What do you think of this fact?
Pay attention to your breathing for a second. Chances are one nostril is doing most of the work. That’s not a cold and not a crooked nose. It’s called the nasal cycle, and it runs around the clock.
Your nose works in shifts
Inside your nose sits erectile tissue that can fill up with blood and shrink again. When it swells on one side, that passage narrows, and the lion’s share of the air takes the other route. Every few hours, your autonomic nervous system, the same autopilot that runs things like your heart rate, flips the setup. The narrow side opens up, the open side narrows.
You don’t decide any of this. It just happens, all day and all night, while at least 12,000 liters of air pass through your nose every day, according to Ynetnews.
33 people, 24 hours, two nostrils
In 2016, researchers described in PLOS ONE how they built a nasal airflow logger for about 500 dollars. It measures the air in each nostril separately, and 33 healthy, right-handed adults wore it for 24 hours. Every single one of them cycled.
While they were awake, one nostril stayed in the lead for about 2 hours on average (2.02 hours) before the other took over. During sleep, these stretches grew to about 4.5 hours. Overall, the participants spent slightly longer in left-nostril mode, 2.63 hours on average, than in right-nostril mode, at 2.17 hours. Slower breathing came with a stronger nasal cycle.
Your sleeping position plays along too. In the study, lying on one side was linked to more airflow through the opposite nostril: lie on your left, and the right one tends to take over, and the other way round.
Bonus fact: You’re in good company. According to the study, the nasal cycle showed up in every mammal species where it was investigated.
So your nose isn’t one airway, it’s two, quietly taking turns. Right now, one of them is on a break.