Table 4.
HRV parameters used in the selected papers
| HRV parameters | Definition | Physiological interpretation |
|---|---|---|
| Time-domain measure | ||
| Standard deviation, SD (ms) [40, 41] | Standard deviation of RR-interval | Total HRV |
| Frequency-domain measure | ||
| Low frequency power, LF (ms2) [35] | Spectral power in the low frequency band (0.04–0.15 Hz) | Cardiac sympathetic modulation |
| High frequency power, HF (ms2) [35] | Spectral power in the high frequency band (0.15–0.4 Hz) | Cardiac vagal modulation |
| Total power, TP (ms2) [35] | Total spectral power (0.01–0.5 Hz) | – |
| LF/HF ratio [35] | Ratio of LF power to HF power | Cardiac sympathovagal balance |
| Spectral power density at frequency of 0.1Hz (in absolute unit, ms2/Hz, and relative units) [40, 41] | – | Likely due to the baroreceptor reflex, which reflects the 0.1 Hz arterial blood pressure oscillations (Mayer wave) [52] |