Why your nose runs when it’s cold outside

• A runny nose is common when we’re sick, but it can come unexpected when we’re perfectly healthy.
• So why do we get runny noses in the middle of summer or in the winter when we don’t have a cold? NYU otolaryngologist Dr. Erich Voigt says it has to do with the temperature of the air we breathe.
• In the video above, Dr. Erich explains what’s actually happening in your nose.

Following is a transcript of the video.

Dr. Erich Voigt: What is our nose doing? It’s actually able to take air that might be zero degrees or 100 degrees, and as you breathe it in, it gets the air to body temperature. The nose is probably one of the least appreciated organs in the body. The nose’s job is unbelievable when you start to think about it.

So, we breathe in liters and liters of air. And what is our nose doing? It’s actually able to take air that might be zero degrees or 100 degrees, and as you breathe it in, it gets the air to body temperature. The air could be very dry or very moist with humidity. It actually brings the air to a particular state of humidity, and it filters all the particles that we’re breathing in.

It does this through massive amounts of blood flow through the nasal membranes. These membranes are very reactive, they react to temperature changes, they react to particulate matter in the air, and the blood flow will actually change very dramatically inside of the nose. With these extreme changes in temperature, from hot to cold, the blood flow changes, and with that comes changes in the flow of mucus.

So, one's nose may run watery when we're in really cold temperatures because the nose is actually trying to moisturize and heat that air. It's using blood flow and mucus to do the job.

EDITOR'S NOTE: This video was originally published on August 25, 2016.