Some people may notice that they are breathing more through one nostril, rather than equally through both. This may be due to the nasal cycle. However, some conditions may also cause a person to breathe solely through one nostril.

The nose and the nasal cavity have many different functions, including allowing people to breathe. This is a natural process that many people perform subconsciously. People may notice changes to their breathing due to nasal issues, such as a stuffy nose. However, it is not uncommon to breathe more through one nostril.

The nasal septum is the tissue that separates the nasal cavity into two nostrils. The septum consists of a framework of bone and cartilage that helps keep its shape. The nasal passages also contain other cells and tissues that help it perform its other functions, such as warming and filtering air.

This article explores what may lead a person to breathe through one nostril, what other symptoms a person may experience, and when a person should contact a doctor.

A person's nostrils.Share on Pinterest
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The airflow between both nostrils is not always equal. The air flowing into one nostril is often greater than the other due to a process known as the nasal cycle. Therefore, a person may feel they are breathing more through one nostril than the other.

The autonomic nervous system (ANS) component of the brain is responsible for the nasal cycle. The ANS refers to a collection of neurons that influence the activity of many different organs, including the lungs. In many people, the ANS spontaneously switches the dominant nostril throughout the day. However, there may be an underlying cause if a person breathes exclusively through one specific nostril.

The nasal cycle is the unconscious sequence of congestion and decongestion of the nasal cavity during the day. This means that when congestion occurs in one nostril, decongestion occurs in the other. During the nasal cycle, unequal blood flow in the nostrils causes the tissue in one nostril to fill with blood and block that nostril, while the other remains open. Researchers believe 70–80% of adults have a regular nasal cycle.

There are four different types of nasal cycles:

  • Classic: This occurs when there is equal decongestion and congestion occurring with a constant total volume.
  • Parallel: This type takes place when congestion or decongestion occurs in both nostrils at the same time.
  • Irregular: This is where equal decongestion and congestion occur with a constant total volume, but there is no regular pattern.
  • Acyclic: This happens when the total nasal volume and nasal volume in each nostril do not differ.

A person’s nasal cycle may change due to different factors, such as body posture and age. Different conditions may also affect a person’s nasal cycle.

A 2021 study suggests that nasal congestion that arises due to the nasal cycle may act as a defense mechanism against respiratory viruses due to higher temperatures in the nasal passages.

Nasal congestion is a symptom that often occurs due to swelling and inflammation in the nasal mucosa. This is the tissue that lines the nostrils and nasal cavity. Congestion typically occurs due to excess fluid entering the blood vessels of the mucosa, which results in swelling. Some common causes of nasal congestion may include:

However, nasal congestion is not always a response to an irritant, pathogen, or allergen. In some cases, it may occur due to structural issues within the nose or other conditions that make it difficult for the nasal passages to clear mucus.

A nasal obstruction occurs when there is a blockage in the nostrils and nasal passages. A person experiencing nasal obstruction may present with lower airflow in the nostrils and a feeling of “fullness” in the nostrils. Causes of nasal obstruction can include:

  • A deviated septum: A deviated septum is when the left and right nasal passages are unequal in size. This occurs when the nasal septum is off-center rather than exactly in the middle.
  • Foreign object: Nasal foreign bodies may lodge in the nostrils and block the airflow. These scenarios commonly occur in children and may include objects such as batteries and magnets.
  • Tumor: Certain types of tumors may develop in the nostrils or the nasal sinuses, which can block airflow in the nostrils.
  • Nasal polyps: Nasal polyps describe outgrowths, or fleshy swellings, of the nasal mucosa lining that can cause breathing difficulties.
  • Enlarged turbinates: Enlarged turbinates, or turbinate hypertrophy, occurs when the lining of the turbinate bones of the nose enlarges and swells.

A person with nasal obstruction or congestion may also experience other symptoms. These may include:

A person should seek the advice of a doctor if they experience nasal obstruction or congestion that is interfering with their daily life or affecting their breathing.

A person should also consult a doctor if they are experiencing other symptoms along with the blockage or congestion that have lasted more than 2 weeks.

In many cases, breathing out of one nostril is harmless. It often occurs due to the nasal cycle. This term refers to the spontaneous congestion and decongestion in the nostrils. As the airflow is not always equal in both nostrils, a person may feel that they breathe in through one nostril more so than the other.

In other cases, a person may also experience nasal obstruction or congestion, which may block airflow in one or both nostrils. As such, it is important that people are aware of other symptoms, such as changes in vision or smell, nosebleeds, discharge, headaches, and fevers, which may suggest an underlying problem.

A person should consult their doctor if they notice other symptoms or breathing becomes difficult.