Table 2

Results of the group comparisons. (T1—young healthy males versus older healthy males and T2—older healthy females versus older healthy males (10 subjects in every group). Significance value: n.s., not significant; *p<0.05, **p<0.01, ***p<0.001; TD, time-domain indices; FD, frequency-domain indices; A, fractal measures; B, entropy measures; C, symbolic dynamics measures; D, Poincaré plot representation. For standard HRV parameters in TD and FD, see Task Force (1996); for parameters in A, B and D, see §2; for parameters in C, see Voss et al. (1996). CE, compression entropy; pW110, pW021 and pW321—single word type probabilities from SDyn; ‰, per mille.)

group testsmean value±s.d.


parameterT1T2young malesolder malesolder females
age (years)***n.s.32.43±8.0455.90±5.3656.40±2.46
TDmeanNN (ms)n.s.n.s.819.5±120.7894.5±127.9899.6±129.1
sdNN (ms)n.s.n.s.47.2±13.140.0±9.443.4±15.2
rmssd (ms)n.s.n.s.29.4±13.822.2±12.334.0±17.1
FDLF/HF (arb. units)n.s.n.s.3.79±2.493.86±2.342.40±1.57
LFn (arb. units)n.s.n.s.0.74±0.130.71±0.210.64±0.17
HFn (arb. units)n.s.n.s.0.26±0.130.29±0.210.36±0.17
Aα1 (arb. units)n.s.n.s.1.02±0.181.18±0.231.02±0.23
α2 (arb. units)n.s.n.s.0.90±0.200.97±0.130.98±0.12
BCE (arb. units)n.s.n.s.0.64±0.080.58±0.060.60±0.11
CShannon (bit)*n.s.3.12±0.322.73±0.383.10±0.49
Forbword (arb. units)n.s.*24.63±9.5233.80±9.5320.60±14.83
Renyi025 (bit)n.s.*3.57±0.273.30±0.263.63±0.32
pW110 (arb. units, ‰)*n.s.38.5±11.124.0±12.021.0±12.5
pW021 (arb. units, ‰)n.s.**1.6±2.21.6±4.25.1±5.1
DSD1 (ms)n.s.n.s.20.8±9.822.8±16.134.5±17.1
SD2 (ms)n.s.n.s.63.3±16.456.3±12.361.0±20.4