"Bundle up out there or you're going to catch a cold." That's what all of our mothers told us before going outside to play in the snow when we were kids. We've learned to equate cold weather with an increased risk of actually catching a cold.
It's true that the annual cold season suspiciously overlaps the cold weather seasons so well it couldn't possibly be coincidence ... right? It makes sense that being out in the cold causes you to catch a cold.
Cold weather does cause your nose to run, but that's very different than harboring one of the many cold viruses out there.
One of the purposes of your nose is to warm up and moisten the air you breathe before it reaches your lungs. Mucus helps facilitate that process and acts as a filter for harmful contaminants at the same time. The colder it gets, the more mucus your nose has to produce to warm up the air you breath. Some of it inevitably drips out.
Additionally, most mucus gets whisked through the back of your nose and down your throat by tiny hairs in your nose called cilia (different than nose hairs). But when it's cold outside, the cilia don't work quite as fast, also allowing some mucus to drip out the nostrils.
One of the main ingredients in mucus and air is water. When warm air leaves your nose as you exhale, it suddenly finds itself surrounded by cold winter air. This can cause condensation around your nostrils. As the warm air cools, it abandons some of the water it carries, which ends up sticking to your warm skin. The same thing happens when the mirror fogs up in your bathroom when you take a hot shower.
Anyway, that's why your nose runs when it's cold, but that doesn't mean you're going to catch a cold virus.
As it turns out, that assumption that cold weather causes colds isn't exactly correct. The weather is not the root cause of your raw nose, it's how we react to that weather that matters.
Where do you go when it's cold outside? How do your habits change between summer and winter?
If you're anything like me, you head indoors. That's what researchers Dr. Sorana Segal-Maurer and Dr. James J. Rahal Jr. concluded as well.
Segal-Maurer told CNN a few years ago, "When the weather turns cold, we all run indoors, where air is recycled and we're often in close quarters with other people and viruses. We all sneeze on top of each other."
And that's where we catch that winter cold.
This doesn't mean wearing that coat isn't important. Segal-Maurer also mentioned that cold weather can dry out your nose and throat, which provides a more ideal environment for cold viruses to take hold and grow.
So while the cold weather may not directly give you a cold, it can make it easier for that cold to stick around once that 3-year-old sneezes in your face.
Further research suggests that the when the rhinovirus attacks (that's the most common cold virus), warmer cells trigger a more effective immune response than colder cells. Our cooler nostril cells may be allowing the virus to replicate faster.