Introduction: Abnormalities in autonomic nervous system control, which produce an elevation in parasympathetic activity may play a role in the pathogenesis of airway disorders. To date, no study has explored the relationship between autonomic balance, measured by heart rate variability, and disease severity in adults with obstructive airway disorders.

Methods: Forty-one respiratory patients (n = 24) and controls (n = 17) participated in this study. Heart rate was recorded for 15 minutes via ECG in the seated position, with HRV measures determined by spectral analysis of heart rate measurements using analysis software (LabChart 5.0, ADInstruments, Sydney). Participants also performed a spirometry evaluation to record forced expiratory volume in 1 second (FEV1.0) and forced vital capacity (FVC) according to standardized guidelines. A cohort of patients (n = 9) were asked to undergo a further spirometry and 15 minute HRV analysis following administration of a bronchodilator.

Results: The sample size was reduced to 29 due to invalid recordings. No correlation existed between autonomic balance, determined by the LF:HF ratio, and severity of airway disorders, quantified by %predicted FEV1.0 (P>0.05). A comparison of HRV measures between groups revealed no significant differences in either LF or HF activity (P > 0.05). There were no significant differences in HRV measures following bronchodilator administration in respiratory patients.

Conclusion: This study showed no correlation between autonomic balance and the degree of disease severity in adults with airway disorders, therefore, it does not show HRV can be used as an additional measure in the diagnosis of airway disorders.