A systematic review on heart rate variability in Bulimia Nervosa

Momentary physiological indices related to eating disorders: A systematic and methodological review

Eating disorders (ED) are serious psychiatric illnesses, with no everyday support to intervene on the high rates of relapse. Understanding physiological indices that can be measured by wearable sensor technologies may provide new momentary interventions for individuals with ED. This systematic review, searching large databases, synthesises studies investigating peripheral physiological (PP) indices commonly included in wearable wristbands (heart rate [HR], heart rate variability [HRV], electrodermal activity [EDA], peripheral skin temperature [PST], and acceleration) in ED. Inclusion criteria included: (a) full peer-reviewed empirical articles in English; (b) human participants with active ED; and (c) containing one of five wearable physiological measures. Kmet risk of bias was assessed. Ninety-four studies were included (Anorexia nervosa [AN; N = 4418], bulimia nervosa [BN; N = 916], binge eating disorder [BED; N = 1604], other specified feeding and eating disorders [OSFED; N = 424], and transdiagnostic [N = 47]). Participants with AN displayed lower HR and EDA and higher HRV compared to healthy individuals. Those with BN showed higher HRV, and lower EDA and PST compared to healthy individuals. Other ED and Transdiagnostic samples showed mixed results. PP differences are indicated through various assessments in ED, which may suggest diagnostic associations, although more studies are needed to validate observed patterns. Results suggest important therapeutic potential for PP in ED, and larger studies including diverse participants and diagnostic groups are needed to fully uncover their role in ED.

Sympathovagal quotient and resting-state functional connectivity of control networks are related to gut Ruminococcaceae abundance in healthy men

INTRODUCTION

Heart rate variability (HRV), brain resting-state functional connectivity (rsFC), and gut microbiota (GM) are three recognized indicators of health status, whose relationship has not been characterized. We aimed to identify the GM genera and families related to HRV and rsFC, the interaction effect of HRV and rsFC on GM taxa abundance, and the mediation effect of diet on these relationships.

METHODS

Eighty-eight healthy, young Colombian men were included in this cross-sectional study. HRV metrics were extracted from 24-hour Holter monitoring data and the resting functional connectivity strength (FCS) of 15 networks were derived from functional magnetic resonance imaging. Gut microbiota composition was assessed using the sequences of the V3-V4 regions of the 16 S rRNA gene, and diet was evaluated using a food frequency questionnaire. Multivariate linear regression analyses were performed to evaluate the correlations between the independent variables (HRV metrics and FCS) and the dependent variables (GM taxa abundance or alpha diversity indexes). Mediation analyses were used to test the role of diet in the relationship between HRV and GM.

RESULTS

The sympathovagal quotient (SQ) and the FCS of control networks were positively correlated with the abundance of the gut Ruminococcaceae family and an unclassified Ruminococcaceae genus (Ruminococcaceae_unc). Additionally, the interaction between the FCS of the control network and SQ reduced the individual main effects on the Ruminococcaceae_unc abundance. Finally, reduced habitual fiber intake partially mediated the relationship between SQ and this genus.

CONCLUSION

Two indicators of self-regulation, HRV and the rsFC of control networks, are related to the abundance of gut microbiota taxa in healthy men. However, only HRV is related to habitual dietary intake; thus, HRV could serve as a marker of food choice and GM composition in the future.

Impact of virtual adjunctive cognitive remediation therapy on cognitive flexibility and treatment outcomes in comorbid anorexia nervosa and exercise dependence as quantified using novel biomarkers: A stage 1 registered report

OBJECTIVE

Anorexia nervosa (AN) is associated with significant individual mental and physical suffering and public health burden and fewer than half of patients recover fully with current treatments. Comorbid exercise dependence (ExD) is common in AN and associated with significantly worse symptom severity and treatment outcomes. Research points to cognitive inflexibility as a prominent executive function inefficiency and transdiagnostic etiologic and maintaining mechanism linking AN and ExD. This study will evaluate the initial efficacy of adjunctive Cognitive Remediation Therapy (CRT), which has been shown to produce cognitive improvements in adults with AN, in targeting cognitive inflexibility in individuals with comorbid AN and ExD. As an exploratory aim, this study also addresses the current lack of quick and cost-effective assessments of cognitive flexibility by establishing the utility of two proposed biomarkers, heart rate variability and salivary oxytocin.

METHOD

We will conduct a single-group, within-subjects trial of an established CRT protocol delivered remotely as an adjunct to inpatient or intensive outpatient treatment as usual (TAU) to adult patients (n = 42) with comorbid AN and ExD. Assessments, including self-report, neuropsychological, and biomarker measurements, will occur at three time points.

RESULTS

We expect CRT to increase cognitive flexibility transdiagnostically and consequently, along with TAU, positively impact AN and ExD compulsivity and symptom severity, including weight gain.

DISCUSSION

Findings will inform the development of more effective integrative interventions for AN and ExD targeting shared mechanisms and facilitate the routine assessment of cognitive flexibility as a transdiagnostic risk and maintaining factor across psychopathologies in clinical and research settings.

PUBLIC SIGNIFICANCE

Patients with anorexia nervosa often engage in excessive exercise, leading to harmful outcomes, including increased suicidal behavior. This study examines the preliminary efficacy of an intervention that fosters flexible and holistic thinking in patients with problematic eating and exercise to, along with routine treatment, decrease harmful exercise symptoms. This study also examines new biological markers of the inflexible thinking style thought to be characteristic of anorexia nervosa and exercise dependence.

Assessment and management of cardiovascular complications in eating disorders

BACKGROUND

Eating disorders (EDs) are serious conditions predominantly affecting adolescents and young adults (AYAs) and pose a considerable threat to their health and wellbeing. Much of this increased morbidity and mortality is linked to medical compromise, especially cardiovascular abnormalities. Rates of presentation to both community and inpatient medical settings have increased in all age groups following the Covid-19 pandemic and subsequent "lockdowns", with patients presentations being more medically compromised compared to previous years. This has implications for clinicians with regard to the performance of competent cardiovascular assessments and management of findings.

AIMS

This paper is a practical resource for clinicians working with AYAs in whom EDs may present. It will provide a brief summary of the physiological context in which cardiovascular complications develop, systematically outline these complications and suggest a pragmatic approach to their clinical evaluation.

METHODS

Relevant literature, guidelines and academic texts were critically reviewed. Conclusions were extracted and verified by a Child and Adolescent Psychiatrist and Adolescent Paediatrician, with suitable expertise in this clinical cohort.

CONCLUSIONS

The cardiovascular complications in EDs are primarily linked to malnutrition, and patients presenting with Anorexia Nervosa are most often at greatest risk of structural and functional cardiac abnormalities, including aberrations of heart rate and rhythm, haemodynamic changes and peripheral vascular abnormalities. Other cardiovascular abnormalities are secondary to electrolyte imbalances, as seen in patients with Bulimia Nervosa. More recently defined EDs including Avoidant/Restrictive Food Intake Disorder and Binge Eating Disorder are also likely associated with distinct cardiovascular complications though further research is required to clarify their nature and severity. Most cardiovascular abnormalities are fully reversible with nutritional restoration, and normalisation of eating behaviours, including the cessation of purging, though rare cases are linked to cardiac deaths. A detailed clinical enquiry accompanied by a thorough physical examination is imperative to ensure the medical safety of AYAs with EDs, and should be supported by an electrocardiogram and laboratory investigations. Consideration of cardiovascular issues, along with effective collaboration with acute medical teams allows community clinicians identify those at highest risk and minimise adverse outcomes in this cohort.

Volume and Connectivity Differences in Brain Networks Associated with Cognitive Constructs of Binge Eating

Bulimia nervosa (BN) and binge eating disorder (BED) are characterized by episodes of eating large amounts of food while experiencing a loss of control. Recent studies suggest that the underlying causes of BN/BED consist of a complex system of environmental cues, atypical processing of food stimuli, altered behavioral responding, and structural/functional brain differences compared with healthy controls (HC). In this narrative review, we provide an integrative account of the brain networks associated with the three cognitive constructs most integral to BN and BED, namely increased reward sensitivity, decreased cognitive control, and altered negative affect and stress responding. We show altered activity in BED/BN within several brain networks, specifically in the striatum, insula, prefrontal cortex (PFC) and orbitofrontal cortex (OFC), and cingulate gyrus. Numerous key nodes in these networks also differ in volume and connectivity compared with HC. We provide suggestions for how this integration may guide future research into these brain networks and cognitive constructs.

Relationship between heart rate variability and body mass index: A cross-sectional study of preschool children

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Heart rate variability and BMI are inversely related in preschool children.

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One unit increase in BMI resulted in a reduction in RMSSD(ln) of 0.06%

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Age, sex and physical activity levels did not influence this relationship.

Reduced heart rate variability (HRV) is associated with overweight and obesity in adults. However, little is known about this relationship in early childhood. We investigated the relationship between resting vagally-mediated HRV and body mass index (BMI) in Australian preschool children. Children were recruited from 13 non-government early learning centres located in Queensland and New South Wales, Australia. From this population-based sample, data from 146 healthy children (58 females) between 3 and 5 years of age (mean age 4.35 ± 0.44 years) were analysed. BMI was calculated from child body weight and height. Physical activity was recorded using an Actigraph wGT3x accelerometer worn at the waist of participants over 3 consecutive days. A Polar H10 chest strap measured seated, resting RR intervals for the calculation of HRV with the root mean square of successive differences (RMSSD) reflecting vagally-mediated activity. The relationship between HRV and BMI was analysed using a linear mixed model adjusted for age, sex and physical activity. Analysis revealed that RMSSD (ln) demonstrated a significant inverse relationship with BMI (β = -0.06; 95% CI = -0.12 – −0.01; p = 0.032), and the model accounted for 23% of the variance in RMSSD (ln). Notably, a one unit increase in BMI resulted in a reduction in RMSDD (ln) of 0.06. This investigation demonstrated evidence for a significant inverse linear relationship between vagally-mediated HRV and BMI in 3 – 5-year-old Australian children, similar to that of adults. Furthermore, this relationship was independent of age, sex and physical activity levels. Results may indicate that the cardiometabolic health of preschool children is, in part, influenced by the relationship between vagally-mediated HRV and weight status.

Rapid response is predictive of treatment outcomes in a transdiagnostic intensive outpatient eating disorder sample: a replication of prior research in a real-world setting

OBJECTIVE

There is a growing call to identify specific outcome predictors in real-world eating disorder (ED) treatment settings. Studies have implicated several ED treatment outcome predictors [rapid response (RR), weight suppression, illness duration, ED diagnosis, and psychiatric comorbidity] in inpatient settings or randomized controlled trials of individual outpatient therapy. However, research has not yet examined outcome predictors in intensive outpatient programs (IOP). The current study aimed to replicate findings from randomized controlled research trials and inpatient samples, identifying treatment outcome predictors in a transdiagnostic ED IOP sample.

METHOD

The current sample comprised 210 consecutive unique IOP patient admissions who received evidence-based ED treatment, M(SD)_Duration = 15.82 (13.38) weeks. Weekly patient measures of ED symptoms and global functioning were obtained from patients' medical charts.

RESULTS

In relative weight analysis, RR was the only significant predictor of ED symptoms post treatment, uniquely accounting for 45.6% of the predicted variance in ED symptoms. In contrast, baseline ED pathology was the strongest unique predictor of end-of-treatment global functioning, accounting for 15.89% of predicted variance. Baseline factors did not differentiate patients who made RR from those who did not.

CONCLUSIONS

Consistent with findings in more controlled treatment settings, RR remains a robust predictor of outcome for patients receiving IOP-level treatment for EDs. Future work should evaluate factors that mediate and moderate RR, incorporating these findings into ED treatment design and implementation.

LEVEL OF EVIDENCE

Level IV, uncontrolled intervention.

Autonomic Nervous System Response to Psychosocial Stress in Anorexia Nervosa: A Cross-Sectional and Controlled Study

To foster understanding in the psychopathology of patients with anorexia nervosa (P_AN) at the psychological and physiological level, standardized experimental studies on reliable biomarkers are needed, especially due to the lack of disorder-specific samples. To this end, the autonomic nervous system (ANS) response to a psychosocial stressor was investigated in n = 19 P_AN (BMI: 18.7 ± 3.3 kg/m²), age, and gender-matched to n = 19 healthy controls (HC; BMI: 24.23 ± 3.0 kg/m²). For this purpose, heart rate (HR) and heart rate variability (HRV) parameters were assessed in a cross-sectional study design under two experimental conditions: (1) rest and (2) stress (Trier Social Stress Test). In addition, psychological indicators of stress were assessed. An 2 × 2 × 8 ANOVA demonstrated similar HR and HRV patterns (except LF-HRV) between P_AN and HC at rest. Under stress, P_AN (vs. HC) demonstrated a blunted HR [condition^*time^*group: F_{(2.91, 104.98)} = 9.326, p = 0.000, η² = 0.206] and an attenuated HRV response (reduced SNS/PNS reactivity). Significant effects of stress appraisal (SA) and BMI on HRV-reactivity were revealed. SA on SDNN = Condition^*time^*SA = F_{(4.12, 140.15)} = 2.676, p = 0.033, η² = 0.073. BMI on LF/HF-Ratio = Condition^*time^*BMI = F_{(3.53, 60.16)} = 3.339, p = 0.019, η² = 0.164. Psychological indices suggested higher levels of chronic and appraised stress in P_AN relative to HC. Additional analyses demonstrated that ED-symptoms are highly correlated with the latter constructs, as well as with psychological burden, but not with weight. Further, it was shown that abnormalities in reactivity persisted despite normalized ANS activity. Overall, we suggested that besides weight recovery, improvement in stress appraisal could be beneficial for cardiac health. In this light, a combination of therapy (e.g., development and activation of coping skills, cognitive reappraisal) and biofeedback training may improve treatment outcomes and regulate stress reactivity.

Heart rate variability as a biobehavioral marker of diverse psychopathologies: A review and argument for an "ideal range"

Heart rate variability (HRV), a measure of the variability in intervals between subsequent heart beats, is now widely considered an index of emotion regulatory capacity and the ability to adapt flexibly to changing environmental demands. Abnormalities in HRV are implicated in a host of psychopathologies, making it a potentially powerful transdiagnostic biobehavioral change mechanism in treatment interventions. While most mental illnesses are associated with low HRV, eating disorders have been linked to elevated HRV. We examined 62 research articles on HRV in psychopathology to test the hypothesis that there is an "ideal range" of HRV that predicts optimal functioning. Relationships between symptom severity and parameters that quantify HRV were examined graphically. More extreme time-domain HRV measures, both high and low, were associated with psychopathology, whereas healthy controls displayed mid-range values. Findings preliminarily support the hypothesis that there is an "ideal range" of HRV that could be targeted in biofeedback interventions.

Autonomic response to the Adult Attachment Projective in anorexia nervosa

PURPOSE

Cardiovascular complications associated with anorexia nervosa (AN) are well recognized. Whether a wide array of studies has investigated autonomic nervous system (ANS) functioning at rest in people with AN, few is yet known on their reactivity ability during stress conditions. The aim of the current study is testing ANS reactivity to a stressful task activating attachment system among adolescents with AN.

METHODS

Heart rate (HR) and its variability, as derived by high-frequency-heart rate variability (HF-HRV), were continuously assessed while 13 AN patients and 12 healthy controls (HCs) responded to a set of attachment-related drawings (Adult Attachment Projective, AAP).

RESULTS

Findings showed that patients with AN displayed a stronger parasympathetic activity, as indicated by generally a lower heart rate (HR) during the entire task and a higher HF-HRV for drawings eliciting dyadic interactions compared to HCs.

CONCLUSION

The study findings suggest a novel understanding of cardiovascular functioning in AN.

LEVEL OF EVIDENCE

Level V, descriptive study.

Neuroendocrinology of reward in anorexia nervosa and bulimia nervosa: Beyond leptin and ghrelin

The pathophysiology of anorexia nervosa (AN) and bulimia nervosa (BN) are still poorly understood, but psychobiological models have proposed a key role for disturbances in the neuroendocrines that signal hunger and satiety and maintain energy homeostasis. Mounting evidence suggests that many neuroendocrines involved in the regulation of homeostasis and body weight also play integral roles in food reward valuation and learning via their interactions with the mesolimbic dopamine system. Neuroimaging data have associated altered brain reward responses in this system with the dietary restriction and binge eating and purging characteristic of AN and BN. Thus, neuroendocrine dysfunction may contribute to or perpetuate eating disorder symptoms via effects on reward circuitry. This narrative review focuses on reward-related neuroendocrines that are altered in eating disorder populations, including peptide YY, insulin, stress and gonadal hormones, and orexins. We provide an overview of the animal and human literature implicating these neuroendocrines in dopaminergic reward processes and discuss their potential relevance to eating disorder symptomatology and treatment.

Toward Quantifying the Psychopathology of Eating Disorders From the Autonomic Nervous System Perspective: A Methodological Approach

The phenomenology of Eating Disorders (ED) relates with altered functioning of the Autonomic Nervous System (ANS). The lack of agreement in what comes to the direction and significance of such alterations is possibly due to the variability in the ED spectrum. As the stress response system is an integral part of the ANS, we propose to investigate ANS tonic variations and phasic activations in response to stressors. We hypothesize that, while using stress as a test probe, characteristic ANS dysregulations in ED may be found when considering several physiological signals measured over time, and weighted by the individual psychological profiles. In this article we describe a novel methodological approach to investigate this hypothesis with the aim of providing further clarification on the ED spectrum conceptualization. The proposed methodology has been designed to be easily integrated in clinical practice and, eventually, in daily life. The population under observation includes both patients in treatment for ED, and matched controls. The study session has the duration of 1 day, including: (1) the administration of a stress task in a controlled environment and (2) naturalistic data collection. The stress task is designed to elicit both mentally and physically driven ANS activation. The naturalistic component intends to illustrate the psychophysiology in everyday life. We use wearable devices to continuously and non-invasively measure bio-signals related to ANS functioning. This information is complemented with psychometric information from validated stress and ED scales and ecological momentary assessments. The protocol has received ethical approval and has been implemented in practice, currently accounting for 37 patients (out of 120) and 16 controls (out of 60). Ongoing work focus on the definition and implementation of a data processing pipeline to quantitatively test our hypothesis, both standard statistical methods and more exploratory machine learning approaches will be considered.

Impact of supportive therapy modalities on heart rate variability in cancer patients - a systematic review

Purpose: To systematically review literature for interventional studies and their impact on autonomic dysfunction assessed by heart rate variability in cancer patients.Methods: Research was conducted using the databases Medline/Pubmed, Scopus, and Web of science from their inception to October 2017. Original articles with an interventional design that reported changes in at least one heart rate variability parameter as outcome parameter were included and described.Results: Ten studies were identified as eligible for subsequent analysis. The main application field in oncological therapy setting was music therapy intervention, Traditional Chinese Medicine related treatments, exercise interventions, relaxation, and myofascial release techniques. Breast cancer was the most frequently described single cancer entity. Heart rate variability recording was performed with standard electrocardiography devices or wearable heart rate monitors, within a time range between 5 and 20 min and a sampling rate varying from 200 to 1000 Hz. No adverse events were reported in all studies.Conclusions: Supportive therapy modalities may have the potential to enhance vegetative functioning. In this context, heart rate variability analysis appears to be an easily applicable and safe method to evaluate cancer related autonomic dysfunction. More large prospective multicentre randomised controlled trials are needed.Implication for rehabilitationMost cancer patients face autonomic dysfunction due to the disease itself the applied treatments or combination of both.HRV measurement is an easy and safe method to asses autonomic dysfunction.Supportive treatments targeting on an elevation of the vagal tone and autonomic balance in general might have beneficial effects for cancer patients.

The potential of calibrated fMRI in the understanding of stress in eating disorders

Eating disorders (ED), including Anorexia Nervosa (AN), Bulimia Nervosa (BN), and Binge Eating Disorder (BED), are medically dangerous psychiatric disorders of unknown etiology. Accumulating evidence supports a biopsychosocial model that includes genetic heritability, neurobiological vulnerability, and psychosocial factors, such as stress, in the development and maintenance of ED. Notably, stress hormones influence appetite and eating, and dysfunction of the physiological stress response has been implicated in ED pathophysiology. Stress signals also appear associated with food reward neurocircuitry response in ED, providing a possible mechanism for the role of stress in appetite dysregulation. This paper provides a review of some of the interacting psychological, behavioral, physiological, and neurobiological mechanisms involved in the stress response among individuals with ED, and discusses novel neuroimaging techniques to address potential physiological confounds of studying neural correlates of stress in ED, such as calibrated fMRI.

Effects of Cold Stimulation on Cardiac-Vagal Activation in Healthy Participants: Randomized Controlled Trial

Background

The experience of psychological stress has not yet been adequately tackled with digital technology by catering to healthy individuals who wish to reduce their acute stress levels. For the design of digitally mediated solutions, physiological mechanisms need to be investigated that have the potential to induce relaxation with the help of technology. Research has shown that physiological mechanisms embodied in the face and neck regions are effective for diminishing stress-related symptoms. Our study expands on these areas with the design for a wearable in mind. As this study charts new territory in research, it also is a first evaluation of the viability for a wearables concept to reduce stress.

Objective

The objectives of this study were to assess whether (1) heart rate variability would increase and (2) heart rate would decrease during cold stimulation using a thermode device compared with a (nonstimulated) control condition. We expected effects in particular in the neck and cheek regions and less in the forearm area.

Methods

The study was a fully randomized, within-participant design. Volunteer participants were seated in a laboratory chair and tested with cold stimulation on the right side of the body. A thermode was placed on the neck, cheek, and forearm. We recorded and subsequently analyzed participants’ electrocardiogram. The cold stimulation was applied in 16-second intervals over 4 trials per testing location. The control condition proceeded exactly like the cold condition, except we manipulated the temperature variable to remain at the baseline temperature. We measured heart rate as interbeat intervals in milliseconds and analyzed root mean square of successive differences to index heart rate variability. We analyzed data using a repeated-measures ANOVA (analysis of variance) approach with 2 repeated-measures factors: body location (neck, cheek, forearm) and condition (cold, control).

Results

Data analysis of 61 participants (after exclusion of outliers) showed a main effect and an interaction effect for body location and for condition, for both heart rate and heart rate variability. The results demonstrate a pattern of cardiovascular reactivity to cold stimulation, suggesting an increase in cardiac-vagal activation. The effect was significant for cold stimulation in the lateral neck area.

Conclusions

The results confirmed our main hypothesis that cold stimulation at the lateral neck region would result in higher heart rate variability and lower heart rate than in the control condition. This sets the stage for further investigations of stress reduction potential in the neck region by developing a wearable prototype that can be used for cold application. Future studies should include a stress condition, test for a range of temperatures and durations, and collect self-report data on perceived stress levels to advance findings.

Self-reported emotion regulation difficulties are associated with mood but not with the biological stress response to thin ideal exposure

BACKGROUND

Difficulties in emotion regulation have been related to psychological and physiological stress responses such as lower mood and lower parasympathetic activation (HF-HRV) under resting condition, but evidence on the potential link to the hypothalamic-pituitary-adrenal (HPA) axis functioning and to physiological stress responses during a stress task is still scarce. The aim of the study was to investigate stress responses in young women when confronted to a daily stressor such as exposure to thin ideals and to understand the role of correlates of self-reported trait-like emotion regulation difficulties (ERD).

METHODS

Heart rate variability (HRV) and salivary cortisol data were collected in a sample of 273 young women aged 18-35 with and without mental disorders during a vivid imagination of thin ideals (experimental condition) or landscapes (control condition). Changes in mood states were measured on a visual analogue scale (0-100). Correlates of trait-like ERD were self-reported using the Difficulties in Emotion Regulation Scale (DERS).

RESULTS

Participants with higher ERD showed a stronger decline in self-reported mood after vivid imagination of thin ideals compared to participants with lower ERD in the experimental condition but also a stronger increase of positive mood with increasing ERD in the control condition. ERD were not related to baseline HF-HRV or baseline salivary cortisol levels nor to any physiological response during and after the imagination of thin ideals.

DISCUSSION AND CONCLUSION

The results corroborate the role of ERD regarding the immediate psychological impact of daily stressors. Exposition to daily stressors in the laboratory results in discrepant psychological and physiological reactivity. Future studies should investigate under what conditions the complex interrelations between immediate and long-term ERD and biological activation are amenable to assessment in a laboratory setting. The additive effects of multiple exposition to stressors, such as thin ideals in daily life, also need to be addressed.

Is intuitive eating related to resting state vagal activity?

Efferent and afferent fibers of the vagus nerve are involved in regulating hunger and satiety. Vagally-mediated heart rate variability (vmHRV) reflects vagal activity. Previously no study addressed a potential association between resting state vagal activity and intuitive eating. Self-reports on intuitive eating and measures of resting state vmHRV were obtained in 39 students (16 female, mean age: 19.64±1.44years). Hierarchical multiple regression models showed that, after controlling for gender, age, and body mass index, resting vagal activity was inversely related to the Unconditional Permission to Eat subscale of the Intuitive Eating scale. Individuals with higher resting vagal activity tend to be less willing to eat desired foods and are more likely to label certain foods as forbidden. Future studies should include measures of self-regulation and eating disorder symptomatology to identify potential mediators or moderators when attempting to replicate these preliminary findings in larger samples.

From psychological moments to mortality: A multidisciplinary synthesis on heart rate variability spanning the continuum of time

Heart rate variability (HRV) indexes functioning of the vagus nerve, arguably the most important nerve in the human body. The Neurovisceral Integration Model has provided a structural framework for understanding brain-body integration, highlighting the role of the vagus in adaptation to the environment. In the present paper, we emphasise a temporal framework in which HRV may be considered a missing, structural link between psychological moments and mortality, a proposal we label as Neurovisceral Integration Across a Continuum of Time (or NIACT). This new framework places neurovisceral integration on a dimension of time, highlighting implications for lifespan development and healthy aging, and helping to bridge the gap between clearly demarcated disciplines such as psychology and epidemiology. The NIACT provides a novel framework, which conceptualizes how everyday psychological moments both affect and are affected by the vagus in ways that have long-term effects on mortality risk. We further emphasize that a longitudinal approach to understanding change in vagal function over time may yield novel scientific insights and important public health outcomes.

Non-suicidal Self-Injury in Eating Disordered Patients: Associations with Heart Rate Variability and State-Trait Anxiety

Background: Non-suicidal self-injury (NSSI) is commonly present in individuals with eating disorders (EDs) and is often employed as a maladaptive emotion regulation strategy to avoid or abate negative emotions. One of the most prevalent negative emotions experienced by self-injurers is anxiety; however, this emotion has not been extensively studied in this population. Thus, the aim of our study was to investigate the influence of anxiety on NSSI in patients with ED from two different dimensions: state anxiety and trait anxiety.

Methods: The study comprised a total of 66 females: 12 ED patients with NSSI, 32 ED patients without a history of NSSI, and 22 healthy controls. State and trait anxiety were assessed by means of State-Trait Anxiety Inventory (STAI-S-T) and physiological data [i.e., heart rate variability (HRV)] were collected.

Results: STAI-trait scores were significantly higher in ED patients with NSSI than ED patients without NSSI. Furthermore, when conducting logistic regression analyses higher STAI-trait scores were associated with NSSI in ED patients. However, no differences in STAI-state scores and HRV were found between ED patients with and without NSSI.

Discussion: The present findings suggest that anxiety as a trait is associated with the use of maladaptive strategies (i.e., NSSI) in ED patients. These results uphold the need to target trait anxiety in ED treatment in order to prevent possible NSSI behaviors.

Heart rate variability indices as bio-markers of top-down self-regulatory mechanisms: A meta-analytic review

Theoretical perspectives posit that heart-rate variability (HRV) reflects self-regulatory capacity and therefore can be employed as a bio-marker of top-down self-regulation (the ability to regulate behavioral, cognitive, and emotional processes). However, existing findings of relations between self-regulation and HRV indices are mixed. To clarify the nature of such relations, we conducted a meta-analysis of 123 studies (N=14,347) reporting relations between HRV indices and aspects of top-down self-regulation (e.g., executive functioning, emotion regulation, effortful control). A significant, albeit small, effect was observed (r=0.09) such that greater HRV was related to better top-down self-regulation. Differences in relations were negligible across aspects of self-regulation, self-regulation measurement methods, HRV computational techniques, at-risk compared with healthy samples, and the context of HRV measurement. Stronger relations were observed in older relative to younger samples and in published compared to unpublished studies. These findings generally support the notion that HRV indices can tentatively be employed as bio-markers of top-down self-regulation. Conceptual and theoretical implications, and critical gaps in current knowledge to be addressed by future work, are discussed.

Non-suicidal Self-Injury in Eating Disordered Patients: Associations with Heart Rate Variability and State-Trait Anxiety

Background: Non-suicidal self-injury (NSSI) is commonly present in individuals with eating disorders (EDs) and is often employed as a maladaptive emotion regulation strategy to avoid or abate negative emotions. One of the most prevalent negative emotions experienced by self-injurers is anxiety; however, this emotion has not been extensively studied in this population. Thus, the aim of our study was to investigate the influence of anxiety on NSSI in patients with ED from two different dimensions: state anxiety and trait anxiety. Methods: The study comprised a total of 66 females: 12 ED patients with NSSI, 32 ED patients without a history of NSSI, and 22 healthy controls. State and trait anxiety were assessed by means of State-Trait Anxiety Inventory (STAI-S-T) and physiological data [i.e., heart rate variability (HRV)] were collected. Results: STAI-trait scores were significantly higher in ED patients with NSSI than ED patients without NSSI. Furthermore, when conducting logistic regression analyses higher STAI-trait scores were associated with NSSI in ED patients. However, no differences in STAI-state scores and HRV were found between ED patients with and without NSSI. Discussion: The present findings suggest that anxiety as a trait is associated with the use of maladaptive strategies (i.e., NSSI) in ED patients. These results uphold the need to target trait anxiety in ED treatment in order to prevent possible NSSI behaviors.

A Meta-analysis on Resting State High-frequency Heart Rate Variability in Bulimia Nervosa

OBJECTIVE

Autonomic nervous system function is altered in eating disorders. We aimed to quantify differences in resting state vagal activity, indexed by high-frequency heart rate variability comparing patients with bulimia nervosa (BN) and healthy controls.

METHODS

A systematic search of the literature to identify studies eligible for inclusion and meta-analytical methods were applied. Meta-regression was used to identify potential covariates.

RESULTS

Eight studies reporting measures of resting high-frequency heart rate variability in individuals with BN (n = 137) and controls (n = 190) were included. Random-effects meta-analysis revealed a sizeable main effect (Z = 2.22, p = .03; Hedge's g = 0.52, 95% CI [0.06;0.98]) indicating higher resting state vagal activity in individuals with BN. Meta-regression showed that body mass index and medication intake are significant covariates.

DISCUSSION

Findings suggest higher vagal activity in BN at rest, particularly in unmedicated samples with lower body mass index. Potential mechanisms underlying these findings and implications for routine clinical care are discussed. Copyright © 2016 John Wiley & Sons, Ltd and Eating Disorders Association.