Why am I always sick in the winter?
As I was sniffling away during a Skype call, my friend commented, "Everybody's sick right now! It seems like as soon as the temperature drops, everybody catches a cold." I nodded as I blew my nose like a foghorn and sipped some more tea from my lair underneath a pile of blankets.
She's right - as soon as the weather gets colder and the days get shorter, it's a veritable field day for pesky pathogens (disease-causing microbes). Everybody knows this, but it seems like most don't quite know why. Does the cold weather itself make you sick? Or is the full story something more mysterious?
It turns out, it may be a combination of both.
Let's start with the more mysterious side of things, by putting ourselves in the tiny imaginary shoes of a rhinovirus, one of the viruses that causes the common cold. It's called 'rhinovirus' because in Greek 'rhino' means nose, but that's way less cool than my recent realization that the rhinovirus looks like it has horns. Like a rhino. So next time you have a common cold, picture tiny, tiny rhinos wreaking havoc inside your face. I hope this makes you feel a little better.
Anyways, back to the tiny rhinovirus shoes. If you were a miniscule rhino that travelled from cozy nose to cozy nose by air travel (read: shot out at high velocity with a sneeze), would you rather travel to lots of interesting, welcoming places on short flights or risk your life taking painfully long, leg-numbing, brain-frying plane rides between each luxury destination? Probably the first choice, right? Well, the rhinovirus thinks that, too. It's much preferable to travel between people that are packed close together, and without too many pesky air currents to sweep one off course. In other words, it's much more preferable to travel between people while they're indoors, and people tend to be indoors a lot more in the winter months. It's a probability game: you're more likely to catch a cold when you're inside, and you're more likely to be inside when it's too cold for you to willingly venture outside.
But what about the cold weather itself? Is there something innately horrid and evil about cold weather that makes your body decide to put up a vacancy sign for airway infections? Well, maybe. At least in mouse cells, scientists found that cells from the airway were less able to protect themselves from rhinoviruses at colder temperatures. This doesn't say anything for sure about human cells' relationship with rhinoviruses, but it could be a hint that your grandmother knew something about immunology after all.
Til next time - stay healthy, and don't forget your hat and gloves!