened next? I had a terrible headache and body aches, as though I was having a fever.
What strikes me immediately is the advise that old folks often give: if you're in a cold place, don't suddenly go out into the hot sun.
The fever probably isn't caused by a virus, because there was no one else I interacted closely with and I have recovered rather quickly too in the comfort of my house.
What I think has happened is that the momentary inability to perspire caused the heat from the sun to be trapped in my body, upsetting our basic homeostasis. Regardless of whether I'm having a real fever or not, a rise in body temperature signals that there is potentially a bacterial or viral invasion, and subsequently fever-like symptoms (which actually functionally exist to protect you, not to make you feel miserable) emerge.
I might be wrong, but the observation is still fascinating. Regardless of whether one stands on the side of determinism or free will, it's still pretty cool to see how a human can survive off chain reactions triggered by the environment without conscious input.