Table 2.
Descriptive HRV values for concussed participants at the subacute evaluation.
| HRV Variable | Mean ± SD | 25th Percentile | 50th Percentile | 75th Percentile |
|---|---|---|---|---|
| Resting State | ||||
| HR dispersion | 28.8 ± 8.8 | 25.0 | 28.0 | 32.4 |
| SDNN | 71.4 ± 29.7 | 47.8 | 68.0 | 94.3 |
| RMSSD | 79.2 ± 35.9 | 49.7 | 71.5 | 103.3 |
| SampEn | 1.75 ± 0.21 | 1.68 | 1.76 | 1.90 |
| Isometric Handgrip Contraction | ||||
| HR dispersion | 29.8 ± 1.3 | 21.7 | 29.6 | 35.7 |
| SDNN | 114.4 ± 6.9 | 83.3 | 106.1 | 143.7 |
| RMSSD | 93.9 ± 8.1 | 53.0 | 75.5 | 111.8 |
Abbreviations: HRV, heart rate variability; HR, heart rate; SDNN, standard deviation of normal-to-normal (NN) intervals; RMSSD, root mean square of successive NN interval differences; and SampEn, sample entropy.