system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:How does our body generate heat during fever?
gpt
The exact same way it always generates heat, through something called metabolism where sugars and fats are "burned" in chemical reactions to create energy.

The difference is that when the body is sick with some medical conditions such as the flu or an infection, it is programmed to raise the level of metabolic activity to scoot your temperature up. It does this because many forms of infection and disease don't reproduce as well at warmer temperatures. But it doesn't work all the time and in runaway fevers can raise the body temperature so high that organ failure or brain damage can occur.