Table 2. Comparison of heart rate variability parameters between autoregressive and fast Fourier transform methods.
| HRV parameters | AR | FFT | Effect size | p value |
|---|---|---|---|---|
| Total power (ms2) | 3,992±3,138 | 3,902±3,188 | 0.03 | <0.001 |
| LF (ms2) | 1,268±1,024 | 1,165±1,014 | 0.10 | 0.001 |
| HF (ms2) | 1,377±1,424 | 1,352±1,429 | 0.02 | <0.001 |
| LF (n.u.) | 52.9±15.6 | 51.4±16.8 | 0.09 | <0.001 |
| HF (n.u.) | 47.1±15.6 | 48.6±16.8 | 0.09 | <0.001 |
| LF/HF ratio | 1.41±1.18 | 1.44±1.08 | 0.02 | 0.039 |
HRV: heart rate variability; AR: autoregressive; FFT: fast Fourier transform; LF: low frequency; HF: high frequency; n.u: normalized units.