Allergic rhinitis may attenuate the sympathovagal imbalances in patients with severe obstructive sleep apnea: pilot...

The effect of allergic rhinitis (AR) on autonomic nervous system in patients with obstructive sleep apnea (OSA) remains unclear. We utilized heart rate variability (HRV) analysis to assess cardiac autonomic activity in patients with OSA, comparing those with and without allergic rhinitis (AR).

We enrolled 182 patients who visited our sleep clinic complaining of habitual snoring or apnea during sleep. All patients underwent full-night polysomnography (PSG) and multiple allergen simultaneous tests. We calculated the HRV extracted from the electrocardiography of the PSG. Participants were divided into a normal group and an AR group, and HRV indices were compared according to OSA severity in each group.

The low-frequency (LF) to high-frequency (HF) ratio (LF/HF; r = 0.336, p < 0.001), LF normalised unit (LFnu; r = 0.345, p < 0.001), and HFnu (r = -0.345, p < 0.001) were significantly correlated with the apnea-hypopnea index. The HRV index comparison between non-severe and severe OSA in the normal group showed significant differences in LFnu (64.7 ± 12.5 in non-severe and 72.4 ± 11.7 in severe, p < 0.001), LF/HF (2.3 ± 1.6 in non-severe and 3.3 ± 2.0 in severe, p = 0.002), and HFnu (35.3 ± 12.5 in non-severe and 27.6 ± 11.7 in severe, p < 0.001). However, in the AR group, LFnu (p = 0.648), LF/HF (p = 0.441), and HFnu (p = 0.648) were comparable between non-severe and severe OSA.

Considering that LFnu, HFnu, and LF/HF represent sympathetic activity, parasympathetic activity, and sympathovagal balance, respectively, AR may attenuate the sympathetic predominance and sympathovagal imbalance associated with cardiovascular morbidity in severe OSA.