Table 2. Comparison of heart rate variability between the two groups.
| Highland | Lowland | P | |
|---|---|---|---|
| RMSSD(asleep state) | 29.25 ± 12.22 | 40.64 ± 21.28 | 0.032 |
| RMSSD(awake state) | 18.93 ± 6.92 | 22.55 ± 13.61 | 0.264 |
| SDNN | 110.82 ± 33.34 | 141.44 ± 40.38 | 0.008 |
| LF/HF | 858.86 ± 699.24 | 371.33 ± 171.46 | 0.003 |
| LF | 1144.14 ± 555.85 | 1100.46 ± 576.53 | 0.797 |
| HF | 568.25 ± 461.03 | 965.23 ± 897.09 | 0.067 |
| VLF | 165.88 ± 82.45 | 135.45 ± 68.72 | 0.187 |
Notes.
Abbreviations: Root mean square of successive RR interval differences (RMSSD); RMSSD derived from daytime and nighttime, RMSSD (awake state) and RMSSD (asleep state), respectively; standard deviation of NN intervals (SDNN); ratio of low- and high- frequency bands (LF/HF); low frequency (LF); high frequency band (HF); very low frequency band (VLF). Values are expressed as means ± SD (standard deviation).