Effect of Sahaja Yoga Meditation on Heart Rate Variability.

Introduction: Nowadays, people are showing a keen interest in yoga and meditation as an alternative therapy to manage psychological stress and stress-related diseases. Yoga is a spiritual discipline with many proven health benefits. There are different types of yoga techniques practiced worldwide for their known health enhancement effects and for reduction of stress and its related disorders. One of the meditation techniques is Sahaja Yoga. It is a unique technique of meditation that involves mental state of internalized attention characterized by mental silence and emotionally positive experience of bliss. The present study has been undertaken to find out the heart rate variability (HRV) in Sahaja Yoga meditators during rest and meditation. Objectives: To study the HRV in Sahaja Yoga meditators during rest and meditation. Materials and methods: A total of 20 volunteers aged 25 to 40 years were considered for the study. The volunteers were practicing Sahaja Yoga meditation (SYM) regularly for 5 years or more. The HRV was recorded during rest with eyes closed and 15 minutes of SYM in a quiet room. Results: Statistical analysis was done using student paired t test. Results are given as mean ± standard deviation (SD). The mean R-R interval, total power (TP), low frequency (LF), high frequency (HF), and LF/HF ratio were studied during rest and during meditation. The HF (during rest 16.2383 ± 11.1896 and during meditation 28.4875 ± 14.5112) was high and LF/HF ratio (during rest 2.262211 ± 1.346382 and during meditation 1.30545 ± 1.200041) was low during meditation compared with that during rest, which was statistically significant. Conclusion: Increase in HF and decrease in LF/HF ratio during meditation signifies that meditation shifts sympathovagal balance toward the parasympathetic side, hence signifying a relaxed state of body and mind in Sahaja Yoga meditators.

Efeitos da acupuntura nos acupontos Shenmen (C-7) e Neiguan (PC-6) sobre a frequência cardíaca, a variabilidade da frequência cardíaca e o ritmo cardíaco em cães saudáveis / Effects of acupuncture at Shenmen (C-7) and Neiguan (PC-6) acupoints on the heart hate, heart rate variability and cardiac rhythm in healthy dogs

Acupuncture derives from traditional Chinese medicine, which aims to restore homeostasis. The action mechanism of this technique involves stimulation of certain points on the skin by inserting a needle. The aim of this study was to evaluate the influence of stimulation of acupoints C7 and PC6 on the heart rate variability, heart rate and heart rhythm in healthy dogs. 30 male and female adult dogs were used, with no breed restriction. The animals were analyzed at two different times in weekly intervals. Firstly were applied needles in the true acupoints, and on the second time we applied needles in false acupoints. Previously to the acupuncture an ECG with 2 minutes of recorder was performed, and after an insertion of needles the electrocardiographic recording was maintained during the 30 minutes of acupuncture. Results showed no significant difference between the HR when comparing true and false acupoints (p = 0.890). For heart rate variability a small difference was observed between the groups (p = 0.0051), however, when comparing the baseline with 15 and 25 minutes of monitoring in the false acupoint group, no significant results were found when compared with true acupoint. In conclusion, it is suggested that the stimulation of acupoints C-7 and PC-6 in healthy dogs does not promote change in sympathovagal balance, specifically on the heart rate variability, heart rate and heart rhythm on healthy dogs.(AU)

Effect of Moderate Physical Exercise on Autonomic Balance in Irritable Bowel Syndrome.

Background: Altered autonomic balance has been noted in Irritable bowel syndrome Regular physical exercise may cause restoration of autonomic balance in health and disease. Objective: To assess the effect of brisk walking on the autonomic balance by analysis of heart rate variability in patients with Irritable bowel syndrome (IBS). Methods: This prospective study was conducted in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University (BSMMU) in 2013.Seventy seven male IBS patients aged 20-50 years, were enrolled from Gastroenterology OPD, BSMMU, Dhaka. Twenty eight healthy sedentary male with similar age were control. HRV measures were recorded once prior to exercise and then after 3 months of brisk walking. For assessing autonomic balance, LF/HF ratio and Max/Min RR was evaluated by Polyrite D machine and software. ANOVA, Independent sample t-test and paired t-test were used for statistical analysis. Results: The pre-exercise mean values of LF/HF ratio were significantly higher (p<0.001) in all IBS patients compared to those of control. The post exercise LF/HF ratio were significantly lower (p<0.05) in all IBS patients compared to their pre-exercise values. Conclusion: This study concluded that the sympathovagal balance was towards sympathetic predominance in IBS and regular moderate physical exercise may shift the balance towards parasympathetic predominance in them.

Heart rate variability responses to standing are attenuated in drug naive depressed patients.

Depression has been linked to altered cardiac autonomic regulation. Previous studies have been inconsistent in terms of measurement of heart rate variability (HRV), selection of depressed patients with cardiac disorders and not controlling for co-morbid conditions such as substance use and anxiety disorders. The objective of this study is to compare the effect of posture on spectral measures of HRV in drug naive healthy patients with major depression with age and gender matched healthy controls. Spectral measures of HRV in supine position and with active standing were obtained (using Task force recommendations). Repeated measure ANOVA revealed an attenuated response in HRV parameters (HF normalized units & LH/HF ratio) to active standing in depressed subjects compared to healthy controls. We conclude that there is an impaired parasympathetic modulation in response to physiological maneuver (orthostatic challenge) in drug naive subjects with major depression (co-morbid medical or psychiatric conditions) compared to healthy controls.

Effects of ergoreflex on respiration and other efferent effects in adult male patients with chronic obstructive pulmonary disease.

In COPD, overactivation of ergoreceptors may be a link between peripheral changes, sympathetic over activation and increased hemodynamic and ventilatory responses to exercise. The current study was undertaken to test the hypothesis that, ergoreflex in COPD patients is hyperactive and contributes to breathlessness and exercise limitation. The aim of study was to (1) demonstrate its hyperactivity in COPD (2). To record other efferent effects. Twenty stable COPD male patients aged 50±2.5 years and twenty healthy male subjects aged 48±3.5 years were studied under experimental and control groups. The ergoreflex contribution to cardio respiratory parameters was assessed by post-handgrip regional circulatory occlusion method (PH-RCO) and computed as the difference in heart rate and respiratory rate response between PH-RCO and control run without PHRCO. Results were analyzed for significance between two groups by repeated measures ANOVA. COPD patients showed over activation of ergoreflex as compared to control subjects in terms of heart rate during sustained hand grip (SHG) exercise (117±1.22 versus 89±0.89) beats/min, recovery heart rate (p<0.001), and respiratory rate during SHG (24±0.54 versus 19±03.24) breaths/min and recovery respiratory rate (p<0.001). Degree of overactivation of ergoreflex was significant in COPD patients (p<0.001). In COPD, overactivity of ergoreflex is associated with abnormal cardio respiratory reflex control. COPD patients showed overactivation of sympathetic nervous system as evidenced by heart rate changes during exercise and delayed recovery.

Study of sympathovagal imbalance by spectral analysis of heart rate variability in young prehypertensives.

Though prehypertension has recently been considered as a risk factor for cardiovascular accidents, the pathophysiological mechanism that causes the development of prehypertension in normotensive subjects has not been fully elucidated. Therefore, the present study was conducted to assess the sympathovagal imbalance in prehypertensives and normotensives by spectral analysis of heart rate variability (HRV) to understand the nature of change in autonomic balance in this dysfunction. Body mass index (BMI), waist-hip ratio (WHR), basal heart rate (BHR), blood pressure (BP), rate-pressure product (RPP) and spectral indices of HRV such as total power (TP), normalized low frequency power (LFnu), normalized high frequency power (HFnu), ratio of low frequency power to high frequency power (LF-HF ratio), mean heart rate (mean RR), square root of the mean squared differences of successive normal to normal intervals; (RMSSD), the number of interval differences of successive NN intervals greater than 50 ms (NN50) and the proportion derived by dividing NN50 by the total number of NN intervals (pNN50) were assessed in two groups of young subjects: normotensives (n=68) and prehypertensives (n=66). Sympathovagal balance (SVB) was analyzed and correlated with BMI, WHR, BHR, BP and RPP in both the groups. It was observed that autonomic imbalance in prehypertensives was due to increase in both sympathetic activity and vagal inhibition. LF-HF ratio, the sensitive indicator of SVB was significantly correlated with BMI, WHR, BHR, BP and RPP in prehypertensive subjects. It was concluded that vagal inhibition might be important in the critical alteration of sympathovagal balance in the development of prehypertension in young normotensive subjects.

Heart rate variability in normotensive subjects with family history of hypertension.

Hypertension (HT) is a major silent disease affecting young people because of their hereditary and modern lifestyles. Target organ damages occur before overt hypertension is diagnosed. Many offspring of HT parents show early changes in their cardiovascular autonomic functions. Heart rate variability (HRV) provides a window to understand the cardiac autonomic balance. This study was designed to quantify and to compare the HRV among the normotensive young male offspring without history of parenteral hypertension & diabetic (control group, n=25, age 20.8±2.4, BMI 24.4±3.1) with parenteral history of hypertension & non diabetic (study group n=25, age 19.7±1.9, 24.05±3.5). Blood pressure, heart rate (HR), indices of short term HRV during supine rest and quiet standing, HR variation during timed controlled deep breathing was compared between the two groups. There were significant difference in low frequency (LF) power, HF power, total power. LF and HF expressed also in normalized units at rest and standing. In time domain standard deviation of normal to normal RR interval (SDNN) at supine rest and standing were significant. Respiratory sinus arrthymia (RSA), HF in normalized units, deep breathing difference (BDD) and the ratio of maximum RR to minimum RR were also significant in the control group than study group. In the present study there was an increased sympathetic and decreased parasympathetic activity in the study group. These findings are an early marker of cardiovascular autonomic impairment in subjects with parenteral history of hypertension.

Ovariectomy does not affect the cardiac sympathovagal balance of female SHR but estradiol does

The low incidence of cardiovascular diseases, including hypertension, in premenopausal women has led to the conclusion that ovarian hormones may have a protective effect on the cardiovascular system. We evaluated the effects of ovariectomy and/or estradiol on sympathovagal balance and heart rate variability (HRV) in female spontaneously hypertensive rats (SHR) with tachycardia and compared them to Wistar rats (12 weeks old; N = 8-12). Ovariectomy (OVX) and/or estradiol (10 µg/kg) did not affect basal arterial pressure in either rat strain, but estradiol increased basal heart rate (HR) in OVX SHR (454 ± 18 vs 377 ± 9 bpm). HR changes elicited by methylatropine and propranolol were used to evaluate the sympathovagal balance. Ovariectomy did not affect the cardiac sympathovagal balance of any group, while estradiol increased sympathetic tone in OVX SHR (120 ± 8 vs 56 ± 10 bpm) and sham-operated Wistar rats (57 ± 7 vs 28 ± 4 bpm), and decreased the parasympathetic tone only in OVX SHR (26 ± 7 vs 37 ± 5 bpm). HRV was studied in the frequency domain (Fast Fourier Transformation). Spectra of HR series were examined at low frequency (LF: 0.2-0.75 Hz) and high frequency (HF: 0.75-3 Hz) bands. The power of LF, as well as the LF/HF ratio, was not affected by ovariectomy, but estradiol increased both LF (29 ± 4 vs 18 ± 3 nu in Wistar sham-operated, 26 ± 5 vs 15 ± 3 nu in Wistar OVX, 50 ± 3 vs 38 ± 4 nu in SHR sham-operated, and 51 ± 3 vs 42 ± 3 nu in SHR OVX) and LF/HF (0.48 ± 0.08 vs 0.23 ± 0.03 nu in Wistar sham-operated, 0.41 ± 0.14 vs 0.19 ± 0.05 nu in Wistar OVX, 0.98 ± 0.11 vs 0.63 ± 0.11 nu in SHR sham-operated, and 1.10 ± 0.11 vs 0.78 ± 0.1 nu in SHR OVX). Thus, we suggest that ovariectomy did not affect the cardiac sympathovagal balance of SHR or Wistar rats, while estradiol increased the sympathetic modulation of HR.

Changes of sympathovagal balance in endotoxemia rats / 中华创伤杂志

Objective To investigate the changes of sympathovagal balance and the effects of va- gus stimulation on sympathovagal balance in endotoxemia rats.Methods Twenty-four Spragne Dawley rats were randomly divided into four groups.The frequency domain of heart rate variability(HRV)com- ponent was analyzed at 0 min,2 ,4 and 6 hours after intravenous injection of lipopolysaccharide(LPS, 5mg/kg)or physiologic saline,and cervical vagal nerve was stimulated(5mv,2ms,1Hz,5 min lasted, 20 min interval)when LPS or physiologic saline was injected.The levels of Noepinephine(NE)and Ace- tylcholin(ACh)were measured in liver tissues.Results Normalized low frequency(LFnm),hormali- zed high frequency(HFnm),very low frequency(VLF),LF/HF values and liver ACh were significantly increased(P＜0.05)and the level of liver NE was significantly decreased (P＜0.05)after LPS admin- istration.Vagal nerve stimulation markedly increased HFnm but decreased LFnm,VLF,LF/HF values, and the liver ACh also significant increased(P＜0.05 ).Conclusion The results suggest that the ac- tivity of sympathetic and vagal nerve was increased during endotoxemia,but the sympathetic activity was more excitable than that of vagal nerve.Vagal nerve stimulation increased the tone of vagus nerve while the tone of sympathetic nerve was decreased in this study.This may be beneficial for anti-inflammatory activity of vagal nerve.