Table 6. Changes in HRV as stress related parameters within training and detraining periods in each group.
| Items | Groups | 0 weeks | 4 weeks | 8 weeks | 12 weeks | F-value | |
|---|---|---|---|---|---|---|---|
| Training | Mean RR (ms) |
HRLT | 842.39 ± 122.26 | 805.31 ± 103.28 | 824.68 ± 85.55 | 828.22 ± 83.26 | T: 10.504* G: .579 TxG: .720 |
| HRLT + 5% | 815.24 ± 84.30 | 794.85 ± 86.48 | 835.83 ± 85.37b | 854.01 ± 102.54b | |||
| SDNN (ms) |
HRLT | 37.75 ± 16.58 | 33.43 ± 9.03 | 35.30 ± 9.68 | 34.33 ± 6.26 | T: 15.704* G: 1.068 TxG: 1.324 |
|
| HRLT + 5% | 35.88 ± 11.12 | 34.98 ± 9.40 | 34.79 ± 9.15 | 37.90 ± 10.12c | |||
| RMSSD (ms) |
HRLT | 22.62 ± 15.98 | 20.24 ± 10.76 | 21.08 ± 8.38 | 21.84 ± 7.80 | T: 14.094* G: 1.623 TxG: 1.035 |
|
| HRLT + 5% | 17.93 ± 6.71 | 20.34 ± 9.02 | 22.59 ± 9.49a | 23.80 ± 9.09ab | |||
| TP (ms2) |
HRLT | 7.01 ± 0.77 | 6.78 ± 0.56 | 6.88 ± 0.57 | 6.87 ± 0.36 | T: 7.658* G: .526 TxG: .701 |
|
| HRLT + 5% | 7.01 ± 0.77 | 6.86 ± 0.59 | 6.89 ± 0.52 | 7.05 ± 0.52c | |||
| LF (ms2) |
HRLT | 5.37 ± 0.83 | 5.25 ± 0.61 | 5.39 ± 0.46 | 5.30 ± 0.50 | T: 8.583* G: .430 TxG: .838 |
|
| HRLT + 5% | 5.42 ± 0.68 | 5.44 ± 0.61 | 5.39 ± 0.72 | 5.54 ± 0.72c | |||
| HF (ms2) |
HRLT | 5.52 ± 1.40 | 5.08 ± 1.08 | 5.08 ± 1.00 | 5.13 ± 0.82 | T: 10.885* G: 1.430 TxG: .834 |
|
| HRLT + 5% | 5.15 ± 0.88 | 5.06 ± 0.94 | 5.16 ± 0.73 | 5.27 ± 0.81 | |||
| Detraining | Mean RR (ms) |
HRLT | 828.22 ± 83.26 | 839.54 ± 65.77 | 818.68 ± 82.55 | 820.12 ± 115.29 | T: 3.265* G: .547 TxG: .301 |
| HRLT + 5% | 854.01 ± 102.54 | 876.39 ± 92.60 | 847.69 ± 94.55b | 858.89 ± 98.82 | |||
| SDNN (ms) |
HRLT | 34.33 ± 6.26 | 36.59 ± 9.80 | 34.38 ± 10.05 | 32.31 ± 9.21 | T: .536 G: .509 TxG: .551 |
|
| HRLT + 5% | 37.90 ± 10.12 | 40.94 ± 12.52 | 38.73 ± 11.25 | 38.67 ± 10.54 | |||
| RMSSD (ms) |
HRLT | 21.84 ± 7.80 | 22.63 ± 9.28 | 22.15 ± 9.22 | 19.65 ± 7.60 | T: 1.832 G: 1.674 TxG: 1.033 |
|
| HRLT + 5% | 23.80 ± 9.09 | 26.60 ± 12.58 | 24.89 ± 11.54 | 25.07 ± 10.07 | |||
| TP (ms2) |
HRLT | 6.87 ± 0.36 | 6.92 ± 0.60 | 6.78 ± 0.60 | 6.69 ± 0.62 | T: 1.206 G: .666 TxG: .960 |
|
| HRLT + 5% | 7.05 ± 0.52 | 7.16 ± 0.61 | 7.02 ± 0.58 | 7.07 ± 0.49 | |||
| LF (ms2) |
HRLT | 5.30 ± 0.50 | 5.37 ± 0.48 | 5.20 ± 0.68 | 5.00 ± 0.71b | T: 1.381 G: 1.073 TxG: 1.639 |
|
| HRLT + 5% | 5.54 ± 0.72 | 5.59 ± 0.73 | 5.50 ± 0.62 | 5.47 ± 0.52 | |||
| HF (ms2) |
HRLT | 5.13 ± 0.82 | 5.09 ± 0.95 | 5.10 ± 1.05 | 5.00 ± 0.57 | T: 4.966* G: 2.211 TxG: 1.106 |
|
| HRLT + 5% | 5.27 ± 0.81 | 5.41 ± 0.86 | 5.32 ± 0.85 | 5.40 ± 0.74 |
Note. HRV = heart rate variability, SDNN = standard deviation of NN intervals, RMSSD = root mean square of successive differences, TP = total power, LF = low frequency, HF = high frequency, HRLT = heart rate at lactate threshold, T = time, G = group.
* significant interaction or main effect, a p<.05 vs training at 0 weeks, b p<.05 vs training at 12 weeks, # p<.05 vs HRLT group