The diving reflex in non-eosinophilic non-allergic rhinitis

Area of Science:

• Physiology
• Otorhinolaryngology
• Medical Research

Background:

• The diving reflex, characterized by increased nasal airflow resistance, is present in humans and linked to autonomic nervous system imbalance.
• Non-eosinophilic non-allergic rhinitis (NENAR) may stem from a similar autonomic imbalance affecting nasal vasculature.

Purpose of the Study:

• To investigate whether the human diving reflex is abnormal in patients diagnosed with non-eosinophilic non-allergic rhinitis.
• To compare the nasal airway resistance response to a simulated diving stimulus between healthy individuals and NENAR patients.

Main Methods:

• A simulated diving test (cold face test) was administered to assess the diving reflex.
• Expiratory total nasal airway resistance (ETR) was measured using active anterior rhinomanometry before and after the cold face test.
• The study included 16 healthy subjects and 18 subjects with NENAR.

Main Results:

• Normal subjects showed no significant change in ETR after the simulated diving test.
• NENAR subjects exhibited a significant increase in ETR post-test (median ETR increased from 0.464 to 0.667 kPa.s.l(-1)).
• The increase in ETR was significantly greater in the NENAR group compared to the normal group (P = 0.04).

Conclusions:

• The nasal airway response to simulated diving is abnormal in individuals with non-eosinophilic non-allergic rhinitis.
• Findings suggest an altered physiological response to cold stimuli in NENAR patients.
• The study supports the hypothesis of an autonomic imbalance contributing to NENAR symptoms.