system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do I get a metallic taste in my mouth and a fuzzy ache in my head and hands after a nap, but not a full night of sleep?
gpt
Those are two different things.

The metallic taste is bacteria growing in your mouth. (Nice huh.) You don't get it during the day because you regularly swallow, and you generally don't get it overnight because brushing your teeth kills off a lot of the bacteria.

If you brush your teeth before a nap (especially use mouthwash) you'll avoid the mouth gunk.