Link between runny noses and rhinoviral infections

Question

Trying to answer another question about the link between the winter temperatures and catching the common cold, I remembered something one of my tutors said, namely that 'we catch more viruses when it is cold because our noses run and the exposed mucosa is a perfect virus catching ground' or something to that effect. So

1. does a cold temperature make our nose run?
2. does it mean we 'catch' viruses more easily this way?

To be honest, I can't find any evidence of my tutor's theory except for the runny nose being the symptom of an infection, not the cause...

Answer 1

As the Wikipedia article on mucus states, cold weather does cause runny noses:

During cold weather, the cilia, which normally sweep mucus away from the nostrils and toward the back of the throat (see respiratory epithelium), become sluggish or completely cease functioning. This results in mucus running down the nose and dripping (a runny nose). Mucus also thickens in cold weather; when an individual comes in from the cold, the mucus thaws and begins to run before the cilia begin to work again.

Mucus also functions as a trap for bacteria and viruses (again, quoting Wikipedia):

A major function of (mucus) is to protect against infectious agents such as fungi, bacteria and viruses. ... In the respiratory system, mucus aids in the protection of the lungs by trapping foreign particles that enter it, in particular, through the nose, during normal breathing.

I don't have any source on this, but I should think that a runny nose would be no better or worse than a dry nose for protecting against viral infections. If anything, I think it would be better to have a runny nose, as bacteria and viruses would have to "swim upstream" to reach their target destination.

Answer 2

You catch viruses more easily with dry mucosa. A running nose not only wets your mucosa but it also helps you transporting all the bacteria out of your body.

Rhinoviral infections in the winter are more common because people are more crowded indoors. That makes it easier for viruses to spread. And yes, you can even get a cold in the summer...