Gender Matters: Nonlinear Relationships Between Heart Rate Variability and Depression and Positive Affect.

Vagally mediated heart rate variability (vmHRV), a measure of the parasympathetic nervous system's control over the heart, is often negatively related to maladaptive emotional outcomes. Recent work suggests that quadratic relationships involving these factors may be present; however, research has not investigated gender differences in these nonlinear functions. To address this gap, the current study tested for quadratic relationships between resting vmHRV and depression and positive affect while investigating gender differences in these relationships. Significant quadratic effects were found between resting vmHRV and reports of both depression symptoms and positive affect in women but not men. Specifically, the lowest levels of depression and the highest levels of positive affect were found at moderate vmHRV in women. These results suggest that examinations of vmHRV's nonlinear associations require the consideration of gender. Our findings are interpreted based on proposed differential neuropsychological mechanisms of vmHRV in men versus women.

Resting Heart Rate Variability, Facets of Rumination and Trait Anxiety: Implications for the Perseverative Cognition Hypothesis.

The perseverative cognition hypothesis (PCH) posits that perseveration, defined as the repetitive or sustained activation of cognitive representations of a real or imagined stressor, is a primary mechanism linking psychological (or stress) vulnerability with poor health and disease. Resting vagally mediated heart rate variability (vmHRV) is an important indicator of self-regulatory abilities, stress vulnerability and overall health. Those with lower resting vmHRV are more vulnerable to stress, and thus more likely to engage in perseverative cognition and experience subsequent negative mental health outcomes such as anxiety. Recent research suggests that rumination-one of the core mechanisms underlying perseveration-is a construct containing (at least) two maladaptive (depressive and brooding) and one adaptive (reflective) types of rumination. However, to date, research has not examined how the association between resting vmHRV may differ between these three facets of rumination, in addition to these facets' mechanistic role in linking lower resting vmHRV with greater trait anxiety. The current cross-sectional study explores these relationships in a sample of 203 participants (112 females, 76 ethnic minorities, mean age = 19.43, standard deviation = 1.87). Resting vmHRV was assessed during a 5-min-resting period using an Electrocardiogram (ECG). Both trait rumination (including the three facets) and anxiety were assessed via self-report scales. Significant negative associations were found between resting vmHRV and maladaptive, but not adaptive, forms of perseveration. Similarly, mediation analyses showed a significant indirect relationship between resting vmHRV and anxiety through maladaptive, but not adaptive, facets of rumination. Our findings support the PCH such that those with stress vulnerability, as indexed by lower resting vmHRV, are more likely to engage in maladaptive perseverative cognition and thus experience negative outcomes such as anxiety. Our data also lend a novel outlook on the PCH; resting vmHRV is not related to reflective rumination and thus, this facet of perseveration may be a neutral, but not beneficial, factor in the link between stress vulnerability and psychological well-being.

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.

A systematic review on heart rate variability in Bulimia Nervosa.

Eating disorders are associated with alterations of the autonomic nervous system (ANS). Among other indices, heart rate variability (HRV) provides a readily available index of ANS function. While ANS dysfunction indexed by HRV in Anorexia Nervosa has been addressed in previous reviews, here we aimed to review the current evidence on HRV in Bulimia Nervosa (BN). A systematic literature search in Web of Science, PsycInfo, Scopus, and PubMed identified 17 studies reporting HRV in patients with BN. Studies described (i) differences in resting state HRV in patients compared to controls, (ii) alterations in the stress response in BN indexed by HRV, and (iii) treatment effects on HRV in patients with BN. Despite a number of conflicting results, we conclude that BN is characterized by increased resting state vagally-mediated HRV and an impaired stress-response. Intervention-studies suggest that altered ANS-activity in BN is at least partially reversible. Future studies on the complex relation between BN and HRV should investigate the effect of comorbid disorders, subtypes of BN, and mechanisms affecting treatment outcome.

Resting state vagal tone in borderline personality disorder: A meta-analysis.

Borderline personality disorder (BPD) is the most common personality disorder in clinical settings. It is characterized by negative affectivity, emotional liability, anxiety, depression, as well as disinhibition (i.e., impulsivity and risk taking), all of which have been linked to lower resting state vagal tone, which may be indexed by vagally-mediated heart rate variability (vmHRV). Here, we aimed to quantify the current evidence on alterations in resting state vmHRV in individuals with BPD, relative to healthy controls. A rigorous search of the literature, according to the "Preferred Reporting Items for Systematic Reviews and Meta-Analyses", revealed 5 studies suitable for meta-analysis, reporting vmHRV in individuals with BPD (n=95), relative to healthy controls (n=105). Short-term measures of resting state vmHRV were extracted and subjected to meta-analysis using both random- and fixed effect models in RevMan. BPD displayed lower resting state vmHRV relative to healthy controls in random- (Hedges' g=-0.59, 95% CI [-1.11; -0.06], k=5) and fixed-effect meta-analysis (Hedges' g=-0.56, 95% CI [-0.86; -0.27], k=5). Control for potential publication bias did not change observed findings. Lowered resting state vagal tone may be an important trait characteristic underlying BPD. As prior studies have observed lowered vmHRV in a variety of psychiatric disorders, we propose that lowered vmHRV may reflect a common psychophysiological mechanism underlying difficulties in emotion regulation and impulsivity, in particular.