Table 1.
Heart rate variability time-and frequency-domain variables in children
| Boys (n = 481, 46.4 %)
|
Girls (n = 555, 53.6 %)
|
Total
|
||||
|---|---|---|---|---|---|---|
| M (n) | SD (%) | M (n) | SD (%) | M (n) | SD (%) | |
| Age (years) | 10.2 | 0.3 | 10.2 | 0.3 | 10.2 | 0.3 |
| Gonadarche pubertal stage | 1.8 | 0.6 | 1.9 | 0.7 | 1.9 | 0.6 |
| BMI %ilea | 61.7 | 28.1 | 58.4 | 27.4 | 60.0 | 27.8 |
| Waist circumference (cm) | 64.8 | 9.7 | 63.9 | 9.1 | 64.3 | 9.4 |
| Weight (kg) | 36.5 | 7.9 | 36.6 | 8.2 | 36.5 | 8.1 |
| Height (cm) | 140.2 | 6.6 | 140.5 | 7.1 | 140.4 | 6.9 |
| Sleep duration (HH:MM) | 9:50 | 0:42 | 9:54 | 0:40 | 9:52 | 0:40 |
| Physical activity (yes) | (21) | (5.3) | (18) | (2.1) | (49) | (3.6) |
| SBP (mmHg) | 97 | 10 | 97 | 10 | 97 | 10 |
| DBP (mmHg) | 62 | 9 | 61 | 8 | 62 | 8 |
| Recording start time (HH:MM) | 10:32 | 3:06 | 10:49 | 3:17 | 10:41 | 3:13 |
| Mean RR (ms)* | 691.0 | 71.7 | 669.5 | 63.3 | 679.5 | 68.2 |
| Mean heart rate (beats/min)* | 79.1 | 10.5 | 81.1 | 9.8 | 80.2 | 10.2 |
| Time-domain | ||||||
| SDNN (ms)* | 89.4 | 26.1 | 84.4 | 23.1 | 86.7 | 24.7 |
| SDANN (ms)* | 42.3 | 17.1 | 39.3 | 15.2 | 40.7 | 16.2 |
| SDNNi (ms)* | 77.4 | 22.9 | 73.0 | 21.0 | 75.0 | 22.0 |
| rMSSD (ms)* | 45.1 | 13.7 | 41.1 | 12.9 | 42.9 | 13.4 |
| pNN50 (%)* | 21.3 | 11.4 | 18.3 | 10.8 | 19.7 | 11.2 |
| Frequency-domain | ||||||
| VLF (ms2)* | 1,621.9 | 1,139.5 | 1,448.3 | 840.8 | 1,528.9 | 994.0 |
| LF (ms2)* | 1,587.7 | 1,040.1 | 1,411.2 | 934.4 | 1,493.1 | 988.3 |
| HF (ms2)* | 896.3 | 684.4 | 770.7 | 622.2 | 828.0 | 654.5 |
| lnVLF | 7.2 | 0.6 | 7.1 | 0.5 | 7.2 | 0.6 |
| lnLF* | 7.2 | 0.6 | 7.1 | 0.6 | 7.1 | 0.6 |
| lnHF* | 6.5 | 0.8 | 6.4 | 0.8 | 6.4 | 0.8 |
| LF:HF ratio* | 2.1 | 0.8 | 2.2 | 0.9 | 2.1 | 0.9 |
SBP systolic blood pressure, DBP diastolic blood pressure, mmHG millimeters of mercury, bpm beats per minute, HH:MM hours:minutes, RR R–R interval, Ln natural log transformed, ms milliseconds
*
Indicate significant sex difference at p < 0.01
a
Z scores used in statistical models