Table 3.

Time domain parameters.

Index	T0	T20	T30	T40	T60
μHP [ms]	1003 ± 147	927 ± 137	885 ± 129	806 ± 113*	688 ± 120*
${\sigma }_{\text{HP}}^2$ [ms2]	5442 ± 3440	4553 ± 3652	4346 ± 2605	3005 ± 1817	2498 ± 939
μSAP [mmHg]	122.8 ± 21.4	123.0 ± 17.9	125.2 ± 20.4	124.2 ± 15.6	122.3 ± 16.7
${\sigma }_{\text{SAP}}^2$ [mmHg2]	13.7 ± 9.2	11.8 ± 6.8	14.8 ± 8.9	21.9 ± 14.2	35.5 ± 22.2*
μDAP [mmHg]	67.6 ± 11.4	68.6 ± 11.1	70.0 ± 14.9	72.9 ± 11.3	75.5 ± 14.8
${\sigma }_{\text{DAP}}^2$ [mmHg2]	10.5 ± 7.7	10.5 ± 5.7	10.3 ± 6.1	13.6 ± 7.2	23.4 ± 10.9*
μMSNA [bursts.s−1]	0.33 ± 0.09	0.37 ± 0.08	0.47 ± 0.13	0.50 ± 0.13*	0.45 ± 0.16
${\sigma }_{\text{MSNA}}^2$ [bursts2.s−2]	0.033 ± 0.010	0.043 ± 0.015	0.044 ± 0.008	0.057 ± 0.018*	0.055 ± 0.021*

μ_HP, HP mean; ${\sigma }_{\text{HP}}^2$, HP variance; μ_SAP, SAP mean; ${\sigma }_{SAP}^2$, SAP variance; μ_DAP, DAP mean; ${\sigma }_{DAP}^2$, DAP variance; μ_MSNA, MSNA burst rate mean; ${\sigma }_{\text{MSNA}}^2$, MSNA burst rate variance; T0, T20, T30, T40, and T60, head-up tilt at 0, 20, 30, 40, and 60 degrees. Values are expressed as mean ± standard deviation. The symbol

^*indicates a p < 0.05 vs. T0.