Table 3.
Comparison of HRV parameters observed during the daytime and nighttime in the study population grouped by blood pressure
| Group | Total HRV | Parasympathetic activity | Sympathetic activity | Balance of sympathetic and parasympathetic activity | |||||
|---|---|---|---|---|---|---|---|---|---|
| Mean RR interval | SDNN | RMSSD | PNN50 | HF | LF | ULF | LF/HF | ||
| HS Group | Day Time | 616.3 (24.9) | 87.1 (32.8) | 85.7 (49.5) | 18.9 (15.3) | 805.4 (2.6) | 626.5 (6.5) | 548.5 (96.5) | 1.2 (0.6) |
| Night time | 803.5 (21.4) | 890.1 (107.6) | 76.9 (43.3) | 34.4 (23.8) | 913.9 (41.8) | 546.4 (28.7) | 823.9 (348.4) | 1.1 (0.5) | |
| P Value | <0.001 ‡ | 0.7 | 0.4 | <0.001* | 0.8 | 0.1 | 0.6 | 0.1 | |
| NS Group | Day Time | 624.9 (71.8) | 100.1 (29.7) | 92.9 (44.0) | 22.8 (13.7) | 1040.9 (935.4) | 961.1 (726.2) | 862.7 (968.9) | 1.2 (0.6) |
| Night Time | 639.4 (73.8) | 114.9 (44.4) | 99.9 (60.7) | 44.5 (26.5) | 1375.1 (1379.3) | 944.8 (795.6) | 1604.4 (6629.3) | 0.9 (0.5) | |
| P Value | <0.001 ‡ | 0.01* | 0.4 | <0.001* | 0.04* | 0.8 | 0.3 | <0.001* | |
| HD Group | Day time | 617.2 (75.8) | 95.0 (44.8) | 87.7 (59.1) | 22.5 (17.4) | 861.8 (988.9) | 794.3 (731.3) | 890.2 (1057.3) | 1.3 (0.6) |
| Night Time | 835.6 (148.1) | 100.0 (25.6) | 86.5 (42.1) | 41.4 (23.6) | 967.7(796.6) | 686.7 (452.8) | 558.7 (327.4) | 1.1 (0.6) | |
| P Value | <0.001 ‡ | 0.5 | 0.7 | <0.001* | 0.5 | 0.5 | 0.8 | 0.4 | |
| ND Group | Day time | 625.7 (81.6) | 96.9 (25.2) | 92.0 (40.5) | 21.5 (13.1) | 1017.3 (873.1) | 898.5 (650.9) | 746.9 (822.1) | 1.2 (0.5) |
| Night time | 876.1 (104.9) | 115.5 (50.3) | 96.4 (61.4) | 41.9 (26.9) | 1346.3 (1043.4) | 893.9 (806.2) | 1682.9 (614.4) | 0.9 (0.5) | |
| P Value | <0.001 * | 0.01* | 0.6 | <0.001* | 0.06 | 0.6 | 0.07 | <0.001 * | |
The values are mean (standard error). HS: high SBP; NS: normal SBP; HD: high DBP; ND: normal DBP; SDNN: standard deviation of normal-to-normal RR intervals; RMSSD: the root mean square successive difference; PNN50: RR intervals greater than 50 ms; ULF: ultra low frequency; LF: low frequency; HF: high frequency; LF/HF: LF-HF ratio.
‡
< 0.05 nighttime HRV vs. daytime HRV by paired t-test
*
P <0.05 nighttime HRV vs. daytime HRV by Wilcoxon test