The dynamic interactions among physiological rhythms imbedded in the heart rate signal can give valuable insights into autonomic modulation in conditions of reduced outward attention.

Aim: 

Therefore, we used two methods to analyze the behavior of heart rate variability and breathing in Zen Buddhist meditation (Zazen): the Fast Fourier Transform, which reflects the strengths of the frequency components of the signal, and the Continuous Wavelet Transform, which decomposes a series into time-scale or time-frequency domains and allows for the identification of temporal changes of dominant modes of variability.

Methods: 

Twenty subjects with variable experience in Zazen took part in this preliminary study. Also a control group was requested. Data from heart rate and breathing were collected simultaneously during twenty minutes of quietly sitting meditation.

Results: 

We found that, with more years of meditation, there is a tendency towards a coupling between the breathing and the rhythms underlying the low and very low frequency ranges of heart rate variability.

Conclusion: 

The Wavelet transform was more effective when identifying temporal patterns of behaviour during Zen meditation, especially in more advanced practitioners.