system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why when your stressed are you more susceptible to illnesses?
gpt
When you are stressed, your body is producing certain chemicals and hormones to deal with that. These hormones are good for handling something in the here and now, especially the sort of threats we used to face when we were hunter/gatherers, but over longer periods of time these hormones have the side-effect of suppressing the immune system. In addition to that, they also generally suppress your appetite (harder to fight off bugs if you are low on energy) and can wreak havoc on your sleeping (again making it harder to fight off disease)