Cardiorespiratory phase synchronization during normal rest and inward-attention meditation

Shr Da Wu, Pei-Chen Lo*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


The cardiac and respiratory systems can be viewed as two self-sustained oscillators with various interactions between them. In this study, the cardiorespiratory phase synchronization (CRPS) quantified by synchrogram was investigated to explore the phase synchronization between these two systems. The synchrogram scheme was applied to electrocardiogram (ECG) and respiration signals. Particular focus was the distinct cardiac-respiratory regulation phenomena intervened by inward-attention meditation and normal relaxation. Four synchronization parameters were measured: frequency ratio, lasting length, number of epochs, and total length. The results showed that normal rest resulted in much weaker CRPS. Statistical analysis reveals that the number of synchronous epochs and the total synchronization length significantly increase (p = 0.024 and 0.034 respectively) during meditation. Furthermore, a predominance of 4:1 and 5:1 rhythm-ratio synchronizations was observed during meditation. Consequently, this study concludes that CRPS can be enhanced during meditation, compared with normal relaxation, and reveals a predominance of specific frequency ratios.

Original languageEnglish
Pages (from-to)325-328
Number of pages4
JournalInternational Journal of Cardiology
Issue number3
StatePublished - 11 Jun 2010


  • Cardiorespiratory interaction
  • Cardiorespiratory phase synchronization (CRPS)
  • Inward-attention meditation
  • Self-sustained oscillator
  • Synchrogram

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