system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do some terminal patients appear to show a marked improvement toward the end, within days of ultimately succumbing (especially cancer patients)?
gpt
The term for it is "Terminal lucidity" and we don't have a great grasp of why it happens.  The explanation I've heard is that it is the body burning everything it has to keep going, effectively spending all of its reserves to return to something closer to regular operation.  Once those reserves run out, the person dies.