Cardiorespiratory coupling in young healthy subjects.

Area of Science:

• Physiology
• Biomedical Engineering
• Autonomic Nervous System Research

Background:

• Cardiorespiratory interaction is crucial for maintaining homeostasis.
• Quantifying the interplay between cardiac and respiratory systems aids in understanding autonomic balance.
• Existing methods for assessing cardiorespiratory coupling (CRC) and interaction (CRI) have limitations.

Purpose of the Study:

• To quantify cardiorespiratory interaction in healthy subjects using a subset of the Ewing test battery.
• To investigate the temporal relationship between cardiac and respiratory events.
• To compare the sensitivity of different methods for detecting CRC and CRI.

Main Methods:

• Measurement of cardiorespiratory coupling time (RI) from ECG and respiratory belt data.
• Determination of cardiorespiratory coupling (CRC) and interaction (CRI) using Shannon entropy, synchrograms, and coordigrams.
• Analysis of the empirical distribution and asymmetry of RI histograms.

Main Results:

• The RI distribution is asymmetric and nonuniform, indicating a causal link from R-peaks to inspiration onset.
• Cardiorespiratory coupling (CRC) was present in 46% of subjects, primarily during resting states.
• CRC strength diminished under stress (orthostasis, exercise).
• RI histogram asymmetry is more sensitive to CRI than synchrograms or coordigrams.
• A dual structure in RI histograms suggests a potential twofold mechanism for respiratory rhythmogenesis.

Conclusions:

• Asymmetry analysis of RI histograms is a sensitive method for studying cardiorespiratory interaction and autonomic balance.
• RI histogram analysis can aid in assessing physical and mental health.
• The observed dual structure of RI histograms supports theories of a twofold respiratory rhythmogenesis mechanism.