This is why you only breathe out of one nostril at a time
This is why you only breathe out of one nostril at a time
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Seasonal allergies or illness often lead to nasal congestion, making breathing through the nose a challenge. Yet, even when healthy, you may observe that air flows predominantly through one nostril at a time. This natural occurrence is part of a process called the nasal cycle, which regulates airflow between nostrils as part of the body’s routine.
During waking hours, the nasal cycle alternates dominance every two hours, though this rhythm slows when sleeping. The cycle involves two phases: one where airflow is restricted in one nostril and another where the opposite nostril becomes more open. This shift helps prevent overexposure to harmful particles and allows the nasal passages to rest and recover.
Studies suggest the left nostril is more commonly dominant, particularly in right-handed individuals. When the right nostril is active, it may signal heightened alertness or stress, while the left nostril’s dominance is linked to a relaxed state. This pattern is governed by the hypothalamus, a brain region that subconsciously controls the process.
Understanding the nasal cycle reveals its dual purpose: protecting the nasal lining and maintaining respiratory health. Approximately 12,000 litres of air traverse the nasal passages daily, making them a critical barrier against pathogens. By alternating dominance, the cycle ensures one nostril remains less exposed, reducing wear and tear on the nasal tissues.
Disruptions to the nasal cycle can arise from various causes. Respiratory conditions like colds or flu increase mucus, limiting the nostrils’ ability to switch effectively. Allergens such as pollen or dust mites trigger inflammation, further impairing the cycle. Medications for high blood pressure affect blood vessels, potentially irritating the nasal lining. Overuse of decongestants can even lead to rhinitis medicamentosa, a type of chronic congestion.
Structural issues, including nasal polyps and a deviated septum, also interfere with normal function. Nasal polyps, affecting up to 4% of people, may block airflow, while a deviated septum often requires surgical intervention to restore balance. These conditions highlight how both functional and anatomical factors influence the nasal cycle’s effectiveness.
