Table 4 Intraclass correlation coefficients (ICCs) with 95% confidence intervals for heart rate variability (HRV) absolute metrics across various measurement conditions. SDNN (standard deviation of NN intervals), HR (heart rate), RMSSD (root mean square of successive differences), PNN50% (percentage of successive NN intervals that differ by more than 50 ms), VLF (very low frequency), LF (low frequency), HF (high frequency), TP (total power), LFnu (low frequency normalized units), HFnu (high frequency normalized units). Symbols indicate whether the variable differs significantly between the compared sessions. * (p < 0.05), ** (p < 0.01), *** (p < 0.001).
5 measurements | A vs. B | A vs. D | B vs. C | B vs. E | |
|---|---|---|---|---|---|
Supine | |||||
SDNN (ms) | 0.816 (0.723–0.891) | 0.842 (0.708–0.917) | 0.846 (0.713–0.92) | 0.875 (0.766–0.936) | 0.8 (0.638–0.895) |
HR (bpm) | 0.836 (0.739–0.906) | 0.837 (0.668–0.919) | 0.884 (0.78–0.94) | 0.913 (0.542–0.971)*** | 0.856 (0.732–0.925) |
RMSSD (ms) | 0.841 (0.757–0.907) | 0.856 (0.733–0.925) | 0.917 (0.84–0.958) | 0.904 (0.817–0.951)* | 0.817 (0.664–0.905) |
PNN50% | 0.833 (0.747–0.902) | 0.811 (0.657–0.901) | 0.834 (0.692–0.914) | 0.942 (0.887–0.97) | 0.863 (0.744–0.929) |
VLF (ms2) | 0.486 (0.332–0.651) | 0.39 (0.0803–0.635)* | 0.547 (0.262–0.745) | 0.476 (0.179–0.696) | 0.459 (0.149–0.688)* |
LF (ms2) | 0.778 (0.672–0.866) | 0.781 (0.607–0.884) | 0.864 (0.744–0.93) | 0.822 (0.675–0.907) | 0.683 (0.445–0.829) |
HF (ms2) | 0.644 (0.505–0.774) | 0.807 (0.648–0.898) | 0.792 (0.623–0.89) | 0.72 (0.511–0.849) | 0.653 (0.405–0.81) |
LF/HF | 0.483 (0.329–0.649) | 0.502 (0.209–0.714) | 0.255 (-0.0899-0.544) | 0.588 (0.322–0.769) | 0.673 (0.436–0.823) |
LF + HF (ms2) | 0.721 (0.598–0.828) | 0.827 (0.681–0.91) | 0.866 (0.749–0.931) | 0.779 (0.601–0.884) | 0.605 (0.345–0.78) |
TP (ms2) | 0.735 (0.616–0.838) | 0.789 (0.617–0.888) | 0.826 (0.679–0.909) | 0.781 (0.607–0.884) | 0.604 (0.34–0.78) |
HF/HR | 0.663 (0.527–0.788) | 0.841 (0.707–0.917) | 0.793 (0.624–0.891) | 0.696 (0.474–0.835) | 0.657 (0.412–0.813) |
LF + HF/HR | 0.726 (0.604–0.831) | 0.832 (0.692–0.912) | 0.874 (0.763–0.935) | 0.775 (0.595–0.881) | 0.605 (0.345–0.78) |
LFnu | 0.649 (0.51–0.778) | 0.537 (0.244–0.739) | 0.567 (0.288–0.758) | 0.802 (0.642–0.896) | 0.683 (0.451–0.828) |
HFnu | 0.649 (0.51–0.778) | 0.537 (0.244–0.739) | 0.567 (0.288–0.758) | 0.802 (0.642–0.896) | 0.683 (0.451–0.828) |
Standing | |||||
SDNN (ms) | 0.659 (0.51–0.792) | 0.67 (0.276–0.849) | 0.694 (0.453–0.84) | 0.757 (0.516–0.881)* | 0.637 (0.368–0.807) |
HR (bpm) | 0.788 (0.655–0.882) | 0.77 (0.45–0.897)* | 0.851 (0.714–0.925) | 0.96 (0.917–0.981) | 0.877 (0.761–0.938) |
RMSSD (ms) | 0.656 (0.512–0.788) | 0.694 (0.453–0.84) | 0.749 (0.546–0.87) | 0.777 (0.577–0.887)* | 0.453 (0.117–0.695) |
PNN50% | 0.539 (0.379–0.701) | 0.481 (0.154–0.712) | 0.768 (0.575–0.881) | 0.637 (0.374–0.806)* | 0.143 (-0.23-0.474) |
VLF (ms2) | 0.248 (0.104–0.44) | 0.246 (-0.11-0.547) | 0.287 (-0.0616-0.576) | 0.232 (-0.133-0.54)* | 0.124 (-0.231-0.452) |
LF (ms2) | 0.589 (0.433–0.74) | 0.776 (0.434–0.904)*** | 0.691 (0.451–0.838) | 0.571 (0.273–0.768) | 0.375 (0.0214–0.643) |
HF (ms2) | 0.638 (0.49–0.776) | 0.752 (0.55–0.872) | 0.694 (0.454–0.84) | 0.877 (0.76–0.938) | 0.229 (-0.139-0.538) |
LF/HF | 0.498 (0.311–0.68) | 0.537 (0.126–0.77)*** | 0.822 (0.666–0.91) | 0.681 (0.432–0.833) | 0.707 (0.478–0.847) |
LF + HF (ms2) | 0.59 (0.436–0.741) | 0.778 (0.492–0.899)* | 0.682 (0.437–0.833) | 0.597 (0.309–0.783) | 0.344 (-0.0147-0.621) |
TP (ms2) | 0.498 (0.337–0.669) | 0.684 (0.423–0.837)* | 0.556 (0.258–0.757) | 0.437 (0.0995–0.683) | 0.267 (-0.0957-0.565) |
LF/HR | 0.578 (0.423–0.731) | 0.749 (0.453–0.883)** | 0.687 (0.446–0.836) | 0.552 (0.249–0.756) | 0.333 (-0.0277-0.614) |
LFnu | 0.442 (0.258–0.632) | 0.306 (-0.043-0.594)*** | 0.615 (0.335–0.795) | 0.704 (0.469–0.846) | 0.595 (0.313–0.781) |
HFnu | 0.442 (0.258–0.632) | 0.306 (-0.043-0.594)*** | 0.615 (0.335–0.795) | 0.704 (0.469–0.846) | 0.595 (0.313–0.781) |
