Predicting sympathovagal balance using parameters of breathing patterns in abdominal breathing

Introduction. Abdominal breathing is utilized as a non-pharmacological treatment method for various stress-related conditions and autonomic dysfunctions. The objective of the study was to determine the predictors in the modulation of sympathovagal balance, as indicated by the ratio of low frequency to high frequency power of heart rate variability, by utilizing the respiratory pattern parameters recorded during the abdominal breathing model. Material and methods. The study involved a group of 101 healthy subjects, where the breathing pattern was recorded using a respiratory induction plethysmograph. Heart activity was estimated through electrocardiography, followed by heart rate variability analysis during both resting and abdominal breathing. Eight parameters of the breathing pattern were recorded in the subjects during resting breathing and abdominal breathing, presumed to be predictors of the ratio of low frequency to high frequency power of heart rate variability. Separate predictive models were created for this ratio for both the resting and abdominal breathing types. Results. The multilinear regression analysis revealed that the primary predictor with the highest predictive power for determining the balance between sympathetic and parasympathetic cardiac influence, as indicated by the low frequency spectral power to high frequency spectral power ratio, in individuals practicing abdominal breathing is Tidal Volume (unstandardized coefficient = 5.007). This was followed by the duration of expiration (coefficient = -3.831) and respiratory minute-volume (coefficient = 4.415), both of which were recorded during resting breathing. In the abdominal breathing model, the most effective predictors were found to be time-related parameters, specifically the frequency of breathing during abdominal breathing (coefficient = -5.953), the duration of the inspiratory phase (coefficient = -4.037), and the duration of the expiration phase (coefficient = -4.194). Conclusions. Abdominal breathing has the potential to normalize sympathovagal balance by adjusting the duration of inspiration or expiration. Further studies should be conducted to investigate the practical application of breathing pattern parameters in restoring the low frequency to high frequency (LF/HF) ratio, particularly in disorders characterized by elevated sympathovagal balance.