Heart rate variability biofeedback: how and why does it work?

A comprehensive evaluation of linear and non-linear HRV parameters between paced breathing and stressful mental state

Background

Heart rate variability (HRV) is a crucial metric that provides valuable insight into the balance between relaxation and stress. Previous research has shown that most HRV parameters improve during periods of mental relaxation, while decreasing during tasks involving cognitive workload. Although a comprehensive analysis of both linear and non-linear HRV parameters has been carried out in existing literature, there still exists a need for further research in this area. Additionally, limited knowledge exists regarding how specific interventions may influence the interpretation of these parameters and how the different parameters correlate under different interventions. This study aims to address these gaps by conducting a thorough comparison of different linear and non-linear HRV parameters under mentally relaxed versus stressful states.

Methodology

Participants were randomly and equally divided among two between-subjects groups: relaxed-stress (RS) (N = 22) and stress-relaxed (SR) (N = 22). In the RS group, a paced breathing task was given for 5 min to create relaxation, and was followed by a 5-min time-based mental calculation task to create stress. In the SR group, the order of the stress and relaxed tasks was reversed. There was a washout period of 15 min after the first task in both groups.

Results

Of the 37 HRV parameters, 33 differed significantly between the two interventions. The majority of the parameters exhibited an improving and degrading tendency of HRV parameters in the relaxed and stressed states, respectively. The correlation of the majority of HRV parameters decreases during stress, while prominent time domain and geometric domain parameters stand out in the correlation.

Conclusion

Overall, HRV parameters can be reliably used to assess a person's relaxed and stressed mental states during paced breathing and mental arithmetic task respectively. Furthermore, non-linear HRV parameters provide accurate estimators of the mental state, in addition to the commonly used linear parameters.

Publication guidelines for human heart rate and heart rate variability studies in psychophysiology-Part 1: Physiological underpinnings and foundations of measurement

This Committee Report provides methodological, interpretive, and reporting guidance for researchers who use measures of heart rate (HR) and heart rate variability (HRV) in psychophysiological research. We provide brief summaries of best practices in measuring HR and HRV via electrocardiographic and photoplethysmographic signals in laboratory, field (ambulatory), and brain-imaging contexts to address research questions incorporating measures of HR and HRV. The Report emphasizes evidence for the strengths and weaknesses of different recording and derivation methods for measures of HR and HRV. Along with this guidance, the Report reviews what is known about the origin of the heartbeat and its neural control, including factors that produce and influence HRV metrics. The Report concludes with checklists to guide authors in study design and analysis considerations, as well as guidance on the reporting of key methodological details and characteristics of the samples under study. It is expected that rigorous and transparent recording and reporting of HR and HRV measures will strengthen inferences across the many applications of these metrics in psychophysiology. The prior Committee Reports on HR and HRV are several decades old. Since their appearance, technologies for human cardiac and vascular monitoring in laboratory and daily life (i.e., ambulatory) contexts have greatly expanded. This Committee Report was prepared for the Society for Psychophysiological Research to provide updated methodological and interpretive guidance, as well as to summarize best practices for reporting HR and HRV studies in humans.

Can Pulse Rate Variability be Used to Monitor Compliance with a Breath Pacer?

Slow paced breathing has been demonstrated to provide significant health benefits for a person's health, and, during breathing sessions, it is desirable to monitor that a person is actually compliant with the breath pacer. We explore the potential use of pulse rate variability to monitor compliance with a breath pacer during meditation sessions. The study involved 6 human subjects each participating in 2-3 trials, where they are asked to follow or not to follow the breath pacer, where we collected data on how the magnitude of pulse rate variability changed. Two methods, logistic regression and a running standard deviation technique, were developed to detect non-compliance with the breath pacer based on pulse rate variability metrics. Results indicate that using pulse rate variability alone may not reliably detect non-compliance with the breath pacer. Both models exhibited limitations in terms of false positives and false negatives, with accuracy ranging from 67 to 65%. Existing methods involving visual, audio, and motion signals currently perform better for monitoring compliance with the breath pacer.

A Pilot Feasibility Evaluation of a Heart Rate Variability Biofeedback App to Improve Self-Care in COVID-19 Healthcare Workers

COVID-19 exacerbated burnout and mental health concerns among the healthcare workforce. Due to high work stress, demanding schedules made attuned eating behaviors a particularly challenging aspect of self-care for healthcare workers. This study aimed to examine the feasibility and acceptability of a heart rate variability biofeedback (HRVB) mobile app for improving well-being among healthcare workers reporting elevated disordered eating during COVID-19. We conducted a mixed methods pre-mid-post single-arm pilot feasibility trial (ClinicalTrials.gov NCT04921228). Deductive content analysis of participants' commentary generated qualitative themes. Linear mixed models were used to examine changes in pre- mid- to post-assessment scores on well-being outcomes. We consented 28 healthcare workers (25/89% female; 23/82% Non-Hispanic White; 22/79% nurses) to use and evaluate an HRVB mobile app. Of these, 25/89% fully enrolled by attending the app and device training; 23/82% were engaged in all elements of the protocol. Thirteen (52%) completed at least 10 min of HRVB on two-thirds or more study days. Most participants (18/75%) reported being likely or extremely likely to continue HRVB. Common barriers to engagement were busy schedules, fatigue, and technology difficulties. However, participants felt that HRVB helped them relax and connect better to their body's signals and experiences. Results suggested preliminary evidence of efficacy for improving interoceptive sensibility, mindful self-care, body appreciation, intuitive eating, stress, resilience, and disordered eating. HRVB has potential as a low-cost adjunct tool for enhancing well-being in healthcare workers through positively connecting to the body, especially during times of increased stress when attuned eating behavior becomes difficult to uphold.

Short-Term Effects of Heart Rate Variability Biofeedback on Working Memory

Drawing upon the well-documented impact of long-term heart rate variability biofeedback (HRVB) on psychophysiological responses, this study seeks to explore the short-term effects arising from a single HRVB session during and after paced breathing exercise. The research aligns with the neurovisceral integration model, emphasizing the link between heart rate variability (HRV) levels and cognitive performance. Therefore, a randomized controlled trial employing a between-subjects design was conducted with 38 participants. Each participant was assigned to either the paced breathing intervention group or the spontaneous breathing control group. The study assessed various parameters such as cardiac vagal tone, evaluated through vagally mediated HRV measures, and working memory, measured using the N-back task. Additionally, participants' affective states were assessed through self-reported questionnaires, specifically targeting attentiveness, fatigue, and serenity. The results notably reveal enhancements in the working memory task and an elevated state of relaxation and attention following the HRVB session, as evidenced by higher averages of correct responses, serenity and attentiveness scores. However, the findings suggest that this observed improvement is not influenced by changes in cardiac vagal tone, as assessed using a simple mediation analysis. In conclusion, this study presents promising insights into the impact of a single HRVB session, laying the foundation for future research advancements in this domain.

Respiratory dysfunction in persistent somatic symptoms: A systematic review of observational studies

OBJECTIVE

This systematic review aims to analyze the existing literature investigating respiratory functioning in people with Persistent Somatic Symptoms (PSS) compared to healthy controls, to identify patterns of respiratory disturbances by symptom or syndrome, and describe any respiratory outcomes consistent across diagnoses.

METHODS

A systematic review following PRISMA guidelines was conducted. A comprehensive search was carried out across five databases (PubMed (NCBI), PsycArticles (Ovid), Web of Science (Core Collection), Embase, and Scopus) using two customised search strings for persistent somatic symptoms and objective respiratory parameters. Title/abstract screening and data extraction were carried out independently by two reviewers. The modified Newcastle-Ottawa Scale was used for quality assessment of the studies. Studies investigating baseline respiratory functioning in adult patients with PSS compared to healthy controls, using at least one objective respiratory were included.

RESULTS

18 studies met the inclusion criteria for the review, with a pooled sample size of n = 3245. Chronic pain conditions were found to be the most prevalent subset of diagnoses of interest, comprising six of the studies. 10 studies included measures of lung capacity, flow and/or volume, nine studies reported measures of ventilation, and four studies investigated respiratory muscle functioning. 13 of the included studies reported significant differences in at least one objective respiratory measure between groups (at rest). Scores on self-reported measures of dysnpea and breathlessness were higher in patients compared to healthy controls, while objective respiratory outcomes were varied.

CONCLUSION

The current systematic review is consistent with previous literature suggesting more pronounced experiences of breathlessness in patients with PSS, and significant disparities between reported dyspnea and objective respiratory outcomes. Research investigating the uncoupling between subjective and objective respiratory outcomes is needed to understand the mechanisms behind breathing disturbances in PSS.

"Brain-IT": Exergame training with biofeedback breathing in neurocognitive disorders

INTRODUCTION

The combination of exergame-based motor-cognitive training with resonance breathing guided by heart-rate variability biofeedback (HRV-BF) targets various relevant mechanisms of action to alleviate the pathological state in mild neurocognitive disorders (mNCD).

METHODS

This randomized controlled trial (RCT) investigated the effectiveness of adding this novel intervention approach to usual care in mNCD. The individualized intervention was delivered via the "Brain-IT" training concept, which was iteratively co-designed, tested, and refined with patient and public involvement.

RESULTS

We observed statistically significant effects with large effect sizes for global cognitive performance, immediate verbal recall, and delayed verbal recall in favor of the intervention group. Fifty-five percent of participants showed a clinically relevant improvement in response to training.

DISCUSSION

Confirmatory RCTs are warranted to investigate whether the observed improvements in cognitive performance translate to affecting the rates of progression to or onset of dementia and test the implementation of the training in clinical practice.

HIGHLIGHTS

We proposed a novel intervention approach for mild neurocognitive disorders. It combines exergame-based training with biofeedback-guided resonance breathing. Our results confirm the effectiveness of this approach. Fifty-five percent of participants showed a clinically relevant improvement in response to training.

Autonomic and cognitive control in memory: Investigating the psychophysiological link using heart rate variability biofeedback

Vagally mediated heart rate variability (vmHRV) at resting state has been associated to cognitive functions dependent on cognitive control, such as memory. However, little is known about the phasic interaction between cognitive and autonomic control. In a pre-registered within-between-subject designed experiment, the potential of vmHRV biofeedback to simultaneously stimulate vmHRV during memory processing and cognitive control over long-term memory was tested, along with investigating psychophysiological association. 71 young healthy adults completed (twice) a false memory task in virtual reality. Immediately before memory encoding and retrieval, participants practiced either vmHRV biofeedback or a control breathing exercise. Cognitive control over long-term memory was assessed as the confidence toward false memories and the capability to discriminate them from true memories. Resting-state vmHRV before each test and phasic vmHRV during memory encoding and retrieval were measured as the root mean square differences (RMSSD) in the heart period. vmHRV biofeedback had neither an immediate effect on measures of cognitive control over long-term memory nor on phasic RMSSD. Moreover, neither resting-state nor phasic vmHRV correlated to the cognitive scores. Consequently, the utility of HRV biofeedback as a psychophysiological stimulation tool and a link between vmHRV and cognitive control over long-term memory could not be verified. Exploratory analyses revealed that baseline shift in parasympathetic activity confounded the psychophysiological association. Future directions are provided that could shed light on the relationship between cognition and vmHRV.

Designing and developing a nature-based virtual reality with heart rate variability biofeedback for surgical anxiety and pain management: evidence from total knee arthroplasty patients

OBJECTIVES

Total knee arthroplasty (TKA) is one of the most common joint surgeries, with over a million procedures performed annually in the US. Over 70% of patients report moderate to high pain and anxiety surrounding TKA surgery, and 96% are discharged with an opioid prescription. This population requires special attention as approximately 90% of TKA patients are older adults and one of the riskiest groups prone to misusing opioids. This study aimed to develop and compare the efficacy of nature-based virtual reality (VR) with heart rate variability biofeedback (HRVBF) to mitigate surgical pain and anxiety.

METHODS

This randomized control trial recruited 30 patients (mean age = 66.3 ± 8.2 years, 23 F, 7 M) undergoing TKA surgery and randomly assigned to a control, 2D video with HRVBF, or VR with HRVBF group. A visual analog scale (VAS) was used to measure pain levels before and after the intervention. In addition, a second VAS and the State-Trait Anxiety Inventory (STAI) were used to measure anxiety before and after the intervention. Electrocardiogram (ECG) was used to continuously measure HRV and respiration rate in preoperative and postoperative settings.

RESULTS

VR and 2D-video with HRVBF decreased pain and anxiety post-intervention compared with the control group, p's <.01. On analyzing physiological signals, both treatment groups showed greater parasympathetic activity levels, and VR with HRVBF reduced pain more than the 2D video, p < .01.

CONCLUSIONS

Nature-based VR and 2D video with HRVBF can mitigate surgical pain and anxiety. However, VR may be more efficacious than 2D video in reducing pain.

Remote Short Sessions of Heart Rate Variability Biofeedback Monitored With Wearable Technology: Open-Label Prospective Feasibility Study

BACKGROUND

Heart rate variability (HRV) biofeedback is often performed with structured education, laboratory-based assessments, and practice sessions. It has been shown to improve psychological and physiological function across populations. However, a means to remotely use and monitor this approach would allow for wider use of this technique. Advancements in wearable and digital technology present an opportunity for the widespread application of this approach.

OBJECTIVE

The primary aim of the study was to determine the feasibility of fully remote, self-administered short sessions of HRV-directed biofeedback in a diverse population of health care workers (HCWs). The secondary aim was to determine whether a fully remote, HRV-directed biofeedback intervention significantly alters longitudinal HRV over the intervention period, as monitored by wearable devices. The tertiary aim was to estimate the impact of this intervention on metrics of psychological well-being.

METHODS

To determine whether remotely implemented short sessions of HRV biofeedback can improve autonomic metrics and psychological well-being, we enrolled HCWs across 7 hospitals in New York City in the United States. They downloaded our study app, watched brief educational videos about HRV biofeedback, and used a well-studied HRV biofeedback program remotely through their smartphone. HRV biofeedback sessions were used for 5 minutes per day for 5 weeks. HCWs were then followed for 12 weeks after the intervention period. Psychological measures were obtained over the study period, and they wore an Apple Watch for at least 7 weeks to monitor the circadian features of HRV.

RESULTS

In total, 127 HCWs were enrolled in the study. Overall, only 21 (16.5%) were at least 50% compliant with the HRV biofeedback intervention, representing a small portion of the total sample. This demonstrates that this study design does not feasibly result in adequate rates of compliance with the intervention. Numerical improvement in psychological metrics was observed over the 17-week study period, although it did not reach statistical significance (all P>.05). Using a mixed effect cosinor model, the mean midline-estimating statistic of rhythm (MESOR) of the circadian pattern of the SD of the interbeat interval of normal sinus beats (SDNN), an HRV metric, was observed to increase over the first 4 weeks of the biofeedback intervention in HCWs who were at least 50% compliant.

CONCLUSIONS

In conclusion, we found that using brief remote HRV biofeedback sessions and monitoring its physiological effect using wearable devices, in the manner that the study was conducted, was not feasible. This is considering the low compliance rates with the study intervention. We found that remote short sessions of HRV biofeedback demonstrate potential promise in improving autonomic nervous function and warrant further study. Wearable devices can monitor the physiological effects of psychological interventions.

The International Performance, Resilience and Efficiency Program Protocol for the Application of HRV Biofeedback in Applied Law Enforcement Settings

Law enforcement officers are routinely exposed to high-threat encounters that elicit physiological stress responses that impact health, performance, and safety. Therefore, self-regulation using evidence-based approaches is a priority in police research and practice. This paper describes a five-module heart rate variability biofeedback (HRVB) protocol that is part of a larger resilience program (the International Performance Resilience and Efficiency Program - iPREP) established in 2014. Supported by 10 years of user-informed research and development, our methods are tailored to address occupational stressors and the practical realities of training and resource availability in operational settings. Building on existing clinical methods that comprise five to six weekly sessions and up to 40-min of daily practice, our iPREP HRVB protocol is typically delivered in a condensed format across 2-3 days and is seamlessly integrated with reality-based training scenarios commonly employed in policing. By combining best practices in clinical HRVB with police-specific pedagogical frameworks, officers receive accelerated and job-relevant training to adaptively modulate autonomic responses to acute and chronic stress. Efficacy of the iPREP HRVB protocol is supported by several research studies of various methodological designs (i.e., randomized control trial, longitudinal cohort) that demonstrate immediate and sustained improvements in police performance and physiological health outcomes. We conclude with a critical appraisal of the available empirical evidence contrasting common and emerging breathing techniques proposed for use in operational policing contexts. The critical appraisal guide is intended to serve as a resource for law enforcement agencies, governing bodies, and operators when choosing appropriate and effective self-regulation training approaches.

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.

Oscillatory Coupling Between Neural and Cardiac Rhythms

Oscillations serve a critical role in organizing biological systems. In the brain, oscillatory coupling is a fundamental mechanism of communication. The possibility that neural oscillations interact directly with slower physiological rhythms (e.g., heart rate, respiration) is largely unexplored and may have important implications for psychological functioning. Oscillations in heart rate, an aspect of heart rate variability (HRV), show remarkably robust associations with psychological health. Mather and Thayer proposed coupling between high-frequency HRV (HF-HRV) and neural oscillations as a mechanism that partially accounts for such relationships. We tested this hypothesis by measuring phase-amplitude coupling between HF-HRV and neural oscillations in 37 healthy adults at rest. Robust coupling was detected in all frequency bands. Granger causality analyses indicated stronger heart-to-brain than brain-to-heart effects in all frequency bands except gamma. These findings suggest that cardiac rhythms play a causal role in modulating neural oscillations, which may have important implications for mental health.

Feasibility and Acceptability of Biofeedback-Based Virtual Reality System Use in Children and Adolescents Undergoing Surgery: Phase 1 of a Pilot Observational Study

BACKGROUND

Biofeedback-based virtual reality (VR-BF) is a novel, nonpharmacologic method for teaching patients how to control their breathing, which in turn increases heart rate variability (HRV) and may reduce pain. Unlike traditional forms of biofeedback (BF), VR-BF is delivered through a gamified virtual reality environment, increasing the accessibility of BF. This is the first study to systematically integrate VR-BF use in the pediatric perioperative setting, with the ultimate goal of evaluating the efficacy of VR-BF to reduce pain, anxiety, and opioid consumption once feasibility and acceptability has been established.

OBJECTIVE

The primary objective was to develop a clinical trial protocol for VR-BF use in the pediatric perioperative setting, including preoperative education/training and postoperative application of VR-BF in children undergoing surgery. A secondary objective was to evaluate the patient/parent experience with VR-BF.

METHODS

A total of 23 patients (12-18 years of age) scheduled for surgery at Nationwide Children's Hospital were recruited using purposive sampling. Following training, participants independently completed a daily, 10-minute VR-BF session for seven days before surgery and during their inpatient stay. Participants could use VR-BF up to two weeks after hospital discharge. Patient and session-level data of VR-BF usage and achievement of target HRV parameters were measured to identify the optimal frequency and duration of sessions before and after surgery for this population. Standardized questionnaires and semi-structured interviews were conducted to obtain qualitative information about patients' experiences with VR-BF.

RESULTS

Patient-level data indicated that the highest odds of achieving 1 session under target HRV parameters was after 4 sessions (OR 4 vs. 3 sessions=5.1, 95% CI 1.3-20.6; OR 3 vs. 2 sessions=16.6, 95% CI 1.2-217.0). Session-level data showed that a session duration of 9 to 10 minutes provided the greatest odds of achieving 1 session under target HRV parameters (OR 9 vs. 8 minutes=1.3, 95% CI 1.1-1.7; OR 8 vs. 7 minutes=1.4, 95% CI 1.1-1.8; OR 10 vs. 9 minutes=1.0, 95% CI 0.9-1.2). Qualitative data revealed patient satisfaction with the VR-BF technology, particularly in managing perioperative stress (n=17, 85%). Few patients reported VR-BF as beneficial for pain (n=8, 40%).

CONCLUSIONS

Children and adolescents undergoing surgery successfully learned behavioral strategies with VR-BF with once-daily 10-minute sessions for 5 days. To integrate VR-BF as a therapeutic intervention in a subsequent clinical trial, patients will be instructed to complete three 10-minute sessions a day for 7 days after surgery.

CLINICALTRIAL

ClinicalTrials.gov; NCT04943874; https://clinicaltrials.gov/ct2/show/NCT04943874.

Do Longer Exhalations Increase HRV During Slow-Paced Breathing?

Slow-paced breathing at an individual's resonance frequency (RF) is a common element of heart rate variability (HRV) biofeedback training (Laborde et al. in Psychophysiology 59:e13952, 2022). Although there is strong empirical support for teaching clients to slow their respiration rate (RR) to the adult RF range between 4.5 and 6.5 bpm (Lehrer & Gevirtz, 2014), there have been no definitive findings regarding the best inhalation-to-exhalation (IE) ratio to increase HRV when breathing within this range. Three methodological challenges have frustrated previous studies: ensuring participants breathed at the target RR, IE ratio, and the same RR during each IE ratio. The reviewed studies disagreed regarding the effect of IE ratios. Three studies found no IE ratio effect (Cappo & Holmes in J Psychosom Res 28:265-273, 1984; Edmonds et al. in Biofeedback 37:141-146, 2009; Klintworth et al. in Physiol Meas 33:1717-1731, 2012). One reported an advantage for equal inhalations and exhalations (Lin et al. in Int J Psychophysiol 91:206?211, 2014). Four studies observed an advantage for longer exhalations than inhalations (Bae et al. in Psychophysiology 58:e13905, 2021; Laborde et al. in Sustainability 13:7775, 2021; Strauss-Blasche et al. in Clin Exp Pharmacol Physiol 27:601?60, 2000; Van Diest et al. in Appl Psychophysiol Biofeedback 39:171?180, 2014). One study reported an advantage for longer inhalations than exhalations (Paprika et al. in Acta Physiol Hung 101:273?281, 2014). We conducted original (N = 26) and replication (N = 16) studies to determine whether a 1:2 IE ratio produces different HRV time-domain, frequency-domain, or nonlinear metrics than a 1:1 ratio when breathing at 6 bpm. Our original study found that IE ratio did not affect HRV time- and frequency-domain metrics. The replication study confirmed these results and found no effect on HRV nonlinear measurements.

Integrated use of biofeedback and neurofeedback techniques in treating pathological conditions and improving performance: a narrative review

In recent years, the scientific community has begun tо explore the efficacy оf an integrated neurofeedback + biofeedback approach іn various conditions, both pathological and non-pathological. Although several studies have contributed valuable insights into its potential benefits, this review aims tо further investigate its effectiveness by synthesizing current findings and identifying areas for future research. Our goal іs tо provide a comprehensive overview that may highlight gaps іn the existing literature and propose directions for subsequent studies. The search for articles was conducted on the digital databases PubMed, Scopus, and Web of Science. Studies to have used the integrated neurofeedback + biofeedback approach published between 2014 and 2023 and reviews to have analyzed the efficacy of neurofeedback and biofeedback, separately, related to the same time interval and topics were selected. The search identified five studies compatible with the objectives of the review, related to several conditions: nicotine addiction, sports performance, Autism Spectrum Disorder (ASD), and Attention Deficit Hyperactivity Disorder (ADHD). The integrated neurofeedback + biofeedback approach has been shown to be effective in improving several aspects of these conditions, such as a reduction in the presence of psychiatric symptoms, anxiety, depression, and withdrawal symptoms and an increase in self-esteem in smokers; improvements in communication, imitation, social/cognitive awareness, and social behavior in ASD subjects; improvements in attention, alertness, and reaction time in sports champions; and improvements in attention and inhibitory control in ADHD subjects. Further research, characterized by greater methodological rigor, is therefore needed to determine the effectiveness of this method and the superiority, if any, of this type of training over the single administration of either. This review іs intended tо serve as a catalyst for future research, signaling promising directions for the advancement оf biofeedback and neurofeedback methodologies.

The Physiological and Clinical-Behavioral Effects of Heart Rate Variability Biofeedback in Adolescents with Autism: A Pilot Randomized Controlled Trial

Adolescents with autism present lower levels of cardiac vagal modulation. It was hypothesized that Heart Rate Variability Biofeedback (HRVB) increases cardiac vagal modulation in adolescents with autism, resulting in positive effects on physiological and psychosocial parameters. It was also hypothesized that home-based HRVB training is feasible. In a single-blind, randomized sham-controlled pilot trial, adolescents with autism performed supervised HRVB (n = 24) or sham training (n = 20). Subsequently, half of the adolescents received HRVB training at home, whereas the other subset did not practice. Physiological, cortisol and behavioral data were collected during stress-provoking assessments before and after each training period. Supervised HRVB resulted in a late increase in cardiac vagal modulation in adolescents with autism. Heart rate increased and cortisol decreased significantly immediately after supervised HRVB, but none of these effects remained after follow-up. Following supervised HRVB, no significant change in psychosocial functioning was found. Home-based HRVB was feasible, adolescents reported lower symptoms of stress, but a significant decrease in compliance rate was found. HRVB is feasible and effective in adolescents with autism given the late-emerging increases in cardiac vagal modulation and decrease in stress symptoms. Replicating this study with a larger sample and further exploration of the working mechanisms of HRVB are recommended. ClinicalTrials.gov , NCT04628715.

A Comparison Between Pre-Sleep Heart Rate Variability Biofeedback and Electroencephalographic Biofeedback Training on Sleep in National Level Athletes with Sleep Disturbances

The current study compared the effects of heart rate variability biofeedback (HRV-BF) and electroencephalographic biofeedback (EEG-BF) on sleep, mood, and reaction time. Fourteen highly trained male athletes with sleep disturbances participated in this randomised crossover study. Participants took part in HRV-BF and EEG-BF training, with each condition consisting of eight sessions over 15 days. Polysomnography (PSG) and the Pittsburgh sleep quality index (PSQI) were used to assess sleep quality, the profile of mood states (POMS) questionnaire to monitor mood, and reaction time to measure performance pre and post intervention. HRV-BF training improved PSG sleep efficiency (SE) (P = 0.022, d = 0.35, 95% CI 0.01 to 0.16) and subjective sleep duration (P = 0.011, ES = 0.40) when compared to EEG-BF. Only HRV-BF reduced reaction time pre to post biofeedback training (P = 0.020, d = 0.75, 95% CI 0.006 to 0.059). The PSQI showed that both HRV-BF (P = 0.025, ES = 0.31) and EEG-BF (P = 0.003, ES = 0.32) resulted in improved global PSQI scores. Total mood disturbance was also reduced though HRV-BF (P = 0.001, ES = 0.40) and EEG-BF (P = 0.001, ES = 0.30). HRV-BF and EEG-BF enhanced some subjective parameters of sleep and mood. HRV-BF increased PSG SE and subjective sleep duration more than EEG-BF in highly trained athletes with sleep disturbances.

Influence of Respiratory Frequency of Slow-Paced Breathing on Vagally-Mediated Heart Rate Variability

Breathing techniques, particularly slow-paced breathing (SPB), have gained popularity among athletes due to their potential to enhance performance by increasing cardiac vagal activity (CVA), which in turn can help manage stress and regulate emotions. However, it is still unclear whether the frequency of SPB affects its effectiveness in increasing CVA. Therefore, this study aimed to investigate the effects of a brief SPB intervention (i.e., 5 min) on CVA using heart rate variability (HRV) measurement as an index. A total of 75 athletes (22 female; Mage = 22.32; age range = 19-31) participated in the study, attending one lab session where they performed six breathing exercises, including SPB at different frequencies (5 cycles per minute (cpm), 5.5 cpm, 6 cpm, 6.5 cpm, 7 cpm), and a control condition of spontaneous breathing. The study found that CVA was significantly higher in all SPB conditions compared to the control condition, as indexed by both root mean square of the successive differences (RMSSD) and low-frequency HRV (LF-HRVms2). Interestingly, LF-HRVms2 was more sensitive in differentiating the respiratory frequencies than RMSSD. These results suggest that SPB at a range of 5 cpm to 7 cpm can be an effective method to increase CVA and potentially improve stress management and emotion regulation in athletes. This short SPB exercise can be a simple yet useful tool for athletes to use during competitive scenarios and short breaks in competitions. Overall, these findings highlight the potential benefits of incorporating SPB into athletes' training and competition routines.

A Synthesized Model for Applying Stress Management and Biofeedback Interventions in Research Utilization: A Systematic Review and Meta-analysis

Background

Stress management and biofeedback interventions have been shown to be effective in improving mental and physical health outcomes. However, previous research studies and synthesized models for applying these interventions in research utilization are insufficient.

Objective

This study aimed to synthesize a model for applying stress management and biofeedback interventions in research utilization.

Methods

A systematic review and meta-analysis were conducted according to the PRISMA guidelines.Multiple studies were used to assess the effectiveness of applying stress management and biofeedback interventions published from 2017 to 2023. The process included identifying the research questions, conducting a comprehensive literature search, assessing study quality, extracting data, synthesizing the data, analyzing and interpreting the findings, drawing conclusions, and making recommendations.

Results

The results indicated a significant mean effect size without evidence of publication bias. The effect sizes of the subgroups among the study variables were not significantly different [Q = 4.02, p = .26]. However, there were significant differences regarding the mean effect sizes among the studies [Q = 63.59, p < .001] and also in terms of the test of subgroups among the participants [Q = 8.49, p = .04].

Conclusion

The results emphasize the importance of evidence-based practice and highlight the need for ongoing evaluation and refinement of interventions. The proposed model was supported by related theories and research studies in order to ensure the robustness and reliability to guide practice and future research in the field of biofeedback interventions. By following this model, researchers and practitioners can ensure that stress management and biofeedback interventions are evidence-based and are effective in improving mental and physical health outcomes.

"Brain-breath" interactions: respiration-timing-dependent impact on functional brain networks and beyond

Breathing is a natural daily action that one cannot do without, and it sensitively and intensely changes under various situations. What if this essential act of breathing can impact our overall well-being? Recent studies have demonstrated that breathing oscillations couple with higher brain functions, i.e., perception, motor actions, and cognition. Moreover, the timing of breathing, a phase transition from exhalation to inhalation, modulates specific cortical activity and accuracy in cognitive tasks. To determine possible respiratory roles in attentional and memory processes and functional neural networks, we discussed how breathing interacts with the brain that are measured by electrophysiology and functional neuroimaging: (i) respiration-dependent modulation of mental health and cognition; (ii) respiratory rhythm generation and respiratory pontomedullary networks in the brainstem; (iii) respiration-dependent effects on specific brainstem regions and functional neural networks (e.g., glutamatergic PreBötzinger complex neurons, GABAergic parafacial neurons, adrenergic C1 neurons, parabrachial nucleus, locus coeruleus, temporoparietal junction, default-mode network, ventral attention network, and cingulo-opercular salience network); and (iv) a potential application of breathing manipulation in mental health care. These outlines and considerations of "brain-breath" interactions lead to a better understanding of the interoceptive and cognitive mechanisms that underlie brain-body interactions in health conditions and in stress-related and neuropsychiatric disorders.

Determining the Right Levels of Health Coaching and Heart Rate Variability Biofeedback in a Workplace Behavior Change Intervention: Multiphase Optimization Strategy Preparation Study

BACKGROUND

Work-related stress is associated with poor job performance and negative health outcomes. Changing health behaviors through corporate wellness programs can improve physical and mental health and help employees manage stress. This project sought to pilot the potential addition of brief coaching and biofeedback to an 8-week web-based self-help program to improve employee stress using the multiphase optimization strategy.

OBJECTIVE

This study aims to determine which candidate components will be tested in a later optimization phase and at what dose they will be tested, examine the feasibility and acceptability of delivering the different components, investigate whether the outcomes can be feasibly measured, and review evidence to build a conceptual model before the optimization phase.

METHODS

The study was positioned within the preparation phase of the multiphase optimization strategy. It is a 2×2×2×2 design with 4 components: 2 types of health coaching and 2 types of biofeedback. All components were tested by turning them on or off. A total of 16 adult office workers (mean age 40, SD 14.3 years; n=15 women) completed an 8-week self-paced web-based stress management and health behavior change program and were randomly assigned to 1 of the 16 conditions, created from a combination of the 4 candidate components. Assessments included web analytics, surveys, and interviews regarding program recommendations, likes, and dislikes.

RESULTS

Findings from the interviews provided suggestions to improve the intervention (eg, separating wellness from stress content) and trial conduct (eg, streamlining the onboarding process). On average, participants logged into the wellness program 83 times (range 36-291), with 75% (12/16) participant retention and 67% (8/12) survey completion. There were no reported problems with coaching or obtaining data from interviews or apps. The interview findings suggested potential mediators to include and assess in a future conceptual model.

CONCLUSIONS

The results provided areas to improve the intervention content and trial methods. Instead of progressing to the next scheduled large-scale optimization phase, our plan to iterate through a second preparation phase after making changes to the protocol, apps, and corporate coaching partner.

The importance of self-regulation and mental health for effective recovery after traffic injuries: A comprehensive network analysis approach

OBJECTIVE

Traffic injuries significantly impact people's psychological, physical and social wellbeing, and involve complex self-regulation responses. Psychological impacts are seldom recognized and addressed holistically. This study employs network analysis to investigate the interconnectedness between different dimensions that influence mental health vulnerability and recovery after traffic injuries.

METHODS

120 adults with mild-to-moderate traffic injuries and 112 non-injured controls were recruited. The network investigation employed two main approaches. Four cross-sectional networks examined the interrelationships between self-regulation responses (cognitive and autonomic) and various health dimensions (psychological, physical, social) over time (1, 3, 6, 12 months). Three predictive networks explored influences of acute self-regulation responses (1 month) on long-term outcomes. Network analyses focused on between-group differences in overall connectivity and centrality measures (nodal strength).

RESULTS

An overall measure of psychological wellbeing consistently emerged as the most central (strongest) node in both groups' networks. Injured individuals showed higher overall connectivity and differences in the centrality of self-regulation nodes compared to controls, at 1-month and 12-months post-injury. These patterns were similarly observed in the predictive networks, including differences in cognitive and autonomic self-regulation influences.

CONCLUSIONS

Network analyses highlighted the crucial role of psychological health and self-regulation, in promoting optimal wellbeing and effective recovery. Post-traffic injury, increased connectivity indicated prolonged vulnerability for at least a year, underscoring the need of ongoing support beyond the initial improvements. A comprehensive approach that prioritizes psychological health and self-regulation through psychologically informed services, early psychological screening, and interventions promoting cognitive and autonomic self-regulation is crucial for mitigating morbidity and facilitating recovery.

TRIAL REGISTRATION

IMPRINT study, ACTRN 12616001445460.

Feasibility of a remote heart rate variability biofeedback intervention for reducing anxiety in cardiac arrest survivors: A pilot trial

Background

Heart rate variability biofeedback (HRVB) is a promising non-pharmacologic approach for reducing anxiety. This intervention's feasibility needs testing in psychologically distressed cardiac patients for whom heart-related anxiety is a core concern. To enhance scalability and convenience, remote delivery of HRVB also needs to be assessed. Accordingly, we evaluated the feasibility of remote HRVB in survivors of cardiac arrest (CA) with elevated CA-related psychological distress.

Methods

The intervention was comprised of daily sessions of diaphragmatic paced breathing and real-time monitoring of cardiac activity guided by a smartphone app and heart rate monitor. This single-arm feasibility trial assessed the percentage of eligible contacted patients who consented and engaged in the study and the self-reported acceptability, feasibility, appropriateness, and usability of the intervention. Exploratory analyses assessed pre-to-post changes in trait anxiety, negative affect, cardiac-related interoceptive fear, and resting-state HRV.

Results

Of 12 eligible CA survivors contacted, 10 enrolled. All 10 patients completed the virtual study visits and the majority (>50 %) of prescribed training sessions. Ninety percent reported good scores for intervention acceptability and feasibility, and 80 % reported good scores for its appropriateness and usability for reducing fear. Trait anxiety decreased significantly pre-to-post intervention. There were no changes in negative affect, interoceptive fear, or resting state HRV.

Conclusion

A remotely delivered HRVB intervention was acceptable, feasible, and useable for cardiac patients with CA-related psychological distress. A phase 2 randomized controlled trial evaluating the efficacy of HRVB on cardiac patients' psychological distress, health behaviors, and autonomic dysfunction may be warranted.

Heart Rate Variability and Cognition: A Narrative Systematic Review of Longitudinal Studies

BACKGROUND

Heart rate variability (HRV) is a reliable and convenient method to assess autonomic function. Cross-sectional studies have established a link between HRV and cognition. Longitudinal studies are an emerging area of research with important clinical implications in terms of the predictive value of HRV for future cognition and in terms of the potential causal relationship between HRV and cognition. However, they have not yet been the objective of a systematic review. Therefore, the aim of this systematic review was to investigate the association between HRV and cognition in longitudinal studies.

METHODS

The review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The Embase, PsycINFO and PubMed databases were searched from the earliest available date to 26 June 2023. Studies were included if they involved adult human subjects and evaluated the longitudinal association between HRV and cognition. The risk of bias was assessed with the Newcastle-Ottawa Scale for Cohort Studies. The results were presented narratively.

RESULTS

Of 14,359 records screened, 12 studies were included in this systematic review, with a total of 24,390 participants. Two thirds of the studies were published from 2020 onwards. All studies found a longitudinal relationship between HRV and cognition. There was a consistent association between higher parasympathetic nervous system (PNS) activity and better cognition, and some association between higher sympathetic nervous system activity and worse cognition. Also, higher PNS activity persistently predicted better executive functioning, while data on episodic memory and language were more scant and/or controversial.

CONCLUSIONS

Our results support the role of HRV as a biomarker of future cognition and, potentially, as a therapeutic target to improve cognition. They will need confirmation by further, more comprehensive studies also including unequivocal non-HRV sympathetic measures and meta-analyses.

Self-regulating arousal via pupil-based biofeedback

The brain's arousal state is controlled by several neuromodulatory nuclei known to substantially influence cognition and mental well-being. Here we investigate whether human participants can gain volitional control of their arousal state using a pupil-based biofeedback approach. Our approach inverts a mechanism suggested by previous literature that links activity of the locus coeruleus, one of the key regulators of central arousal and pupil dynamics. We show that pupil-based biofeedback enables participants to acquire volitional control of pupil size. Applying pupil self-regulation systematically modulates activity of the locus coeruleus and other brainstem structures involved in arousal control. Furthermore, it modulates cardiovascular measures such as heart rate, and behavioural and psychophysiological responses during an oddball task. We provide evidence that pupil-based biofeedback makes the brain's arousal system accessible to volitional control, a finding that has tremendous potential for translation to behavioural and clinical applications across various domains, including stress-related and anxiety disorders.

Subjective and physiological reactivity to emotional stressors in somatic symptom disorder

OBJECTIVE

We examined whether autonomic flexibility to experimentally presented stressors is reduced in somatic symptom disorder (SSD) as this would point to reduced vagal control as a proposed indicator of emotion regulation deficits.

METHOD

In this experimental study, the influence of health-related and social stressors on subjective and physiological reactivity was investigated in 29 subjects with SSD without any medical condition SSD(mc-), 33 subjects with SSD with medical condition SSD(mc+) and 32 healthy controls at the age from 18 to 70 years. Self-report and physiological variables were measured before and after/during stressor exposure, using state ratings of symptom intensity, disability, tension and mood, heart rate (HR), and heart rate variability (HRV).

RESULTS

Overall, the tension increased and the mood worsened after exposure to stressors compared to pre-exposure. Compared to HC, the two SSD groups showed higher symptom intensity, disability, tension and worse mood. The SSD(mc-) group revealed higher HR than HC (p = .012, d = -0.77). Compared to pre-exposure, symptom impairment increased after social stressor exposure in SSD(mc-) (p < .001, d = 1.36). HRV-root mean square of successive differences (RMSSD) only decreased in HC during exposure (p = .003, d = -1.09), not in the SSD groups. The two SSD groups did not differ in their reactivity to stressors.

CONCLUSION

HRV in SSD, seems to respond less flexibly to stressors, potentially reflecting overall physiological disturbance through reduced parasympathetic influence on HR. Stress reactivity in SSD(mc-) and SSD(mc+) do not seem to differ.

HEART Rate Variability Biofeedback for LOng COVID Dysautonomia (HEARTLOC): Results of a Feasibility Study

Introduction

Post-COVID-19 syndrome, or Long Covid (LC) refers to symptoms persisting 12 weeks after the COVID-19 infection. LC comprises a wide range of dysautonomia symptoms, including fatigue, breathlessness, palpitations, dizziness, pain and brain fog. This study tested the feasibility and estimated the efficacy, of a Heart Rate Variability Biofeedback (HRV-B) programme via a standardised slow diaphragmatic breathing technique in individuals with LC.

Methods

LC patients underwent a 4-week HRV-B intervention for 10 minutes twice daily for 4 weeks using the Polar H10 ECG (Electrocardiogram) chest strap and Elite HRV phone application. Outcome measures C19-YRSm (Yorkshire Rehabilitation Scale modified), Composite Autonomic Symptom Score (COMPASS-31), WHO Disability Assessment Schedule (WHODAS), EQ5D-5L (EuroQol 5 Dimensions) and Root Mean Square of Successive Differences between heartbeats (RMSSD) using a Fitbit device were recorded before and after the intervention. The study was pre-registered at clinicaltrials.gov NCT05228665.

Results

A total of 13 participants (54% female, 46% male) completed the study with high levels of independent use of technology, data completeness and intervention adherence. There was a statistically significant improvement in C19YRS-m (P = .001), COMPASS-31 (P = .007), RMSSD (P = .047), WHODAS (P = .02) and EQ5D Global Health Score (P = .009). Qualitative feedback suggested participants could use it independently, were satisfied with the intervention and reported beneficial effects from the intervention.

Conclusion

HRV-B using diaphragmatic breathing is a feasible intervention for LC. The small sample size limits generalisability. HRV-B in LC warrants further exploration in a larger randomised controlled study.

Pilot randomized controlled trial of biofeedback on reducing psychological and physiological stress among persons experiencing homelessness

People experiencing homelessness report increased exposure to traumatic life events and higher rates of depression, anxiety, and post-traumatic stress disorder as compared with the general population. Heart rate variability-biofeedback (HRV-BF) has been shown to decrease symptoms of stress, anxiety, depression, and PTSD. However, HRV-BF has not been tested with the most vulnerable of populations, homeless adults. The purpose of this randomized controlled trial was to compare the effectiveness of an HRV-BF intervention versus a Health Promotion (HP) active control intervention focused on improving mental health symptoms among homeless adults. Guided by a community advisory board, homeless adults residing in Skid Row, Los Angeles (n = 40) were randomized to either the HRV-BF or an active HP control group and received eight weekly, 30-min sessions over two months, delivered by a nurse-led community health worker team. Dependent variables of HRV, mental health, anxiety, depression, and PTSD were measured at baseline, the 8-week session, and/or 2-month follow-up. All intervention sessions were completed by 90% (36/40) of participants. Both the HRV-BF and HP interventions showed significant increases in HRV from baseline to 2-month follow-up, with no significant difference between the intervention groups. The HRV-BF programme revealed a somewhat greater, although non-significant, improvement in anxiety, depression, and PTSD symptoms than the HP programme. The usefulness of both interventions, focused on emotional and physical health, warrants future studies to examine the value of a combined HRV-BF and HP intervention.

Heart Rate Variability Biofeedback in Adults with a Spinal Cord Injury: A Laboratory Framework and Case Series

Heart rate variability biofeedback (HRV-F) is a neurocardiac self-regulation therapy that aims to regulate cardiac autonomic nervous system activity and improve cardiac balance. Despite benefits in various clinical populations, no study has reported the effects of HRV-F in adults with a spinal cord injury (SCI). This article provides an overview of a neuropsychophysiological laboratory framework and reports the impact of an HRV-F training program on two adults with chronic SCI (T1 AIS A and T3 AIS C) with different degrees of remaining cardiac autonomic function. The HRV-F intervention involved 10 weeks of face-to-face and telehealth sessions with daily HRV-F home practice. Physiological (HRV, blood pressure variability (BPV), baroreflex sensitivity (BRS)), and self-reported assessments (Fatigue Severity Scale, Generalised Anxiety Disorder Scale, Patient Health Questionnaire, Appraisal of Disability and Participation Scale, EuroQol Visual Analogue Scale) were conducted at baseline and 10 weeks. Participants also completed weekly diaries capturing mood, anxiety, pain, sleep quality, fatigue, and adverse events. Results showed some improvement in HRV, BPV, and BRS. Additionally, participants self-reported some improvements in mood, fatigue, pain, quality of life, and self-perception. A 10-week HRV-F intervention was feasible in two participants with chronic SCI, warranting further investigation into its autonomic and psychosocial effects.

Benefits of cardiac coherence combined with medical hypnosis on preoperative anxiety before cancer surgery: the COHEC II study trial protocol

INTRODUCTION

Preoperative anxiety is a frequent problem that can lead to complications both during anaesthesia and in the postoperative period, especially in oncology. Studies have shown that it can be managed using non-pharmacological approaches, but few works have evaluated psychoeducational programmes. The aim of the COHErence Cardiaque (COHEC) II Study is to evaluate the combination of medical hypnosis (MH) and cardiac coherence (CC) training to manage preoperative anxiety in patients with cancer.

METHODS AND ANALYSIS

COHEC II is an ongoing multicentre randomised clinical trial carried out in three French comprehensive cancer centres. In total, 296 patients who will undergo surgery for cancer will be recruited during 18 months and will be randomised in the control arm or the intervention arm. Patients in the intervention arm will follow a daily programme that combines MH and CC, starting 7 days before surgery. The control arm will receive the standard treatment to manage preoperative anxiety. The primary endpoint is the anxiety level on surgery day, measured using a Visual Analogue Scale. Secondary endpoints are patient adherence to the programme, satisfaction and postsurgery recovery quality.

ETHICS AND DISSEMINATION

The study protocol was approved by the French Ethics Committee (Comité de Protection des Personnes EST-II) on 24 November 2021 and will be carried out following the good practice guidelines and the Declaration of Helsinki. Results will be published in peer-reviewed journals and presented at conferences.

TRIAL REGISTRATION NUMBER

NCT05197972.

The Effect of Heart Rate Variability Biofeedback on Basketball Performance Tests

The purpose of this study is to investigate the effects of 10-week heart rate variability biofeedback training on basketball skills, free throws, and heart rate variability parameters. Twenty-four basketball players (experimental, n = 12 and control, n = 12) aged 18-24 years volunteered to participate in this study. The experimental group participated in a 10-week heart rate variability biofeedback and basketball training program, while the control group only participated in the 10-week basketball training session. Basketball free-throw performance, basketball skills, and heart rate variability tests were conducted on the experimental and control groups before and after the 10-week intervention. Consequently, we discovered that basketball free-throw performance, breathing frequency, and heart rate variability parameters, which reflect vagal modulation of parasympathetic activity, improved in participants who underwent the 10-week heart rate variability biofeedback and basketball training, and not in those who took basketball training only. Our findings propose that heart rate variability biofeedback, alongside basketball workouts, can contribute to better basketball free-throw performance potentially through improved autonomic nervous system functioning.

Interoceptive ability moderates the effect of physiological reactivity on social judgment

Social judgments-that others are kind or cruel, well intentioned, or conniving-can ease or disrupt social interactions. And yet a person's internal state can alter these judgments-a phenomenon known as affective realism. We examined the factors that contribute to, and mitigate, affective realism during a stressful interview. Using data collected between 2015 and 2019, we hypothesized and found that individuals' ability (N = 161; 57.6% female; 57.6% European American, 13.6% African American, 13.6% Asian American, 6.4% Latinx, 6.0% biracial, and 2.8% that identified with none or 1 + of the races presented; Mage = 19.20 years) to accurately perceive their own internal sensations (i.e., heartbeats) influenced whether they attributed their own heightened stress reactions (i.e., sympathetic nervous system reactivity) to the behavior of two impassive interviewers. Participants who were poor heartbeat detectors perceived their interviewers as less helpful, polite, or professional, and more apathetic, judgmental, and aggressive when experiencing heightened levels of cardiovascular sympathetic nervous system reactivity during their interview. Being aware of one's internal state may be one pathway to reducing bias in social perceptions in circumstances where such biases may lead us astray. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Daily biofeedback to modulate heart rate oscillations affects structural volume in hippocampal subregions targeted by the locus coeruleus in older adults but not younger adults

Using data from a clinical trial, we tested the hypothesis that daily sessions modulating heart rate oscillations affect older adults' volume of a region-of-interest (ROI) comprised of adjacent hippocampal subregions with relatively strong locus coeruleus (LC) noradrenergic input. Younger and older adults were randomly assigned to one of two daily biofeedback practices for 5 weeks: (1) engage in slow-paced breathing to increase the amplitude of oscillations in heart rate at their breathing frequency (Osc+); (2) engage in self-selected strategies to decrease heart rate oscillations (Osc-). The interventions did not significantly affect younger adults' hippocampal volume. Among older adults, the two conditions affected volume in the LC-targeted hippocampal ROI differentially as reflected in a significant condition × time-point interaction on ROI volume. These condition differences were driven by opposing changes in the two conditions (increased volume in Osc+ and decreased volume in Osc-) and were mediated by the degree of heart rate oscillation during training sessions.

Heart Rate Variability Biofeedback for Mild Traumatic Brain Injury: A Randomized-Controlled Study

To determine whether heart rate variability biofeedback (HRV-BF) training, compared to a psychoeducation control condition can strengthen the integration of the central and autonomic nervous systems as measured by neuropsychological measures in patients with mild traumatic brain injury (mTBI). Participants were recruited from two university hospitals in Taipei, Taiwan. A total of 49 participants with mTBI were recruited for this study. Forty-one participants completed the study, 21 in the psychoeducation group and 20 in the HRV-BF group. Randomized controlled study. The Taiwanese Frontal Assessment Battery, the Semantic Association of Verbal Fluency Test, the Taiwanese version of the Word Sequence Learning Test, the Paced Auditory Serial Addition Test-Revised, and the Trail Making Test were used as performance-based neuropsychological functioning measures. The Checklist of Post-concussion Symptoms, the Taiwanese version of the Dysexecutive Questionnaire, the Beck Anxiety Inventory, the Beck Depression Inventory, and the National Taiwan University Irritability Scale were used as self-report neuropsychological functioning measures. Furthermore, heart rate variability pre- vs. post-training was used to measure autonomic nervous system functioning. Executive, information processing, verbal memory, emotional neuropsychological functioning, and heart rate variability (HRV) were improved significantly in the HRV-BF group at the posttest whereas the psychoeducation group showed no change. HRV biofeedback is a feasible technique following mild TBI that can improve neuropsychological and autonomic nervous system functioning. HRV-BF may be clinically feasible for the rehabilitation of patients with mTBI.

Validity and Efficacy of the Elite HRV Smartphone Application during Slow-Paced Breathing

Slow-paced breathing is a clinical intervention used to increase heart rate variability (HRV). The practice is made more accessible via cost-free smartphone applications like Elite HRV. We investigated whether Elite HRV can accurately measure and augment HRV via its slow-paced breathing feature. Twenty young adults completed one counterbalanced cross-over protocol involving 10 min each of supine spontaneous (SPONT) and paced (PACED; 6 breaths·min-1) breathing while RR intervals were simultaneously recorded via a Polar H10 paired with Elite HRV and reference electrocardiography (ECG). Individual differences in HRV between devices were predominately skewed, reflecting a tendency for Elite HRV to underestimate ECG-derived values. Skewness was typically driven by a limited number of outliers as median bias values were ≤1.3 ms and relative agreement was ≥very large for time-domain parameters. Despite no significant bias and ≥large relative agreement for frequency-domain parameters, limits of agreement (LOAs) were excessively wide and tended to be wider during PACED for all HRV parameters. PACED significantly increased low-frequency power (LF) for Elite HRV and ECG, and between-condition differences showed very large relative agreement. Elite HRV-guided slow-paced breathing effectively increased LF values, but it demonstrated greater precision during SPONT and in computing time-domain HRV.

The effect of a single-session heart rate variability biofeedback on attentional control: does stress matter?

Introduction

Vagally mediated heart rate variability is an index of autonomic nervous system activity that is associated with a large variety of outcome variables including psychopathology and self-regulation. While practicing heart rate variability biofeedback over several weeks has been reliably associated with a number of positive outcomes, its acute effects are not well known. As the strongest association with vagally mediated heart rate variability has been found particularly within the attention-related subdomain of self-regulation, we investigated the acute effect of heart rate variability biofeedback on attentional control using the revised Attention Network Test.

Methods

Fifty-six participants were tested in two sessions. In one session each participant received a heart rate variability biofeedback intervention, and in the other session a control intervention of paced breathing at a normal ventilation rate. After the biofeedback or control intervention, participants completed the Attention Network Test using the Orienting Score as a measure of attentional control.

Results

Mixed models revealed that higher resting baseline vagally mediated heart rate variability was associated with better performance in attentional control, which suggests more efficient direction of attention to target stimuli. There was no significant main effect of the intervention on attentional control. However, an interaction effect indicated better performance in attentional control after biofeedback in individuals who reported higher current stress levels.

Discussion

The results point to acute beneficial effects of heart rate variability biofeedback on cognitive performance in highly stressed individuals. Although promising, the results need to be replicated in larger or more targeted samples in order to reach stronger conclusions about the effects.

Prognostic role of short-term heart rate variability and deceleration/acceleration capacities of heart rate in extensive-stage small cell lung cancer

Background: Prior research suggests that autonomic modulation investigated by heart rate variability (HRV) might act as a novel predictive biomarker for cancer prognosis, such as in breast cancer and pancreatic cancer. It is not clear whether there is a correlation between autonomic modulation and prognosis in patients with extensive-stage small cell lung cancer (ES-SCLC). Therefore, the purpose of the study was to examine the association between short-term HRV, deceleration capacity (DC) and acceleration capacity (AC) of heart rate and overall survival in patients with ES-SCLC. Methods: We recruited 40 patients with ES-SCLC, and 39 were included in the final analysis. A 5-min resting electrocardiogram of patients with ES-SCLC was collected using a microelectrocardiogram recorder to analyse short-term HRV, DC and AC. The following HRV parameters were used: standard deviation of the normal-normal intervals (SDNN) and root mean square of successive interval differences (RMSSD). Overall survival of patients with ES-SCLC was defined as time from the date of electrocardiogram measurement to the date of death or the last follow-up. Follow-up was last performed on 07 June 2023. There was a median follow-up time of 42.2 months. Results: Univariate analysis revealed that the HRV parameter SDNN, as well as DC significantly predicted the overall survival of ES-SCLC patients (all p < 0.05). Multivariate analysis showed that the HRV parameters SDNN (hazard ratio = 5.254, 95% CI: 1.817-15.189, p = 0.002), RMSSD (hazard ratio = 3.024, 95% CI: 1.093-8.372, p = 0.033), as well as DC (hazard ratio = 3.909, 95% CI: 1.353-11.293, p = 0.012) were independent prognostic factors in ES-SCLC patients. Conclusion: Decreased HRV parameters (SDNN, RMSSD) and DC are independently associated with shorter overall survival in ES-SCLC patients. Autonomic nervous system function (assessed based on HRV and DC) may be a new biomarker for evaluating the prognosis of patients with ES-SCLC.

Ancient medicine for a modern disease: traditional Amazonian medicine to treat substance use disorders

Background: There exists an underexploited opportunity to develop innovative therapeutic approaches to SUDs based upon the complementarity between modern and traditional health systems.Objectives: Illustrate the feasibility and potentiality of such an approach through the comprehensive description of Takiwasi Center's treatment model and program, where health concepts and practices from traditional Amazonian medicine work synergistically with modern psychotherapy and medicine in an intercultural dialog to assist in the rehabilitation of people suffering from SUDs.Methods: The description was built from a review of the literature, institutional data, participatory observation and unstructured interviews with staff, researchers and patients during treatment.Results: Since the foundation of the Takiwasi Center in 1992 in the peruvian Amazon, more than a thousand patients with different socio-cultural, ethnic and religious backgrounds have received residential treatment. We present how traditional Amazonian medicine techniques and health concepts cooperate to complement modern psychology in a therapeutic community setting and propose some hypotheses about the neurobiological, psycho-emotional and spiritual healing mechanisms triggered by the program to help people identify and heal the roots of their substance misuse and addictive behavior. We also summarize quantitative outcomes during treatment showing significant improvements in a wide variety of mental health indicators.Conclusion: Takiwasi Center's program is an option for people seeking non-conventional treatment who are sensitive to traditional Amazonian medicine practices and ready to explore the roots of their addiction. From this intercultural approach, some lessons could emerge toward a broader understanding of SUDs that may result in better patient care.

The Effectiveness of A Slow-Paced Diaphragmatic Breathing Exercise in Children's Daily Life: A Micro-Randomized Trial

OBJECTIVE

Breathing exercises have been proposed as an effective intervention to improve subjective well-being and manage anxiety symptoms. As they are comparatively easy to learn and to implement, breathing exercises may be particularly beneficial for children. Although breathing exercises are ultimately supposed to provide salutary effects in individuals' everyday lives, immediate effects of breathing exercises in naturalistic contexts have received limited empirical attention. The purpose of this study was to examine immediate effects of slow-paced diaphragmatic breathing on negative affect as well as on relaxation in an ecologically valid setting. To that end, we conducted a micro-randomized trial in children's daily life.

METHOD

On each of 15 days, children (N = 171, aged 9-13 years, 54% female) were randomized to different conditions: performing a video-guided slow-paced diaphragmatic breathing exercise (experimental condition), watching a different video (active control condition), or a passive control condition.

RESULTS

The breathing exercise had no immediate effects on negative affect or relaxation compared to both control conditions. However, in situations when children reported higher levels of worries than usual, relaxation was higher when children performed the breathing exercise compared to the passive control condition. Compared to the active control condition, the breathing exercise did not result in higher levels of relaxation in situations when children worried more than normally.

CONCLUSIONS

Findings highlight that context-specific factors can modulate the effectiveness of breathing exercises and should be taken into account to tailor interventions to individuals' needs.

Comparing two relaxation procedures to ease fatigue in multiple sclerosis: a single-blind randomized controlled trial

BACKGROUND

Various relaxation procedures have been proposed to reduce fatigue in multiple sclerosis (MS). However, it is unknown, which type of relaxation has the largest effect on fatigue reduction and on autonomic nervous system (ANS) activity.

OBJECTIVE

We aimed to compare two biofeedback-supported relaxation exercises: a deep breathing (DB) exercise and progressive muscle relaxation (PMR), which may ameliorate MS fatigue and alter ANS activity.

METHODS

We performed a single-blind randomized clinical trial, introducing MS patients (n = 34) to the DB or PMR exercise. We first tested cardiovagal integrity, reflected by changes in heart rate variability (HRV) in response to DB. Participants then performed a fatigue-inducing vigilance task, followed by the DB or PMR. State fatigue was recorded consecutively at baseline, after the vigilance task, and after the relaxation exercise, along with HRV reflecting ANS activity.

RESULTS

Only patients assigned to the PMR group experienced a significant drop in fatigue, whereas both relaxation exercises changed ANS activity. MS patients showed the expected autonomic response during the cardiovagal reflex test. The vigilance task elevated short-term feelings of fatigue and significantly reduced HRV parameters of parasympathetic activity. Trait fatigue was negatively correlated with HRV during the second half of the vigilance task.

CONCLUSION

PMR alleviates short-term feelings of fatigue in persons with MS. The vigilance task in combination with HRV measurements may be helpful for evaluating relaxation procedures as a treatment of fatigue. Hereby, future studies should ensure longer and more frequent relaxation exercises and focus on patients with weak to moderate fatigue.

TRIAL REGISTRATION

Trial Registry: DRKS00024358.

Daily heart rate variability biofeedback training decreases locus coeruleus MRI contrast in younger adults in a randomized clinical trial

As an arousal hub region in the brain, the locus coeruleus (LC) has bidirectional connections with the autonomic nervous system. Magnetic resonance imaging (MRI)-based measures of LC structural integrity have been linked to cognition and arousal, but less is known about factors that influence LC structure and function across time. Here, we tested the effects of heart rate variability (HRV) biofeedback, an intervention targeting the autonomic nervous system, on LC MRI contrast and sympathetic activity. Younger and older participants completed daily HRV biofeedback training for five weeks. Those assigned to an experimental condition performed biofeedback involving slow, paced breathing designed to increase heart rate oscillations, whereas those assigned to a control condition performed biofeedback to decrease heart rate oscillations. At the pre- and post-training timepoints, LC contrast was assessed using turbo spin echo MRI scans, and RNA sequencing was used to assess cAMP-responsive element binding protein (CREB)-regulated gene expression in circulating blood cells, an index of sympathetic nervous system signaling. We found that left LC contrast decreased in younger participants in the experimental group, and across younger participants, decreases in left LC contrast were related to the extent to which participants increased their heart rate oscillations during training. Furthermore, decreases in left LC contrast were associated with decreased expression of CREB-associated gene transcripts. On the contrary, there were no effects of biofeedback on LC contrast among older participants in the experimental group. These findings provide novel evidence that in younger adults, HRV biofeedback involving slow, paced breathing can decrease both LC contrast and sympathetic nervous system signaling.

PhysioKit: An Open-Source, Low-Cost Physiological Computing Toolkit for Single- and Multi-User Studies

The proliferation of physiological sensors opens new opportunities to explore interactions, conduct experiments and evaluate the user experience with continuous monitoring of bodily functions. Commercial devices, however, can be costly or limit access to raw waveform data, while low-cost sensors are efforts-intensive to setup. To address these challenges, we introduce PhysioKit, an open-source, low-cost physiological computing toolkit. PhysioKit provides a one-stop pipeline consisting of (i) a sensing and data acquisition layer that can be configured in a modular manner per research needs, and (ii) a software application layer that enables data acquisition, real-time visualization and machine learning (ML)-enabled signal quality assessment. This also supports basic visual biofeedback configurations and synchronized acquisition for co-located or remote multi-user settings. In a validation study with 16 participants, PhysioKit shows strong agreement with research-grade sensors on measuring heart rate and heart rate variability metrics data. Furthermore, we report usability survey results from 10 small-project teams (44 individual members in total) who used PhysioKit for 4-6 weeks, providing insights into its use cases and research benefits. Lastly, we discuss the extensibility and potential impact of the toolkit on the research community.

Using the Research Domain Criteria as a framework to integrate psychophysiological findings into stress management and psychotherapy interventions

Research on the psychophysiology of stress is expanding rapidly, but the field lacks a clear integrative framework to help translate research findings into empirically supported stress interventions. The Research Domain Criteria (RDoC) is an excellent candidate to explore as a framework to integrate stress research. The RDoC framework is a dimensional, multi-modal approach to psychopathology proposed as an alternative to categorical approaches used by the International Classification of Diseases (ICD) and the Diagnostic and Statistical Manual (DSM). The goal of this paper is to explore the RDoC as a framework to integrate psychophysiology research into therapeutic interventions for stress. The RDoC consists of six domains: negative valence systems, positive valence systems, cognitive systems, social processes systems, arousal/regulatory systems, and sensorimotor systems, and provides an excellent structure for integrating information from multiple levels of functioning including physiology, behavior, and self-report, as well as genes, molecules, cells, and brain circuits. Integrating psychophysiological research on stress using the RDoC framework can direct and amplify stress management and psychotherapeutic interventions. First, the RDoC provides a clear foundation for conceptualizing the stress response in terms of important concepts such as allostasis and adaptation. In this perspective, the terms "allostatic response" or "adaptation response" are more descriptive terms than "stress response" in understanding bodily responses to life threats and challenges. Second, psychophysiological approaches can be used in the context of modalities such as biofeedback and mindfulness to both collect psychophysiological data and then integrate that data into a broader therapeutic framework. Heart rate variability (HRV) biofeedback is being used more frequently as part of a therapeutic intervention package with stress management and psychotherapy, and HRV data is also used to provide outcome evidence on the efficacy of treatment. Mindfulness practices are commonly used in combination with stress management and psychotherapy, and psychophysiological data (HRV, EEG, blood pressure, etc.) is often collected to explore and understand mind/body relationships. In conclusion, the lack of a clear framework to assess and understand mind/body functioning limits current stress research and interventions. The RDoC provides a strong framework to assess and integrate physiological and psychological data and improve stress interventions.

Expiratory-gated Transcutaneous Auricular Vagus Nerve Stimulation (taVNS) does not Further Augment Heart Rate Variability During Slow Breathing at 0.1 Hz

As cardiac vagal control is a hallmark of good health and self-regulatory capacity, researchers are seeking ways to increase vagally mediated heart rate variability (vmHRV) in an accessible and non-invasive way. Findings with transcutaneous auricular vagus nerve stimulation (taVNS) have been disappointing in this respect, as its effects on vmHRV are inconsistent at best. It has been speculated that combining taVNS with other established ways to increase vmHRV may produce synergistic effects. To test this idea, the present study combined taVNS with slow breathing in a cross-over design. A total of 22 participants took part in two sessions of breathing at 6 breaths/min: once combined with taVNS, and once combined with sham stimulation. Electrical stimulation (100 Hz, 400 µs) was applied during expiration, either to the tragus and cavum conchae (taVNS) or to the earlobe (sham). ECG was recorded during baseline, 20-minutes of stimulation, and the recovery period. Frequentist and Bayesian analyses showed no effect of taVNS (in comparison to sham stimulation) on the root mean square of successive differences between normal heartbeats, mean inter-beat interval, or spectral power of heart rate variability at a breathing frequency of 0.1 Hz. These findings suggest that expiratory-gated taVNS combined with the stimulation parameters examined here does not produce acute effects on vmHRV during slow breathing.

Is Biofeedback for Vertigo Effective in Ordinary Medical Centers? A Controlled Trial in Northern Italy

The aim of this study was to assess the therapeutic effectiveness of biofeedback, in a medical center's routine for treating vestibular disorders, reducing emotional, functional, and physical disability at three-month follow-up. A total of 197 outpatients were recruited from a medical center to treat vestibular disorders. Patients in the control group received treatment as usual, consisting of one monthly visit with an otolaryngologist and pharmacological treatment specific for vertigo, while the experimental group attended biofeedback training. Patients in the experimental group received pharmacological therapy only in the phase before the start of biofeedback in order to stabilize the acute phase. During the three-month follow-up, the experimental group did not receive any booster sessions of biofeedback. At three-month follow-up there was a statistically significant difference between the groups, both in the mean total score of the dizziness handicap inventory and in the three subscales: physical, emotional, and functional. Moreover, the biofeedback group had reduced psycho-physiological parameters for all average values at three-month follow-up compared to the baseline. This is one of few studies assessing the effectiveness of biofeedback in a naturalistic setting for vestibular disorder treatment. The data confirmed that biofeedback can impact illness course, in terms of self-perceived disability reduction, assessed on emotional, functional, and physical aspects of daily living.

Silence and its effects on the autonomic nervous system: A systematic review

This systematic review explores the influence of silence on the autonomic nervous system. The Polyvagal Theory has been used as a reference model to describe the autonomic nervous system by explaining its role in emotional regulation, social engagement, and adaptive physiological responses. PubMed, Scopus, PsycInfo, EMBASE, and Google Scholar were systematically searched up until July 2023 for relevant studies. The literature search yielded 511 results, and 37 studies were eventually included in this review. Silence affects the autonomic nervous system differently based on whether it is inner or outer silence. Inner silence enhances activity of the ventral vagus, favoring social engagement, and reducing sympathetic nervous system activity and physiological stress. Outer silence, conversely, can induce a heightened state of alertness, potentially triggering vagal brake removal and sympathetic nervous system activation, though with training, it can foster inner silence, preventing such activation. The autonomic nervous system response to silence can also be influenced by other factors such as context, familiarity with silence, presence and quality of outer noise, and empathy.

A Pilot Study of the Biofeedback Training to Reduce Salivary Cortisol Level and Improve Mental Health in Highly-Trained Female Athletes

Biofeedback (BFB) training can provide a useful resource for athletes to cope with stress. However, the effects of BFB training on acute and chronic endocrine stress responses, parasympathetic activity, and mental health in competitive athletes have not been explored yet. This pilot study examined the effects of a 7-week BFB training on psychophysiological parameters in highly trained female athletes. Six highly trained female volleyball players (mean age: 17.50 ± 1.05 years) volunteered to participate in the study. Athletes individually attended 21-session heart rate variability (HRV)-BFB training consisting of six minutes for 7 weeks. A BFB device (Nexus 10) was used to measure the athletes' physiological responses reflecting HRV. To assess the cortisol awakening response (CAR), saliva samples were collected immediately after awakening and 15 min, 30 min, and 60 min post-awakening. The Depression Anxiety Stress Scale-21 was filled out before and after the intervention to assess mental health. Furthermore, athletes provided saliva samples during eight sessions pre- and immediately post-session. Mid-day cortisol levels decreased significantly after the intervention. No significant change was observed in CAR and physiological responses after the intervention. A significant decrease in cortisol level was observed in BFB sessions in which cortisol level was assessed, except for two sessions. We concluded that short sessions of 7-week HRV-BFB training could be used as an effective method to control autonomic functions and stress of female athletes. Although the present study provides strong evidence for the psychophysiological well-being of athletes, further investigations with larger samples are needed.

Methods for Heart Rate Variability Biofeedback (HRVB): A Systematic Review and Guidelines

Heart Rate Variability Biofeedback (HRVB) has been widely used to improve cardiovascular health and well-being. HRVB is based on breathing at an individual's resonance frequency, which stimulates respiratory sinus arrhythmia (RSA) and the baroreflex. There is, however, no methodological consensus on how to apply HRVB, while details about the protocol used are often not well reported. Thus, the objectives of this systematic review are to describe the different HRVB protocols and detect methodological concerns. PsycINFO, CINALH, Medline and Web of Science were searched between 2000 and April 2021. Data extraction and quality assessment were based on PRISMA guidelines. A total of 143 studies were finally included from any scientific field and any type of sample. Three protocols for HRVB were found: (i) "Optimal RF" (n = 37), each participant breathes at their previously detected RF; (ii) "Individual RF" (n = 48), each participant follows a biofeedback device that shows the optimal breathing rate based on cardiovascular data in real time, and (iii) "Preset-pace RF" (n = 51), all participants breathe at the same rate rate, usually 6 breaths/minute. In addition, we found several methodological differences for applying HRVB in terms of number of weeks, duration of breathing or combination of laboratory and home sessions. Remarkably, almost 2/3 of the studies did not report enough information to replicate the HRVB protocol in terms of breathing duration, inhalation/exhalation ratio, breathing control or body position. Methodological guidelines and a checklist are proposed to enhance the methodological quality of future HRVB studies and increase the information reported.

The Effect of a Biofeedback-Based Integrated Program on Improving Orthostatic Hypotension in Community-Dwelling Older Adults: A Pilot Study

BACKGROUND

Orthostatic hypotension (OH) is prevalent among community-dwelling older adults and is associated with multiple negative health outcomes. Older adults are susceptible to developing OH because aging alters autonomic nervous system function. Biofeedback is a noninvasive, nonpharmacological intervention that can modulate autonomic nervous system dysfunction in older adults.

OBJECTIVES

Our aim in this study was to examine the effect of a biofeedback-based integrated program on community-dwelling older adults with OH.

METHODS

We conducted a controlled pilot study. Community-dwelling older adults 65 years or older who had nonneurogenic OH were eligible. Data from 51 participants, comprising 27 in the intervention group and 24 in the control group, were analyzed. Weekly biofeedback-based integrated program consisting of biofeedback training along with group education about behavioral modification, physical activities, and telephone counseling was provided for 12 weeks. Orthostatic hypotension was evaluated by measuring the drop in systolic and diastolic blood pressure after postural changes. Autonomic nervous system function was measured using heart rate variability.

RESULTS

Among the indicators of heart rate variability, total power (P = .037) and low frequency (P = .017) increased significantly, suggesting that autonomic function improved. Severity of orthostatic symptoms (P < .001) and drops in systolic (P = .003) and diastolic (P = .012) blood pressure after postural changes decreased significantly in the intervention group.

CONCLUSION

Biofeedback-based integrated program was effective in improving autonomic nervous system function and alleviated OH. Therefore, biofeedback-based integrated program should be tested in a larger randomized controlled study with long-term follow-up.