Is it normal to breathe only through one nostril? Nasal cycle demystified!

empty nose syndrome - nasal cycle - breathing through nose

Certain individuals might observe a disparity in their breathing, with one nostril allowing more airflow while the other feels less accommodating for deep inhalation. This phenomenon could be attributed to the nasal cycle or potentially related to other respiratory ailments.

Understanding the Nasal Cycle: A Natural Rhythm of Breathing

The nasal cycle is a fascinating and natural phenomenon that often goes unnoticed in our daily lives. It involves the alternating congestion (blocked sensation) and decongestion (opening sensation) of the nasal passages, resulting in the perception of easier breathing through one nostril at a time.

While this may seem like a minor aspect of our respiratory system, the nasal cycle plays a crucial role in maintaining optimal airflow, filtering air, and supporting overall nasal health. In this patient information article, we will explore the mechanics, significance, and management of the nasal cycle.

The Mechanics of the Cycle:

The nasal cycle is governed by the autonomic nervous system, which regulates involuntary bodily functions such as breathing, heartbeat, and digestion. The cycle involves the expansion and contraction of blood vessels in the nasal tissues, which leads to changes in the size of the nasal passages.

This alternation results in one nostril being more open (dominant) while the other is more constricted (non-dominant) at any given time.

Phases of the Cycle:

The cycle consists of two main phases: the congestion phase and the decongestion phase.

  • Congestion Phase: During this phase, the blood vessels in the nasal tissues expand, causing the nasal passages to narrow. The non-dominant nostril becomes more congested, and the airflow through that nostril is reduced. This phase typically lasts for about 3-6 hours.
  • Decongestion Phase: In this phase, the blood vessels in the non-dominant nostril constrict, allowing it to open up and facilitate easier airflow. The previously congested nostril now becomes the dominant nostril, while the other nostril enters the congestion phase. This phase lasts for a similar duration as the congestion phase.

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.

Significance of the Nasal Cycle:

The cycle is not merely a random occurrence; it serves several important functions:

  • Airflow Regulation: The alternating cycle helps regulate the airflow to different regions of the lungs, optimizing oxygen exchange and maintaining respiratory efficiency.
  • Nasal Filtration: The nasal passages are lined with tiny hair-like structures called cilia, which trap and filter out airborne particles such as dust, pollen, and bacteria. The nasal cycle ensures that both sides of the nasal passages contribute to effective filtration.
  • Moisturization: The nasal cycle assists in evenly distributing mucus, which helps keep the nasal passages moist and prevents them from becoming too dry.
  • Olfactory Sensation: The cycle can also impact our sense of smell. The dominance of one nostril over the other can influence our perception of odors, enhancing our ability to detect a wider range of scents.

Factors Influencing:

Several factors can influence the timing and intensity of the nasal cycle:

  • Time of Day: The nasal cycle tends to follow a regular pattern throughout the day, with one nostril being dominant for several hours before switching.
  • Sleep Position: Sleeping on one side can affect the nasal cycle, causing the lower nostril to become congested due to increased blood flow and pressure on that side.
  • Physical Activity: Engaging in physical activities, such as exercise, can affect the nasal cycle, with increased breathing leading to changes in nasal airflow.
  • Temperature and Humidity: Environmental factors like temperature and humidity can impact the nasal cycle. Cold air may lead to vasoconstriction, while warm and humid air may lead to vasodilation.
  • Stress and Emotions: The autonomic nervous system responds to stress and emotions, potentially influencing the nasal cycle.

Managing the Nasal Cycle:

While the nasal cycle is a natural and involuntary process, certain strategies can help manage nasal congestion and promote optimal breathing:

  • Nasal Irrigation: Saline nasal sprays or irrigation solutions can help cleanse the nasal passages, reducing congestion and promoting clear airflow.
  • Decongestants: Over-the-counter decongestant sprays or medications can provide temporary relief from nasal congestion by constricting blood vessels in the nasal tissues.
  • Steam Inhalation: Inhaling steam from a bowl of hot water or using a humidifier can help soothe irritated nasal passages and ease congestion.
  • Sleep Hygiene: Maintaining proper sleep posture and using extra pillows to elevate your head slightly can help minimize nighttime congestion.
  • Breathing Exercises: Practicing deep breathing exercises can help improve nasal airflow and promote relaxation of nasal tissues.
  • Stay Hydrated: Drinking an adequate amount of water helps keep the mucous membranes moist and supports overall nasal health.

When to Seek Medical Attention:

While the cycle is a natural process, persistent or severe nasal block could be indicative of an underlying issue. It’s advisable to consult an ENT surgeon if you experience:

  • Chronic Congestion: If one nostril remains consistently congested for an extended period, it may warrant further evaluation.
  • Nasal Discharge: If the congestion is accompanied by abnormal nasal discharge, such as thick mucus or blood, medical attention is recommended.
  • Breathing Difficulty: Severe breathing difficulties, especially during physical activity or at rest, should be addressed promptly.
  • Allergy Symptoms: If you suspect allergies are contributing to your nasal congestion, a healthcare provider can help identify triggers and recommend appropriate treatment.


The nasal cycle is an intriguing and essential aspect of our respiratory system that ensures optimal airflow, filtration, and overall nasal health. Understanding its mechanics, significance, and factors that influence it can help us appreciate the intricacies of our body’s natural rhythms.

By practicing simple management techniques and seeking medical attention, when necessary, we can maintain clear nasal passages and support our respiratory well-being.


Dr. Sanu. P. Moideen, MBBS, MS (ENT), DNB (ENT), FHNOS, is an otolaryngologist (ENT surgeon), head and neck oncosurgeon practising in Muvattupuzha, Kerala, India. After finishing his postgraduate training, he pursued specialist training in paediatric ENT and head and neck oncosurgery from eminent institutions in India and the US.

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