Table 4.

P-values obtained from the Friedman rank sum test and the multiple comparison tests performed between HRV and PRV from each location (F, Finger; T, Toe; EC, Ear canal; EL, Earlobe), during each stage (BM, baseline measurement; CE, cold exposure; CR, cold recovery) and with each index.

Stage	Index	Friedman test	PRV vs. HRV (Nemenyi's test)
			F	T	EC	EL
BM	SDNN (s)	<0.001	0.028	0.001	<0.001	0.067
	RMSSD (s)	<0.001	0.001	<0.001	<0.001	0.005
	pNN50	<0.001	0.488	<0.001	<0.001	0.429
	LF (s2)	<0.001	1.000	1.000	0.610	1.000
	HF (s2)	<0.001	0.270	0.007	0.002	0.488
	TP (s2)	<0.001	0.940	0.302	0.143	0.992
	nLF (n.u.)	0.527	–	–	–	–
	nHF (n.u.)	<0.001	0.013	0.001	0.007	0.016
	LF/HF	0.107	–	–	–	–
	SD1 (s)	<0.001	0.001	<0.001	<0.001	0.005
	SD2 (s)	<0.001	0.954	0.650	0.372	1.000
	SD1/SD2	<0.001	0.001	<0.001	<0.001	0.007
CE	SDNN (s)	<0.001	0.988	<0.001	<0.001	0.529
	RMSSD (s)	<0.001	0.302	<0.001	<0.001	0.028
	pNN50	<0.001	1.000	<0.001	0.061	0.429
	LF (s2)	<0.001	0.988	0.092	0.019	1.000
	HF (s2)	<0.001	0.954	<0.001	<0.001	0.569
	TP (s2)	<0.001	0.999	<0.001	<0.001	0.923
	nLF (n.u.)	0.558	–	–	–	–
	nHF (n.u.)	0.026	0.997	0.107	0.650	0.213
	LF/HF	0.431	–	–	–	–
	SD1 (s)	<0.001	0.302	<0.001	<0.001	0.028
	SD2 (s)	<0.001	0.988	0.005	0.014	0.960
	SD1/SD2	<0.001	0.270	<0.001	<0.001	0.013
CR	SDNN (s)	<0.001	0.372	<0.001	<0.001	0.336
	RMSSD (s)	<0.001	0.164	<0.001	<0.001	0.092
	pNN50	<0.001	0.762	0.001	0.003	1.000
	LF (s2)	<0.001	0.992	0.001	0.040	0.975
	HF (s2)	<0.001	0.610	<0.001	<0.001	0.448
	TP (s2)	<0.001	0.940	<0.001	0.008	0.855
	nLF (n.u.)	0.387	–	–	–	–
	nHF (n.u.)	0.160	–	–	–	–
	LF/HF	0.390	–	–	–	–
	SD1 (s)	<0.001	0.164	<0.001	<0.001	0.092
	SD2 (s)	0.001	1.000	0.143	0.187	0.827
	SD1/SD2	<0.001	0.057	<0.001	<0.001	0.107

Values in red indicate statistically significant differences (p-value < 0.05).