Why can’t we breathe equally through both nostrils? The reason for this is a process called the nasal cycle, which we will discuss in this article in Wironal.
If you go in front of the mirror and breathe through your nose, the mirror will be full of steam. Two signs of water vapor appear on the surface of the mirror, each corresponding to one of the nostrils, But one sign is bigger than the other; Because one nostril always dominates the other.
According to Dr. Michael Benninger of the Cleveland Clinic, 75 percent of breathing is normally through one nostril and 25 percent through the other. The predominant nostrils change throughout the day; This process is called the nasal cycle.

We usually do not notice; But during the nasal cycle, one of the nostrils condenses and transmits less airflow; While the other has a lower density. According to a small study published in 2016 in the journal PLOS One, the average density pattern shifts every two hours. According to Benninger, the cause of the nasal cycle is still unknown; But there is a common theory:
Some people think that the nasal cycle helps to allow moisture to enter the nostrils to prevent them from drying out.
Most people are not aware of their nasal cycle; But during sleep, they feel it more. For example, if a person leans to the right side, gravity causes the right nostril to come down and become denser. If the nasal cycle at that time is dedicated to the right nostril and its greater density, it will not have a noticeable effect; But if the nasal cycle at that moment is dedicated to the density of the left nostril and the right nostril becomes congested due to gravity, breathing becomes difficult and the person may wake up.
People usually notice the nasal cycle when one of their nostrils is permanently blocked. This happens to people with a deviated wall or blade. In this position, the wall moves between the nostrils and pushes it to one side. Some people have soft, painless cartilage called a polyp in their nose that causes the same effect. Tumors can have similar consequences, But they are less common.
You may have difficulty breathing through your nose when you have a cold, But the reason for this is not the nasal cycle. Generally, when you are sick, both nostrils become congested; As a result, you have trouble breathing through your nose. There are ways to reduce the density of both nostrils so that people can breathe equally through both nostrils. Medications such as condensing sprays as well as exercise can have a similar effect. According to research in the journal Ear, Nose & Throat , sex can also open the nose and be a natural alternative to compression drugs.