Table 2.

Parameter estimates of daily/circadian profiles of heart rate variability measures. Results were obtained using bootstrap. Amplitudes in 24-h and 12-h components are peak to mesor values.

	Group T (n=20)	Group C (n=20)	Group difference
	mean ± SD	mean ± SD	P-value
Mean RR (msec)
24-h component
Amplitude	99.24 ± 3.15	79.73 ± 2.62	0.001
Acrophase(h)	3.83 ± 0.13	3.51 ± 0.14	NS
12-h harmonic
Amplitude	23.99 ± 3.18	35.96 ± 2.80	0.005
Acrophase(h)	4.13 ± 0.27	3.19 ± 0.14	0.003
Overall
Peak-trough amplitude	201.50 ± 6.78	179.07 ± 5.71	0.012
Peak time(h)	3.98 ± 0.17	3.30 ± 0.13	0.002
Trough time(h)	14.62 ± 1.14	18.68 ± 1.67	0.045
Peak value	920.21 ± 5.17	882.46 ± 3.73	0.001
Trough value	718.70 ± 4.61	703.19 ± 3.87	0.011
SDNN (msec)
24-h component
Amplitude	5.29 ± 0.59	5.22 ± 0.6	NS
Acrophase(h)	8.33 ± 0.42	10.32 ± 0.44	0.001
Overall
Peak-trough amplitude	13.20 ± 1.46	14.25 ± 1.52	NS
Peak time(h)	7.98 ± 0.31	8.74 ± 0.34	NS
Trough time(h)	22.84 ± 3.05	24.95 ± 0.37	NS
Peak value	65.18 ± 1.10	64.53 ± 1.09	NS
Trough value	51.93 ± 0.70	50.28 ± 0.89	NS
pNN50 (%)
24-h component
Amplitude	4.16 ± 0.34	1.74 ± 0.27	0.001
Acrophase(h)	4.5 ± 0.26	5.52 ± 0.6	NS
12-h harmonic
Amplitude	1.36 ± 0.31	0.43 ± 0.21	0.014
Acrophase(h)	4.64 ± 0.48	3.68 ± 1.96	NS
Overall
Peak-trough amplitude	8.81 ± 0.75	3.77 ± 0.58	0.0001
Peak time(h)	4.58 ± 0.31	4.85 ± 0.89	NS
Trough time(h)	15.99 ± 2.70	18.56 ± 1.59	NS
Peak value	15.17 ± 0.60	10.50 ± 0.44	0.001
Trough value	6.43 ± 0.35	6.73 ± 0.38	NS
HF
24-h component
Amplitude	0.17 ± 0.01	0.10 ± 0.01	0.001
Acrophase(h)	4.93 ± 0.26	5.83 ± 0.50	NS
12-h harmonic
Amplitude	0.03 ± 0.01	0.04 ± 0.01	NS
Acrophase(h)	2.34 ± 1.14	1.95 ± 0.64	NS
Overall
Peak-trough amplitude	0.35 ± 0.03	0.23 ± 0.03	0.002
Peak time(h)	4.06 ± 0.46	3.64 ± 0.76	NS
Trough time(h)	18.00 ± 0.57	19.08 ± 0.50	NS
Peak value	2.37 ± 0.02	2.36 ± 0.02	NS
Trough value	2.02 ± 0.02	2.13 ± 0.02	0.001