# runny noses **URL:** \ **Category:** Factual Questions\ **Created:** [October 4, 2009, 5:57am UTC](https://boards.straightdope.com/t/runny-noses/512521 "2009-10-04T05:57:58Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![BigBertha](https://avatars.discourse-cdn.com/v4/letter/b/d78d45/32.png) [@BigBertha](https://boards.straightdope.com/u/BigBertha)\ **Post date:** [October 4, 2009, 5:57am UTC](https://boards.straightdope.com/t/runny-noses/512521/1 "2009-10-04T05:57:58Z")
No, I’m not going to ask my doctor, because its not really important, but i am wondering why Every time I get a cold, one eye and one nostril get runny. Only one side. Its just odd. ---
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [October 4, 2009, 8:53am UTC](https://boards.straightdope.com/t/runny-noses/512521/2 "2009-10-04T08:53:44Z")
Well, I’m not sure about the tear ducts, but I know that at any given time, one nostril is closed and barely allows any air through (whether you have a cold or not). > [@Wikipedia](#): > > In humans, the nasal cycle is the normal ultradian cycle of each nostril’s blood vessels becoming engorged in swelling, then shrinking. During the course of a day, they will switch over approximately every four hours or so, meaning that only one nostril is used at any one time. I’m not sure which nostril has the tendancy to run when you have a cold; the closed one or the open one. But there’s definitely a difference. ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [October 4, 2009, 9:13am UTC](https://boards.straightdope.com/t/runny-noses/512521/3 "2009-10-04T09:13:17Z")
I’ve noticed that when I have a cold or allergies, one nostril is typically stuffed at a time, and they will switch back and forth during the day. One thing that really surprises me is the speed of the switch, often the left nostril will “depressurize” (and make weird sounds) for a few seconds, then the right, previously functioning perfectly, is blocked like a hairball in the drain. One interesting thing I learned a while ago is that nasal congestion isn’t actually caused by too much snot, but the inside of the nostrils becoming swollen due to irritation. That’s why you can blow your nose all day long and still be unable to breathe. ---
**Author:** ![BigBertha](https://avatars.discourse-cdn.com/v4/letter/b/d78d45/32.png) [@BigBertha](https://boards.straightdope.com/u/BigBertha)\ **Post date:** [October 4, 2009, 6:51pm UTC](https://boards.straightdope.com/t/runny-noses/512521/4 "2009-10-04T18:51:38Z")
This is interesting! But my eye runs a lot more than the nose (and always on the side of the runny nostril). What makes eyes water and why only during a cold? ---
**Author:** ![Lobsang](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lobsang/32/4067_2.png) [@Lobsang](https://boards.straightdope.com/u/Lobsang)\ **Post date:** [October 4, 2009, 7:00pm UTC](https://boards.straightdope.com/t/runny-noses/512521/5 "2009-10-04T19:00:00Z")
> [@Mijin](#): > > Well, I’m not sure about the tear ducts, but I know that at any given time, one nostril is closed and barely allows any air through (whether you have a cold or not). > > > [@Wikipedia](#): > > > > In humans, the nasal cycle is the normal ultradian cycle of each nostril’s blood vessels becoming engorged in swelling, then shrinking. During the course of a day, they will switch over approximately every four hours or so, meaning that only one nostril is used at any one time. > > I’m not sure which nostril has the tendancy to run when you have a cold; the closed one or the open one. But there’s definitely a difference. As an example of “you learn something new every day” that’s a pretty big one! Only one nostril is in use at any one time?? I never knew that before. And it stands up to scrutiny. If I nose-blow onto my palm, I can feel the majority of the air is coming from one nostril. I will never again wonder frustratingly why one nostril is blocked and the other isn’t.