Examining the practical importance of nonstationary cardio-respiratory coupling detection in breathing training: a methodological appraisal

PeerJ. 2024 Nov 19:12:e18551. doi: 10.7717/peerj.18551. eCollection 2024.

Abstract

This study investigates changes in cardiorespiratory coupling during clinic breathing training and its impact on autonomic nervous functioning compared with heart rate variability (HRV). A total of 39 subjects undergoing dynamic electrocardiogram-recorded breathing training were analyzed. Subjects were divided into early- and late-training periods, and further categorized based on changes in HRV indexes. Subtypes were identified using time-frequency cardiorespiratory coupling diagrams. Significant differences were observed in the high-frequency (HF) index between training stages in the subgroup with increasing HF-HRV (p = 0.0335). Both unimodal and bimodal subtypes showed significant high-frequency coupling (HFC) in the mid-training period compared with early and late stages (both p < 0.0001), suggesting improved parasympathetic cardiac regulation or reduced sympathetic control. This study highlights the potential of nonstationary cardiorespiratory coupling analysis alongside traditional HRV in evaluating the therapeutic effect of breathing training on autonomic nervous function. Cardiorespiratory coupling analysis could provide valuable adjunctive information to HRV measures for assessing the impact of breathing training.

Keywords: Autonomic nervous system; Breathing training; Cardiorespiratory coupling; Heart rate variability; Nonstationary signals.

MeSH terms

  • Adult
  • Autonomic Nervous System* / physiology
  • Breathing Exercises* / methods
  • Electrocardiography* / methods
  • Female
  • Heart Rate* / physiology
  • Humans
  • Male
  • Middle Aged
  • Respiration
  • Young Adult

Grants and funding

This work was supported by tthe National Natural Science Foundation of China (grant no. 62171028, no. 62471043, no. 62171471), the Beijing Natural Science Foundation (grant no. L232139), the Open Project of Key Laboratory of Medical Electronics and Digital Health of Zhejiang Province (no. MEDC202303), and the National High-level Fellow Research Fund Program (grant no. 3050012222022). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.