system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What causes you to get sick of the taste of your own breath when you've slept longer than usual?
gpt
If you're asking about what causes morning breath, it really boils down to a couple of factors:

* Firstly, if you've been asleep for eight hours, that's eight hours in which you haven't brushed your teeth. That's eight hours for your standard minty-freshness to disappear, but also eight hours for bacterial colonies to multiply. It's these bacterial colonies breaking down food that makes bad breath in the first place. The more bacteria (and the more food they have), the worse the morning stink. (This is why it's not good to brush your teeth, then have a snack, then go to bed; you get rid of the bacteria, but you give them a fresh food source to gorge on when they build up their numbers.)

* Secondly, saliva production lessens during the night. (After all, your body doesn't really *need* it; it's not like you're going to be chewing anything.) One of the things saliva does is wash things from your mouth down into your stomach -- including bacteria. If you're the kind of person who sleeps with their mouth open, this situation is made much worse; evaporation causes your mouth to dry out, which makes it a lot easier for bacterial colonies to grow, as they're not constantly being swept away.