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

Table 4. Descriptive statistics and results of Mann-Whitney U tests with respect to nonlinear HRV indices according to Tests I comparing each two age clustered (25–49 years and 50–74 years) female and/or male subject groups.

		Mean ± standard deviation				Mann-Whitney U test
MA	HRV-index	YF	YM	EF	EM	YM-EM	YF-EF	YF-YM	EF-EM
	Number (N =)	571	744	211	380
SD	shannon_SD	3.08 ± 0.49	2.99 ± 0.47	2.50 ± 0.52	2.44 ± 0.49	^****	^****	^*	NS
	forbword	26.9 ± 11.0	28.9 ± 9.9	37.0 ± 10.2	38.5 ± 8.8	^****	^****	^*	NS
	wpsum02	0.49 ± 0.25	0.52 ± 0.23	0.73 ± 0.20	0.73 ± 0.20	^****	^****	NS	NS
	wpsum13	0.09 ± 0.09	0.10 ± 0.09	0.05 ± 0.06	0.07 ± 0.08	^****	^****	NS	NS
	wsdvar	1.24 ± 0.45	1.24 ± 0.44	0.85 ± 0.43	0.88 ± 0.48	^****	^****	NS	NS
	phvar5	0.44 ± 0.20	0.42 ± 0.20	0.25 ± 0.18	0.23 ± 0.17	^****	^****	NS	NS
	plvar20	0.09 ± 0.18	0.12 ± 0.22	0.31 ± 0.32	0.35 ± 0.32	^****	^****	^*	NS
	fwrenyi025	3.43 ± 0.37	3.37 ± 0.35	3.02 ± 0.42	2.97 ± 0.40	^****	^****	^*	NS
	fwrenyi4	2.49 ± 0.61	2.36 ± 0.58	1.82 ± 0.54	1.75 ± 0.50	^****	^****	^**	NS
DFA	α1	0.92 ± 0.23	0.98 ± 0.22	1.06 ± 0.24	1.13 ± 0.23	^****	^****	^**	^*
DFA	α2	0.91 ± 0.20	0.87 ± 0.22	0.98 ± 0.17	0.97 ± 0.20	^****	^**	^*	NS
CE	H_c ^3,3	0.78 ± 0.08	0.77 ± 0.09	0.68 ± 0.09	0.67 ± 0.09	^****	^****	NS	NS
STSD	ST_MP	0.70 ± 0.08	0.72 ± 0.07	0.74 ± 0.07	0.75 ± 0.07	^**	^**	^**	NS
	ST_0V	0.06 ± 0.07	0.05 ± 0.07	0.04 ± 0.07	0.03 ± 0.06	^****	^****	^**	NS
	ST_1V	0.46 ± 0.12	0.51 ± 0.13	0.54 ± 0.14	0.55 ± 0.15	^**	^****	^****	NS
	ST_2V	0.27 ± 0.10	0.24 ± 0.10	0.20 ± 0.10	0.20 ± 0.11	^****	^****	^**	NS
	ST_INC	0.09 ± 0.05	0.09 ± 0.05	0.06 ± 0.04	0.07 ± 0.04	^****	^**	NS	NS
	ST_DESC	0.08 ± 0.04	0.08 ± 0.04	0.06 ± 0.04	0.06 ± 0.04	^**	^****	NS	NS
	ST_PEAK	0.15 ± 0.05	0.13 ± 0.05	0.14 ± 0.05	0.15 ± 0.06	^*	NS	^*	NS
	ST_VAL	0.16 ± 0.06	0.14 ± 0.05	0.16 ± 0.05	0.15 ± 0.05	^*	NS	^****	NS
	ST_2LV	0.16 ± 0.07	0.17 ± 0.08	0.12 ± 0.07	0.13 ± 0.08	^****	^****	NS	NS
	ST_2UV	0.31 ± 0.09	0.27 ± 0.08	0.30 ± 0.09	0.29 ± 0.09	^**	NS	^****	NS
PPA	SD1	25.8 ± 14.2	24.1 ± 13.0	15.5 ± 9.3	14.5 ± 7.8	^****	^****	NS	NS
	SD2	57.5 ± 24.4	59.7 ± 24.2	41.3 ± 17.6	43.9 ± 20.1	^****	^****	NS	NS
	SD1/SD2	0.45 ± 0.16	0.40 ± 0.13	0.38 ± 0.15	0.34 ± 0.14	^****	^****	^**	^*
SPPA	SPPA_c_4	2.14 ± 1.23	2.06 ± 1.22	2.09 ± 1.17	2.29 ± 1.35	^*	NS	NS	NS
	SPPA_c_5	12.5 ± 3.1	12.4 ± 3.3	12.0 ± 3.4	12.1 ± 3.4	NS	NS	NS	NS
	SPPA_c_6	34.5 ± 4.9	34.6 ± 5.1	34.3 ± 5.1	33.7 ± 5.3	^*	NS	NS	NS
	SPPA_c_7	35.1 ± 5.4	35.3 ± 5.5	36.2 ± 6.2	36.4 ± 6.4	NS	NS	NS	NS
	SPPA_c_8	13.4 ± 2.4	13.2 ± 2.5	12.9 ± 2.7	13.2 ± 2.7	NS	NS	NS	NS
	SPPA_c_9	1.84 ± 1.11	1.88 ± 1.13	1.87 ± 1.30	1.66 ± 1.24	^*	NS	NS	NS
	SPPA_r_4	1.73 ± 0.97	2.08 ± 0.98	1.83 ± 0.93	1.87 ± 0.86	^*	NS	^**	NS
	SPPA_r_5	13.5 ± 2.7	12.5 ± 2.8	12.5 ± 3.2	11.8 ± 3.4	^*	^*	^****	NS
	SPPA_r_6	35.6 ± 4.1	34.6 ± 4.3	35.0 ± 4.3	36.0 ± 4.3	^**	NS	^**	^*
	SPPA_r_7	31.9 ± 5.1	34.6 ± 5.2	35.1 ± 5.2	35.3 ± 4.8	NS	^****	^****	NS
	SPPA_r_8	15.2 ± 3.0	14.0 ± 3.2	13.2 ± 3.4	12.5 ± 3.4	^**	^****	^****	NS
	SPPA_r_9	1.66 ± 0.81	1.53 ± 0.82	1.75 ± 1.03	1.79 ± 0.84	^**	NS	^*	NS
	SPPA_entropy	4.03 ± 0.10	4.01 ± 0.11	3.99 ± 0.15	3.98 ± 0.16	^*	NS	NS	NS
IA	AS1	49.3 ± 3.5	50.7 ± 3.7	50.5 ± 3.5	50.0 ± 2.9	^*	^**	^****	NS
	AS2	51.3 ± 5.9	53.5 ± 6.3	53.3 ± 7.4	53.0 ± 7.0	NS	^*	^****	NS
	AS3	0.01 ± 0.07	0.03 ± 0.06	0.04 ± 0.11	0.04 ± 0.1	^**	^**	^**	NS
ACOR and AMI	a21rr	−2.38 ± 0.31	−2.26 ± 0.32	−2.15 ± 0.33	−2.07 ± 0.34	^****	^****	^****	NS
	a31rr	−1.31 ± 0.12	−1.28 ± 0.13	−1.21 ± 0.14	−1.19 ± 0.15	^****	^****	^**	NS
	x2peakrr	5.73 ± 1.99	6.31 ± 2.22	6.74 ± 2.42	7.40 ± 2.77	^***	^**	^**	NS
	y2peakrr	0.46 ± 0.15	0.42 ± 0.13	0.49 ± 0.17	0.47 ± 0.18	^**	^**	^**	NS
	amax21rr	−0.50 ± 0.15	−0.46 ± 0.14	−0.41 ± 0.13	−0.39 ± 0.14	^****	^****	^**	NS
	a21rrcor	−0.34 ± 0.19	−0.29 ± 0.15	−0.26 ± 0.18	−0.22 ± 0.16	^****	^****	^**	NS
	a31rrcor	−0.31 ± 0.13	−0.29 ± 0.12	−0.22 ± 0.11	−0.20 ± 0.09	^****	^****	^*	^*
	x2peakrrcor	5.96 ± 3.32	7.56 ± 3.80	8.28 ± 5.51	9.78 ± 5.78	^**	^**	^****	^**
	y2peakrrcor	0.42 ± 0.18	0.35 ± 0.17	0.39 ± 0.23	0.33 ± 0.22	NS	NS	^****	^*
	amax21rrcor	−0.12 ± 0.05	−0.11 ± 0.05	−0.09 ± 0.05	−0.09 ± 0.05	^**	^****	^**	NS

Abbreviations: YF, young females; YM, young males; EF, elderly females; EM, elderly males; MA, method of analysis; SD, symbolic dynamic; DFA, detrended fluctuation analysis; CE, compression entropy; STSD, short-term symbolic dynamic; PPA, Poincaré plot analysis; SPPA, segmented Poincaré plot analysis; IA, irreversibility analysis; ACOR and AMI, auto-correlation and auto-mutual information; level of significance:

****p<10⁻²⁰,

***p<10⁻¹⁰,

**p<Bonferroni criterion = 0.0007,

*p<0.01, NS, no significance.