Table 3. Descriptive statistics of raw and natural log transformed SDNN and RMSSD of 3,387 individuals categorized by recording period.
| Recording | SDNN mean (SD) | lnSDNN mean (SD) | RMSSD mean (SD) | lnRMSSD mean (SD) |
|---|---|---|---|---|
| 10s recording 1 | 25.48 (18.35) | 3.05 (0.60) | 27.78 (23.27) | 3.13 (0.59) |
| 10s recording 2 | 26.18 (19.99) | 3.07 (0.61) | 28.57 (25.92) | 3.15 (0.61) |
| 10s recording 3 | 25.95 (19.04) | 3.06 (0.61) | 28.16 (23.78) | 3.14 (0.60) |
| Avg10s | 25.87 (16.86) | 3.06 (0.53) | 28.17 (22.17) | 3.14 (0.55) |
| 30s recording | 29.14 (17.87) | 3.23 (0.53) | 28.22 (21.99) | 3.17 (0.55) |
| 120s recording | 33.96 (18.64) | 3.40 (0.49) | 29.15 (22.43) | 3.21 (0.53) |
| total recording | 35.81 (18.57) | 3.47 (0.46) | 29.48 (22.51) | 3.23 (0.53) |
s: seconds; SDNN: standard deviation of normal-to-normal intervals in milliseconds; RMSSD: root mean square of successive differences in milliseconds; lnSDNN: natural logarithm of SDNN; lnRMSSD: natural logarithm of RMSSD; SD: Standard Deviation; Avg10s: the average of the measurements from the three 10s recordings.