Table 4.
Comparison of effects of yoga intervention on heart rate variability between groups over 4 time-points measures.
| YG (n = 16) Mean (SD) |
CG (n = 18) Mean (SD) |
Group-by-time Interaction |
Group Effect |
Time Effect |
|||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| T1 | T2 | T3 | T4 | T1 | T2 | T3 | T4 | F-value | p | Effect size, ηp2 | F-value | p | Effect size, ηp2 | F-value | p | Effect size, ηp2 | |
| Heart rate variability | |||||||||||||||||
| Minimum HR (bpm) | 68.06 (8.71) | 63.38 (15.00) | 66.44 (9.19) | 68.75 (10.30) | 69.83 (9.67) | 67.07 (7.24) | 67.72 (8.44) | 66.89 (5.65) | 0.991 | 0.400 | 0.030 | 0.222 | 0.641 | 0.007 | 1.844 | 0.144 | 0.054 |
| Maximum HR (bpm) | 84.50 (13.83) | 89.50 (12.34) | 85.81 (12.34) | 88.00 (12.70) | 89.56 (13.10) | 87.17 (8.67) | 87.06 (9.48) | 87.11 (7.19) | 1.951 | 0.145 | 0.057 | 0.052 | 0.821 | 0.002 | 0.492 | 0.635 | 0.015 |
| Time-Domain | |||||||||||||||||
| -RRi (ms) | 823.00(104.66) | 814.88(104.01) | 837.75(99.86) | 773.75 (79.70) | 781.56 (90.49) | 753.50(95.19) | 752.56 (89.98) | 748.06 (76.00) | 1.175 | 0.323 | 0.035 | 4.817 | 0.036* | 0.131 | 2.323 | 0.080 | 0.068 |
| -SDNN (ms) | 24.88 (11.08) | 30.24 (13.03) | 34.93 (13.30) | 28.44 (10.02) | 24.70 (9.78) | 23.45 (9.54) | 27.54 (11.29) | 24.91 (9.99) | 2.594 | 0.072 | 0.075 | 1.791 | 0.190 | 0.053 | 6.974 | 0.001* | 0.179 |
| -RMSSD (ms) | 28.00 (11.78) | 28.26 (12.07) | 34.33 (14.05)# | 28.88 (10.39) | 28.44 (11.55) | 30.12 (13.25) | 25.63 (7.96) | 27.49 (9.77) | 4.264 | 0.008* | 0.118 | 0.325 | 0.573 | 0.010 | 0.575 | 0.633 | 0.018 |
| Frequency-Domain | |||||||||||||||||
| -LF (nu) | 38.13 (13.61) | 45.89 (21.27) | 43.49 (18.09) | 40.89 (21.27) | 37.99 (13.12) | 41.98(12.27) | 38.39 (15.20) | 39.42(15.48) | 0.545 | 0.604 | 0.017 | 0.281 | 0.600 | 0.009 | 2.541 | 0.079 | 0.074 |
| -HF (nu) | 65.15 (13.66) | 60.29 (14.82) | 58.27 (18.92) | 58.90 (21.40) | 62.40 (13.96) | 60.61(11.91) | 61.18 (15.16) | 61.72(16.95) | 0.579 | 0.630 | 0.018 | 0.049 | 0.827 | 0.002 | 1.172 | 0.325 | 0.035 |
| -LF/HF ratio | 2.01 (1.06) | 1.77 (1.15) | 1.96 (1.75) | 2.27 (1.91) | 1.99 (1.20) | 1.62 (0.67) | 2.05 (1.38) | 2.01 (1.32) | 0.278 | 0.841 | 0.009 | 0.047 | 0.830 | 0.001 | 1.664 | 0.180 | 0.049 |
T1, baseline; T2, mid-intervention; T3, post-intervention, T4, 1-month follow-up; YG, yoga intervention group; CG, control group.
HR, heart rate; bpm, beat per minute, RRi, mean normal to normal (NN) interval; SDNN, standard deviation of NN intervals; RMSSD, root mean square of the successive difference of NN intervals; LF, low-frequency; HF, high-frequency; ms, millisecond; nu, normalized unit.
*p < 0.05, group-by-time interaction, group and time effect; #p < 0.05, between-group comparison at each time-point.