Why do my eyes tear when it’s cold out?
Unless you love weather below zero, the answer to this question could just be crying. But if you’re like me, you’re tearing up for no good reason.
Your eyes would beg to differ. Keeping your sensitive eyeballs and their associated fluids necessary to see is a pretty good reason. Enter the tear reflex.
According to a study by Hirata and Meng in 2010, cold receptors on your cornea (the outer surface on the front of your eyes) are activated by dropping temperatures (duh) and by dry-eye receptors. When it’s cold and windy, you get a simultaneous and very active reflex. Which is why some Alaskan’s should invest in waterproof mascara.
The reasoning is this: in your eye, you have two kinds of fluid that are exposed and sensitive. If they freeze, you could be left in the dark. But, if you’ve got tears, you’ve got a watery substance kept at body heat that will dispense warmth around the eye to make sure freezing doesn’t happen.
But why does my nose run?
This is a two-pronged answer. First, your nose runs because if the tears don’t fall out of your eyes, they fall down through your sinus and out of your nose. Well, not directly because they have to mix with snot first, but you get the picture.
Second, this snot flows so freely because your nose has cold receptors in it too. But instead of directly making snot (like how the eyes directly make tears), the nose makes too much of it by mistake.
When your nose’s cold receptors are activated, they urge more blood to flow through your sinuses to keep the air flowing into your lungs warm and moist. Now that more blood (and therefore more nutrients) are in your sinus, more boogers are produced.
They can’t drip down the back of your throat; there’s just too much. So they flow like Niagara Falls until you can step inside and deactivate the cold receptors.
For those of you with over-sensitive cold receptors in your eyes and nose, I surmise it would be wise to count your blessings. Yes, even when your eyelashes freeze together and random good Samaritans ask if everything is “ok?” and offer a tissue. It all means that your reflexes are in working order.