Table 5.
Heart rate variability of patients with Post-COVID-19 Syndrome by relative impairment of physical exercise capacity.
| VO2, % predicted at VT1 | p-value | VO2peak, % predicted | p-value | |||
|---|---|---|---|---|---|---|
| ≤ 49.1% | > 49.1% | ≤ 72.7% | > 72.7% | |||
| Time-related variables (24 h) | ||||||
| NN interval, ms | 790.33 ± 96.71 | 798.57 ± 88.33 | 0.68 | 805.0 ± 99.24 | 782.49 ± 80.59 | 0.24 |
| SDNN Index, ms | 62.42 ± 20.82 | 57.84 ± 15.64 | 0.13 | 62.17 ± 17.92 | 57.54 ± 18.62 | 0.34 |
| rMSSD, ms | 43.74 ± 22.96 | 42.78 ± 19.50 | 0.42 | 45.10 ± 19.46 | 40.71 ± 22.85 | 0.12 |
| Frequency-related variables (24 h) | ||||||
| LF power, ms2 | 853.24 ± 459.77 | 704.84 ± 396.74 | 0.06 | 841.37 ± 427.86 | 703.67 ± 426.24 | 0.10 |
| HF power, ms2 | 292.09 ± 255.25 | 282.62 ± 244.56 | 0.43 | 319.35 ± 282.76 | 248.03 ± 193.90 | 0.07 |
| LF/HF ratio | 4.16 ± 2.54 | 3.31 ± 2.04 | 0.04 | 4.01 ± 2.73 | 3.39 ± 1.66 | 0.09 |
| LFnu | 76.97 ± 8.51 | 72.14 ± 11.11 | 0.01 | 75.24 ± 10.03 | 73.75 ± 10.27 | 0.25 |
| HFnu | 23.03 ± 8.51 | 27.86 ± 11.11 | 0.01 | 24.77 ± 10.03 | 26.25 ± 10.27 | 0.25 |
| Non-linear variables (24 h) | ||||||
| SD1, ms | 40.47 ± 64.40 | 26.76 ± 14.50 | 0.09 | 34.98 ± 55.41 | 31.32 ± 32.85 | 0.36 |
| VAI | 0.63 ± 0.38 | 0.54 ± 0.28 | 0.13 | 0.60 ± 0.36 | 0.57 ± 0.31 | 0.39 |
| Time-related variables (6 h day) | ||||||
| NN interval, ms | 738.52 ± 87.09 | 746.74 ± 88.22 | 0.66 | 739.69 ± 81.18 | 746.63 ± 93.95 | 0.712 |
| SDNN, ms | 125.33 ± 37.68 | 126.73 ± 28.04 | 0.42 | 126.02 ± 35.86 | 126.02 ± 29.07 | 0.50 |
| rMSSD, ms | 42.30 ± 23.68 | 39.84 ± 20.66 | 0.30 | 42.90 ± 20.42 | 38.51 ± 23.80 | 0.18 |
| Frequency-related variables (6 h day) | ||||||
| LF power, ms2 | 744.67 ± 484.12 | 602.91 ± 351.69 | 0.06 | 729.51 ± 429.79 | 608.84 ± 410.71 | 0.09 |
| HF power, ms2 | 273.81 ± 299.14 | 220.06 ± 210.60 | 0.16 | 285.07 ± 307.35 | 193.83 ± 163.73 | 0.07 |
| LF/HF ratio | 4.26 ± 2.52 | 3.67 ± 2.29 | 0.13 | 4.25 ± 2.79 | 3.63 ± 1.80 | 0.11 |
| LFnu | 76.85 ± 9.64 | 74.16 ± 10.14 | 0.10 | 74.47 ± 11.02 | 75.44 ± 8.54 | 0.47 |
| HFnu | 23.16 ± 9.64 | 25.84 ± 10.14 | 0.10 | 25.54 ± 11.02 | 24.56 ± 8.54 | 0.47 |
| Time-related variables (6 h night) | ||||||
| NN interval, ms | 892.05 ± 142.05 | 915.44 ± 111.23 | 0.39 | 905.63 ± 139.05 | 904.34 ± 109.97 | 0.961 |
| SDNN, ms | 115.05 ± 36.73 | 96.51 ± 27.26 | 0.01 | 110.48 ± 34.35 | 99.59 ± 31.20 | 0.14 |
| pNN50, % | 15.26 ± 15.01 | 13.64 ± 12.74 | 0.30 | 16.00 ± 15.35 | 12.49 ± 11.55 | 0.18 |
| Frequency-related variables (6 h night) | ||||||
| LF power, ms2 | 1058.33 ± 552.41 | 896.45 ± 649.99 | 0.11 | 1051.68 ± 576.39 | 883.36 ± 627.63 | 0.22 |
| HF power, ms2 | 387.22 ± 373.98 | 392.27 ± 380.04 | 0.48 | 425.16 ± 408.78 | 328.29 ± 309.76 | 0.11 |
| LF/HF ratio | 4.28 ± 3.11 | 3.53 ± 2.35 | 0.1 | 4.08 ± 3.08 | 3.63 ± 2.26 | 0.44 |
| LFnu | 76.24 ± 10.45 | 70.70 ± 14.62 | 0.02 | 74.47 ± 11.98 | 72.20 ± 13.98 | 0.64 |
| HFnu | 23.76 ± 10.45 | 29.30 ± 14.62 | 0.02 | 25.54 ± 11.98 | 27.80 ± 13.98 | 0.64 |
Data is presented as mean ± SD. Differences of HRV variables between PCS patients with lower or higher physical fitness (determined by group mean of performance at ventilatory threshold 1 [VT1] and peak oxygen uptake [VO2peak]) were analyzed using unpaired t-test or Mann–Whitney U test.
Significant values are in bold.