Table 4.
Descriptive statistics of heart rate variability variables for females.
| Variable | N | Mean (SD) | Range | 25th percentile | 50th percentile | 75th percentile |
|---|---|---|---|---|---|---|
| SDNN (ms) | 166 | 177.91 (52.89) | 77.16–502.95 | 145.26 | 170.40 | 200.42 |
| RMSSD (ms) | 166 | 65.65 (28.58) | 21.87–156.93 | 44.68 | 61.20 | 78.33 |
| pNN50 (%) | 166 | 25.28 (12.32) | 0.93–54.68 | 15.99 | 24.51 | 32.84 |
| HF (ms2)* | 86 | 307.91 (306.49) | 61.64–2,324.95 | 175.08 | 283.48 | 495.08 |
| HFnu* | 86 | 35.02 (8.61) | 14.38–58.07 | 29.89 | 33.67 | 40.05 |
| LF (ms2)* | 86 | 624.52 (310.59) | 173.77–1,905.63 | 364.48 | 590.09 | 779.69 |
| LFnu* | 86 | 64.98 (8.61) | 41.93–85.62 | 59.94 | 66.33 | 70.10 |
| Total power (ms2)* | 86 | 2,574.99 (1,660.58) | 944.00–7,305 | 1,611.71 | 2,455.76 | 3,272.76 |
*A smaller N based on the inability to analyze those participants (N = 147) who had sporadic and multiple start and stop times within the 24-h recording. According to rigorous analysis methodology, it is not sound to link multiple recordings within one larger recording for the purpose of deriving frequency domain variables (RHRV, R Core Programming, 2013).