Yoga Nidra relaxation increases heart rate variability and is unaffected by a prior bout of Hatha yoga

Psychological and physiological effects of an acute bout of yoga before a simulated academic exam in university students

Objective: Test anxiety is common among nursing students. Yoga is one form of physical activity which may be beneficial for pretest anxiety. Participants: Thirteen undergraduate students (85% nursing majors, 15% awaiting program entry, 20 ± 4.9 years of age) completed the crossover design study. Methods: Participants completed a yoga or control intervention (independent quiet study) on opposing testing days. At three time points, participants provided ratings of anxiety (visual analog scales), saliva samples for cortisol and alpha amylase, and seated heart rate variability (HRV, time and frequency domains) was recorded. Results: Yoga prior to a simulated exam had a positive impact on subjective measures of stress but did not positively impact cortisol or HRV compared to the control condition. Conclusions: There may be benefits to participating in 30 min of moderate intensity yoga for reduced perception of stress before a scholarly examination. Further research regarding the impacts of acute yoga on physiological measures of HRV and/or cortisol are warranted.

Dreaming while awake: The beneficial effects of yoga Nidra on mental and physical recovery in two elite karate athletes

Yoga Nidra (YN) naturally stimulates a hypnagogic state wherein an individual is physiologically asleep yet maintains a certain awareness to follow a guide's instructions. The aim of this study was to investigate the effects of this aware sleep state on recovery-stress balance in two elite karate athletes adopting an idiosyncratic and multimodal approach. One male and one female athlete underwent a YN intervention. Before intervention, after intervention and three weeks later, recovery-stress balance specific scales, perceived stress, cognitive and somatic anxiety, subjective and objective sleep quality, and individual alpha peak frequency (iAPF) values were assessed. Perceived quality of recovery was continuously monitored for three months including the period of the investigation. Feelings and arousal levels before and after each YN session were also examined. Our results showed a YN general positive effect; however, the intervention had higher sport specific effects in the male compared to the female athlete. On the other hand, in the female athlete, YN seems to have effects both from an emotional and physical point of view. We also noted the intertwined relationship among interoception, perceived stress and YN effects. Also, findings suggest that iAPF modulation reflected improved recovery skills or a better control of stressful situations, while the acute effects on arousal levels were expression of anxiety or energy reduction. Overall, YN improved both the perceived quality of recovery and sleep quality, shedding light on the importance of YN for recovery-stress balance enhancement in the sport context.

Yoga Nidra, a Nonpharmacological Technique in Management of Insomnia and Overall Health in Postmenopausal Women

Yoga Nidra is a promising technique through which body is consciously simulated into a profound relaxation state similar to attained during naturally occurring deep sleep. It is aimed to attain complete emotional, physical, and mental relaxation of body and mind. In postmenopausal phase of life, regular practice of Yoga Nidra at home preferably in morning, can help in reduction in anxiety and pain associated with early morning awakenings. This nonpharmacological technique has a therapeutic potential to improve sleep quality and quantity, and overall well-being.

Exploring the uses of yoga nidra: An integrative review

AIM

The purpose of this paper was to review and synthesize published research articles that have utilized yoga nidra as an intervention.

BACKGROUND

Yoga nidra is a form of guided meditation that has emerged in the literature in the past two decades as an intervention for a variety of medical conditions such as stress and mental health. It differs from traditional yoga, in that it does not require yoga poses. It is a noninvasive, cost-effective approach that is also easily accessible so it can be done in the privacy and comfort of the home.

DESIGN

The integrative review methodology by Whittemore and Knafl (2005) provided the framework for this review.

METHODS

The databases CINAHL, PubMed, SCOPUS, and PsycINFO were used to search for articles. Inclusion criteria consisted of journal articles in English with no limitations on dates of publication. Studies were excluded if any form of traditional yoga requiring poses was used as an intervention. Also excluded were all types of meditation that were not yoga nidra, systematic reviews, studies that utilized multiple intervention types (i.e., traditional yoga and yoga nidra), and commentaries/brief reports. Twenty-nine studies met the inclusion criteria. Quality appraisal was completed for each study.

RESULTS

The 29 studies that were reviewed consisted of 12 randomized controlled trials, 13 quasi-experimental studies, 3 mixed-methods studies, and 1 qualitative study. Outcome variables were categorized according to themes and results were systemically synthesized and reported by theme: (a) stress, (b) mood, (c) well-being, (d) psychologic dysfunction, (e) biomarkers, (f) sleep, and (g) miscellaneous.

CONCLUSION

Yoga nidra was found to be effective in most of these studies. However, there was some clinical heterogeneity in the sample populations and intervention session lengths, frequencies, and durations, making it difficult to draw conclusions about yoga nidra intervention based solely on the findings presented in this review. More studies are needed overall, particularly ones with larger sample sizes and stronger experimental designs.

CLINICAL RELEVANCE

Yoga nidra has the potential to be a useful, noninvasive, nonpharmacologic treatment or adjunct for a variety of conditions, particularly mental health.

Embodied Learning for Well-Being, Self-Awareness, and Stress Regulation: A Randomized Trial with Engineering Students Using a Mixed-Method Approach

The continuous changes in our society require adapted training that encompasses both technical and competency knowledge. There is a high level of demand, especially in areas such as engineering, which can affect the mental health of students, producing high levels of stress and psychological distress, hindering self-efficacy and academic performance. Embodied learning working on self-awareness, stress reduction and self-knowledge can help to generate healthier environments. Creative therapies can be a tool to promote the prevention of health problems in this group of the population. In particular, Dance Movement Therapy has demonstrated its effectiveness in improving health in clinical and non-clinical settings. In this work, a body awareness program based on Dance Movement Therapy is developed and implemented in engineering students. Through a mixed pre-post methodology, its impact is evaluated and analyzed in an experimental group of engineering students. Psychometric tests, physiological variables and reflective diaries are used as data sources. The results show that the experimental group, compared with the control group, increased their levels of body awareness and connectedness, well-being and life satisfaction and reduced their stress levels. The results were supported by cortisol measures. Likewise, the students acknowledged having increased their levels of self-awareness and self-knowledge and considered the inclusion of these bodily approaches in higher education to be necessary.

Investigating components of pranayama for effects on heart rate variability

OBJECTIVE

Traditional Indian breath control practices of Pranayama have been shown to increase indices of heart rate variability (HRV) that are generally held to reflect parasympathetic nervous system (PNS) tone. To our knowledge, individual components of pranayama have not been separately evaluated for impact on HRV. The objective of this study was to isolate five components of a pranayama practice and evaluate their impact on HRV.

METHODS

In a crossover clinical trial, 46 healthy adults were allocated to complete five activities in random order, over five separate visits: 1) sitting quietly; 2) self-paced deep breathing; 3) externally-paced deep breathing; 4) self-paced Sheetali/Sheetkari pranayama; and 5) externally paced Sheetali/Sheetkari pranayama RESULTS: Our final sample included 25 participants. There was a significant increase in a time-domain index of HRV, the root mean square successive differences between RR intervals (RMSSD), during the five interventions. The change in logRMSSD ranged from 0.2 to 0.5 (p < .01 in all conditions by paired t-test). Greater increases were evident during externally-paced breathing than during self-paced breathing (mean pre-during logRMSSD change of 0.50 vs. 0.36, p = .02) or sitting quietly (mean, 0.17 ms; p = .005 and 0.02 when comparing Activities 3 and 5 to Activity 1 by random intercept model with Tukey correction for multiple comparisons). Lastly, pre-during increase in RMSSD was greater for Sheetali/Sheetkari vs. deep breathing, when controlling for respiration rate, though not significantly different (p = .07 in random intercept model) CONCLUSIONS: RMSSD increased with paced breathing, deep breathing, and Sheetali/Sheetkari pranayama, reinforcing evidence of a physiologic mechanism of pranayama.

TRIAL REGISTRATION

NCT03280589 https://www.clinicaltrials.gov/ct2/show/NCT03280589?term=sheetali&draw=2&rank=1.

Bispectral Index Alterations and Associations With Autonomic Changes During Hypnosis in Trauma Center Researchers: Formative Evaluation Study

BACKGROUND

Previous work performed by our group demonstrated that intermittent reductions in bispectral index (BIS) values were found during neurofeedback following mindfulness instructions. Hypnosis was induced to enhance reductions in BIS values.

OBJECTIVE

This study aims to assess physiologic relaxation and explore its associations with BIS values using autonomic monitoring.

METHODS

Each session consisted of reading a 4-minute baseline neutral script and playing an 18-minute hypnosis tape to 3 researchers involved in the BIS neurofeedback study. In addition to BIS monitoring, autonomic monitoring was performed, and this included measures of electromyography (EMG), skin temperature, skin conductance, respiratory rate, expired carbon dioxide, and heart rate variability. The resulting data were analyzed using two-tailed t tests, correlation analyses, and multivariate linear regression analyses.

RESULTS

We found that hypnosis was associated with reductions in BIS (P<.001), EMG (P<.001), respiratory rate (P<.001), skin conductance (P=.006), and very low frequency power (P=.04); it was also associated with increases in expired carbon dioxide (P<.001), skin temperature (P=.04), high frequency power (P<.001), and successive heart interbeat interval difference (P=.04) values. Decreased BIS values were associated with reduced EMG measures (R=0.76; P<.001), respiratory rate (R=0.35; P=.004), skin conductance (R=0.57; P<.001), and low frequency power (R=0.32; P=.01) and with increased high frequency power (R=-0.53; P<.001), successive heart interbeat interval difference (R=-0.32; P=.009), and heart interbeat interval SD (R=-0.26; P=.04) values.

CONCLUSIONS

Hypnosis appeared to induce mental and physical relaxation, enhance parasympathetic neural activation, and attenuate sympathetic nervous system activity, changes that were associated with BIS values. Findings from this preliminary formative evaluation suggest that the current hypnosis model may be useful for assessing autonomic physiological associations with changes in BIS values, thus motivating us to proceed with a larger investigation in trauma center nurses and physicians.

Yoga nidra practice shows improvement in sleep in patients with chronic insomnia: A randomized controlled trial

Background Yoga nidra is practised by sages for sleep. The practice is simple to use and has been clearly laid out, but its role in the treatment of chronic insomnia has not been well studied. Methods In this randomized parallel-design study conducted during 2012-16, we enrolled 41 patients with chronic insomnia to receive conventional intervention of cognitive behavioural therapy for insomnia (n=20) or yoga nidra (n=21). Outcome measures were both subjective using a sleep diary and objective using polysomnography (PSG). Salivary cortisol levels were also measured. PSG was done before the intervention in all patients and repeated only in those who volunteered for the same. Results Both interventions showed an improvement in subjective total sleep time (TST), sleep efficiency, wake after sleep onset, reduction in total wake duration and enhancement in subjective sleep quality. Objectively, both the interventions improved TST and total wake duration and increased N1% of TST. Yoga nidra showed marked improvement in N2% and N3% in TST. Salivary cortisol reduced statistically significantly after yoga nidra (p=0.041). Conclusion Improvement of N3 sleep, total wake duration and subjective sleep quality occurred following yoga nidra practice. Yoga nidra practice can be used for treatment of chronic insomnia after supervised practice sessions.

A Closer Look at Yoga Nidra: Sleep Lab Protocol

Extended sleep onset latency (SOL), or "sleep onset insomnia," can decrease total sleep time, increasing risk for many health conditions, including heart disease, stroke, and all-cause mortality. Sleep disorders persist in the United States despite current behavioral/pharmaceutical remedies, with 10% to 15% of the population suffering from insomnia. Mind-body therapies offer additional solutions, as meditation has been correlated with decreased SOL. More research on use of mind-body practices for insomnia is needed. This study investigates the guided meditation practice of Yoga Nidra (yogic sleep) as a promising intervention for sleep disorders because of its purported ability to induce mental, physical, and emotional relaxation. In this pilot study, we address the feasibility of Yoga Nidra for insomnia, appropriateness of our selected measurement systems, and effect of Yoga Nidra on brainwaves, sleep onset, and the autonomic nervous system. Our study sample includes 22 adults, ages 18-45, with insomnia. The design includes two clinic visits (V1, lying quietly for 90 min; V2, randomization to 90-min lying quietly vs. 30-min Yoga Nidra plus 60-min lying quietly), taking place 1 to 14 days apart. Outcomes measured during/after Yoga Nidra (vs. control) include sleep onset, electroencephalography (EEG) power, heart rate variability (HRV), and respiratory rate. Self-reported mood and anxiety will be measured before/after each visit. Resulting physiological, psychological, and feasibility data will be used to inform future clinical studies of Yoga Nidra for sleep and relaxation.

Sympathetic hyperactivity in patients with hypertension: pathogenesis and treatment. Part I

The article is devoted to the influence of sympathetic  nervous system (SNS) on the cardiovascular  system.  Influence of SNS activity on the blood pressure  level and the pathogenesis of hypertension  development, as well as the effect of SNS on many biochemical and metabolic parameters playing a key role in the development  of metabolic syndrome and hypertension  are considered. Possible mechanisms  of action of various methods that reduce  the SNS activity, restore  the function of autonomic nervous system  and normalize the cardiovascular system and blood pressure  are considered.

Tantra and Modern Neurosciences: Is there any Correlation?

BACKGROUND AND AIMS

Many studies have conclusively proven that meditative techniques derived from the Indian systems of philosophy, meditation and ritual classified as "Tantra" can bring about sustained changes in the structure and function of the nervous system of practitioners. The aim of this study is to provide neuroscientists a framework through which to interpret Tantra, and thereby provide a foundation upon which future interdisciplinary study can be built.

METHODS

We juxtapose Tantric concepts such as the subtle body, nadis and mantras with relevant neuroscientific findings. Our premise is that through sustained internalization of attention, Tantric practitioners were able to identify and document subtle changes in their field of awareness, which usually do not cross the threshold to come into our perception.

RESULTS

The descriptions left by Tantric philosophers are often detailed and empirical, but they are about subjective phenomena, rather than external objects. They also focus on individual experiences, rather than the group-level analyses favored by modern medical science.

CONCLUSION

Systematic exploration of Tantric texts can be of tremendous value in expanding our understanding of human beings' experiential reality, by enabling us to build bridges between first-person and third-person approaches to the nervous system. This may open up new avenues for cognitive enhancement and treating neurological diseases.

Yoga in Arterial Hypertension

BACKGROUND

Yoga seems to exert its effect against arterial hypertension mainly through the associated breathing and meditation techniques, and less so through yoga postures. The goal of this trial was to compare the blood pressure-lowering effect of yoga interventions with and without yoga postures in patients with arterial hypertension.

METHODS

75 patients taking medications for arterial hypertension (72% women, mean age 58.7 ± 9.5 years) were randomized into three groups: a yoga intervention group with yoga postures (25 patients, of whom 5 dropped out of the trial before its end), a yoga intervention group without yoga postures (25 patients, 3 dropouts), and a wait list control group (25 patients, one dropout). The interventions consisted of 90 minutes of yoga practice per week for twelve weeks. The data collectors, who were blinded to the intervention received, assessed the primary outcome measures "systolic 24-hour blood pressure" and "diastolic 24-hour blood pressure" before and after the intervention. In this report, we also present the findings on secondary outcome measures, including follow-up data.

RESULTS

After the intervention, the systolic 24-hour blood pressure in the yoga intervention group without yoga postures was significantly lower than in the control group (group difference [Δ]= -3.8 mmHg; [95% confidence interval (CI): (-0.3; -7.4) p = 0.035]); it was also significantly lower than in the yoga intervention group with yoga postures (Δ = -3.2 mmHg; 95% CI: [-6.3; -0.8]; p = 0.045). Diastolic blood pressures did not differ significantly across groups. No serious adverse events were encountered in the course of the trial.

CONCLUSION

In accordance with the findings of earlier studies, we found that only yoga without yoga postures induced a short-term lowering of ambulatory systolic blood pressure. Yoga is safe and effective in patients taking medications for arterial hypertension and thus can be recommended as an additional treatment option for persons in this category.

The risks and benefits of yoga for patients with chronic obstructive pulmonary disease: a systematic review and meta-analysis

OBJECTIVES

To determine the effectiveness and safety of yoga interventions on disease symptoms, quality of life and function in patients diagnosed with chronic obstructive pulmonary disease (COPD).

DATA SOURCES

Medline/PubMed, Scopus, and CENTRAL (Cochrane Central Register of Controlled Trials) were searched through 6 June 2019.

REVIEW METHODS

Randomized controlled trials assessing the effects of yoga on quality of life, dyspnea, exercise capacity, and pulmonary function (FEV1) in patients with COPD were included. Safety was defined as secondary outcome. Mean differences (MD) and standardized mean differences (SMD) with 95% confidence intervals (CIs) were computed. Risk of bias was assessed using the Cochrane tool.

RESULTS

Eleven randomized controlled trials with a total of 586 patients were included. Meta-analysis revealed evidence for effects of yoga compared to no treatment on quality of life on the COPD Assessment Test (MD = 3.81; 95% CI = 0.97 to 6.65; P = 0.009, I² = 70%), exercise capacity assessed by the 6-minute walk test (MD = 25.53 m; 95% CI = 12.16 m to 38.90 m; P = 0.001, I² = 0%), and pulmonary function assessed by FEV1 predicted (MD  = 3.95%; 95% CI = 2.74% to 5.17%; P < 0.001, I² = 0%). Only the effects on exercise capacity and pulmonary function were robust against methodological bias. Effects were only present in breathing-focused yoga interventions but not in interventions including yoga postures. Adverse events were reported infrequently.

CONCLUSION

This meta-analysis found robust effects of yoga on exercise capacity and pulmonary function in patients with COPD. Yoga, specifically yoga breathing techniques, can be an effective adjunct intervention for patients with COPD. Yoga's safety needs to be assessed in more depth in future studies.

Effects of Mind⁻Body Exercises (Tai Chi/Yoga) on Heart Rate Variability Parameters and Perceived Stress: A Systematic Review with Meta-Analysis of Randomized Controlled Trials

Background: Heart rate variability (HRV) as an accurate, noninvasive measure of the Autonomous Nervous System (ANS) can reflect mental health (e.g., stress, depression, or anxiety). Tai Chi and Yoga (Tai Chi/Yoga), as the most widely practiced mind–body exercises, have shown positive outcomes of mental health. To date, no systematic review regarding the long-lasting effects of Tai Chi/Yoga on HRV parameters and perceived stress has been conducted. Objective: To critically evaluate the existing literature on this topic. Methods: Five electronic databases (Web of Science, PubMed, Scopus, SportDiscus and Cochrane Library) were searched from the start of the research project to July 2018. Study selection, data extraction, and study quality assessment were independently carried out by two reviewers. The potentially identified randomized controlled trials (RCT) reported the useful quantitative data that were included only for meta-analysis. Results: meta-analysis of 17 medium-to-high quality RCTs showed significantly beneficial effects on HRV parameters (normalized low-frequency, Hedge’s g = −0.39, 95% CI −0.39 to −0.56, p < 0.001, I2 = 11.62%; normalized high-frequency, Hedge’s g = 0.37, 95% CI 0.22 to −0.52, p < 0.001, I2 = 0%; low-frequency to high-frequency ratio, Hedge’s g = −0.58, 95% CI −0.81 to −0.35, p < 0.001, I2 = 53.78%) and stress level (Hedge’s g = −0.80, 95% CI −1.17 to −0.44, p < 0.001, I2 = 68.54%). Conclusions: Stress reduction may be attributed to sympathetic-vagal balance modulated by mind–body exercises. Tai Chi/Yoga could be an alternative method for stress reduction for people who live under high stress or negative emotions.

Breath of Life: The Respiratory Vagal Stimulation Model of Contemplative Activity

Contemplative practices, such as meditation and yoga, are increasingly popular among the general public and as topics of research. Beneficial effects associated with these practices have been found on physical health, mental health and cognitive performance. However, studies and theories that clarify the underlying mechanisms are lacking or scarce. This theoretical review aims to address and compensate this scarcity. We will show that various contemplative activities have in common that breathing is regulated or attentively guided. This respiratory discipline in turn could parsimoniously explain the physical and mental benefits of contemplative activities through changes in autonomic balance. We propose a neurophysiological model that explains how these specific respiration styles could operate, by phasically and tonically stimulating the vagal nerve: respiratory vagal nerve stimulation (rVNS). The vagal nerve, as a proponent of the parasympathetic nervous system (PNS), is the prime candidate in explaining the effects of contemplative practices on health, mental health and cognition. We will discuss implications and limitations of our model.

The Impact of Yoga Nidra and Seated Meditation on the Mental Health of College Professors

BACKGROUND

World statistics for the prevalence of anxiety and mood disorders shows that a great number of individuals will experience some type of anxiety or mood disorder at some point in their lifetime. Mind-body interventions such as Hatha Yoga and seated meditation have been used as a form of self-help therapy and it is especially useful for challenging occupations such as teachers and professors.

AIMS

In this investigation, we aimed at observing the impact of Yoga Nidra and seated meditation on the anxiety and depression levels of college professors.

MATERIALS AND METHODS

Sixty college professors, men and women, aged between 30 and 55 years were randomly allocated in one of the three experimental groups: Yoga Nidra, seated meditation, and control group. Professors were evaluated two times throughout the 3-month study period. Psychological variables included anxiety, stress, and depression.

RESULTS

Data analysis showed that the relaxation group presented better intragroup results in the anxiety levels. Meditation group presented better intragroup results only in the anxiety variable (physical component). Intergroup analysis showed that, except for the depression levels, both intervention groups presented better results than the control group in all other variables.

CONCLUSIONS

Prepost results indicate that both interventions represent an effective therapeutic approach in reducing anxiety and stress levels. However, there was a tendency toward a greater effectiveness of the Yoga Nidra intervention regarding anxiety, which might represent an effective tool in reducing both cognitive and physiological symptoms of anxiety.

Yoga Offers Cardiovascular Protection in Early Postmenopausal Women

CONTEXT

Postmenopause, an estrogen deficient state comes with increased incidence of cardiovascular diseases (CVDs). Yoga has been described as having a beneficial effect on heart rate variability (HRV), a marker for cardiac autonomic activity which can assess cardiovascular risk, in various populations.

AIM

the aim of the study was to study the effect of 3-month long Yoga practice on HRV in early postmenopausal women.

SETTINGS AND DESIGN

A prospective longitudinal study of 67 women within 5 years of menopause between 45 and 60 years of age attending menopause clinic of Department of Gynaecology, Sucheta Kriplani Hospital fulfilling inclusion and exclusion criteria and consenting were enrolled for the study.

SUBJECTS AND METHODS

HRV of 37 cases (Yoga group) and 30 controls (non-Yoga group) was recorded pre and 3-month postintervention.

STATISTICAL ANALYSIS USED

GraphPad Prism Version 5 software was used. Values are a mean and standard error of mean. Statistical significance was set up at P < 0.05.

RESULTS

In HRV, frequency domain analysis showed a significant fall in low frequency (LF) in normalized units (nu) and LF: high frequency (HF) ratio and significant rise in HF in nu in the Yoga group (depicting parasympathetic dominance) against a significant rise in LF (nu) and LF: HF ratio and significant fall in HF (nu) in non-Yoga group (indicating sympathetic dominance). Time domain analysis showed a significant decrease in Standard Deviation of NN intervals in Non-Yoga group against nonsignificant changes in Yoga group indicating deterioration in parasympathetic activity in non-Yoga group.

CONCLUSIONS

Three-month long Yoga practice improved HRV in early postmenopausal women significantly and has the potential to attenuate the CVD risk in postmenopausal women.

The efficacy of a preparatory phase of a touch-based approach in treating chronic low back pain: a randomized controlled trial

Background

Massage therapy is an important element of rehabilitation in the treatment of chronic low back pain (CLBP). The objective of this study was to determine the relative efficacy of massage therapy between traditional massage and a new massage approach for CLBP. We also examined whether any reduction in pain was linked to interoceptive awareness and parasympathetic activation.

Methods

A single-blind, randomized, controlled trial of 51 patients who were allocated into a traditional massage therapy group (TMG; N=24, mean age: 50.54±9.13 years) or experimental massage therapy group (SMG; N=27, mean age: 50.77±6.80 years). The primary outcome was the reduction in pain per the visual analog scale (VAS); the secondary outcome measures were multidimensional pain intensity on the McGill Pain Questionnaire, pain-related disability per the Waddel Disability Index, interoceptive awareness per the Multidimensional Assessment of Interoceptive Awareness Questionnaire, quality of life per the Short Form - 12 Health Survey, and heart rate variability, expressed as the coherence ratio (CR) by photoplethysmography. The following outcome measures were assessed at baseline, at the end of the treatment program, and at the 3-month follow-up. The mean and standard deviation were calculated for continuous data. Mann–Whitney U test was used to perform between-group comparisons, Friedman’s analysis was used for data on the 3 assessment times in each group, and Spearman’s R coefficient was used to analyze correlations.

Results

Both approaches had a positive result on pain, an effect that was more acute in the SMG versus TMG for all pain scales, with better maintenance at the 3-month follow-up (VAS p=0.005 and p=0.098; Waddell Index p=0.034 and 0.044; McGill total p=0.000 and 0.003). In the SMG, CR scores were significant at baseline and at the end of the treatment program (p=0.000 and 0.002).

Conclusion

The new massage approach with a preparatory phase that is pleasant to the touch was more effective than the traditional approach for CLBP.

Yoga and heart rate variability: A comprehensive review of the literature

Heart rate variability (HRV) has been used as a proxy for health and fitness and indicator of autonomic regulation and therefore, appears well placed to assess the changes occurring with mind.-body practices that facilitate autonomic balance. While many studies suggest that yoga influences HRV, such studies have not been systematically reviewed. We aimed to systematically review all published papers that report on yoga practices and HRV. A comprehensive search of multiple databases was conducted and all studies that reported a measure of HRV associated with any yoga practice were included. Studies were categorized by the study design and type of yoga practice. A total of 59 studies were reviewed involving a total of 2358 participants. Most studies were performed in India on relatively small numbers of healthy male yoga practitioners during a single laboratory session. Of the reviewed studies, 15 were randomized controlled trials with 6 having a Jadad score of 3. The reviewed studies suggest that yoga can affect cardiac autonomic regulation with increased HRV and vagal dominance during yoga practices. Regular yoga practitioners were also found to have increased vagal tone at rest compared to non-yoga practitioners. It is premature to draw any firm conclusions about yoga and HRV as most studies were of poor quality, with small sample sizes and insufficient reporting of study design and statistical methods. Rigorous studies with detailed reporting of yoga practices and any corresponding changes in respiration are required to determine the effect of yoga on HRV.

Yoga for Heart Rate Variability: A Systematic Review and Meta-analysis of Randomized Clinical Trials

The objective of this systematic review is to summarize and critically assess the effects of yoga on heart rate variability (HRV). Nine databases were searched from their inceptions to June 2014. We included randomized clinical trials (RCTs) comparing yoga against any type of control intervention in healthy individuals or patients with any medical condition. Risk of bias was assessed using the Cochrane criteria. Two reviewers performed the selection of studies, data extraction, and quality assessments independent of one another. Fourteen trials met the inclusion criteria. Only two of them were of acceptable methodological quality. Ten RCTs reported favourable effects of yoga on various domains of HRV, whereas nine of them failed to do so. One RCT did not report between-group comparisons. The meta-analysis (MA) of two trials did not show favourable effects of yoga compared to usual care on E:I ratio (n = 61, SMDs = 0.63; 95% CIs [-0.72 to 1.99], p = 0.36; heterogeneity: r(2) = 0.79, χ(2) = 5.48, df = 1, (p = 0.02); I(2) = 82%). The MA also failed to show statistically significant differences between the groups regarding the 30:15 ratio (n = 61, SMDs = 0.20; 95% CIs [-0.43 to 0.84], p = 0.53; heterogeneity: r(2) = 0.07, χ(2) = 1.45, df = 1, (p = 0.23); I(2) = 31%). The data from the remaining RCTs were too heterogeneous for pooling. These results provide no convincing evidence for the effectiveness of yoga in modulating HRV in patients or healthy subjects. Future investigations in this area should overcome the multiple methodological weaknesses of the previous research.

A yoga & exercise randomized controlled trial for vasomotor symptoms: Effects on heart rate variability

OBJECTIVES

Heart rate variability (HRV) reflects the integration of the parasympathetic nervous system with the rest of the body. Studies on the effects of yoga and exercise on HRV have been mixed but suggest that exercise increases HRV. We conducted a secondary analysis of the effect of yoga and exercise on HRV based on a randomized clinical trial of treatments for vasomotor symptoms in peri/post-menopausal women.

DESIGN

Randomized clinical trial of behavioral interventions in women with vasomotor symptoms (n=335), 40-62 years old from three clinical study sites.

INTERVENTIONS

12-weeks of a yoga program, designed specifically for mid-life women, or a supervised aerobic exercise-training program with specific intensity and energy expenditure goals, compared to a usual activity group.

MAIN OUTCOME MEASURES

Time and frequency domain HRV measured at baseline and at 12 weeks for 15min using Holter monitors.

RESULTS

Women had a median of 7.6 vasomotor symptoms per 24h. Time and frequency domain HRV measures did not change significantly in either of the intervention groups compared to the change in the usual activity group. HRV results did not differ when the analyses were restricted to post-menopausal women.

CONCLUSIONS

Although yoga and exercise have been shown to increase parasympathetic-mediated HRV in other populations, neither intervention increased HRV in middle-aged women with vasomotor symptoms. Mixed results in previous research may be due to sample differences. Yoga and exercise likely improve short-term health in middle-aged women through mechanisms other than HRV.

Yoga increased serum estrogen levels in postmenopausal women-a case report

OBJECTIVE

This case report aimed to evaluate 4 months of yoga practice on the quality of life (QOL) and estradiol levels of two postmenopausal women.

METHODS

Participants were clinically healthy postmenopausal women, with follicle-stimulating hormone levels greater than or equal to 30 mIU/mL and a body mass index lower than 30 kg/m. The participants practiced yoga for 4 months in two 1-hour sessions per week.

RESULTS

The participants exhibited an abnormal estrogen-level increase after 4 months of yoga practice and showed QOL improvements.

CONCLUSIONS

In some cases, yoga practice can affect the female neuroendocrine system, increasing estrogen and improving QOL.

Characteristics of randomized controlled trials of yoga: a bibliometric analysis

Background

A growing number of randomized controlled trials (RCTs) have investigated the therapeutic value of yoga interventions. This bibliometric analysis aimed to provide a comprehensive review of the characteristics of the totality of available randomized yoga trials.

Methods

All RCTs of yoga were eligible. Medline/PubMed, Scopus, the Cochrane Library, IndMED, and the tables of content of yoga specialty journals not listed in medical databases were screened through February 2014. Bibliometric data, data on participants, and intervention were extracted and analyzed descriptively.

Results

Published between 1975 and 2014, a total of 366 papers were included, reporting 312 RCTs from 23 different countries with 22,548 participants. The median study sample size was 59 (range 8–410, interquartile range = 31, 93). Two hundred sixty-four RCTs (84.6%) were conducted with adults, 105 (33.7%) with older adults and 31 (9.9%) with children. Eighty-four RCTs (26.9%) were conducted with healthy participants. Other trials enrolled patients with one of 63 varied medical conditions; the most common being breast cancer (17 RCTs, 5.4%), depression (14 RCTs, 4.5%), asthma (14 RCTs, 4.5%) and type 2 diabetes mellitus (13 RCTs, 4.2%). Whilst 119 RCTs (38.1%) did not define the style of yoga used, 35 RCTs (11.2%) used Hatha yoga and 30 RCTs (9.6%) yoga breathing. The remaining 128 RCTs (41.0%) used 46 varied yoga styles, with a median intervention length of 9 weeks (range 1 day to 1 year; interquartile range = 5, 12). Two hundred and forty-four RCTs (78.2%) used yoga postures, 232 RCTs (74.4%) used breath control, 153 RCTs (49.0%) used meditation and 32 RCTs (10.3%) used philosophy lectures. One hundred and seventy-four RCTs (55.6%) compared yoga with no specific treatment; 21 varied control interventions were used in the remaining RCTs.

Conclusions

This bibliometric analysis presents the most complete up-to-date overview on published randomized yoga trials. While the available research evidence is sparse for most conditions, there was a marked increase in published RCTs in recent years.

Electronic supplementary material

The online version of this article (doi:10.1186/1472-6882-14-328) contains supplementary material, which is available to authorized users.

The Effects of Short-Term Relaxation Therapy on Indices of Heart Rate Variability and Blood Pressure in Young Adults

Purpose.

Assessment of short-term practice of relaxation therapy on autonomic and cardiovascular functions in first-year medical students.

Design.

Case-control, interventional study.

Setting.

Medical college laboratory.

Subjects.

Sixty-seven medical students, divided into two groups: study group (n = 35) and control group (n = 32).

Intervention.

Study group subjects practiced relaxation therapy (shavasana with a soothing background music) daily 1 hour for 6 weeks. Control group did not practice relaxation techniques.

Measures.

Cardiovascular parameters and spectral indices of heart rate variability (HRV) were recorded before and after the 6-week practice of relaxation therapy.

Analysis.

The data between the groups and the data before and after practice of relaxation techniques were analyzed by one-way analysis of variance and Student t-test. In the study group, prediction of low-frequency to high-frequency ratio (LF-HF) of HRV, the marker of sympathovagal balance, to blood pressure (BP) status was assessed by logistic regression.

Results.

In the study group, there was significant reduction in heart rate (p = .0001), systolic (p = .0010) and diastolic (p = .0021) pressure, and rate pressure product (p < .0001), and improvement in HRV indices, following 6 weeks of relaxation therapy. As determined by regression model, prediction of LF-HF to BP status was more significant (odds ratio, 2.7; p = .009) after practice of relaxation therapy. There was no significant alteration in these parameters in control subjects.

Conclusion.

Short-term practice of relaxation therapy can improve autonomic balance and promote cardiovascular health of medical students. Sympathovagal balance is directly linked to BP status in these individuals.