The heart rate variability parameters of the participants
| Variables | Mean ± SD | 95% CI | P-value |
|---|---|---|---|
| MRR | 911.3 ± 109.0 | 869.8–952.8 | 0.206 |
| SDNN | 60.6 ± 25.7 | 50.8–70.4 | 0.665 |
| RMSSD | 60.6 ± 25.7 | 50.8–70.4 | 0.643 |
| pNN50 | 30.6 ± 19.8 | 23.0–38.1 | 0.197 |
| LF | 56.5 ± 18.2 | 49.5–63.4 | 0.271 |
| HF | 43.7 ± 18.6 | 36.6–50.8 | 0.159 |
| LF/HF | 1.98 ± 1.95 | 1.23–2.72 | < 0.001 |
Where MRR is the mean of the normal sinus (NN) intervals; SDNN is the standard deviation (SD) of all NN intervals; RMSSD is the root mean square of the successive differences between adjacent NN intervals; pNN50 is the percentage of times that the change in consecutive NN sinus intervals exceeded 50 ms; LF is low frequency; HF is high frequency. Values are mean ± SD, 95% CI is the confidence interval around 95% of the mean and the P-value of Shapiro-Wilk test