Table 2.
Variable | Units | Description | Frequency range |
---|---|---|---|
Analysis of short-term recordings (5 min) | |||
5-min total power | ms2 | The variance of NN intervals over the temporal segment | ≈≤0.4 Hz |
VLF | ms2 | Power in VLF range | ≤0.04 Hz |
LF | ms2 | Power in LF range | 0.04–0.15 Hz |
LF norm | nu | LF power in normalized units LF/(total power-VLF)×100 | |
HF | ms2 | Power in HF range | 0.15–0.4 Hz |
HF norm | nu | HF power in normalized units HF/(total power-VLF)×100 | |
LF/HF | Ratio LF (ms2)/HF (ms2) | ||
Analysis of entire 24 hours | |||
Total power | Variance of all NN intervals | ≈≤0.4 Hz | |
ULF | Power in the ULF range | ≤0.003 Hz | |
LF | Power in the VLF range | 0.003–0.04 Hz | |
VLE | Power in the LF range | 0.04–0.15 Hz | |
HF | Power in the HF range | 0.15–0.4 Hz | |
α | Slope of the linear interpolation of the spectrum in a log-log scale | ≈≤0.04 Hz |
VLF: very low frequency band, LF: low-frequency band, HF: high-frequency band, ULF: ultra low frequency band