Anyone else wake up more tired when the air feels “stale” around your face?

I’ve been noticing something odd lately.

Some nights I sleep 7–8 hours, but I still wake up feeling a bit foggy. It seems worse when the room is closed, the air feels kind of “stale,” or when I stay under the blanket for a while.

But when there’s some airflow (like a slightly open window or a fan moving air around), I feel noticeably better in the morning.

I didn’t expect the air quality right around the face to matter that much, but it seems like it does. Has anyone else experienced this?

Curious what actually made a difference for you—is it just a temperature thing, or is it the air itself?