Feeling like you can only breathe through one nostril is a common experience. While it might seem unusual, this sensation is often a normal physiological process, not a cause for concern. Understanding its scientific basis can clarify this everyday occurrence.
Understanding the Nasal Cycle
The feeling of one-sided nasal breathing is often due to the nasal cycle, a natural process. This cycle involves the unconscious, alternating congestion and decongestion of the nasal passages. At any given time, one nostril is more open, allowing greater airflow, while the other becomes more congested due to increased blood flow to its turbinates.
Turbinates are bony structures in the nasal cavities, covered by erectile tissue that swells and shrinks. The autonomic nervous system, specifically its sympathetic and parasympathetic branches, regulates this process. This alternation, typically shifting every few hours, ensures one side of the nose remains moist, aiding humidification and filtration of inhaled air.
Everyday Reasons for One-Sided Blockage
While the nasal cycle is a normal occurrence, certain conditions can cause persistent or more pronounced one-sided nasal blockage. Allergies (allergic rhinitis) can trigger inflammation in nasal tissues, leading to swelling and congestion. This reaction can make an existing nasal cycle more noticeable or cause one nostril to feel significantly more blocked.
Common viral infections like colds or flu also cause inflammation and increased mucus production in the nasal passages. When sick, nasal blood vessels dilate and mucus accumulates, making the normally congested side of the nasal cycle feel more obstructed. Sinus infections (sinusitis) involve inflammation and infection within the sinus cavities, which can lead to persistent one-sided blockage, often accompanied by pain and pressure.
Anatomical variations, such as a deviated septum, can also contribute to one-sided breathing difficulties. A deviated septum occurs when the wall of cartilage and bone separating the nasal passages shifts to one side, physically obstructing airflow. This can make breathing harder through the narrower nostril and may worsen with colds or allergies.
Nasal polyps, non-cancerous growths in the nasal and sinus linings, can block airflow, often causing unilateral obstruction. Enlarged turbinates (turbinate hypertrophy) can also cause persistent nasal blockage. Chronic inflammation from allergies, infections, or environmental irritants can cause turbinates to remain enlarged, leading to breathing difficulty.
Environmental irritants like smoke, strong odors, or air pollution can inflame the nasal lining. This inflammation contributes to congestion and can make one-sided blockage more prominent.
When Professional Help is Needed
While one-sided nasal blockage is often normal due to the nasal cycle, certain symptoms warrant medical attention. Consult a healthcare provider if the blockage is persistent, does not resolve with time or home remedies, or significantly impacts daily life or sleep.
Accompanying symptoms such as pain, pressure, fever, facial swelling, or vision changes could indicate a more serious underlying issue. Unilateral discharge, especially if discolored, foul-smelling, or bloody, should also prompt a medical evaluation. If the blockage occurs after a nasal injury or is associated with recurrent nosebleeds, seeking professional help is recommended.