kjhp Korean Journal of Health Promotion Korean J Health Promot 2234-2141 2093-5676 The Korean Society of Health Promotion and Disease Prevention 10.15384/kjhp.2014.14.4.147 kjhp-14-147 Original Article Effect of Yoga on Heart Rate Variability in Women with Metabolic Syndrome KimHa-Na SeoJin-A SongSang-Wook Department of Family Medicine, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Suwon, Korea Corresponding author：Sang-Wook Song, MD, PhD Department of Family Medicine, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, 93 Jungbudaero, Paldal-gu, Suwon 442-723, Korea Tel: +82-31-249-8246, Fax: +82-31-249-8253 E-mail: sswkoj@unitel.co.kr 01 2014 20 01 2014 14 4 147 154 09052014 06102014 Copyright © 2014 The Korean Society of Health Promotion and Disease Prevention 2014 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Background

The purpose of this study was to investigate the correlation between yoga and autonomic nervous system in women with metabolic syndrome.

 Methods

A randomized controlled study was performed in participants recruited from a public center for managing chronic diseases located in Gyeong-gi Province. The 39 women participants diagnosed with metabolic syndrome were randomly assigned to the 12-week yoga exercise group (n=22) or the wait-listed control group (n=17). Biochemical laboratory tests and heart rate variability were measured before and after the 12-week program.

 Results

In post-menopausal women, the low frequency power of frequency domain significantly decreased in the yoga exercise group compared to the control group (P=0.07). On the time domain of heart rate variability and metabolic syndrome components, there were no significant differences between the groups.

 Conclusions

Sympathetic activity was decreased in post-menopausal women with metabolic syndrome who practiced yoga. Our results suggest that yoga might be beneficial in improving the autonomic nervous system in post-menopausal women with metabolic syndrome.

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Description of yoga positions

Position Description
Kapalbhati (‘forehead brightener') Sit straight in kneeling position with eyes closed. Place hands on knees and perform rapid abdominal breathing.
Baddha-Konasana (‘bound angle pose') Sit with the soles of feet together and move them to the perineal region until legs naturally are bent to the shape of the butterfly. Then, bend the upper part of the body forward.
Paschimottanasana (‘sitting forward bend pose') Sit with legs straight in front of you, hold toes with both hands, and try to bend the upper part of the body forward.
Upavistha-Konasana (‘wide-angle seatedforward bend pose') Sit and stretch legs out to each side. Grasp the toes of each foot with the respective hand and bend the upper part of body forward.
Gomukhasana (‘cow face pose') Sit with legs crossed, left leg under the right leg. Place a hand on each sole and bend upper body forward.
Virasana (‘hero pose') Sit on the floor on knees and position calves to either side of buttocks, then touch kneecaps as shown.
Bhujangasana (‘cobra pose') Lie in the prone position and raise the upper body, pushing against the floor with the palms of hands.
Marjaryasana (‘cat stretch pose') Start on palms of hands and knees, then round back as you form the ‘cat's posture.'
Salabhasana (‘locust pose') Lie on stomach and rest head on the ground. Lift legs until entire body rests on chest. Keep hands firmly on the ground.
Halasana (‘plough pose') Lie on back and then lift legs over head while keeping hands flat on the ground.
Uttanasana (‘standing forward bend pose') Stand and do ‘Paschimottanasana'.
Utthita-Trikonasana (‘extended triangle pose') Stand with feet at double shoulder width and bring arms straight out from the sides of body. Then, lean to the right side and touch the ground with right palm as you raise left arm in the air. Look toward the fingertips of left hand. Repeat for left side.
Setu-Bandha-Sarvangasana (‘bridge shoulder stand pose') Support body with soles and shoulder as you raise pelvis and abdomen, keeping hands flat on the ground. Hold body in the shape of a bridge.
Pavanamuktasana (‘wind removing pose') Lie on back and bend legs toward chest. Clasp them with arms and then raise head up to
Savasana (‘dead posture') touch knee as shown. Lie on the ground with arms placed on both sides of body and relax closing eyes.

Baseline characteristics of participantsa

Characteristics Yoga exercise (n=22) Control (n=17) Pb
Age, y 51.05±8.26 48.24±7.22 0.273
Height, cm 160.55±0.05 158.47±0.05 0.214
Weight, kg 64.8±10.03 66.29±7.06 0.612
BMI, kg/m2 25.12±3.88 26.35±2.32 0.258
TChol, mg/dL 196.91±32.46 197.88±26.72 0.920
Tbil, mg/dL 0.51±0.15 0.53±0.23 0.673
AST, mg/dL 19.82±3.51 20.29±6.03 0.784
ALT, mg/dL 17.00±6.44 22.47±14.37 0.161
Cr, mg/dL 0.73±0.08 0.73±0.10 0.941
Family history
 Hypertension 14 (63.6) 12 (70.6) 0.747
 Diabetes 6 (27.3) 8 (47.1) 0.310
 CVA 9 (40.9) 11 (45.8) 0.754

Abbreviations: BMI, body mass index; TChol, total cholesterol; Tbil, total bilirubin; AST, aspartate transaminase; ALT, alanine transaminase; Cr, creatinine; CVA, Cerebro-vascular accident.

Data are presented as means ± standard deviations or N (%).

P values were obtained by t-test or chi-square test.

Changes in metabolic syndrome components at baseline and post-yoga exercisea

  Yoga exercise (n=22)
 Control (n=17)
 Pb
Baseline Post Baseline Post
WC, cm 90.14±7.98 90.41±8.73 91.12±6.60 90.03±5.17 0.201
SBP, mm Hg 120.91±11.09 121.36±13.20 118.24±10.74 114.71±8.74 0.108
DBP, mm Hg 79.09±8.11 78.64±8.34 77.65±7.52 7 7.06±5.88 0.533
FBS, mg/dL 105.82±15.88 95.45±15.23 115.76±33.54 99.88±24.55 0.792
HDL-C, mg/dL 44.59±13.15 47.55±12.98 46.76±10.64 54.29±15.26 0.145
TG, mg/dL 186.05±99.92 154.95±85.83 176.06±84.31 129.29±52.95 0.312

Abbreviations: WC, waist circumference; SBP, systolic blood pressure; DBP, diastolic blood pressure; FBS, fasting blood sugar; HDL-C, high-density lipoprotein cholesterol; TG, triglyceride.

Values are presented as mean ± standard deviations.

P values correspond to between-group comparisons for the differences over time for each variable, and are obtained by analysis of covariance.

Changes in heart rate variability indices at baseline and post-yoga exercisea

  Yoga exercise (n=22)
 Control (n=17)
 Pb
Baseline Post Baseline Post
SDNN, ms 33.96±16.10 32.03±11.47 27.63±11.66 25.56±9.27 0.213
RMSSD, ms 25.02±12.93 19.80±9.53 20.63±12.36 18.59±9.05 0.662
cln TP, ms2 6.41±0.98 6.23±0.89 5.87±0.91 5.86±1.02 0.927
cln LF, ms2 4.74±1.16 4.40±1.26 4.09±0.83 4.50±0.98 0.061
cln HF, ms2 4.74±1.20 4.13±1.12 4.20±1.35 4.00±1.13 0.585
LF/HF ratio 1.52±1.29 2.43±4.25 1.91±3.00 2.27±2.10 0.819

Abbreviations: SDNN, standard deviation of normal to normal intervals; RMSSD, square root of the mean squared differences of successive normal to normal intervals; TP, total power for the 5-minute cycle (1.15×10–5–0.40Hz); LF, low frequency power (0.004–0.15 Hz); HF, high frequency power (0.15–0.40Hz); LF/HF ratio, ratio of power in LF/HF.

Values are presented as mean ± standard deviations.

P values correspond to between-group comparisons for the differences over time for each variable, and are obtained by analysis of covariance.

ln: natural logarithm. (The spectral power data were log transformed).

Changes in heart rate variability indices at baseline and post-yoga exercise in pre-menopausal womena

  Yoga exercise (n=8)
 Control (n=10)
 Pb
Baseline Post Baseline Post
SDNN, ms 32.57±17.56 33.76±13.35 23.57±12.40 24.54±9.42 0.210
RMSSD, ms 23.35±15.93 20.93±10.76 19.45±14.91 16.44±7.12 0.373
cln TP, ms2 6.15±1.03 6.56±0.87 5.65±0.95 5.54±1.18 0.098
cln LF, ms2 4.67±1.42 4.98±1.36 4.19±0.95 4.36±1.20 0.590
cln HF, ms2 4.35±1.53 4.21±1.46 4.03±1.58 3.97±1.22 0.895
LF/HF ratio 1.80±1.38 4.21±6.78 2.22±3.46 1.87±1.44 0.312

Abbreviations: SDNN, standard deviation of normal to normal intervals; RMSSD, square root of the mean squared differences of successive normal to normal intervals; TP, total power for the 5-minute cycle (1.15×10–5–0.40Hz); LF, low frequency power (0.004–0.15 Hz); HF, high frequency power (0.15–0.40Hz); LF/HF ratio, ratio of power in LF/HF.

Values are presented as mean ± standard deviations.

P values correspond to between-group comparisons for the differences over time for each variable, and are obtained by analysis of covariance

ln: natural logarithm (The spectral power data were log transformed).

Changes in heart rate variability indices at baseline and post-yoga exercise in post-menopausal womena

  Yoga exercise (n=14)
 Control (n=7)
 Pb
Baseline Post Baseline Post
SDNN, ms 34.75±15.83 31.05±10.66 33.43±8.06 28.43±8.94 0.613
RMSSD, ms 25.97±11.44 19.15±9.11 22.32±8.27 21.66±11.13 0.153
cln TP, ms2 6.57±0.76 6.05±0.87 6.19±0.79 6.31±0.49 0.062
cln LF, ms2 4.79±1.04 4.08±1.12 3.94±0.66 4.70±0.55 0.007
cln HF, ms2 4.95±0.97 4.09±0.92 4.42±1.02 4.05±1.07 0.429
LF/HF ratio 1.35±1.26 1.41±1.16 1.46±2.39 2.83±2.83 0.064

Abbreviations: SDNN, standard deviation of normal to normal intervals; RMSSD, square root of the mean squared differences of successive normal to normal intervals; TP, total power for the 5-minute cycle (1.15×10–5–0.40Hz); LF, low frequency power (0.004–0.15 Hz); HF, high frequency power (0.15–0.40Hz); LF/HF ratio, ratio of power in LF/HF.

Values are presented as mean ± standard deviations.

P values correspond to between-group comparisons for the differences over time for each variable, and are obtained by analysis of covariance.

ln: natural logarithm (The spectral power data were log transformed).