. 2015 Mar 30;10(3):e0118308. doi: 10.1371/journal.pone.0118308

Table 7. Descriptive statistics and results of Kruskal-Wallis test followed by Mann-Whitney U tests with respect to linear HRV indices comparing each two age decades in males (Tests II, comparison of five different age decades: 1 = 25–34, 2 = 35–44, 3 = 45–54, 4 = 55–64 and 5 = 65–74 years).

		1 (N = 330)	2 (N = 292)	3 (N = 235)	4 (N = 183)	5 (N = 84)	1–5	1 vs. 2	2 vs. 3	3 vs. 4	4 vs. 5
MA	HRV-index	Mean ± standard deviation					KW test	Mann-Whitney U tests
TD	meanNN	939 ± 129	925 ± 138	923 ± 134	904 ± 123	906 ± 123	NS	NS	NS	NS	NS
	sdNN	50.0 ± 20.9	44.6 ± 16.8	36.8 ± 14.6	32.8 ± 14.7	29.6 ± 13.2	^****	^*	^**	^*	NS
	cvNN	0.05 ± 0.02	0.05 ± 0.02	0.04 ± 0.01	0.04 ± 0.01	0.03 ± 0.01	^****	^*	^**	^*	NS
	sdaNN1	18.9 ± 13.0	18.2 ± 10.4	16.4 ± 9.5	14.8 ± 9.5	13.7 ± 8.9	^**	NS	NS	NS	NS
	rmssd	39.7 ± 19.9	32.0 ± 16.5	23.0 ± 10.9	19.9 ± 11.1	19.1 ± 10.7	^****	^**	^**	^*	NS
	pNN50	0.20 ± 0.17	0.13 ± 0.15	0.06 ± 0.08	0.04 ± 0.07	0.04 ± 0.07	^****	^**	^****	^*	NS
	pNNl20	0.45 ± 0.20	0.54 ± 0.21	0.67 ± 0.20	0.75 ± 0.19	0.78 ± 0.18	^****	^**	^****	^**	NS
	renyi4	4.00 ± 0.53	3.86 ± 0.52	3.56 ± 0.56	3.37 ± 0.57	3.22 ± 0.55	^****	^*	^**	^*	NS
	shannon_h	4.45 ± 0.52	4.30 ± 0.51	4.02 ± 0.55	3.83 ± 0.56	3.68 ± 0.54	^****	^*	^**	^*	NS
FD	LF	242 ± 325	191 ± 206	113 ± 141	80 ± 103	70 ± 112	^****	^*	^**	^**	NS
	HF	133 ± 174	89 ± 118	41 ± 49	29 ± 38	22 ± 29	^****	^**	^****	^*	NS
	P	625 ± 660	500 ± 407	348 ± 345	275 ± 290	241 ± 300	^****	NS	^**	^*	NS
	LF/HF	2.79 ± 3.20	3.62 ± 3.73	4.10 ± 3.48	4.17 ± 3.60	4.77 ± 5.34	^***	^*	^*	NS	NS
	LF/P	0.38 ± 0.16	0.38 ± 0.16	0.34 ± 0.15	0.30 ± 0.14	0.29 ± 0.16	^**	NS	NS	NS	NS
	HF/P	0.22 ± 0.13	0.18 ± 0.13	0.13 ± 0.09	0.12 ± 0.11	0.12 ± 0.11	^****	^**	^**	NS	NS
	LFn	0.64 ± 0.17	0.68 ± 0.18	0.72 ± 0.16	0.73 ± 0.16	0.71 ± 0.19	^***	^*	^*	NS	NS
	HFn	0.36 ± 0.17	0.32 ± 0.18	0.28 ± 0.16	0.27 ± 0.16	0.29 ± 0.19	^***	^*	^*	NS	NS

Abbreviations: MA, method of analysis; TD, time domain; FD, frequency domain; N: number of subjects; KW test: Kruskal-Wallis test; level of significance:

****p<10⁻²⁰,

***p<10⁻¹⁰,

**p<Bonferroni criterion = 0.0007,

*p<0.01, NS, no significance.