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Table 2 Estimated means of the three cosine periodic regression parameters and their 95% CIs for each HRV index.

From: Insulin resistance and circadian rhythm of cardiac autonomic modulation

 

Cosine periodic parameter

HRV index

Mean (95% CI)

Amplitude (95% CI)

Acrophase (95% CI)

Log HF (ms2)

4.36 (4.17-4.54)

0.60 (0.53-0.67)*

4:00(3:00-5:00) AM

Log LF (ms2)

5.36 (5.21-5.52)

0.44 (0.39-0.49)*

5:30(4:30-6:45) AM

LF/HF ratio

3.74 (3.33-4.15)

1.16 (0.98-1.34)*

6:00(4:30-7:15) PM

Log VLF (ms2)

6.95 (6.83-7.07)

0.39 (0.35-0.44)*

8:00(7:00-9:00) AM

SDNN (ms)

60.8 (57.2-64.4)

10.5 (9.3-11.7)*

6:45(5:45-7:30) AM

RMSSD (ms)

28.4 (25.7-31.0)

7.24 (6.10-8.37)*

4:15(3:15-5:15) AM

Heart rate (BPM)

76.6 (74.6-78.6)

10.8 (9.8-11.7)*

2:00(1:45-2:30) PM

  1. Abbreviations: BPM, beats per minute; CIs, confidence intervals; HF, high frequency power; HRV, heart rate variability; LF, low frequency power; Log, logarithm; RMSSD, square root of the mean of the sum of the squares of differences between adjacent RR intervals; SDNN, standard deviation of all RR intervals; VLF, very low frequency power.
  2. *: P value < 0.0001 for zero amplitude test of the HRV indices.
  3. †: Calculated as the unit to peak ± 2 standard errors, and translated into clock time.