The central ANS activities significantly correlated with changes to the nasal airway during postural change. The central ANS, especially the sympathetic nervous system, may play a role in controlling nasal airway during postural change.

Background. Very few studies investigate the role of the autonomic nervous system in allergic rhinitis. In this study, we evaluated the autonomic nervous system in allergic rhinitis patients using heart rate variability (HRV) analysis. Methods. Eleven patients with allergic rhinitis and 13 healthy controls, aged between 19 and 40 years old, were enrolled in the study. Diagnosis of allergic rhinitis was based on clinical history, symptoms, and positive Phadiatop test. Electrocardiographic recordings on the sitting and supine positions were obtained for HRV analysis. Results. In the supine position, there were no significant statistical differences in very-low-frequency power (VLF, ≤0.04 Hz), low-frequency power (LF, 0.04–0.15 Hz), high-frequency power (HF, 0.15–0.40 Hz), and the ratio of LF to HF (LF/HF) between the patient and control groups. The mean RR intervals significantly increased, while LF% and LF/HF significantly decreased in the patient group in the sitting position. Moreover, mean RR intervals, LF, and LF/HF, which were significantly different between the two positions in the control group, did not show a significant change with the posture change in the patient group. Conclusion. These suggest that patients with allergic rhinitis may have poor sympathetic modulation in the sitting position. Autonomic dysfunction may therefore play a role in the pathophysiology of allergic rhinitis.

To investigate the responses of nasal airway and autonomic nervous system (ANS) under controlled nasal breathings. Ten healthy volunteers, aged between 21 and 37 years, were enrolled. The participants breathed either through bilateral nostrils (BNB) or unilaterally through the left nostril (UNB) at 0.25 Hz for 5 min. The electrocardiography was simultaneously recorded and the ANS activities were evaluated using heart rate variability analysis. Nasal airway resistance and related factors were measured by rhinomanometry. The results showed that the mean heartbeat interval during UNB was significantly greater than during BNB. The sympathetic modulation decreased significantly during UNB. The correlations between nasal airway resistance and mean heartbeat interval were significant for both UNB and BNB. The increase of heartbeat intervals during UNB was associated with the decrease of cardiac sympathetic activities. The changes of ANS activities and nasal airway resistance during UNB are similar to the changes caused by a prolonged lying.

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