. 2018 Mar 13;18(3):844. doi: 10.3390/s18030844

Table 3.

Comparison of HRV measurements from 20-min acquisitions.

	PPG, Mean ± std.dev.	Reference, Mean ± std.dev.	p Value
Segment 1
NN/RR ratio	0.994 ± 0.007	0.993 ± 0.008	0.181 *
AVNN [ms]	899.144 ± 122.069	898.662 ± 122.258	0.011 *
SDNN [ms]	48.677 ± 19.09	48.576 ± 19.083	0.336 ^†
rMSSD [ms]	37.753 ± 17.667	38.003 ± 18.768	0.569 ^†
pNN50 [%]	17.44 ± 14.876	17.741 ± 15.345	0.29 ^†
LF power [ms²]	654.396 ± 560.816	662.423 ± 576.355	0.378 ^†
HF power [ms²]	746.437 ± 731.819	740.884 ± 745.707	0.381 ^†
LF/HF ratio	1.984 ± 2.852	2.093 ± 3.028	0.002
SD1 [ms]	30.264 ± 16.947	30.89 ± 17.984	0.322 *
SD2 [ms]	65.722 ± 28.181	65.792 ± 28.435	0.495 ^†
Segment 2
NN/RR ratio	0.996 ± 0.003	0.996 ± 0.003	1 *
AVNN [ms]	899.109 ± 134.005	898.624 ± 134.072	<0.001 ^†
SDNN [ms]	47.964 ± 16.901	47.921 ± 16.997	0.601 ^†
rMSSD [ms]	37.201 ± 17.662	37.377 ± 18.721	0.685 ^†
pNN50 [%]	16.345 ± 14.372	16.139 ± 14.766	0.546 ^†
LF power [ms²]	659.338 ± 556.892	672.83 ± 564.52	0.064 *
HF power [ms²]	726.809 ± 811.377	717.345 ± 829.483	0.242 ^†
LF/HF ratio	2.122 ± 2.974	2.252 ± 3.121	0.002 *
SD1 [ms]	28.939 ± 16.707	29.169 ± 17.744	0.77 *
SD2 [ms]	63.831 ± 23.963	63.851 ± 24.204	0.86 ^†
Segment 3
NN/RR ratio	0.996 ± 0.004	0.997 ± 0.003	1 *
AVNN [ms]	907.195 ± 137.581	906.637 ± 137.495	<0.001 ^†
SDNN [ms]	52.471 ± 18.432	52.444 ± 18.698	0.863 ^†
rMSSD [ms]	38.606 ± 16.339	38.737 ± 17.256	0.767 ^†
pNN50 [%]	17.736 ± 13.687	17.371 ± 13.859	0.259 ^†
LF power [ms²]	767.526 ± 583.003	774.654 ± 585.287	0.375 *
HF power [ms²]	734.273 ± 657.889	728.607 ± 704.71	0.084 *
LF/HF ratio	2.006 ± 2.682	2.106 ± 2.75	0.02 *
SD1 [ms]	30.004 ± 15.936	30.181 ± 16.885	0.635 ^†
SD2 [ms]	70.733 ± 26.226	70.653 ± 26.352	0.443 ^†

* Shapiro–Wilk test followed by Wilcoxon (paired) signed rank test. ^† Shapiro-Wilk test followed by one sample (paired) t-test.