We’re not sure if you’ve ever sat down and really asked yourself this question, but you found yourself here which means the question has come up by now. Especially if you, right now, plug one nostril at a time and inhale. You’ll end up finding that one is easier to breathe through than the other at any one time. We also have one trachea too, so why do we have two nostrils?
Two of Everything Else
Intuitively you’re probably drawn to how we have two of many other things on our faces. We have two eyes to give us depth perception. We have two ears so we know whether a sound comes from the left or right.
But there’s no rough equivalent for depth perception in our noses, and we don’t really have an immediate, innate sense for where smells are coming from. We turn our heads.
We do have one mouth though, which we can also breathe out of. So when you think about it, we really have three holes in our heads that can be used for the express purpose of breathing.
But also, if you can help it, do try to avoid breathing out of your mouth. It’s bad for your teeth.
One’s Better Than the Other
So if you did the nose plugging thing we were talking about earlier, you know one nostril is better at inhaling than the other. You obviously don’t really notice this on the day to day because well… You only need one hole to inhale through.
Turns out people have studied this. Your nose alternates which nostril is better for inhaling throughout the day.
So what’s the other nostril doing being useless and not inhaling air?
It’s smelling. Kind of.
Turns out the higher-airflow nostril is not only better at inhaling, it’s also better at smelling certain things. The lower-airflow nostril handles other scents. This is because, when you smell stuff, you’re actually sucking in little particles of the thing you’re smelling. Don’t think too hard about the stuff that smells bad.
The particles that get all up in your nose and give you smell get absorbed at different rates. Things that get absorbed slowly don’t get absorbed quite well through the high-airflow nostril. By the time it would be absorbed enough for you to smell, the particles have already passed through the rest of your respiratory system before you could perceive the smell. So that’s where the lower-airflow nostril comes in.
Is it the same as smelling apples through one nostril and your garbage can through the other? No. But it does tell us our two nostrils have a purpose!
Why Switch Around?
To be honest, nobody really knows why nostrils switch airflow rates every couple hours. The running theory is quite simple. High airflow is going to dry the heck out of your nose, so switching to the lower airflow nostril basically gives your nose a break.
You do get a feel for this whenever you’re congested or have a cold, though. It exacerbates the clogged feeling–especially when you’ve cycled into only being able to breathe out of the lower airflow nostril.
The nose knows. But does the nose know animal noses? See here. We promise it won’t smell unless your computer already does.