The Effects of Mindfulness and Meditation on Vagally Mediated Heart Rate Variability: A Meta-Analysis

Effects of stress management interventions on heart rate variability in adults with cardiovascular disease: a systematic review and meta-analysis

Meta-analysis was used to investigate the potential benefits of stress management interventions (SMIs) on vagally-mediated heart rate variability (HRV) in adults with cardiovascular disease. Electronic bibliographic databases were searched through August 2022. Randomized controlled trials and quasi-experimental studies assessing effects of SMIs on HRV were included. Methodological quality was assessed with a standardized checklist. A pooled effect size was calculated for vagally-mediated HRV indices (standard deviation of normal-to-normal intervals, root mean square of the successive differences, and high frequency power) using random effects models. Fourteen studies (1202 participants, Mage: 59 ± 6.25 years; 25% ± 16% women; 61% ± 22% White) were included. Ten studies (11 effects) reported short-term HRV assessment; a small between-group difference emerged for vagally-mediated HRV (d+ = .27, 95% confidence interval [CI] 0.01-0.52, k = 11). Most interventions examined biofeedback; these studies yielded a small between-group difference on vagally-mediated HRV (d+ = 0.31, 95% CI 0.09-0.53, k = 7, Q [6] = 3.82, p = .70, I2 = 11%). This is the first systematic examination of the effect of SMIs on HRV in adults with CVD. Findings suggest a small effect of SMIs on vagally-mediated HRV, with biofeedback likely driving the effect. More research is required to fully understand whether this benefit on vagally-mediated HRV applies to other SMIs.

The Effects of Heart Rhythm Meditation on Vagal Tone and Well-being: A Mixed Methods Research Study

Many studies have examined the effects of meditation practice focused on the normal breath on vagal tone with mixed results. Heart Rhythm Meditation (HRM) is a unique meditation form that engages in the deep slow full breath, and puts the focus of attention on the heart. This form of breathing likely stimulates the vagus nerve with greater intensity. The purpose of this study was (a) to examine how the practice of HRM affects vagal activity as measured by heart rate variability (HRV); and (b) to examine how it affects participants' well-being. 74 participants signed consent agreeing to: (a) take a six-week course to learn the practice of HRM; (b) engage in a daily practice for 10 weeks; (c) have their heart rate variability read through ECG technology and to take two validated well-being instruments at the beginning and end of the 10 weeks; and (d) participate in a focus group interview examining their perceptions of how the practice affected their well-being. 48 participants completed the study. Quantitative findings show the effect of the practice of HRM approached significance for multiple measures of HRV and vagal tone. An increase in well-being scores for those who did the meditation more than 10-minutes per day did meet statistical significance. Qualitative data indicate: (a) the positive effects of HRM on stress and well-being; (b) the development of a more expanded sense of self; and (c) an increased awareness of the interconnection of the body-heart-emotions and HRM's role in emotion regulation.

Heart rate variability: Evaluating a potential biomarker of anxiety disorders

Establishing quantifiable biological markers associated with anxiety will increase the objectivity of phenotyping and enhance genetic research of anxiety disorders. Heart rate variability (HRV) is a physiological measure reflecting the dynamic relationship between the sympathetic and parasympathetic nervous systems, and is a promising target for further investigation. This review summarizes evidence evaluating HRV as a potential physiological biomarker of anxiety disorders by highlighting literature related to anxiety and HRV combined with investigations of endophenotypes, neuroimaging, treatment response, and genetics. Deficient HRV shows promise as an endophenotype of pathological anxiety and may serve as a noninvasive index of prefrontal cortical control over the amygdala, and potentially aid with treatment outcome prediction. We propose that the genetics of HRV can be used to enhance the understanding of the genetics of pathological anxiety for etiological investigations and treatment prediction. Given the anxiety-HRV link, strategies are offered to advance genetic analytical approaches, including the use of polygenic methods, wearable devices, and pharmacogenetic study designs. Overall, HRV shows promising support as a physiological biomarker of pathological anxiety, potentially in a transdiagnostic manner, with the heart-brain entwinement providing a novel approach to advance anxiety treatment development.

The effectiveness of a single session of mindfulness-based cognitive training on cardiac vagal control and core symptoms in children and adolescents with attention-deficit/hyperactivity disorder (ADHD): a preliminary randomized controlled trial

This study examined the effectiveness of a mindfulness-based intervention (MBI) on Conners' continuous performance test scores (CPTs), cardiac vagal control (CVC) assessed by vagally mediated heart rate variability (HRV), and mood in children and adolescents with ADHD. We conducted a randomized controlled trial (RCT) recruiting 70 children and adolescents (M age 11.03, SD 2.78) with a clinical diagnosis of ADHD, which were allocated to either 1 session of mindfulness cognitive training, or an active control condition and were examined at baseline, post-treatment and 4-week follow-up. See clinicaltrials.gov: NCT04316832. There was a significant main effect of time on the primary outcomes measured by CPT scores of attention-related problems (omission errors, reaction time) and hyperactivity-impulsivity (commission errors). However, time-by-group interaction did not achieve statistical significance for commission errors and hit RT, indicating that the changes over time in these outcomes were not significantly different between the MBI and Control conditions. In addition, there was a significant time-by-group interaction for omission errors. Relative to control, MBI resulted in a small (d = 0.011) non-statistically significant reduction in omission errors post-treatment. Furthermore, there were no significant differences in detectability. Secondary outcomes were CVC and mood. A small treatment effect on CVC (d = 0.37) was observed; there was a slight increase in vagally mediated HRV measure post-treatment. There were no significant differences in mood improvement over time between conditions. One brief session of MBI effectively enhances CVC but does not significantly improve CPT scores of attention-related problems and hyperactivity-impulsivity or mood in children with ADHD.Clinicaltrials.gov: NCT04316832.

Autonomic nervous system modulation during self-induced non-ordinary states of consciousness

Self-induced cognitive trance (SICT) is a voluntary non-ordinary state of consciousness characterized by a lucid yet narrowed awareness of the external surroundings. It involves a hyper-focused immersive experience of flow, expanded inner imagery, modified somatosensory processing, and an altered perception of self and time. SICT is gaining attention due to its potential clinical applications. Similar states of non-ordinary state of consciousness, such as meditation, hypnosis, and psychedelic experiences, have been reported to induce changes in the autonomic nervous system. However, the functioning of the autonomic nervous system during SICT remains poorly understood. In this study, we aimed to investigate the impact of SICT on the cardiac and respiratory signals of 25 participants proficient in SICT. To accomplish this, we measured various metrics of heart rate variability (HRV) and respiration rate variability (RRV) in three conditions: resting state, SICT, and a mental imagery task. Subsequently, we employed a machine learning framework utilizing a linear discriminant analysis classifier and a cross-validation scheme to identify the features that exhibited the best discrimination between these three conditions. The results revealed that during SICT, participants experienced an increased heart rate and a decreased level of high-frequency (HF) HRV compared to the control conditions. Additionally, specific increases in respiratory amplitude, phase ratio, and RRV were observed during SICT in comparison to the other conditions. These findings suggest that SICT is associated with a reduction in parasympathetic activity, indicative of a hyperarousal state of the autonomic nervous system during SICT.

Person-Centered Mindfulness: A Culturally and Spiritually Sensitive Approach to Clinical Practice

Mindfulness meditation is rapidly being integrated into many different forms of counseling and psychotherapy, and there is a growing evidence base for its effectiveness. It is important to understand the spiritual roots of mindfulness, and to apply it in a patient-centered manner, sensitive to the patient's own faith tradition rather than taking a one-size-fits-all approach, assuming that mindfulness-based practice is a purely secular approach. The philosophical underpinning of mindfulness lies squarely in the Buddhist faith tradition. Indeed, mindfulness is the 7th step on the Eightfold Path, which is the heart of Buddhist teachings. Many practitioners, however, may not realize that there are Western meditative techniques that are very similar to mindfulness and that have deep roots within Christian, Jewish, and Muslim faith traditions. Patient-centered mindfulness involves the use of mindfulness and other meditation methods that are based on the patient's own faith tradition, rather than applying Eastern forms of mindfulness claiming these are a secular approach appropriate for everyone regardless of religious beliefs, even if those beliefs are not consistent with the Buddhist religious or philosophical approach. In this article, I briefly examine the evidence for the clinical effectiveness of mindfulness meditation, and then go into greater depth on Hindu, Buddhist, Christian, Jewish, and Muslim forms of mindfulness or similar meditative practices, providing resources that will better equip clinicians and researchers to provide patient-centered culturally-sensitive care.

A brief body scan mindfulness practice has no positive effect on the recovery of heart rate variability and cognitive tasks in female professional basketball players

Introduction

In this study, we examined the acute effects of a short video-based body scan mindfulness practice on the heart rate variability (HRV) and cognitive performance of professional female basketball players after the first half of a simulated basketball game.

Methods

In this crossover randomized controlled trial, nine professional athletes completed a physical loading protocol on two separate days. The protocol consisted of a 10-min Yo-Yo Intermittent Recovery Test Level 1 in the first quarter, followed by a 10-min basketball game in the second quarter. Immediately afterward, they were asked to engage in a 10-min mindfulness practice or watch a 10-min nature-based documentary as a type of mental intervention. Their HRV, Rating of Perceived Exertion (RPE), National Aeronautics and Space Administration Task Load Index 2 (NASA TLX-2), and Go/No-Go test scores were recorded immediately before and after the physical loading and after the mental intervention.

Results

The physical demand, effort, and frustration level subscales of the NASA TLX-2 and the RPE scores were found to be significantly higher after the physical loading, and they returned to the baseline level after both types of mental intervention. The Go/No-Go test scores did not differ depending on the measurement time. All time- and frequency-domain heart rate variability parameters, except the low-to-high frequency ratio, were found to be significantly high immediately after the physical loading protocol. However, these parameters returned to their initial levels after both types of mental intervention.

Discussion

Completing the tests involved in the study protocol successfully induced physical fatigue, as evidenced by consistent measurement tools, but the one-time and short-term mindfulness practice had no additional benefits for the recovery of heart rate variability, cognitive tasks, or subjective assessment methods, such as RPE and NASA TLX-2, in basketball players with no previous experience of mindfulness practice.

Mindfulness-Based Interventions for Patients with Cardiovascular Disease: A Focused Review for Practicing Clinicians

PURPOSE OF REVIEW

With growing scientific and public interest in the health benefits of mindfulness, clinicians increasingly face questions and solicitations for advice from patients about the efficacy of mindfulness-based interventions (MBIs) for cardiovascular disease (CVD). In this clinician-focused review, we aim to revisit empirical studies on MBIs for CVD with the purpose of informing clinicians' decisions on how to provide recommendations consistent with updated scientific findings to patients interested in MBIs.

RECENT FINDINGS

We start by defining MBIs and identifying the possible physiological, psychological, behavioral, and cognitive mechanisms underlying the potentially positive effects of MBIs for CVD. Potential mechanisms include the reduction of sympathetic nervous system activity, improved vagal control, and biological markers (physiological); psychological distress and cardiovascular health behaviors (psychological and behavioral); and executive function, memory, and attention (cognitive). Then, we summarize the extant evidence to identify gaps and limitations in MBI research for the purpose of informing future directions for cardiovascular and behavioral medicine researchers. We conclude with practical recommendations for clinicians communicating with patients with CVD who are interested in MBIs.

Effect of breathwork on stress and mental health: A meta-analysis of randomised-controlled trials

Deliberate control of the breath (breathwork) has recently received an unprecedented surge in public interest and breathing techniques have therapeutic potential to improve mental health. Our meta-analysis primarily aimed to evaluate the efficacy of breathwork through examining whether, and to what extent, breathwork interventions were associated with lower levels of self-reported/subjective stress compared to non-breathwork controls. We searched PsycInfo, PubMed, ProQuest, Scopus, Web of Science, ClinicalTrials.gov and ISRCTN up to February 2022, initially identifying 1325 results. The primary outcome self-reported/subjective stress included 12 randomised-controlled trials (k = 12) with a total of 785 adult participants. Most studies were deemed as being at moderate risk of bias. The random-effects analysis yielded a significant small-to-medium mean effect size, g = - 0.35 [95% CI - 0.55, - 0.14], z = 3.32, p = 0.0009, showing breathwork was associated with lower levels of stress than control conditions. Heterogeneity was intermediate and approaching significance, χ²₁₁ = 19, p = 0.06, I² = 42%. Meta-analyses for secondary outcomes of self-reported/subjective anxiety (k = 20) and depressive symptoms (k = 18) showed similar significant effect sizes: g = - 0.32, p < 0.0001, and g = - 0.40, p < 0.0001, respectively. Heterogeneity was moderate and significant for both. Overall, results showed that breathwork may be effective for improving stress and mental health. However, we urge caution and advocate for nuanced research approaches with low risk-of-bias study designs to avoid a miscalibration between hype and evidence.

Carotid-body modulation through meditation in stage-I hypertensive subjects: Study protocol of a randomized and controlled study

Adjunctive therapy for hypertension is in high demand for clinical research. Therefore, several meta-analyses have provided sufficient evidence for meditation as an adjunct therapy, without being anchored on reliable physiological grounds. Meditation modulates the autonomic nervous system. Herein, we propose a hierarchical-dependent effect for the carotid body (CB) in attenuating blood pressure (BP) and ventilatory variability (VV) fine-tuning due to known nerve connections between the CB, prefrontal brain, hypothalamus, and solitary tract nucleus. The aim of this exploratory study was to investigate the role of CB in the possible decrease in BP and changes in VV that could occur in response to meditation. This was a prospective, single-center, parallel-group, randomized, controlled clinical trial with concealed allocation. Eligible adult subjects of both sexes with stage 1 hypertension will be randomized into 1 of 2 groups: transcendental meditation or a control group. Subjects will be invited to 3 visits after randomization and 2 additional visits after completing 8 weeks of meditation or waiting-list control. Thus, subjects will undergo BP measurements in normoxia and hyperoxia, VV measurements using the Poincaré method at rest and during exercise, and CB activity measurement in the laboratory. The primary outcome of this study was the detection of changes in BP and CB activity after 8 weeks. Our secondary outcome was the detection of changes in the VV at rest and during exercise. We predict that interactions between hyperoxic deactivation of CB and meditation; Will reduce BP beyond stand-alone intervention or alternatively; Meditation will significantly attenuate the effects of hyperoxia as a stand-alone intervention. In addition, VV can be changed, partially mediated by a reduction in CB activity. Trial registration number: ReBEC registry (RBR-55n74zm). Stage: pre-results.

Psychological Intervention Based on Mental Relaxation to Manage Stress in Female Junior Elite Soccer Team: Improvement in Cardiac Autonomic Control, Perception of Stress and Overall Health

Chronic stress may represent one of the most important factors that negatively affects the health and performance of athletes. Finding a way to introduce psychological strategies to manage stress in everyday training routines is challenging, particularly in junior teams. We also must consider that a stress management intervention should be regarded as "efficacious" only if its application results in improvement of the complex underlying pathogenetic substratum, which considers mechanistically interrelated factors, such as immunological, endocrine and autonomic controls further to psychological functioning and behavior. In this study, we investigated the feasibility of implementing, in a standard training routine of the junior team of the Italian major soccer league, a stress management program based on mental relaxation training (MRT). We evaluated its effects on stress perception and cardiac autonomic regulation as assessed by means of ANSI, a single composite percentile-ranked proxy of autonomic balance, which is free of gender and age bias, economical, and simple to apply in a clinical setting. We observed that the simple employed MRT intervention was feasible in a female junior soccer team and was associated with a reduced perception of stress, an improved perception of overall health, and a betterment of cardiac autonomic control. This data may corroborate the scientific literature that indicates psychological intervention based on MRT as an efficacious strategy to improve performance, managing negative stress effects on cardiac autonomic control.

Heart Rate Variability and Perceived Stress in Teacher Training: Facing the Reality Shock With Mindfulness?

Background

The beginning of the career of teachers is a demanding phase. In the combined roles of teacher and trainee, and in the shift from academic to practical learning, trainee teachers have to acquire competencies in teaching as well as coping with stress. In this phase, the phenomenon of "reality shock" is widely observed.

Objective

A mindfulness training was developed to support teacher trainees during their first year. This intervention study investigated perceived and physiological stress at teachers' career start and the stress reducing effects of the mindfulness training in this phase.

Methods

In a quasi-experimental design, 19 out of 42 participants from this sample underwent mindfulness-based stress reduction training and a wait-list control group (N = 23) underwent a compact course after post measurements. We measured physiological stress parameters and perceived stress at 3 different time points. Heart rate signals were acquired in ambulatory assessment sequences, including teaching, rest periods, and cognitive tasks. The data were analyzed in linear mixed-effects models.

Results

We found high physiological stress in the very beginning of teacher training, which attenuated over time. The mindfulness intervention only led to a greater reduction in heart rate (d = .53 to .74) in situations where the intervention group had shown higher heart rate levels initially, but not in heart rate variability. However, the mindfulness group significantly reduced (d = .63) their perceived stress and maintained (d = .55) this improvement, while the control group maintained a highly elevated perceived stress level throughout.

Conclusion

The mindfulness training could reduce subjective stress, which otherwise seems to be a long-lasting aspect of beginning teachers' "reality shock". Indications of a superior reduction of physiological stress in demanding situations were weak, while generally, undue physiological stress seems to be a temporary phenomenon in the initial phase of teacher induction.

Impact of Meditation-Based Lifestyle Modification on HRV in Outpatients With Mild to Moderate Depression: An Exploratory Study

BACKGROUND

The scientific evaluation of mind-body-interventions (MBI), including yoga and meditation, has increased significantly in recent decades. However, evidence of MBI's efficacy on biological parameters is still insufficient.

OBJECTIVES

In this study, we used HRV analysis to evaluate a novel MBI as a treatment of outpatients with mild to moderate depressive disorder. The Meditation-Based Lifestyle Modification (MBLM) program incorporates all major elements of classical yoga, including ethical principles of yoga philosophy, breathing exercises, postural yoga, and meditation.

METHODS

In this exploratory randomized controlled trial, we compared the changes in HRV indices of a MBLM group (N = 22) and a minimal treatment group (MINIMAL, drugs only, N = 17) with those of a multimodal treatment-as-usual group (TAU, according to best clinical practice, N = 22). Electrocardiogram (ECG) recordings were derived from a Holter monitoring device, and HRV indices have been extracted from nearly stationary 20-min periods.

RESULTS

Short-term HRV analysis revealed statistically significant differences in the pre-to-post changes between MBLM and TAU. In particular, the vagal tone mediating RMSSD and the Rényi entropy of symbolic dynamics indicated HRV gains in MBLM participants compared with TAU. Almost no alterations were observed in the MINIMAL group.

CONCLUSIONS

Our results suggest a benefit in selected HRV parameters for outpatients with mild to moderate depression participating in the MBLM program. For further investigations, we propose analysis of complete 24-h HRV recordings and additional continuous pulse wave or blood pressure analysis to assess long-term modulations and cardiovascular effects.

A virtual reality-based mind–body approach to downregulate psychophysiological arousal in adolescent insomnia

Objective

In this study, we describe the rationale, supported by preliminary data, for a novel, digital, immersive virtual reality (VR)-based mind–body approach, designed to reduce bedtime arousal in adolescents with insomnia.

Methods

Fifty-two high-school students (16–20 years; 32 female) with ( N = 18) and without ( N = 34) DSM-5 insomnia symptoms engaged with 20 min of immersive VR-guided meditation and paced breathing (0.1 Hz) ( intervention condition) and 20 min of quiet activity ( control condition), right before bedtime, on two separate evenings.

Results

The intervention resulted in acute autonomic and cortical modulation ( p < 0.05), leading to reduced physiological arousal (↓heart rate, ↓cortisol) compared with the control condition, with similar effects in adolescents with and without insomnia. No significant changes were detected for cognitive arousal levels. During the intervention, all participants were able to achieve the targeted 0.1 Hz breathing rate, and the majority experienced no discomfort associated with the VR exposure. However, 30–40% of the participants experienced some trouble slowing down their breathing.

Conclusions

The study provides supporting preliminary evidence for the mechanism behind a novel VR-based digital approach, designed to regulate psychophysiological arousal levels by acting on neurocognitive and autonomic pathways. Further studies (e.g. randomized clinical trials) are needed to evaluate the isolated and synergistic effects of its components (e.g. VR vs. VR + paced breathing), and its efficacy, acceptance, and feasibility in alleviating insomnia symptoms in adolescents.