Table 2.
Psychological questionnaires, breathing rates, and HRV indices at pretest and posttest between the HRV-BF and the control groups
| Variable | HRV-BF (H) group (n=24) | Control (C) group (n=24) | F | p | ηp2 | Bonferroni’s post-hoc comparison | ||||
|---|---|---|---|---|---|---|---|---|---|---|
|
|
|
|
||||||||
| Pre-test (1) | Post-test (2) | Pre-test (1) | Post-test (2) | Group | Time | Group×time | ||||
| BDI-II | ||||||||||
| Total score | 24.25±14.74 | 15.04±11.68 | 24.92±10.62 | 24.58±11.97 | 2.55 | 9.36** | 8.10** | 0.007 | 0.15 | Group: H<C at post-test Time: 1>2 in H group |
| Cognitive depression | 17.67±12.40 | 10.88±9.57 | 18.92±8.78 | 18.00±9.99 | 2.39 | 10.28** | 5.97* | 0.018 | 0.12 | Group: H<C at post-test Time: 1>2 in H group |
| Somatic depression | 6.58±3.31 | 4.17±2.75 | 6.00±2.36 | 6.58±4.3 | 1.49 | 2.60 | 6.96* | 0.011 | 0.13 | Group: H<C at post-test Time: 1>2 in H group |
| BAI, total score | 20.96±9.45 | 13.08±9.35 | 18.87±9.92 | 19.58±10.85 | 0.74 | 8.29** | 11.89** | 0.001 | 0.21 | Group: H<C at post-test Time: 1>2 in H group |
| PSQI, total score | 12.42±3.20 | 8.92±4.26 | 11.08±3.74 | 10.50±3.49 | 0.02 | 13.34** | 6.81* | 0.012 | 0.13 | Time: 1>2 in H group |
| PSAS | ||||||||||
| Total score | 41.96±13.80 | 34.25±11.58 | 39.33±11.61 | 39.46±11.60 | 0.16 | 7.08* | 7.56** | 0.009 | 0.14 | Time: 1>2 in H group |
| Cognitive arousal | 25.38±9.15 | 18.62±7.38 | 23.96±7.56 | 23.17±7.03 | 0.57 | 17.59*** | 10.98** | 0.002 | 0.19 | Group: H<C at post-test Time: 1>2 in H group |
| Physical arousal | 16.58±6.01 | 15.63±5.69 | 15.79±7.07 | 16.29±5.93 | 0.00 | 0.07 | 0.67 | 0.418 | 0.01 | |
| Breathing rate (breath/min) | 14.98±4.08 | 10.81±3.82 | 14.90±3.53 | 14.68±1.98 | 5.87* | 12.68** | 10.30** | 0.002 | 0.18 | Group: H<C at post-test Time: 1>2 in H group |
| SDNN (ms) | 37.18±17.00 | 46.52±25.00 | 35.60±16.06 | 33.35±16.11 | 2.06 | 3.69 | 9.86 ** | 0.003 | 0.18 | Group: H>C at post-test Time: 1<2 in H group |
| LF (ms2) | 151.64±218.22 | 480.85±825.18 | 149.41±296.59 | 127.57±313.81 | 2.23 | 4.81* | 6.28* | 0.016 | 0.12 | Group: H>C† at post-test Time: 1<2 in H group |
| HF (ms2) | 128.69±120.70 | 174.35±172.64 | 130.97±134.90 | 147.05±209.60 | 0.09 | 2.21 | 0.51 | 0.480 | 0.01 | |
| ln(LF) (ms2) | 4.25±1.36 | 5.19±1.47 | 3.97±1.38 | 3.82±1.27 | 5.15* | 5.84* | 11.10** | 0.002 | 0.19 | Group: H>C at post-test Time: 1<2 in H group |
| ln(HF) (ms2) | 4.27±1.33 | 4.52±1.28 | 4.31±1.23 | 4.17±1.35 | 0.22 | 0.13 | 1.50 | 0.226 | 0.03 | |
| LF/HF ratio | 1.29±0.92 | 6.11±10.23 | 1.12±1.17 | 1.10±1.30 | 5.90* | 5.12* | 5.20* | 0.027 | 0.10 | Group: H>C at post-test Time: 1<2 in H group |
| Total power (ms2) | 532.76±535.25 | 894.31±1,021.84 | 483.90±469.09 | 448.29±506.24 | 1.87 | 5.42* | 8.05** | 0.007 | 0.15 | Group: H>C† at post-test Time: 1<2 in H group |
Values are presented as mean±standard deviation.
HRV, heart rate variability; BF, biofeedback; BDI-II, Beck Depression Inventory-II; BAI, Beck Anxiety Inventory; PSQI, Pittsburgh Sleep Quality Index; PSAS, Pre-Sleep Arousal Scale; SDNN, standard deviation of normal to normal intervals; LF, low frequency; HF, high frequency.
†
p<0.07,
*
p<0.05,
**
p<0.01,
***
p<0.001.