system
Given the following post, respond as if you're commenting on Reddit:
human
How does the body determine how high to raise a fever?

Is it simply just based on the severity of the illness?
gpt
Someone smarter will come along... but the body does not really determine how high to raise its temperature in infection. Its really a product of how whatever insult... be it bacteria, virus, fungus etc triggers immune cells to release cytokines (one way immune cells communicate) and the inflammatory cascade. There are times when this process gets out of control and can lead to sepsis and shock that some people won't survive even in an ICU. So... while the immune system is an amazing evolutionary development, it can be over-reactive and set off a "bomb" when a lesser immune response may have been sufficient.