Did you know your nostrils take turns breathing in air? Well, at least they take turns breathing in the most air, meaning one always takes in a bit more than the other. This also helps explain why nostrils tend to trade off on getting stuffy as well.
How we breathe
According to Dr. Michael Benninger, a head-and-neck doctor at the Cleveland Clinic via Live Science (cited below), “At any given time, people do about 75% of their breathing from one nostril and 25% from the other, said The dominant nostril switches throughout the day. This is called the nasal cycle.”
We even have preferred nostrils. Some of us tend to take in more air through the right and others through the left (this corresponds to your dominant hand). But for the most part, our nostrils trade off about 2 hours.
Why do nostrils take turns?
We typically don’t notice one nostril being stronger than the other during the day. We also don’t really notice the trade-off unless we’re stuffy. But, in general, the nasal cycle continues throughout the day, even at our healthier, with one nostril becoming slightly more congested (and therefore taking in less air) than the other.
Why does this occur? No one knows for sure. However, Benninger told Live Science there’s one popular theory: “Some people have speculated that it has to do with allowing moisture to build up on one side so that it doesn’t get too dry.”
You may notice your nasal cycle more when you sleep, especially if you’re a side sleeper. When sleeping on your side, gravity will cause the lower nostril to become less congested. But this plays into the nasal cycle as well. If it’s your right nostril’s “turn” to be less congested, laying on your right side will simply even things out. But if you lay on the side of your more congested nostril, you may experience extra congestion.
Things aren’t quite the same when you have a cold that stuffs up both nostrils. In that case, your nasal cycle will have little influence over congestion. — WTF fun facts
Source: “Why don’t we breathe equally out of both nostrils?” — Live Science