# Table 4 HRV parameters in different positions in the narrow frequency range (0,04–0,4 Hz)

supine
(S)
supine with tilt (ST)prone with tilt (PT)prone
(P)
p valueap valueb
TP (ms2) Median
(IQR)
498,5 (318–937,5)581,1 (171,4 – 1105,0)305,2 (212,0 – 473,0)253,3 (105,0 – 634,8)p = 0,026S vs ST = 0,92
ST vs PT = 0,42
PT vs P = 0,29
S vs P = 0,06
S vs PT = 0,08
ST vs P = 0,09
HF – (ms2) Median
(IQR)
48,5 (28,8-104,3)51,0 (19,1 – 116,0)45,0 (22,0 – 69,4)46,0 (22,5–77, 8)p = 0,081
HF nu Median (IQR)17,35 (12,68 – 26,13)17,9 (13,8 – 24,4)20,7 (14,7 – 25,6)22,5 (16,1 – 36,1)p = 0,053
LF – (ms2) Median
(IQR)
256 (150–379,8)293,0 (85,7 – 293,0)142,0 (96,0 – 301,0)174,5 (54,8 – 295,8)p = 0,015S vs ST = 0,46
ST vs PT = 0,047*
PT vs P = 0,01*
S vs P = 0,03*
S vs PT = 0,15
ST vs P = 0,028*
LF nu Median (IQR)82,7 (64, 6–87, 6)79,6 (65,1 – 86,2)78,3 (73,0 – 85,3)72,2 (55,9 – 83,0)p = 0,174
LF/HF§ Median
(IQR)
4,7 (2,3 – 7,1)4,3 (3,1 – 6,2)3,6 (2,8 – 5,8)2,72 (1,8 – 4,9)p = 0,039S vs ST = 0,922
ST vs PT = 1,04
PT vs P = 0,29
S vs P = 0,144
S vs PT = 0,975
ST vs P = 0,162
1. aFriedman test
2. bWillcoxon signed rank test
3. *p values < 0,05 (False discovery rate – FDR; corr. Factor Benjamini and Hochberg)
4. IQR – interquartile range; HRV – heart rate variability, TP – total power; HF – high frequency power; LF – low frequency;§LF/HF - ratio of the LF and HF