Does cold temperature make the blood vessels in the nose constrict or dilate?
Common sense tells me it constrict. Sometimes when I step outside into a cold winter day, I feel my nose "openining up" immediately. So it seems the cold constrict the blood vessels. Also, when I have a nosebleed, if I step outside in the winter, the bleeding stops fast. My friends also have this experience. This means the blood vessels get constricted by the cold.
But I also heard the blood vessels in the nose will dilate when it's cold because the nose have to "warm" the cold air and the colder it is the more "warming" it needs to do so more blood get sent to the surface.
Which one seems right? I've always thought that it's "common knowledge" that cold constrict blood vessels on the surface of skins, hence we use icepacks.