Table 2.
Test-retest reliability of HRV for each duration (5-min, 10-min, 1-h, 3-h, 6-h and 24-h) in all participants (n = 45).
| Day 1, median (p25, p75) | Day 2, median (p25, p75) | p-value | ICC (95%CI) | CV | 95% LoA | |
|---|---|---|---|---|---|---|
| 5-min | ||||||
| SDNN (ms) | 45.0 (29.8, 56.7) | 40.7 (30.1, 59.7) | 0.71 | 0.34 (0.05–0.57) | 48.8 | ±1.01 x̄ |
| RMSSD (ms) | 17.0 (10.4, 30.6) | 16.9 (8.8, 25.4) | 0.57 | 0.72 (0.54–0.83) | 43.7 | ±0.93 x̄ |
| HF (ms2) | 129.2 (52.9, 395.6) | 106.8 (44.5, 405.2) | 0.69 | 0.54 (0.30–0.72) | 140.2 | ±1.68 x̄ |
| LF (ms2) | 487.4 (205.0, 773.7) | 277.9 (135.3, 780.6) | 0.45 | 0.40 (0.13–0.62) | 104.6 | ±1.51 x̄ |
| TP (ms2) | 638.6 (236.2, 1105.9) | 418.3 (196.2, 980.7) | 0.96 | 0.48 (0.22–0.68) | 100.4 | ±1.49 x̄ |
| 10-min | ||||||
| SDNN (ms) | 51.6 (33.1, 68.1) | 45.7 (33.9, 67.3) | 0.40 | 0.43 (0.15–0.64) | 49.2 | ±1.01 x̄ |
| RMSSD (ms) | 16.4 (9.8, 30.4) | 17.7 (9.0, 24.9) | 0.79 | 0.76 (0.60–0.86) | 40.6 | ±0.89 x̄ |
| HF (ms2) | 143.7 (56.8, 334.8) | 130.0 (61.1, 364.4) | 0.63 | 0.65 (0.45–0.79) | 132.1 | ±1.65 x̄ |
| LF (ms2) | 393.7 (208.1, 663.4) | 297.2 (172.0, 603.6) | 0.037 | 0.60 (0.37–0.76) | 93.1 | ±1.43 x̄ |
| VLF (ms2) | 1704.1 (774.9, 3269.5) | 1345.6 (618.4, 2529.6) | 0.50 | 0.16 (−0.17–0.43) | 144.1 | ±1.69 x̄ |
| TP (ms2) | 2500.8 (1091.4, 4693.1) | 1818.5 (944.1, 4429.3) | 0.39 | 0.22 (−0.08–0.48) | 125.5 | ±1.62 x̄ |
| 1-h | ||||||
| SDNN (ms) | 61.8 (48.3, 89.0) | 64.0 (44.1, 88.6) | 0.60 | 0.46 (0.19–0.66) | 32.0 | ±0.74 x̄ |
| RMSSD (ms) | 17.3 (10.3, 29.3) | 18.9 (9.5, 25.1) | 0.81 | 0.74 (0.58–0.85) | 40.6 | ±0.89 x̄ |
| HF (ms2) | 146.7 (70.2, 375.3) | 166.3 (111.9, 338.8) | 0.48 | 0.60 (0.37–0.76) | 99.2 | ±1.49 x̄ |
| LF (ms2) | 316.4 (143.4, 712.4) | 300.9 (175.3, 622.2) | 0.66 | 0.76 (0.61–0.86) | 67.8 | ±1.24 x̄ |
| VLF (ms2) | 1120.0 (734.8, 1900.1) | 1192.7 (702.6, 2479.6) | 0.31 | 0.64 (0.43–0.79) | 56.3 | ±1.11 x̄ |
| ULF (ms2) | 2184.2 (1093.5, 4995.2) | 2037.2 (1305.2, 4974.2) | 0.90 | 0.06 (−0.23–0.35) | 123.2 | ±1.62 x̄ |
| TP (ms2) | 4161.4 (2632.4, 7979.5) | 4258.2 (2029.6, 8631.4) | 0.41 | 0.30 (0.01–0.54) | 75.1 | ±1.31 x̄ |
| 3-h | ||||||
| SDNN (ms) | 78.3 (62.0, 109.7) | 74.6 (61.9, 98.5) | 0.50 | 0.72 (0.54–0.84) | 23.1 | ±0.56 x̄ |
| RMSSD (ms) | 19.0 (11.3, 28.2) | 16.6 (9.6, 26.4) | 0.72 | 0.77 (0.62–0.87) | 35.7 | ±0.80 x̄ |
| HF (ms2) | 213.5 (105.9, 372.0) | 126.9 (77.6, 479.0) | 0.70 | 0.60 (0.37–0.76) | 94.9 | ±1.46 x̄ |
| LF (ms2) | 298.9 (195.2, 660.2) | 267.9 (153.2, 584.7) | 0.86 | 0.81 (0.68–0.89) | 64.4 | ±1.20 x̄ |
| VLF (ms2) | 1135.9 (661.1, 2036.7) | 989.7 (672.3, 1943.9) | 0.79 | 0.77 (0.62–0.87) | 52.7 | ±1.06 x̄ |
| ULF (ms2) | 5196.8 (2492.1, 9084.4) | 4177.5 (2243.1, 7548.5) | 0.33 | 0.70 (0.51–0.82) | 76.2 | ±1.31 x̄ |
| TP (ms2) | 7111.8 (3904.4, 12474.0) | 5955.0 (3964.4, 9925.8) | 0.44 | 0.74 (0.57–0.85) | 53.3 | ±1.07 x̄ |
| 6-h | ||||||
| SDNN (ms) | 84.1 (66.3, 107.2) | 79.1 (64.1, 109.8) | 0.30 | 0.83 (0.70–0.90) | 17.0 | ±0.43 x̄ |
| RMSSD (ms) | 16.8 (10.8, 30.6) | 15.6 (10.4, 26.8) | 0.50 | 0.89 (0.81–0.94) | 25.7 | ±0.62 x̄ |
| HF (ms2) | 166.8 (90.2, 386.0) | 183.0 (85.8, 401.4) | 0.77 | 0.77 (0.62–0.87) | 52.9 | ±1.07 x̄ |
| LF (ms2) | 259.0 (178.7, 697.5) | 270.1 (162.5, 669.9) | 1.00 | 0.88 (0.79–0.93) | 40.6 | ±0.89 x̄ |
| VLF (ms2) | 1151.6 (568.9, 2010.3) | 940.1 (611.5, 1694.6) | 0.87 | 0.86 (0.76–0.92) | 39.3 | ±0.87 x̄ |
| ULF (ms2) | 5903.0 (3393.1, 8765.0) | 4787.6 (2901.3, 8571.6) | 0.35 | 0.81 (0.67–0.89) | 53.1 | ±1.06 x̄ |
| TP (ms2) | 7572.6 (4408.3, 11929.8) | 6291.5 (4102.5, 12296.8) | 0.37 | 0.84 (0.73–0.91) | 38.9 | ±0.85 x̄ |
| 24-h | ||||||
| SDNN (ms) | 101.7 (81.4, 130.3) | 109.0 (82.2, 126.4) | 0.76 | 0.82 (0.69–0.90) | 15.7 | ±0.40 x̄ |
| RMSSD (ms) | 20.6 (12.9, 35.2) | 22.1 (11.6, 32.5) | 0.33 | 0.91 (0.85–0.95) | 14.9 | ±0.39 x̄ |
| HF (ms2) | 283.1 (130.3, 656.2) | 318.6 (154.2, 519.7) | 0.80 | 0.80 (0.66–0.88) | 42.4 | ±0.91 x̄ |
| LF (ms2) | 324.1 (211.2, 835.9) | 381.9 (239.7, 839.4) | 0.97 | 0.89 (0.80–0.94) | 30.4 | ±0.71 x̄ |
| VLF (ms2) | 1298.6 (721.6, 2108.5) | 1197.6 (695.0, 1766.3) | 0.47 | 0.92 (0.86–0.95) | 21.0 | ±0.52 x̄ |
| ULF (ms2) | 8549.3 (5405.0, 14469.9) | 10046.0 (5235.0, 14171.0) | 0.88 | 0.82 (0.69–0.89) | 42.5 | ±0.92 x̄ |
| TP (ms2) | 10598.9 (6821.3, 17380.4) | 11745.3 (6949.5, 17532.1) | 0.94 | 0.84 (0.73–0.91) | 34.8 | ±0.79 x̄ |
CI confidence interval, CV coefficient of variation, HF high frequency power, ICC intraclass correlation coefficient, LF low frequency power, LoA limits of agreement, RMSSD root mean square of successive differences between normal heartbeats, SDNN standard deviation of all normal-to-normal R-R intervals, TP total power, ULF ultra-low frequency power, VLF very low frequency power, x̄ data mean.