Skip to main content

Table 3 Time Domain Units – ECG data and HRV (heart rate variability) in study participants at night (02.00-04.00 am) (n = 9)

From: Increased heart rate variability but no effect on blood pressure from 8 weeks of hatha yoga – a pilot study

 

Before/Baseline

After 8 weeks’ yoga

P-value

Effect size

Confidence interval before

Confidence interval after 8 weeks

RR mean [ms]

996.2 ± 105.4 Md 992.3

1019.8 ± 172.8 Md 1057.1

0.82

0.17

915-1077

887-1153

RR triangular index

16.3 ± 4.5 Md18.0

17.5 ± 5.8 Md 17.9

0.50

0.25

12.8-19.7

13.0-22.0

SDNN (stdRR) [ms]

85.6 ± 21.9 Md 83.4

92.7 ± 39.6 Md 95.6

0.57

0.24

68.7-102.5

62.2-123.2

NN50 count

868.4 ± 823.8 Md 731

1208.7 ± 810.0 Md 1497

0.13

0.44

234-1503

585-1832

pNN50 [%]

12.7 ± 12.5 Md 10.6

18.2 ± 13.3 Md 17.1

*0.035

0.45

3.1-22.3

8.0-28.4

RMSSD [ms]

42.1 ± 19.4 Md 41.0

47.6 ± 21.2 Md 50.2

0.30

0.29

27.2-57.0

31.3-63.9

  1. Data are expressed as means ± SD and, when stated, median. ms = milli seconds.
  2. * = P < 0.05 significant.
  3. NN = RR.
  4. RR triangular index = Total number of all NN intervals divided by the height of the histogram of all NN intervals measured on a discrete scale with bins of 7.8125 ms (1/128 s) [21].
  5. SDNN = the standard deviation of all NN intervals.
  6. NN50 count = Number of pairs of adjacent NN intervals differing by more than 50 ms in the entire recording. This is highly correlated with frequency domain measures and recognized to be strongly dependent on vagal tone.
  7. pNN50% = NN50 count divided by the total number of all NN intervals.
  8. RMSSD = the square root of the mean of the sum of the squares of differences between adjacent NN intervals.
  9. Confidence interval = 95%.
  10. Md = Median.