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. 2021 Jan 29;21(3):902. doi: 10.3390/s21030902

Table 3.

HRV indices obtained from PolarH7 and ECG data (n = 67).

PolarH7 ECG p ES
SREST PLF (e−4) 9.78 (3.88 to 24.74) 9.76 (3.85 to 24.78) 0.074 0.155
PHF (e−4) 5.77 (2.30 to 10.91) 5.74 (2.22 to 10.84) 0.067 0.159
MHR (bpm) 62.55 (53.25 to 71.95) 62.84 (53.36 to 72.00) <0.001 * 0.378
SDNN (ms) 60.27 (40.50 to 75.22) 60.28 (40.33 to 75.26) 0.570 0.049
RMSSD (ms) 39.48 (22.48 to 60.04) 39.26 (22.39 to 60.66) 0.336 0.083
SCY60 PLF (e−4) 1.17 (0.62 to 2.01) 1.17 (0.65 to 2.23) 0.112 0.137
PHF (e−4) 0.51 (0.26 to 1.29) 0.86 (0.44 to 2.07) <0.001 * 0.419
MHR (bpm) 106.00 (100.45 to 112.91) 106.66 (100.75 to 113.17) <0.001 * 0.433
SDNN (ms) 15.94 (12.06 to 20.77) 16.21 (12.85 to 20.32) 0.010 * 0.222
RMSSD (ms) 6.48 (4.34 to 8.51) 8.38 (5.67 to 10.65) <0.001 * 0.482
SCY70 PLF (e−4) 0.45 (0.21 to 0.87) 0.46 (0.22 to 0.88) 0.851 0.016
PHF (e−4) 0.30 (0.15 to 0.55) 0.41 (0.24 to 0.75) <0.001 * 0.377
MHR (bpm) 124.24 (115.77 to 130.89) 124.32 (115.76 to 130.92) <0.001 * 0.482
SDNN (ms) 10.22 (8.19 to 12.93) 10.48 (8.40 to 13.10) 0.001 * 0.280
RMSSD (ms) 3.74 (2.96 to 4.91) 4.37 (3.64 to 6.68) <0.001 * 0.443
SCY80 PLF (e−4) 0.13 (0.09 to 0.23) 0.18 (0.10 to 0.26) <0.001 * 0.364
PHF (e−4) 0.23 (0.14 to 0.36) 0.37 (0.25 to 0.66) <0.001 * 0.362
MHR (bpm) 141.01 (130.62 to 148.81) 141.09 (130.69 to 149.05) <0.001 * 0.451
SDNN (ms) 8.11 (6.20 to 9.92) 8.10 (6.34 to 10.65) <0.001 * 0.378
RMSSD (ms) 2.90 (2.32 to 3.90) 3.75 (3.16 to 5.52) <0.001 * 0.405
SREC PLF (e−4) 4.75 (1.83 to 10.25) 4.59 (1.88 to 9.97) 0.881 0.015
PHF (e−4) 2.06 (0.65 to 4.71) 2.12 (0.82 to 4.70) 0.308 0.102
MHR (bpm) 99.76 (90.76 to 112.15) 98.39 (90.12 to 111.35) 0.002 * 0.268
SDNN (ms) 33.11 (23.27 to 58.30) 33.67 (23.04 to 57.40) 0.094 0.147
RMSSD (ms) 12.87 (7.65 to 23.78) 12.90 (7.99 to 23.32) 0.603 0.046

Values are expressed as median and interquartile range. Segments are based on the test phases: resting (SREST), cycling (SCY) and recovery (SREC). SCY was divided in three stages at 60, 70 and 80% of HRmax, denoted as SCY60, SCY70 and SCY80, respectively. PLF = low-frequency power; PHF = high-frequency power; MHR = mean HR; SDNN = SD of the NN intervals; RMSSD = root mean square of successive differences between NN intervals. ES = Effect size. * = Significant differences between devices (p ≤ 0.05, Wilcoxon test for paired samples).