The most annoying thing for me about being cold is a runny nose. Is there an advantage to having a runny nose when cold? What does having a runny nose achieve?
There are two reasons for this:
- Nasal mucus helps warm inhaled air before it reaches the lungs. In cold weather, the mucus tends to dry out, so the membranes increase their production.
- At the same time, exhaled air is warmer than the surrounding air, so it contains more moisture than the outside air can hold. This moisture condenses around the tip of the nose.
Explanation found here.
So there's no particular advantage to getting a runny nose; it's just a normal reaction occurring in extreme conditions.
Rhinorrhea, or runny nose is a response used by our nasal membrane to get rid of foreign particles including pollen dust and infection. As such we get runny noses when we have a cold, allergy or are exposed to high densities of air-born particles. Cold air may irritate our nasal membranes, both because of temperature differences relative to our body and due to the lower amounts of moisture cold air holds. Cold air thus also results in a runny nose.
There are definite advantages to getting a runny nose in cold weather. Rhinoviruses prefer cold weather and deploying large amounts of mucus is a good way to trap them (instead of letting them get in to infect the nose). Additionally, severe dry nose can cause nosebleeds and the mucus helps prevent this from happening.