부산대학교 도서관

It is well-known that heart rate increases during inhalation and decreases during exhalation. This phenomenon is called respiratory sinus arrhythmia. Synchronization between heart rhythm and breathing maximizes when breathing at the so-called resonance frequency, which for most people is about 6 breaths per minute. Heart rate variability biofeedback (HRV-BFB) training for self-regulation improvement is based on these mechanisms, but there is a lack of appropriate quantitative methods for the effectiveness of the impact. We propose a new approach for assessing cardiorespiratory synchronization, which allows us to characterize this state more objectively – cross-correlation coefficient calculation between heart rate and breathing curves. It could be used in real-time recording (essential in BFB training) and probably will be applicable in ultra-short-term epochs for emotional reactions assessment and in other rapid fluctuations of psychophysiological states, where the classic frequency domain method of HRV assessment is not applicable due to short epoch time.