Why not a big hole? Our nostrils work in shifts to help us.
Much more than “doors” for air, our nostrils, contrary to what one might think, are not copies of each other. In fact, they work in shifts, in a “nasal cycle”.
Throughout the day, one nostril is always more open than the other. One conducts most of the airflow, while the other “rests” and processes less air. This alternating balance happens automatically, in cycles of a few hours, without most people realizing it. Researchers explain that this alternation helps keep the nasal mucosa hydrated and functional, allowing the nose to fulfill its main function: preparing air for the lungs, filtering dust and pollutants, warming it to body temperature and humidifying it to close to 100% humidity, explains .
But the impact of the two nostrils goes beyond breathing. THE smell also benefits from this system. Because airflow is faster in one nostril and slower in the other, each side of the nose deals with odorous molecules differently. Substances that dissolve more slowly are better detected by the more “closed” nostril, where the air circulates slowly, giving more time for these molecules to dissolve in the mucus. Substances that dissolve quickly are more easily captured by the more open nostril, where the accelerated flow spreads the molecules over a larger area of olfactory tissue.
The brain combines these two “versions” of the same smell, enriching olfactory perception. Smell experts describe this process as a way for the nervous system to extract more information from very subtle differences between the two air intakes.
Although the nostrils are very close together, they also help locate the source of an odor. Studies with blindfolded participants have shown that when you artificially eliminate the difference between what each nostril smells, people become slower and less accurate at following a scent trail.
It is believed that there is also a possible extra advantage: in case of constipation, congestion tends to be more intense in one nostril, while the other ensures the passage of air. The most blocked nostril heats up more, creating an environment that is less favorable to the replication of some viruses.
