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.

Heart rate variability during mindful breathing meditation

We discuss Heart Rate Variability (HRV) measured during mindful breathing meditation. We provide a pedagogical computation of two commonly used heart rate variability metrics, i.e. the root mean square of successive differences (RMSSD) and the standard deviation of RR intervals (SDRR), in terms of Fourier components. It is shown that the root mean square of successive differences preferentially weights higher frequency Fourier modes, making it unsuitable as a biosignal for mindful breathing meditation which encourages slow breathing. We propose a new metric called the autonomic balance index (ABI) which uses Respiratory Sinus Arrhythmia to quantify the fraction of heart rate variability contributed by the parasympathetic nervous system. We apply this metric to heart rate variability data collected during two different meditation techniques, and show that the autonomic balance index is significantly elevated during mindful breathing, making it a good signal for biofeedback during meditation sessions.

Comparing heart rate variability biofeedback and simple paced breathing to inform the design of guided breathing technologies

Introduction

A goal of inbodied interaction is to explore how tools can be designed to provide external interactions that support our internal processes. One process that often suffers from our external interactions with modern computing technology is our breathing. Because of the ergonomics and low-grade-but-frequent stress associated with computer work, many people adopt a short, shallow breathing pattern that is known to have a negative effect on other parts of our physiology. Breathing guides are tools that help people match their breathing patterns to an external (most often visual) cue to practice healthy breathing exercises.However, there are two leading protocols for how breathing cues are offered by breathing guides used in non-clinical settings: simple paced breathing (SPB) and Heart Rate Variability Biofeedback (HRV-b). Although these protocols have separately been demonstrated to be effective, they differ substantially in their complexity and design. Paced breathing is a simpler protocol where a user is asked to match their breathing pattern with a cue paced at a predetermined rate and is simple enough to be completed as a secondary task during other activities. HRV-b, on the other hand, provides adaptive, real-time guidance derived from heart rate variability, a physiological signal that can be sensed through a wearable device. Although the benefits of these two protocols have been well established in clinical contexts, designers of guided breathing technology have little information about whether one is better than the other for non-clinical use.

Methods

To address this important gap in knowledge, we conducted the first comparative study of these two leading protocols in the context of end-user applications. In our N=28 between-subject design, participants were trained in either SPB or HRV-b and then completed a 10-minute session following their training protocol. Breathing rates and heart rate variability scores were recorded and compared between groups.

Results and discussion

Our findings indicate that the exercises did not significantly differ in their immediate outcomes – both resulted in significantly slower breathing rates than their baseline and both provided similar relative increases in HRV. Therefore, there were no observed differences in the acute physiological effects when using either SPB or HRV-b. Our paper contributes new findings suggesting that simple paced breathing – a straightforward, intuitive, and easy-to-design breathing exercise – provides the same immediate benefits as HRV-b, but without its added design complexities.

Efficacy of Using Retro Games in Multimodal Biofeedback System for Mental Relaxation

Video games are used to increase the engagement of biofeedback systems. For cost-effectiveness, the original Nintendo Entertainment System (NES) games can be used. Therefore, a multimodal biofeedback system was developed to leverage the NES games for biofeedback. This study aims to test the efficacy of the developed system, the motivation of participants, and the usability of the system. A within-group design study was conducted with 16 participants followed through four interventions: deep breathing, stress-test, non-biofeedback game (control), and biofeedback game (experiment), where their HRV was recorded. Participants showed significantly different HRV during interventions (F(1.60, 23.93) = 11.94, p < 0.001) and reported higher HRV when using biofeedback game than the non-biofeedback game (t(15) = 9.14, p < 0.0001). The motivation was reported to be the same with biofeedback and non-biofeedback version of the game and the overall system was reported as usable. The results of this study support the efficacy of using original NES games in biofeedback for mental relaxation.

Relationship between the proficiency level and anxiety-reducing effect in a one-time heart rate variability biofeedback: A randomized controlled trial

INTRODUCTION

Previous studies have reported that the proficiency level of heart rate variability biofeedback (HRVBF) contributes significantly to the anxiety-reducing effects in continuous HRVBF interventions. Meanwhile, anxiety-reducing effects have been confirmed in one-time HRVBF interventions as well as continuous HRVBF; however, no study has analyzed the relationship between the proficiency level of a one-time HRVBF and its anxiety-reducing effects. To pursuit the effectiveness of a one-time HRVBF intervention, it is necessary to clarify whether the proficiency level is an important predictor of anxiety-reducing effects from a dose-response relationship between these 2 variables. The purpose of this study was to examine the dose-response relationship between the proficiency level and anxiety-reducing effects of a one-time HRVBF.

METHODS

This study was a single-blinded, randomized, controlled trial with stratification based on trait anxiety of the State-Trait Anxiety Inventory-JYZ. In total, 45 healthy young males aged 20 to 30 years were allocated to the HRVBF or control group with simple breathing at rest. The intervention was performed for 15 minute in each group. The state anxiety score of the State-Trait Anxiety Inventory-JYZ was measured to evaluate the anxiety-reducing effect before and after training.

RESULTS

The results showed no significant linear relationship between the proficiency level and anxiety-reducing effect, and variations in the proficiency level were observed post-intervention in the HRVBF group. A significant anxiety-reducing effect was only observed in the HRVBF group (P = .001, effect size r = 0.62).

CONCLUSIONS

These results suggest that there is no close relationship between the proficiency level and anxiety-reducing effect in one-time HRVBF and that HRVBF is effective in reducing anxiety regardless of individual differences in the proficiency level. Therefore, a one-time HRVBF may be a useful breathing technique for reducing state anxiety without specific education and breathing techniques.

TRIAL REGISTRATION

University Hospital Medical Information Network Clinical Trial Registry (UMIN000041760).

Resting parasympathetic nervous system activity is associated with greater antiviral gene expression

Parasympathetic nervous system activity can downregulate inflammation, but it remains unclear how parasympathetic nervous system activity relates to antiviral activity. The present study examined associations between parasympathetic nervous system activity and cellular antiviral gene regulation in 90 adolescents (M_age = 16.28, SD = 0.73; 51.1% female) who provided blood samples and measures of cardiac respiratory sinus arrhythmia (RSA), twice, five weeks apart. Using a multilevel analytic framework, we found that higher RSA (an indicator of higher parasympathetic nervous system activity)-both at rest and during paced breathing-was associated with higher expression of Type I interferon (IFN) response genes in circulating leukocytes, even after adjusting for demographic and biological covariates. RSA was not associated with a parallel measure of inflammatory gene expression. These results identify a previously unrecognized immunoregulatory aspect of autonomic nervous system function and highlight a potential biological pathway by which parasympathetic nervous system activity may relate to health.

High-Frequency Heart Rate Variability and Emotion-Driven Impulse Control Difficulties During Adolescence: Examining Experienced and Expressed Negative Emotion as Moderators

Emotion-driven impulse control difficulties are associated with negative psychological outcomes. Extant research suggests that high frequency heart rate variability (HF-HRV) may be indicative of emotion-driven impulse control difficulties and potentially moderated by negative emotion. In the current study, 248 eleven- to 14-year-olds and their parent engaged in a negatively emotionally arousing conflict task at Time 1. Adolescents' HF-HRV and negative emotional expression and experience were assessed before, during, and/or after the task. Adolescents reported on their levels of emotion-driven impulse control difficulties at Time 1 and one year later. Results revealed that higher levels of HF-HRV reactivity (i.e., higher HF-HRV augmentation) predicted higher levels of emotion-driven impulse control difficulties one year later among adolescents who experienced higher negative emotion. These findings suggest that negative emotional context should be considered when examining HF-HRV reactivity as a risk factor for emotion-driven impulse control difficulties and associated outcomes.

Combining proactive transcranial stimulation and cardiac biofeedback to substantially manage harmful stress effects

BACKGROUND

Previous studies have identified the dorsolateral prefrontal cortex (dlPFC) as a core region in cognitive emotional regulation. Transcranial direct current stimulations of the dlPFC (tDCS) and heart-rate variability biofeedback (BFB) are known to regulate emotional processes. However, the effect of these interventions applied either alone or concomitantly during an anticipatory stress remains unexplored.

OBJECTIVE

The study investigated the effect of anodal tDCS and BFB, alone or combined, on psychophysiological stress responses and cognitive functioning.

METHODS

Following a stress anticipation induction, 80 participants were randomized into four groups and subjected to a 15-min intervention: neutral video viewing (ctrl), left dlPFC anodal tDCS (tdcs), heart-rate variability biofeedback (bfb), or a combined treatment (bfb + tdcs). Participants were then immediately confronted with the stressor, which was followed by an assessment of executive functions. Psychophysiological stress responses were assessed throughout the experiment (heart rate, heart-rate variability, salivary cortisol).

RESULTS

The tdcs did not modulate stress responses. Compared with both ctrl and tdcs interventions, bfb reduced physiological stress and improved executive functions after the stressor. The main finding revealed that bfb + tdcs was the most effective intervention, yielding greater reduction in psychological and physiological stress responses than bfb.

CONCLUSIONS

Combining preventive tDCS with BFB is a relevant interventional approach to reduce psychophysiological stress responses, hence offering a new and non-invasive treatment of stress-related disorders. Biofeedback may be particularly useful for preparing for an important stressful event when performance is decisive.

Transcutaneous Auricular Vagus Nerve Stimulation Combined With Slow Breathing: Speculations on Potential Applications and Technical Considerations

OBJECTIVES

Transcutaneous auricular vagus nerve stimulation (taVNS) is a relatively novel noninvasive neurostimulation method that is believed to mimic the effects of invasive cervical VNS. It has recently been suggested that the effectiveness of taVNS can be enhanced by combining it with controlled slow breathing. Slow breathing modulates the activity of the vagus nerve and is used in behavioral medicine to decrease psychophysiological arousal. Based on studies that examine the effects of taVNS and slow breathing separately, this article speculates on some of the conditions in which this combination treatment may prove effective. Furthermore, based on findings from studies on the optimization of taVNS and slow breathing, this article provides guidance on how to combine taVNS with slow breathing.

MATERIALS AND METHODS

A nonsystematic review.

RESULTS

Both taVNS and slow breathing are considered promising add-on therapeutic approaches for anxiety and depressive disorders, chronic pain, cardiovascular diseases, and insomnia. Therefore, taVNS combined with slow breathing may produce additive or even synergistic beneficial effects in these conditions. Studies on respiratory-gated taVNS during spontaneous breathing suggest that taVNS should be delivered during expiration. Therefore, this article proposes to use taVNS as a breathing pacer to indicate when and for how long to exhale during slow breathing exercises.

CONCLUSIONS

Combining taVNS with slow breathing seems to be a promising hybrid neurostimulation and behavioral intervention.

Novel Methodological Tools for Behavioral Interventions: The Case of HRV-Biofeedback. Sham Control and Quantitative Physiology-Based Assessment of Training Quality and Fidelity

Scientific research on heart rate variability (HRV) biofeedback is burdened by certain methodological issues, such as lack of consistent training quality and fidelity assessment or control conditions that would mimic the intervention. In the present study, a novel sham HRV-biofeedback training was proposed as a credible control condition, indistinguishable from the real training. The Yield Efficiency of Training Index (YETI), a quantitative measure based on the spectral distribution of heart rate during training, was suggested for training quality assessment. A training fidelity criterion derived from a two-step classification process based on the average YETI index and its standard deviation (YETI_SD) was suggested. We divided 57 young, healthy volunteers into two groups, each subjected to 20 sessions of either real or sham HRV-biofeedback. Five standard HRV measures (standard deviation of the NN (SDNN), root mean square of the standard deviation of the NN (RMSSD), total power, low-frequency (LF), and high-frequency (HF) power) collected at baseline, after 10 and 20 sessions were subjected to analysis of variance. Application of a training fidelity criterion improved sample homogeneity, resulting in a substantial gain in effect sizes of the group and training interactions for all considered HRV indices. Application of methodological amendments, including proper control conditions (such as sham training) and quantitative assessment of training quality and fidelity, substantially improves the analysis of training effects. Although presented on the example of HRV-biofeedback, this approach should similarly benefit other behavioral training procedures that interact with any of the many psychophysiological mechanisms in the human body.

Resonance frequency is not always stable over time and could be related to the inter-beat interval

Heart Rate Variability Biofeedback (HRVB) is based on breathing at an optimal rate (or resonance frequency, RF) corresponding to the respiratory sinus arrhythmia (RSA). Our aim is to check whether the RF is a stable factor and analyse the HRV parameters individually per each breathing rate, comparing it with free slow breathing. A sample of 21 participants were trained in a test–retest HRVB protocol. The results indicated that RF changed between Test and Retest sessions in 66.7% of participants. This instability could be related to the average of interbeat interval (IBI). HRV time domain parameters (SDNN and RMSSD) were significantly higher for RF than for other breathing rates, including 6 breath/min and free slow breathing. Free slow breathing showed a lower heart rate averages than RF and other slow breathing rates. Overall, our study suggests the relevance of assessing RF individually and before each HRVB session, because the maximum cardiovascular benefits in terms of increasing HRV were found only at RF. Thus, breathing at the individualized and momentary frequency of resonance increases cardiac variability.

Implementing biofeedback as a proactive coping strategy: Psychological and physiological effects on anticipatory stress

Anticipating a stressful situation involves psychophysiological reactions before the occurrence of the overt stress event. The current challenge in the stress domain is to characterize anticipatory stress reactions and how to effectively modulate them. The present study aimed to characterize the anticipation period and evaluate the benefits of a heart-rate variability biofeedback (BFB) intervention designed to manage anticipatory stress. Healthy participants were exposed to an anticipation stress period (15 min) during which they either practised BFB (stress + bfb, n = 15) or watched a neutral video (stress + video, n = 14). Anticipatory stress was effectively induced by the Trier Social Anticipatory Stress (TSAS) protocol, specifically designed for this study. Control participants, without anticipation stress, practised BFB for an equivalent time (ctrl + bfb, n = 15). Subsequently, all participants performed a set of cognitive tasks assessing executive functions. Heart-rate variability (cardiac coherence, standard deviation of the R-R intervals, root mean square of successive difference measure) and the evolution of the perceived psychological state were measured during the anticipation period. Self-reported judgements of how the intervention influenced stress and performance were further assessed. The main result showed that BFB is a relevant proactive stress-coping method. Compared with the stress + video group, participants who practised BFB attained higher cardiac coherence scores. Post-intervention self-reported measures revealed that BFB contributed to reduce psychological stress and increase perceived levels of performance. Together, these findings provide practical guidelines for examining the stress anticipation period by means of the TSAS protocol.

Comparing Effectiveness of HRV-Biofeedback and Mindfulness for Workplace Stress Reduction: A Randomized Controlled Trial

Psychophysiological disorders due to work-related stress continue to be highly costly for health systems and approaches for cost-effective and easily accessible interventions are much needed. Both heart rate variability-biofeedback (HRV-Bfb) and mindfulness-based interventions (MBI) have been empirically shown to reduce stress. This study compares these two interventions in the work context to a wait-list-control-group (WLC). In this three-armed randomized controlled trial (RCT), 69 healthy adults employed in the same organization were randomized to participate in HRV-Bfb, MBI or the WLC. Participants were assessed for psychophysiological parameters of stress (stress perception, coping, HRV parameters and cortisol) and stress related symptoms (depressive symptoms, psychological wellbeing, mindfulness and self-compassion). Participants trained using either HRV-Bfb or MBI for 6 weeks on a daily basis. Outcomes were assessed at baseline, after the intervention and at follow-up 12 weeks later. Results did not show any statistically significant differences between HRV-Bfb and MBI groups, and neither of the intervention groups (IGs) differed from the WLC. Findings suggest an overall reduction in stress for all groups, including the WLC, with mostly small to medium effect sizes. However, it is important to note that participants with higher baseline stress levels might benefit more from mindfulness and biofeedback-based stress reduction interventions. The results have to be interpreted with caution due to the relatively small sample size. MBI might have a slightly stronger effect on stress reduction in comparison to HRV-Bfb, as suggested by the effect sizes. This study highlights issues and challenges of the implementation of such interventions in corporate health management.

Decreasing Heart Rate After Physical Activity Reduces Choking

We occasionally place our bodies under pressure, for example, by playing sports or giving an important presentation at a business meeting. In such situations, most of us have experienced choking, which impairs performance. It has been reported that controlling the heart rate is effective at reducing anxiety, which is one of the causes of choking. Previous studies have proposed a method of reducing choking by undergoing special training for controlling heart rate. Here, we investigated whether a reduction in heart rate after physical activity reduces choking without any special training. Participants bowled under both high-pressure and low-pressure conditions. Before throwing the bowling ball, half of the participants ran on the spot (active condition), whereas the rest of the participants stood instead of running (inactive condition). After controlling for the baseline score, the bowling score in the high-pressure and active condition was significantly better than that in the inactive condition. Additionally, the reduction in heart rate in the active condition was larger than that in the inactive condition. These results suggest that the reduction in heart rate prevented choking without any specific training.

Not All Competitions Come to Harm! Competitive Biofeedback to Increase Respiratory Sinus Arrhythmia in Managers

Despite the positive impact on achievement, competition has been associated with elevated psychophysiological activation, potentially leading to a greater risk of cardiovascular diseases. Competitive biofeedback (BF) can be used to highlight the effects of competition on the same physiological responses that are going to be controlled through BF. However, it is still unknown whether competition could enhance the effects of respiratory sinus arrhythmia (RSA)-BF training in improving cardiac vagal control. The present study explored whether competitive RSA-BF could be more effective than non-competitive RSA-BF in increasing RSA in executive managers, who are at higher cardiovascular risk of being commonly exposed to highly competitive conditions. Thirty managers leading outstanding private or public companies were randomly assigned to either a Competition (n = 14) or a Control (n = 16) RSA-BF training lasting five weekly sessions. Managers in the Competition group underwent the RSA-BF in couples and each participant was requested to produce a better performance (i.e., higher RSA) than the paired challenger. After the training, results showed that managers in the Competition group succeeded in increasing cardiac vagal control, as supported by the specific increase in RSA (p < 0.001), the standard deviation of R-R wave intervals (SDNN; p < 0.001), and root mean square of the successive differences between adjacent heartbeats (rMSSD; p < 0.001). A significant increase in the percentage of successive normal sinus beat to beat intervals more than 50 ms (pNN50; p = 0.023; η2 p = 0.17), low frequency (p = ≤ 0.001; η2 p = 0.44), and high frequency power (p = 0.005; η2 p = 0.25) emerged independently from the competitive condition. Intriguingly, managers who compete showed the same reduction in resting heart rate (HR; p = 0.003, η2 p = 0.28), systolic blood pressure (SBP; p = 0.013, η2 p = 0.20), respiration rate (p < 0.001; η2 p = 0.46), and skin conductance level (SCL; p = 0.001, η2 p = 0.32) as non-competitive participants. Also, the same reduction in social anxiety (p = 0.005; η2 p = 0.25), state (p = 0.038, η2 p = 0.14) and trait anxiety (p = 0.001, η2 p = 0.31), and depressive symptoms (p = 0.023, η2 p = 0.17) emerged in the two groups. The present results showed that managers competing for increasing RSA showed a greater improvement in their parasympathetic modulation than non-competing managers. Most importantly, competition did not lead to the classic pattern of increased psychophysiological activation under competitive RSA-BF. Therefore, competition could facilitate the use of self-regulation strategies, especially in highly competitive individuals, to promote adaptive responses to psychological stress.

A Single Session of Heart Rate Variability Biofeedback Produced Greater Increases in Heart Rate Variability Than Autogenic Training

Heart rate variability biofeedback (HRV-BF) has been confirmed to increase heart rate variability (HRV) and cardiac outflows by baroreflex in healthy populations and clinical patients. Autogenic training (AT) is common used in the psychological intervention. This study integrates a single-session of HRV-BF and AT into a high-technology mobile application (app), and examines the effects on HRV indices, breathing rates, and subjective relaxation scores. Healthy college students were recruited and assigned to the single-session HRV-BF group or AT group. Participants in the HRV-BF group received HRV-BF combined with paced breathing training, which gradually stepped down their breathing rates from 12, to 8, to 6 breaths/per min; and received feedback of HRV indices from the app. Participants in the AT group received autogenic training and feedback of heart rate from the app. A chest belt Zephyr BioHarness was connected through Bluetooth to a Zenfone5 mobile phone, it collected the signals of interbeat intervals and breathing rates at pre-training, mid-training, and post-training stages. The Kubios HRV software was used to analyze HRV indices. The results reveal higher HRV indices and lower breathing rates during mid-training and post-training in the HRV-BF group compared to the AT group. There were higher high-frequency of HRV at post-training than pre-training in the AT group. Participants of both groups increased their subjective relaxation scores after training. The HRV-BF protocol increased cardiac outflows by baroreflex and decreased breathing rates, and the AT protocol increased high-frequency of HRV. These high-technology wearable devices combined with psychological interventions will apply to various populations in the future.

Training of paced breathing at 0.1 Hz improves CO2 homeostasis and relaxation during a paced breathing task

Volitional control of breathing often leads to excessive ventilation (hyperventilation) among untrained individuals, which disrupts CO2 homeostasis and may elicit a set of undesirable symptoms. The present study investigated whether seven days of training without any anti-hyperventilation instructions improves CO2 homeostasis during paced breathing at a frequency of 0.1 Hz (6 breaths/minute). Furthermore, the present study investigated the effects of training on breathing-related changes in affective state to examine the hypothesis that training improves the influence of slow paced breathing on affect. A total of 16 participants performed ten minutes of paced breathing every day for seven days. Partial pressure of end-tidal CO2 (PetCO2), symptoms of hyperventilation, affective state (before and after breathing), and pleasantness of the task were measured on the first, fourth, and seventh days of training. Results showed that the drop in PetCO2 significantly decreased with training and none of the participants experienced a drop in PetCO2 below 30 mmHg by day seven of training (except one participant who already had PetCO2 below 30 mmHg during baseline), in comparison to 37.5% of participants on the first day. Paced breathing produced hyperventilation symptoms of mild intensity which did not decrease with training. This suggests that some participants still experienced a drop of PetCO2 that was deep enough to produce noticeable symptoms. Affective state was shifted towards calmness and relaxation during the second and third laboratory measurements, but not during the first measurement. Additionally, the breathing task was perceived as more pleasant during subsequent laboratory measurements. The obtained results showed that training paced breathing at 0.1 Hz led to decrease in hyperventilation. Furthermore, the present study suggests that training paced breathing is necessary to make the task more pleasant and relaxing.

Effects of a cardiorespiratory synchronization training mobile application on heart rate variability and electroencephalography in healthy adults

Cardiorespiratory synchronization training (CRST) uses diaphragmatic breathing to increase balance in the autonomic nervous system and reduce negative emotions. CRST integrated with high-technology mobile applications affords innovative and convenient home-based training. This study examined the effects of a CRST mobile application on heart rate variability (HRV) and electroencephalography (EEG) parameters in healthy adults. Ninety-six participants were randomly assigned to the CRST, relaxation training (RT; active control group), and control (C) groups. The CRST group received paced breathing training using a wearable device connected to a mobile application and received feedback on the HRV indices. The RT group received muscle relaxation training using a wearable device connected to a mobile application and received feedback on heart rate (HR). The training program was conducted for 1 h per week for 4 weeks. The C group did not receive any wearable device, mobile application, or psychological intervention. Psychological questionnaires on depression and anxiety and physiological measurements of the breathing rates, electrocardiography (ECG), and EEG were measured at the pretest and posttest. The CRST group showed significantly higher HRV indices and lower breathing rates at the posttest than the RT and C groups. There were no significant interaction effects on EEG parameters at pretest and posttest among the three groups. Use of a CRST mobile application increased balance in the autonomic nervous system at the resting state. This clinical evidence-based technologically advanced mobile application could be implemented in future clinical practice.

The effects of breathing at a frequency of 0.1 Hz on affective state, the cardiovascular system, and adequacy of ventilation

The present study aimed to investigate changes induced by breathing at 0.1 Hz in affective state, cardiovascular activity, and adequacy of ventilation as well as the relation between changes in peripheral physiological processes and alteration of affect. Eighty-three participants were randomly assigned to one of three groups: Two groups doing paced breathing at 0.1 Hz, one with and the other without a cover story hiding the goal of the experiment, and, as a control, paced breathing at 0.28 Hz. We measured the effects of breathing at 0.1 Hz on affective state (unpleasant and pleasant arousals), respiratory sinus arrhythmia (RSA), sympathetic control of the heart (preejection period, PEP), and adequacy of ventilation as measured by partial pressure of end-tidal CO₂ (PetCO₂ ). The use of a cover story did not influence the effects of paced breathing on the study outcomes. In the 0.1 Hz groups, unpleasant arousal decreased only among men. Changes in RSA were not related to changes in affect. Respiratory frequency did not influence PEP. However, changes in PEP were inversely related to changes in pleasant arousal. PetCO₂ decreased in all conditions, and a larger drop in PetCO₂ predicted a greater decrease in unpleasant arousal. The results obtained corroborate previous findings showing that slow paced breathing may lead to moderate hyperventilation among untrained participants and suggest that hyperventilation during breathing at 0.1 Hz is not deep enough to produce an increase in affective arousal.

The effect of heart rate variability biofeedback training on stress and anxiety: a meta-analysis

BACKGROUND

Some evidence suggests that heart rate variability (HRV) biofeedback might be an effective way to treat anxiety and stress symptoms. To examine the effect of HRV biofeedback on symptoms of anxiety and stress, we conducted a meta-analysis of studies extracted from PubMed, PsycINFO and the Cochrane Library.

METHODS

The search identified 24 studies totaling 484 participants who received HRV biofeedback training for stress and anxiety. We conducted a random-effects meta-analysis.

RESULTS

The pre-post within-group effect size (Hedges' g) was 0.81. The between-groups analysis comparing biofeedback to a control condition yielded Hedges' g = 0.83. Moderator analyses revealed that treatment efficacy was not moderated by study year, risk of study bias, percentage of females, number of sessions, or presence of an anxiety disorder.

CONCLUSIONS

HRV biofeedback training is associated with a large reduction in self-reported stress and anxiety. Although more well-controlled studies are needed, this intervention offers a promising approach for treating stress and anxiety with wearable devices.

Improving Managers' Psychophysical Well-Being: Effectiveness of Respiratory Sinus Arrhythmia Biofeedback

High work stress has been consistently associated with disturbed autonomic balance, specifically, lowered vagal cardiac control and increased sympathetic activity, which may lead to increased cardiovascular risk. Stress management procedures have been proposed to reduce autonomic dysfunctions related to work stress in different categories of workers exposed to heightened work demands, while a limited number of studies addressed this issue in managers. The present study was aimed at evaluating the effectiveness of a respiratory sinus arrhythmia (RSA) biofeedback (BF) intervention on psychological and physiological outcomes, in managers with high-level work responsibilities. Thirty-one managers leading outstanding private or public companies were randomly assigned to either a RSA-BF training (RSA-BF; N = 16) or a control group (N = 15). The RSA-BF training consisted of five weekly 45 min sessions, designed to increase RSA, whereas controls had to provide a daily stress diary once a week. After the training, managers in both groups reported reduced heart rate at rest, lower anxiety levels and improvement in health-related quality of life. More importantly, managers in the RSA-BF group showed increased vagal control (as indexed by increased RSA), decreased sympathetic arousal (as indexed by reduced skin conductance and systolic blood pressure) and lower emotional interferences, compared to managers in the control group. Results from this study showed that RSA-BF training was effective in improving cardiac autonomic balance at rest. Moreover, findings from this study underline the effectiveness of biofeedback in reducing psychophysiological negative outcomes associated with stress in managers.

BioPad: Leveraging off-the-Shelf Video Games for Stress Self-Regulation

This paper presents an approach to use commercial videogames for biofeedback training. It consists of intercepting signals from the game controller and adapting them in real-time based on physiological measurements from the player. We present three sample implementations and a case study for teaching stress self-regulation via an immersive car racing game. We use a crossover gaming device to manipulate controller signals, and a respiratory sensor to monitor the players' breathing rate. We then alter the speed of the car to encourage slow deep breathing, in this way, allowing players to reduce their arousal while playing the game. We evaluate the approach against an alternative form of biofeedback that uses a graphic overlay to convey physiological information, and a control condition (playing the game without biofeedback). Experimental results show that our approach can promote deep breathing during gameplay, and also during a subsequent task, once biofeedback is removed. Our results also indicate that delivering biofeedback through subtle changes in gameplay can be as effective as delivering them directly through a visual display. These results open the possibility to develop low-cost and engaging biofeedback interventions using a variety of commercial videogames to promote adherence.

Stress Management Apps With Regard to Emotion-Focused Coping and Behavior Change Techniques: A Content Analysis

BACKGROUND

Chronic stress has been shown to be associated with disease. This link is not only direct but also indirect through harmful health behavior such as smoking or changing eating habits. The recent mHealth trend offers a new and promising approach to support the adoption and maintenance of appropriate stress management techniques. However, only few studies have dealt with the inclusion of evidence-based content within stress management apps for mobile phones.

OBJECTIVE

The aim of this study was to evaluate stress management apps on the basis of a new taxonomy of effective emotion-focused stress management techniques and an established taxonomy of behavior change techniques.

METHODS

Two trained and independent raters evaluated 62 free apps found in Google Play with regard to 26 behavior change and 15 emotion-focused stress management techniques in October 2015.

RESULTS

The apps included an average of 4.3 behavior change techniques (SD 4.2) and 2.8 emotion-focused stress management techniques (SD 2.6). The behavior change technique score and stress management technique score were highly correlated (r=.82, P=.01).

CONCLUSIONS

The broad variation of different stress management strategies found in this sample of apps goes in line with those found in conventional stress management interventions and self-help literature. Moreover, this study provided a first step toward more detailed and standardized taxonomies, which can be used to investigate evidence-based content in stress management interventions and enable greater comparability between different intervention types.

A brief review and clinical application of heart rate variability biofeedback in sports, exercise, and rehabilitation medicine

CONTEXT

An important component of the effective management of chronic noncommunicable disease is the assessment and management of psychosocial stress. The measurement and modulation of heart rate variability (HRV) may be valuable in this regard.

OBJECTIVE

To describe the measurement and physiological control of HRV; to describe the impact of psychosocial stress on cardiovascular disease, metabolic syndrome, and chronic respiratory disease, and the relationship between these diseases and changes in HRV; and to describe the influence of biofeedback and exercise on HRV and the use of HRV biofeedback in the management of chronic disease.

DATA SOURCES AND STUDY SELECTION

The PubMed, Medline, and Embase databases were searched (up to August 2013). Additional articles were obtained from the reference lists of relevant articles and reviews. Articles were individually selected for further review based on the quality and focus of the study, and the population studied.

RESULTS

Heart rate variability is reduced in stress and in many chronic diseases, and may even predict the development and prognosis of some diseases. Heart rate variability can be increased with both exercise and biofeedback. Although the research on the effect of exercise is conflicting, there is evidence that aerobic training may increase HRV and cardiac vagal tone both in healthy individuals and in patients with disease. Heart rate variability biofeedback is also an effective method of increasing HRV and cardiac vagal tone, and has been shown to decrease stress and reduce the morbidity and mortality of disease.

CONCLUSION

The assessment and management of psychosocial stress is a challenging but important component of effective comprehensive lifestyle interventions for the management of noncommunicable disease. It is, therefore, important for the sports and exercise physician to have an understanding of the therapeutic use of HRV modulation, both in the reduction of stress and in the management of chronic disease.

An exploratory analysis of the utility of adding cardiorespiratory biofeedback in the standard care of pregnancy-induced hypertension

This study examined the efficacy of a cardiorespiratory biofeedback intervention compared to bed rest in the treatment of 47 women diagnosed with pregnancy-induced hypertension (PIH). The investigation consisted of a historical control group with 31 PIH subjects receiving treatment as usual (TAU), bed rest and antihypertensive medications, and an experimental group with 16 PIH subjects receiving TAU and instruction on using a portable respiratory sinus arrhythmia (RSA) biofeedback device once daily until delivery. Results indicated that systolic and diastolic blood pressure levels were unchanged for either group. Failing to find the intended main effects, a series of exploratory analyses were performed. Findings of associated hypotheses revealed that the RSA BF group had a 35 % higher birth weight than the TAU group. The gestational age at delivery was 10 % greater in the RSA BF group than in the TAU group. A significant relationship was found between the StressEraser Total and the 1-min Apgar score. Eighty-one percent of the subjects stated that the device was relaxing. Fifty percent of the subjects believed that the device helped them fall asleep. Overall, these results suggest that portable RSA biofeedback may be effective in reducing stress during pregnancy and improving perinatal outcomes.

Breathing practices for treatment of psychiatric and stress-related medical conditions

Neurophysiological studies may explain how breathing techniques normalize stress response, emotion regulation, and autonomic and neuroendocrine system function. Breath practices have been shown to reduce symptoms of stress, anxiety, insomnia, post-traumatic stress disorder, mass disasters, depression, and attention deficit disorder. Technology-assisted breathing interventions facilitate therapeutic breathing by using either static cues such as a breath pacer or real-time feedback based on physiological parameters such as heart rate variability. The empirical literature indicates that technology-assisted breathing can be beneficial in mental health treatment, though it may not be appropriate for all individuals. Initial in-person training and evaluation can improve results.

iHeartLift: a closed loop system with bio-feedback that uses music tempo variability to improve heart rate variability

"Musica delenit bestiam feram" translates into "Music soothes the savage beast". There is a hidden truth in this ancient quip passed down from generations. Besides soothing the heart, it also incites the heart to a healthier level of heart rate variability (HRV). In this paper, an approach to use and test music and biofeedback to increase the heart rate variability for people facing daily stress is discussed. By determining the music tempo variability (MTV) of a piece of music and current heart rate variability, iHeartLift is able to compare the 2 trends and locate a musical piece that is suited to increase the user's heart rate variability to a healthier level. With biofeedback, the 2 trends are continuously compared in real-time and the musical piece is changed in accordance with the current comparisons. A study was conducted and it was generally found that HRV can be uplifted by music regardless of language and meaning of musical lyrics but with limitations to musical genre.

Respiratory sinus arrhythmia feedback in a stressed population exposed to a brief stressor demonstrated by quantitative EEG and sLORETA

Previous investigations of electroencephalograms during relaxation have identified increases in slow wave band power, correlations between increased levels of alpha activity with lower levels of anxiety, and autonomic changes characterized by otherwise documented decreased sympathetic activity. This study was carried out to determine the overall changes in quantitative electroencephalographic activity and the current source as a result of an acute session of respiratory sinus arrhythmia (RSA) biofeedback in a population of subjects experiencing stress. This study's findings provide physiological evidence of RSA feedback effect and suggest that RSA training may decrease arousal by promoting an increase of alpha band frequencies and decrease in beta frequencies overall and in areas critical to the regulation of stress. It was of interest that novices could achieve these objective alterations in EEG activity after minimal training and intervention periods considering that the previous literature on EEG and meditative states involve experienced meditators or participants who had been given extensive training. Additionally, these effects were present immediately following the training suggesting that the intervention may have effects beyond the actual practice.