Why does a nose run when you have a cold?

why doesn't your nose run when you're asleep if you have a cold? yet even if you lay down and are awake it will run? just not when you're asleep?

so lately its been COLD out. and i was thinking, EVERYTIME someone goes outside in cold weather, and run around...their nose just about ALWAYS runs. why? im just curious. Thanx yall!! God Bless♥

I work in a cooler, and my nose doesn't run until I get in there, What triggers this? Is this the cold environment and why?

It makes sense that is would run when you eat hot food, but when its cold outside-like say 15 degrees-why does that thing drip?!!

well, whenever i run, i breath ( well durh!), but after a while, my nose start to get really cold, than i start to breath through my mouth, but after a while my mouth get dry and it ...show more

just trying to figure out why my nose wont stop running? what causes the nose to become stuffy?

I get that it's fighting infection, but why so much mucus? How does mucus fight a cold/flu virus?

This has been bothering me for a while, since things tend to solidify with cold, not liquify.

im talking about when you're NOT sick.