Figure 5
From: Resonance frequency is not always stable over time and could be related to the inter-beat interval
HRV time domain parameters: SDNN (A–C) and RMSDD (D–F) for Test (A,D), ReTest (B,E) and RF-RFE comparison (C,F). “RF” represents the optimal resonance frequency, “Other Rates” represents the mean of the other breathing rates, “Lowest RSA” represents the lowest RSA amplitude, “6 b/m” represents the rate of 6 breathes per minute, “Free” represents the free slow breathing session only in retest, and “RFE” represents the expanded RF that consists on taking the SDNN/RMSSD of the nearest below and above rates from the RF. Non-parametric Wilcoxon test has been performed. * (p < 0.05), ** (p < 0.01) and *** (p < 0.001) mean differences with respect to RF in the same session.
