High Performance Sport New Zealand, Auckland, New Zealand.
Int J Sports Physiol Perform. 2014 Sep;9(5):783-90. doi: 10.1123/ijspp.2013-0455. Epub 2013 Dec 11.
To establish the minimum number of days that heart-rate-variability (HRV, ie, the natural logarithm of square root of the mean sum of the squared differences between R-R intervals, Ln rMSSD) data should be averaged to achieve correspondingly equivalent results as data averaged over a 1-wk period.
Standardized changes in Ln rMSSD between different phases of training (normal training, functional overreaching (FOR), overall training, and taper) and the correlation coefficients of percentage changes in performance vs changes in Ln rMSSD were compared when averaging Ln rMSSD from 1 to 7 d, randomly selected within the week.
Standardized Ln rMSSD changes (90% confidence limits, CL) from baseline to overload (FOR) were 0.20 ± 0.28, 0.33 ± 0.26, 0.49 ± 0.33, 0.48 ± 0.28, 0.47 ± 0.26, 0.45 ± 0.26, and 0.43 ± 0.29 on days 1 to 7, respectively. Correlations (90% CL) over the same time sequence and training phase were -.02 ± .23, -.07 ± .23, -.17 ± .22, -.25 ± .22, -.26 ± .22, -.28 ± .21, and -.25 ± .22 on days 1 to 7. There were almost perfect quadratic relationships between standardized changes/r values vs the number of days Ln rMSSD was averaged (r2 = .92 and .97, respectively) in trained triathletes during FOR. This indicates a plateau in the increase in standardized changes/r values' magnitude after 3 and 4 d, respectively, in trained triathletes.
Practitioners using HRV to monitor training adaptation should use a minimum of 3 (randomly selected) valid data points per week.
确定需要平均多少天的心率变异性（HRV，即 RR 间期均方根差的自然对数，Ln rMSSD）数据，才能获得与平均 1 周数据相当的结果。
比较在训练的不同阶段（正常训练、功能性超负荷（FOR）、总训练和调整）时 Ln rMSSD 的标准化变化以及性能百分比变化与 Ln rMSSD 变化之间的相关系数，在每周内随机选择 1 至 7 天的 Ln rMSSD 进行平均。
从基线到过载（FOR）时，Ln rMSSD 的标准化变化（90%置信区间，CL）在第 1 天至第 7 天分别为 0.20±0.28、0.33±0.26、0.49±0.33、0.48±0.28、0.47±0.26、0.45±0.26 和 0.43±0.29。在相同的时间序列和训练阶段，相关性（90%CL）分别为-0.02±0.23、-0.07±0.23、-0.17±0.22、-0.25±0.22、-0.26±0.22、-0.28±0.21 和-0.25±0.22。在 FOR 期间，经过训练的铁人三项运动员的 Ln rMSSD 标准化变化/r 值与平均天数之间存在近乎完美的二次关系（r²分别为.92 和.97）。这表明，在经过训练的铁人三项运动员中，Ln rMSSD 标准化变化/r 值的幅度在第 3 天和第 4 天分别达到平台期。
使用 HRV 监测训练适应性的从业者应每周至少使用 3 个（随机选择）有效数据点。
