Cardiorespiratory coupling functions, synchronization and ageing

We discuss the advent of coupling functions as a new dimension in the analysis of cardiorespiratory interactions. By decomposing the separate coupling components in a phase oscillator model, we infer the cardiorespiratory coupling functions with dynamical Bayesian inference for time-evolving and noisy coupled systems. The inferred coupling functions are themselves time-varying processes. On a longer timescale, application to ageing shows that the coupling functions and the direct influence of respiration decrease as age increases. We find that the coupling functions can give rise to synchronization transitions, and that there are no significant changes in synchronization with age.