Heart rate variability and psychological health: The key role of trait emotional awareness

Studies have shown that Trait Emotional Awareness (TEA) - the ability to recognize one's emotions - and Heart Rate Variability (HRV) are both negatively associated with psychological disorders. Although these studies imply that TEA is related to HRV and may explain the association between HRV and psychological disorders, there is limited research investigating this implication. Such investigation is essential to illuminate the psychophysiological processes linked to psychological disorders. The present study aims to investigate a) the association between TEA and HRV, b) the association between HRV and psychological disorders, and c) whether TEA explains the association between HRV and psychological disorders. A sample of 41 German students completed self-report questionnaires as indicators of psychological disorders, including the Hospital Anxiety and Depression Scale (HADS; Snaith & Zigmond, 1983) for anxiousness and depressiveness, as well as the somatization scale of the Hopkins Symptom Checklist (HSCL; Derogatis et al., 1976) for physical complaints. HRV was measured at baseline (resting HRV) and during exposure to a fear-provoking movie clip (reactive HRV). As hypothesized, a) TEA showed a positive association with reactive HRV, b) HRV showed negative associations with anxiousness and physical complaints, and c) TEA explained the relationships between reactive HRV and anxiousness, as well as physical complaints. Contrary to our hypothesis, we did not find any association between HRV and depressiveness. We discussed the contribution of TEA to psychophysiological health, limited generalizability of the current study, and direct future research to explore the underlying mechanisms linking TEA to health.

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

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

Symptomatic bradyarrhythmias in the athlete-Underlying mechanisms and treatments

Bradyarrhythmias including sinus bradycardia and atrioventricular (AV) block are frequently encountered in endurance athletes especially at night. While these are well tolerated by the young athlete, there is evidence that generally from the fifth decade of life onward, such arrhythmias can degenerate into pathological symptomatic bradycardia requiring pacemaker therapy. For many years, athletic bradycardia and AV block have been attributed to high vagal tone, but work from our group has questioned this widely held assumption and demonstrated a role for intrinsic electrophysiological remodeling of the sinus node and the AV node. In this article, we argue that bradyarrhythmias in the veteran athlete arise from the cumulative effects of exercise training, the circadian rhythm and aging on the electrical activity of the nodes. We consider contemporary strategies for the treatment of symptomatic bradyarrhythmias in athletes and highlight potential therapies resulting from our evolving mechanistic understanding of this phenomenon.

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

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

Evidence of deviant parasympathetic response to social exclusion in women with borderline personality disorder

Stressful social situations like social exclusion are particularly challenging for patients with borderline personality disorder (BPD) and often lead to dysfunctional reactive behaviour of aggression and withdrawal. The autonomous signature of these core symptoms of BPD remains poorly understood. The present study investigated the parasympathetic response to social exclusion in women with BPD (n = 62) and healthy controls (HC; n = 87). In a between-subjects design, participants experienced objective social exclusion or overinclusion in the Cyberball task, a virtual ball-tossing game. Need threat scores served as individual measures of perceived exclusion and the resulting frustration of cognitive-emotional needs. Five-minute measurements of high-frequency heart rate variability (HF-HRV) at three time points (before, during, after Cyberball) indicated parasympathetic tone and regulation. We observed a trend towards lowered baseline HF-HRV in BPD vs. HC in line with previous findings. Interestingly, the parasympathetic response of patients with BPD to objective and perceived social exclusion fundamentally differed from HC: higher exclusion was associated with increased parasympathetic activation in HC, while this autonomic response was reversed and blunted in BPD. Our findings suggest that during social stress, the parasympathetic nervous system fails to display an adaptive regulation in patients with BPD, but not HC. Understanding the autonomous signature of the stress response in BPD allows the formulation of clinically relevant and biologically plausible interventions to counteract parasympathetic dysregulation in this clinical group.

Mobitz type II second-degree atrioventricular block during sleep: true or false?

A number of publications have claimed that Mobitz type II second-degree atrioventricular (AV) block can occur during sleep apnea. None has provided a definition of type II block used in the articles, and representative electrocardiograms have been generally missing. Despite these reports, the existence of type II AV block during sleep must remain questionable.

Common eating habit patterns are associated with a high maximum occlusal force and pre-eating cardiac vagal tone

Background

Masticatory function is associated with nervous function, including autonomic nervous function, and both functions are influenced by human habits. In a previous preliminary study of 53 young women, we found that eating habit patterns were associated with occlusal force as an indicator of masticatory function. Therefore, we hypothesized that relationships exist between occlusal force, the autonomic nervous system, and eating habit patterns.

Methods

To test our hypothesis, we analyzed the relationship between heart rate variability measured before and after lunch in 53 young women, and measured and surveyed maximum occlusal force and eating habit patterns, respectively, in these participants.

Results

High occlusal force was associated with an increased high-frequency (HF) component (vagal tone index) of the heart rate variability index immediately before lunch (standardized regression coefficient (β) = 0.417, P = 0.002). Each of the eating habit items surveyed in a questionnaire showed a similar tendency for the HF component immediately before lunch and maximum occlusal force; in particular, "Habit of eating breakfast" and "Number of meals per day" were significantly associated with both variables. Additionally, total eating habit scores related to higher maximum occlusal force were associated with an increase in the HF component immediately before lunch (β = 0.514, P < 0.001). The maximum occlusal force and the pre-eating HF component values were stratified by total eating habit scores (into low, medium, high categories), and the high scores were significantly higher than the medium or low scores.

Conclusions

Occlusal force and the pre-eating cardiac vagal response of individuals were characterized by their common eating habit patterns, indicating that eating habits may be simultaneously associated with the development of masticatory function, nervous system development, and cardiovascular rhythm. Although further research is needed to investigate these relationships in detail, our findings provide insights that will inform the study of physical functions, neurodevelopment, habitual behaviors, and health in humans.

The heart to make the right choice: Vagal (re)activity and recovery predict advantageous decision-making

From simple everyday choices to life-altering decisions, decision-making is a crucial cognitive process in our daily life. Psychophysiological theories of heart-brain interactions involvement in cognition predict that general self-regulation capacities underlie cognitive processes including decision-making. Yet, in the context of decision-making, the somatic maker hypothesis postulates that the adaptability of the current physiological state should be the best predictor of advantageous decision-making. The present study tests compare self-regulation in general (indexed by resting vagal activity) and in a specific decisional context (vagal reactivity and recovery) to explain advantageous decision-making. Young adults (n = 54) completed a decision-making task while wearing a heart rate monitor. Bayesian regressions show that vagal reactivity and recovery combined is the preferred statistical model to explain advantageous decision-making (BF₁₀ = 163.85). Those findings 1) support the somatic marker hypothesis highlighting the key role of in situ self-regulation in decision-making processes and 2) show that the popular and often used index of general self-regulation, resting vagal activity, is not the best predictor of decision-making performance, and perhaps even for other cognitive functions. A next step could be interventional studies to test whether vagal modulation of heart rate underlies decision-making through interventions that influence vagal activity, which could provide relevant clinical leads.

Isotemporal Associations of Device-Measured Sedentary Time and Physical Activity with Cardiac-Autonomic Regulation in Previously Pregnant Women

BACKGROUND

High sedentary time (ST) and low physical activity may increase cardiovascular risk, potentially though cardiac-autonomic dysregulation. This study investigated associations of statistically exchanging device-measured ST and physical activity with measures of cardiac-autonomic regulation in previously pregnant women.

METHOD

This cross-sectional, secondary analysis included 286 women (age = 32.6 ± 5.7 years; 68% white) measured 7-15 years after delivery. ST and light (LPA), moderate (MPA), vigorous (VPA), and moderate-to-vigorous (MVPA) intensity physical activity were measured by ActiGraph GT3X. ST was further partitioned into long (≥ 30 min) and short (< 30 min) bouts. MVPA was also partitioned into long (≥ 10 min) and short (< 10 min) bouts. Cardiac-autonomic regulation was assessed by heart rate variability (HRV) (resting heart rate, natural log transformed standard deviation of normal R-R intervals [lnSDNN], natural log-transformed root mean square of successive differences [lnRMSSD]) from a 5-min seated ECG. Progressive isotemporal substitution models adjusted for confounders. Sensitivity analyses removed women with related underlying medical conditions and who did not meet respiration rate criteria.

RESULTS

Initial analyses found no significant associations with HRV when exchanging 30 min of ST and physical activity (p > 0.05). Yet, replacing long- and short-bout ST with 30 min of long-bout MVPA yielded significantly higher (healthier) lnRMSSD (B = 0.063 ± 0.030 and B = 0.056 ± 0.027, respectively; both p < 0.05). Sensitivity analyses strengthened these associations and yielded further associations of higher lnSDNN and lnRMSSD when replacing 30 min of short-bout MVPA with equivalent amounts of long-bout MVPA (B = 0.074 ± 0.037 and B = 0.091 ± 0.046, respectively).

CONCLUSION

Replacing ST with long-bout MVPA is a potential strategy to improve cardiac-autonomic function in previously pregnant women.

Getting under the skin: long-term links of adolescent peer relationship difficulties to adult vagal tone

Understanding whether and how the absence of positive relationships may predict longer-term physical health outcomes is central to building a working conceptual model of the interplay of social and physical development across the lifespan. This study sought to examine the extent to which difficulties establishing positive social relationships from adolescence onward serve as long-term predictors of low adult vagal tone, which in turn has been linked to numerous long-term health problems. A diverse community sample of 141 individuals was followed via multiple methods and reporters from age 13 to 29. Across this span, social relationship quality was assessed via close friend and peer reports, observations of romantic interactions, and self-reported romantic relationship satisfaction. A range of potential personality and functional covariates was also considered. Vagal tone while at rest was assessed at age 29. Adult vagal tone was predicted across periods as long as 16 years by: adolescents' difficulty establishing themselves as desirable companions among peers; early adults' inability to establish strong close friendships; and lack of warmth in romantic relationships as an adult. Poor early adult friendship quality statistically mediated the link from adolescent peer difficulties to adult vagal tone. A range of potential confounding factors was examined but was not linked to vagal tone. Within the limits of the correlational design of the study, robust connections between adult vagal tone and social relationship quality from adolescence onward suggest at least a possible mechanism by which relationship difficulties may get 'under the skin' to influence future physiological functioning.

Measures of cardiovascular function suggest autonomic nervous system dysregulation after surgical induction of joint injury in the male Lewis rat

OBJECTIVES

Functional changes in the autonomic nervous system may help explain variability in the progression of knee osteoarthritis (OA). Thus, the objective of this study was to evaluate autonomic nervous system shifts, measured via heart rate response variables, in rat knee joint injury and OA models.

METHODS

Cardiovascular characteristics were measured at baseline and bi-weekly for 8 weeks after skin incision, medial collateral ligament transection (MCLT), or MCLT+medial meniscus transection (MCLT+MMT). Heart rate was also assessed during a mild stressor (elevated maze). At endpoint, cardiovascular responses to mechanical knee stimuli were evaluated, as well as responses to 1-phenylbiguanide, a 5HT_3A receptor agonist with reported ability to stimulate vagal responses.

RESULTS

During low activity, a slower heart rate occurred in MCLT (299 ± 10 bpm) and MCLT+MMT (310 ± 10 bpm) animals compared to controls (325 ± 10 bpm). Furthermore, patellar ligament mechanical stimuli produced an immediate decrease in heart rate and blood pressure in all groups. Finally, a larger drop in heart rate was observed in MCLT (252 ± 40 bpm) and MCLT+MMT (263 ± 49 bpm) following administration of 1-phenylbiguanide compared to skin incision (168 ± 45 bpm).

CONCLUSIONS

Acute mechanical stimulation of the patellar ligament produced drops in heart rate, suggesting a possible joint-brain connection that modulates autonomic responses. With both joint injury, cardiac vagal activation was altered in response to pharmacological stimulation, with chronic longitudinal heart rate reduction. These data provide some preliminary evidence of potential functional shifts in autonomic nervous system function in models of joint injury and OA.

When is Parental Suppression of Black Children's Negative Emotions Adaptive? The Role of Preparation for Racial Bias and Children's Resting Cardiac Vagal Tone

Research demonstrates that Black parents attempt to suppress children's expressions of negative emotions (e.g., anger, fear), in part, to protect them from experiencing racial bias from authority figures. The goal of this study was to examine whether the effectiveness of parental suppression strategies in reducing behavior problems depends on whether parents talk to children about the potential of experiencing racism (i.e., preparation for bias) and children's resting cardiac vagal tone as indexed by baseline respiratory sinus arrhythmia (RSA). Ninety-four parents (97% mothers) who identified their child as Black (56% girls) completed questionnaires about their punitive and minimizing responses to their child's negative emotions and their child's internalizing and externalizing problems at ages 5 and 6. Children's baseline RSA was assessed at age 5. Results indicated that parents' suppression of children's negative emotions predicted decreased externalizing behaviors (e.g., acting out) only when parents talked to their children about racism. When parents did not contextualize their restrictions on children's emotional expressions with discussions about race, children with higher baseline RSA demonstrated increased externalizing behaviors, whereas those with lower baseline RSA were unaffected. Parental suppression strategies led to increased internalizing symptoms (e.g., anxiety, withdrawal) among children with higher baseline RSA regardless of whether parents discussed racism. Black parents face a conundrum in which suppressing their children's negative emotions, in hopes of subverting racism, may reduce their children's externalizing problems under some circumstances, but may increase the risk of their children developing internalizing problems. Implications for systemic policy change to combat racism are discussed.

To thine own self be true: interoceptive accuracy and interpersonal problems

BACKGROUND

Borderline Personality Disorder involves strong interpersonal disruptions, often associated with early maltreatment. However, the individual capacities which alter BPD-related interpersonal problems are unclear. Here, we examine two contributors to interpersonal functioning: interoceptive accuracy and parasympathetic activity. Interoceptive accuracy is the ability to correctly perceive body states, such as how quickly one's heart is beating, and has been associated with emotional experience and various crucial social capacities. Similarly, parasympathetic activity is related to social processing and inhibition of impulses. As such, both may contribute to BPD interpersonal symptoms, albeit different types of interpersonal problems.

METHOD

Sixty-five individuals completed the Inventory of Interpersonal Problems and the Millon Clinical Multiaxial Inventory followed by a task to assess interoceptive accuracy, the heart rate monitoring task, in which participants counted their heartbeats while concurrent physiological data was recorded; and an assessment of vagal tone, used as an index of regulatory flexibility.

RESULTS

Participants who reported poor interpersonal boundaries, consistent with borderline personality disorder styles, had worse interoception, whereas those high in aggression had lower vagal tone. Borderline personality symptoms overall were related to IA and significantly to vagal tone.

CONCLUSIONS

These findings suggest that interoceptive accuracy is associated with interpersonal problems, where people are overly influenced or enmeshed with others, possibly to compensate for the absence of their physical and emotional awareness.

Breath-by-breath analysis of respiratory sinus arrhythmia in dogs

Dogs differ greatly in size, heart (HR) and breathing rates (BR). In addition, they have a clear Respiratory Sinus Arrhythmia (RSA) at rest. Therefore, better than any other mammalian species, dogs offer an opportunity to test whether resting RSA varies with body weight, HR or BR. Sequences of inter-beat-intervals (IBI, ms) a few-minutes long were collected in twenty-three resting dogs of different sizes, together with pneumograms. IBI variability was quantified by standard time-domain criteria. From beat-to-beat instantaneous heart rate (hR, beats/min), RSA was the difference between inspiratory peak (hR-peak) and expiratory trough (hR-trough), in percent of mean HR. RSA averaged 40.1 % ±4.5, or more than three times that of humans, with large inter-animal variability. On average, RSA contributed 38 % of the total IBI variability. RSA did not differ between sexes and did not correlate with body weight. It had modest negative correlations with HR (P < 0.05) and BR (P < 0.05), and a very strong negative correlation with hR-trough (P < 0.001). In two separate dogs, during panting, RSA was absent. In the transition from resting to panting, RSA continued like at rest for several breaths, despite the tachypnea, underlying the importance of central mechanisms in the origin of RSA. In conclusion, RSA in dogs is very large and explains less than half of their sinus arrhythmia. Rather than HR, BR or hR-peak, changes in the vago-sympathetic control, represented by hR-trough, are the most likely source of variability of RSA among subjects.

Coherence Between Feelings and Heart Rate: Links to Early Adversity and Responses to Stress

Past research suggests that higher coherence between feelings and physiology under stress may confer regulatory advantages. Research and theory also suggest that higher resting vagal tone (rVT) may promote more adaptive responses to stress. The present study examines the roles of response system coherence (RSC; defined as the within-individual covariation between feelings and heart rate over time) and rVT in mediating the links between childhood adversity and later-life responses to acute stressors. Using data from 279 adults from the Second Generation Study of the Harvard Study of Adult Development who completed stressful public speaking and mental arithmetic tasks, we find that individuals who report more childhood adversity have lower RSC, but not lower rVT. We further find that lower RSC mediates the association between adversity and slower cardiovascular recovery. Higher rVT in the present study is linked to less intense cardiovascular reactivity to stress, but not to quicker recovery or to the subjective experience of negative affect after the stressful tasks. Additional analyses indicate links between RSC and mindfulness and replicate previous findings connecting RSC to emotion regulation and well-being outcomes. Taken together, these findings are consistent with the idea that uncoupling between physiological and emotional streams of affective experiences may be one of the mechanisms connecting early adversity to later-life affective responses. These findings also provide evidence that RSC and rVT are associated with distinct aspects of self-regulation under stress.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s42761-020-00027-5.

Paradoxical effect of cumulative stress exposure on information processing speed in Hispanics/Latinos with elevated heart rate variability

Chronic stress has a deleterious effect on prefrontal lobe functioning. Empirical evidence suggests elevated vagal tone, indexed by elevated heart rate variability (HRV), mitigates the effect of mental stress on frontal lobe function. Here, the mitigating effect of HRV on stress-related decrements in cognitive performance is assessed based on information processing speed (DSST), word fluency and verbal learning task performance. Artifact free electrocardiogram (ECG) data was analyzed from 1420 Hispanic/Latino adults from the Sociocultural Ancillary of the Hispanic Community Health Study/Study of Latinos (HCHS/SOL). A 12-lead ECG was used to collect short-term recordings of the root mean square of successive differences in all normal R-peak to R-peak intervals (RMSSD) and the change between adjacent beats and the standard deviation of those intervals (SDNN) as indices of total HRV. As predicted, an interaction emerged for HRV and stress on the task presumed to require the greatest prefrontal lobe involvement, i.e., the DSST. After accounting for sociodemographic factors, chronic stress was associated with better DSST performance amongst individuals at higher quartile of SDNN, but not RMSSD. The paradoxical effect for greater stress exposure on DSST performance may in part be explained by increased speed of information processing and decision making often reported in high-stress cohorts. The nature of this interaction highlights the importance of examining the relationship between stress and cognition across a spectrum of vagal tone.

Cardiac autonomic modulation in type 1 diabetes during exercise-heat stress

AIMS

Cardiac autonomic modulation, as assessed by heart rate variability (HRV), is independently attenuated by both type 1 diabetes (T1D) and exercise-heat stress, although their combined effects remain unclear. We therefore assessed HRV during exercise-heat stress in young individuals (18-37 years) with (n = 14) and without type 1 diabetes (n = 14).

METHODS

Participants completed 30-min seated rest and three, 30-min bouts of semi-recumbent cycling at light, moderate, and vigorous metabolic heat productions (200, 250, 300 W/m², respectively), each followed by 30-min recovery. Body core temperature (T_core) and electrocardiogram were recorded throughout and analyzed during the final 5-min of rest and each exercise period.

RESULTS

Relative to baseline, T_core was increased in both groups, albeit to a greater extent in type 1 diabetes during vigorous exercise (T1D, 1.1 ± 0.3 °C; control, 0.8 ± 0.3 °C; P < 0.05). Overall HRV (as reflected by entropy) was attenuated throughout exercise relative to baseline in both groups, with the magnitude of the reduction greater in type 1 diabetes during vigorous exercise (T1D, - 108%; control, - 70%; P < 0.05).

CONCLUSIONS

Given the negative correlations between decreased HRV and cardiac risk, our novel observations indicate that vigorous exercise in hot environments may pose a health concern for individuals with type 1 diabetes.

Case report: Synergetic effect of ischaemia and increased vagal tone inducing ventricular fibrillation in a patient with Brugada syndrome

BACKGROUND

Brugada syndrome (BS) is a hereditary channelopathy associated with syncope, malignant ventricular arrhythmia, and sudden cardiac death. Right ventricular ischaemia and BS have similar underlying substrates precipitating ventricular tachycardia or fibrillation (VF).

CASE SUMMARY

A 72-year-old woman with BS and a stenosis on the proximal right coronary artery received several subsequent implantable cardioverter-defibrillator shocks due to VF during an episode of extreme nausea with vomiting.

DISCUSSION

This case report emphasizes on the synergetic effect of mild ischaemia and increased vagal tone on the substrate responsible for BS to create pathophysiological changes precipitating VF.

Heart Rate Variability, Cortisol and Attention Focus During Shamatha Quiescence Meditation

Cardiac vagal tone can be seen as a stable marker for the ability to sustain attention and regulate emotion, two factors associated with the quality of meditation. In this study, heart rate variability (HRV) has been monitored in different forms of Shamatha quiescence meditation: three breath meditations, Settling the Mind in its natural state, Awareness of Awareness, Loving-kindness and Tonglen. Establish and test a practical means of monitoring neurobiological effects of meditation. Over 6 weeks, two experimental groups practiced Shamatha meditation on a daily basis (n = 20). HRV patterns and cortisol tests were monitored at three measuring points during these weeks, and an attention focus test was performed at the start and after 6 weeks. Six weeks of regular practice in Shamatha meditation were associated with HRV indices suggesting improvements in the homeostatic regulation of the autonomic nervous system (ANS) in 85% of the HRV recordings (tachogram and frequency specter) of all 20 subjects. Further, a substantial decrease in cortisol levels was also noted. The attention focus test showed a significant increase of 18.7% in sustained attention, moving from medium to high attention focus, with a significant result of t(20) = - 8.764 and p < 0.001. Participants reported positive subjective changes in attention focus, sense of happiness and calmness and increased abilities in emotional regulation and attunement. Six weeks of regular practice in Shamatha meditation contributes to a substantial increase of attention focus and a decrease in stress levels evidenced in changes in diurnal cortisol measures. HRV biofeedback shows that the sympathetic nervous system is counterbalanced by increased vagal tone, and autonomic balance is enhanced by all Shamatha meditations, not only breath meditations, but also mind meditations: Settling the Mind in its natural state, Awareness of Awareness, Loving-kindness and Tonglen. Although these results are promising, further research is recommended with HRV biofeedback instruments to report statistical analysis and to understand unique HRV patterns in Shamatha mind meditation.

Resting high frequency heart rate variability and PTSD symptomatology in Veterans: Effects of respiration, role in elevated heart rate, and extension to spouses

Heart rate variability (HRV) associated with parasympathetic activity (i.e., cardiac vagal tone) is reduced in posttraumatic stress disorder (PTSD), but possible confounding effects of respiration have not been studied sufficiently. Further, reduced parasympathetic inhibition might contribute to elevated heart rate (HR) in PTSD. Finally, reduced HRV in PTSD might extend to intimate partners, given their chronic stress exposure. In 65 couples (male Veterans, female partners), elevated PTSD symptomatology (n = 32; 28 met full DSM IV criteria, 4 fell slightly short) was documented by structured interview and self-reports. Baseline HR, high-frequency HRV (HF-HRV), cardiac pre-ejection period (PEP), and respiration rate and depth were measured via impedance cardiography. Veterans with PTSD symptoms displayed reduced lnHF-HRV, even when adjusting for respiration, but their partners did not. In mediational analyses, elevated resting HR in PTSD was accounted for by lnHF-HRV but not PEP. Results strengthen evidence regarding HF-HRV and elevated HR in PTSD.

The Physiological Regulation of Emotion During Social Interactions: Vagal Flexibility Moderates the Effects of a Military Parenting Intervention on Father Involvement in a Randomized Trial

To make prevention programs more effective and understand "what works for whom," evidence regarding what individual characteristics predict intervention responsiveness is needed. Previous studies have evaluated a military parent training program known as After Deployment Adaptive Parenting Tools/ADAPT, yet less is understood about the program's varying effects for fathers. We tested the physiological regulation of emotion during social interactions as a moderator predicting fathers' responsiveness in a randomized trial of ADAPT, in which emotion regulation was operationally measured through vagal flexibility (VF; dynamic changes in cardiac vagal tone). Families with a child aged between 4 and 13 years for whom physiological data were gathered (n = 145) were randomly assigned to ADAPT (14-week face-to-face group intervention) or a control group (services as usual). Fathers in these families were National Guard/Reserve members who had been deployed to war in Iraq and/or Afghanistan and recently returned. Prior to the intervention, cardiac data was collected in-home throughout a set of family interaction tasks and VF was operationalized as the changes in high frequency (HF) power of heart rate variability (HRV) from a reading task to a problem-solving task. Parenting behaviors were observed and coded based on theory-driven indicators pre-intervention and at 1-year follow-up. Results of structural equation modeling showed that VF significantly moderated fathers' intervention responsiveness, such that fathers with higher vs. lower VF exhibited more effective parenting at 1-year follow-up if they were randomized into ADAPT vs. the control group. This study is the first to demonstrate that parasympathetic vagal functioning may be a biomarker to predict response to a military parenting intervention to enhance parenting in combat deployed fathers. The implications for precision-based prevention are discussed.

Cardiac vagal tone in preschool children: Interrelations and the role of stress exposure

INTRODUCTION

Cardiac vagal tone has been understood as the biological correlate of emotion regulation and can be divided into emotion regulation (tonic cardiac vagal tone (TCVT)) and the flexibility to adapt to changing conditions (phasic cardiac vagal tone (PCVT)). There is evidence that TCVT influences PCVT dynamics in adults and that stress exposure impacts on cardiac vagal tone in adults and older children. The aim of the study was to investigate the impact of TCVT on PCVT dynamics in preschoolers and to identify the influence of stress exposures on cardiac vagal tone.

METHOD

Measures of heart rate variability including baseline (TCVT), during an age-adapted stress task (PCVT stress reactivity) and during recovery (PCVT recovery) were assessed in 222 children aged 2-6 years of the SPLASHY study. Further, parents were asked to complete questionnaires on early stress exposure (including pregnancy, birth and early life) and current stress exposure (including family stress and parenting).

RESULTS

Preschool children with high TCVT showed less PCVT reactivity (p < 0.001) and more increase of vagal tone (PCVT) during early recovery (p = 0.016). Further only child's low birth weight was a relevant stress exposure impacting on early and late PCVT recovery (p = 0.03/p = 0.005). None of the other early or late stress exposure conditions, nor the accumulation of stress exposures influenced TCVT or PCVT dynamics in these healthy preschoolers.

DISCUSSION

TCVT impacts on PCVT dynamics in a lab-based stress task in healthy preschool children and only low birth weight is related to more change during early and to less late PCVT recovery.

Cardiac autonomic activity during sleep deprivation with and without caffeine administration

Caffeine is often consumed to mitigate degraded alertness associated with sleep deprivation. Both caffeine and sleep deprivation have been implicated in cardiovascular disease, but evidence is largely anecdotal. We determined the effects of sleep deprivation and caffeine on markers of cardiac autonomic activity. Twelve healthy young adults completed an 18-day laboratory study. They were exposed to three 48 h sessions of acute total sleep deprivation (TSD), each separated by three recovery days. In randomized, counter-balanced order, subjects received 0 mg (placebo), 200 mg, or 300 mg of caffeine at 12 h intervals during each sleep deprivation session. Every 2 h during scheduled wakefulness, a 15-minute neurobehavioral task battery was administered, during which heart rate (HR) and the high frequency (HF) component of the HR variability power spectrum (HF-HRV) were measured. Caffeine administration decreased HR and increased HF-HRV, indicating elevated parasympathetic activity. The 300 mg caffeine dose did not significantly affect autonomic activity to a greater extent than the 200 mg dose. There was no significant effect of 48 h of TSD on HR, whereas there was a small increase across hours awake in HF-HRV. There was no significant interaction of TSD with caffeine. Circadian rhythmicity in HR and HF-HRV surpassed the magnitude of the effects of caffeine and TSD. Caffeine and acute TSD thus produced only modest changes in cardiac autonomic activity, unlikely to have immediate clinical implications in healthy young adults. However, further research is needed to determine the long-term effects of chronic exposure to sleep loss and/or caffeine on cardiac health, and to determine the generalizability of our findings to non-healthy populations.

Heart rate variability and inflammation: A meta-analysis of human studies

The inflammatory reflex is known as the body's primary defense against infection and has been implicated in a number of diseases. The magnitude of the inflammatory response is important, as an extreme or insufficient response can be differentially harmful to the individual. Converging evidence suggests that the autonomic nervous system (ANS) regulates the inflammatory reflex. Heart rate variability (HRV) can be separated into components that primarily reflect parasympathetic (PNS) or vagal activity (i.e., indices of vagally mediated HRV) and a combination of both sympathetic (SNS) and PNS influences. Given the physiological relation between the vagus and inflammatory processes, one would expect to find higher HRV, especially indices of vagally-mediated HRV, to be associated with decreased levels of inflammation via the cholinergic anti-inflammatory pathway. However, existing findings here are mixed, such that studies have also shown a positive association between indices of HRV and markers of inflammation. Therefore, the present meta-analysis aimed to synthesize existing studies, estimating the general direction and strength of the relationship between different indices of HRV and inflammatory markers. A systematic search of the literature yielded 2283 studies that were screened for inclusion eligibility (159 studies eligible for inclusion); in sum, 51 studies reported/provided adequate information for inclusion in meta-analyses. Results generally showed negative associations between indices of HRV and markers of inflammation. In this regard, the standard deviation of R-R intervals (SDNN) and power in the high frequency band of HRV (HF-HRV) showed the strongest and most robust associations with inflammatory markers compared to other time- and frequency-domain measures of HRV. Overall, we propose that indices of HRV can be used to index activity of the neurophysiological pathway responsible for adaptively regulating inflammatory processes in humans.

Young Children's Physiological Reactivity during Memory Recall: Associations with Posttraumatic Stress and Parent Physiological Synchrony

Autonomic reactivity is implicated in stress response and social engagement - both key components of posttraumatic stress disorder (PTSD) - but few studies have examined autonomic reactivity in pediatric samples, and no known studies have examined physiological synchrony among children with PTSD and caregivers. In a sample of 247 young children (94 girls, 153 boys), most (85%) of whom had exposure to trauma and 40% who met criteria for PTSD, we examined children's patterns of respiratory sinus arrhythmia (RSA) at baseline and in response to a memory recall task, as well as correspondence between parents' and children's RSA. Children with PTSD demonstrated significantly higher reactivity than other groups during their recollection of a traumatic memory, but not during other memory tasks. Regarding synchrony, caregivers' and children's RSA were more significantly and positively correlated during the trauma recall task among children who had had exposure to a potentially traumatic event but did not meet PTSD criteria, suggesting physiological synchrony may be protective in contexts of trauma. Overall, findings demonstrate physiological reactivity differences among young children with PTSD. While more work is needed to understand the meaning of parent-child physiological synchrony, these data suggest that children's psychopathology is associated with physiological synchrony processes among young children with exposure to trauma.

Low vagal tone in two rat models of psychopathology involving high or low corticosterone stress responses

The two stress-responsive physiological systems, autonomic nervous system (ANS) and hypothalamus-pituitary-adrenal (HPA) axis exert complementary and interrelated actions in the organism. Individuals that suffer stress-related psychopathologies frequently present simultaneous alterations -i.e., either low or high- responsiveness- in both systems. However, there is scarce evidence establishing whether a priori alterations in these systems -i.e., independent of previous stress exposure- may predispose to the development of psychopathologies possibly due to the lack of animal models simultaneously involving aberrant HPA and SNS responses. In this study, we describe two animal models selectively bred according to their differential (either high, 'High', or low, 'Low') glucocorticoid responsiveness to stress, in comparison to a third line of rats that displays intermediate ('Inter') glucocorticoid responses. The two extreme lines may be considered distinct models of psychopathology; the High line representing a model of constitutive mood alterations while the Low line a model of vulnerability to develop stress-induced psychopathologies. We recorded the electrocardiogram in rats from the three lines and quantified heart rate variability and vagal tone indexes during rest and stress challenges. Rats from both High and Low lines displayed higher heart rate and lower basal vagal tone than the Inter group, both at resting and following stress exposure. Specific pharmacological manipulations probing the relative contribution of sympathetic and parasympathetic components on HR modulation confirmed a relative lower vagal tone in High and Low lines and discarded differences in the sympathetic regulation of heart rate between the lines. Therefore, the two genetically-selected High and Low glucocorticoid rat lines emerge as two valuable preclinical models of psychopathology involving two key risk factors for psychiatric and cardiovascular disorders, namely dysregulations in the HPA axis and cardiac vagal functioning.

Cardiac autonomic activity during simulated shift work

Shift work leads to adverse health outcomes including increased risk of cardiovascular disease. Heart rate (HR) and heart rate variability (HRV) are measures of cardiac autonomic activity and markers of cardiovascular disease and mortality. To investigate the effects of shift work on cardiac autonomic activity, we assessed the influence of simulated night work on HR and HRV, and dissociated the direct effects of circadian misalignment from those of sleep displacement and altered physical activity patterns. A total of 29 subjects each participated in one of two in-laboratory, simulated shift work studies. In both studies, EKG was continuously monitored via Holter monitors to measure HR and the high frequency (HF) component of HRV (HF-HRV). We found endogenous circadian rhythmicity in HR and HF-HRV. Sleep and waking physical activity, both displaced during simulated night work, had more substantial, and opposite, effects on HR and HF-HRV. Our findings show systematic but complex, interacting effects of time of day, sleep/wake state, and physical activity on cardiac autonomic activity. These effects need to be taken into account when evaluating HR and HRV in shift work settings and when interpreting these measures of cardiac autonomic activity as markers of cardiovascular disease.

Stress reactivity in healthy child offspring of parents with anxiety disorders

Several studies suggest that anxiety disorders (AD) involve dysregulation of the autonomic nervous system (ANS) and hypothalamic-pituitary (HPA) axis. However, it is unknown if alterations in these biological systems are premorbid markers of AD risk or a state-dependent feature of anxiety. This study examined ANS and HPA-axis response to a laboratory stressor in healthy child offspring of parents with (n = 55) and without (n = 98) a history of AD. High frequency heart rate variability (HF-HRV) was assessed during sitting and standing baseline conditions and during a speech task where participants remained standing. Salivary cortisol was measured at baseline and at 15, 30, 45 and 60 min post-speech. Subjective anxiety was assessed with a visual analogue scale. Children of parents with AD displayed reduced HRV and a blunted cortisol response to the speech task compared to children of non-anxious parents. No risk group effect was found for anxiety ratings. These preliminary data suggest that healthy children of anxious parents exhibit altered stress reactivity to an acute laboratory stressor. Further research is needed to confirm findings and identify mechanisms that may account for altered self-regulation processes to a stressor in children at familial risk for AD.

Enhancing cardiac vagal activity: Factors of interest for sport psychology

Self-regulation plays a critical role in sport performance. An objective, psychophysiological marker of self-regulation is cardiac vagal activity, the activity of the vagus nerve regulating cardiac functioning. The aim of this paper is to provide an overview of factors influencing cardiac vagal activity, which can be useful for athletes. Specifically, we organize this overview in two main domains: personal factors and environmental factors. Among the personal factors, we discuss the behavioral strategies that can be used by athletes: nutrition, non-ingestive oral habits, water immersion, body temperature reduction, sleeping habits, relaxation methods, cognitive techniques, praying, music, and exercise. Among environmental factors, we discuss those linked to the social (i.e., contact with humans and animals) and physical (i.e., aromas, lights, sounds, temperature, outdoor, altitude) environment. Future research directions are given, as well as practical implications for athletes and coaches.

The magnitude of respiratory sinus arrhythmia of a large mammal (the horse) is like that of humans

Heart rate (FH) accelerates in inspiration and decelerates in expiration, a phenomenon known as Respiratory Sinus Arrhythmia (RSA). Although the presence of RSA has been documented in many species, how its magnitude compares among species is unknown. We asked whether the magnitude of RSA in a large mammal, the horse, differed from that of previously measured humans. From electrocardiogram and pneumography, the peaks and troughs of FH were identified breath-by-breath in four horses (Italian Saddlebred geldings) during resting wakefulness. RSA was computed as the peak-trough FH difference, in percent of mean FH. Horses had lower FH and respiratory frequency (FR) than humans, but similar FH/FR. RSA ranged between 6% and 15%, with an average of 9 ± 2%, not statistically different from the mean value in humans (12 ± 1%). Like in humans, in horses the FH/FR values below the mean had correspondingly lower RSA, while values above the mean had correspondingly higher RSA. If confirmed in other species, these results suggest that RSA is body size-independent. The correlation with FH/FR, rather than FH or FR, supports the view that RSA optimizes the coupling between pulmonary blood flow and ventilation.

Mechanisms of atrial fibrillation in athletes: what we know and what we do not know

Exercise is an emerging cause of atrial fibrillation (AF) in young individuals without coexisting cardiovascular risk factors. The causes of exercise-induced atrial fibrillation remain largely unknown, and conclusions are jeopardised by apparently conflicting data. Some components of the athlete's heart are known to be arrhythmogenic in other settings. Bradycardia, atrial dilatation and, possibly, atrial premature beats are therefore biologically plausible contributors to exercise-induced AF. Challenging findings in an animal model suggest that exercise might also prompt the development of atrial fibrosis, possibly due to cumulative minor structural damage after each exercise bout. However, there is very limited, indirect data supporting this hypothesis in athletes. Age, sex, the presence of comorbidities and cardiovascular risk factors, and genetic individual variability might serve to flag those athletes who are at the higher risk of exercise-induced AF. In this review, we will critically address current knowledge on the mechanisms of exercise-induced AF.

High vagally mediated resting-state heart rate variability is associated with superior action cascading

The neurovisceral integration model suggests that individual differences in heart rate variability (HRV), an index of vagal tone, may relate to prefrontal cortical activity and predict performance on cognitive control tasks. The aim of this study was to further verify this model by investigating the relationship between vagally-mediated resting-state HRV and action cascading, a crucial cognitive control function which refers to the ability to cope with multiple response options when confronted with various task goals. Resting-state HRV and performance on the stop-change paradigm, which provides a relatively well-established diagnostic measure of action cascading and response inhibition, was assessed in 88 healthy volunteers (age range 18-33). Compared to individuals with low resting-state HRV, participants with high resting-state HRV showed enhanced action cascading performance, both when a disruption (stopping) and change towards an alternative response were required simultaneously, and when requirements were cascaded (i.e. when the stopping process had already finished at the time the change was required). Our findings represent an important step towards extending our understanding of the neurovisceral integration model in cognitive control.

Reduced vagal tone in women with the FMR1 premutation is associated with FMR1 mRNA but not depression or anxiety

Background

Autonomic dysfunction is implicated in a range of psychological conditions, including depression and anxiety. The fragile X mental retardation-1 (FMR1) premutation is a common genetic mutation that affects ~1:150 women and is associated with psychological vulnerability. This study examined cardiac indicators of autonomic function among women with the FMR1 premutation and control women as potential biomarkers for psychological risk that may be linked to FMR1.

Methods

Baseline inter-beat interval and respiratory sinus arrhythmia (a measure of parasympathetic vagal tone) were measured in 35 women with the FMR1 premutation and 28 controls. The women completed anxiety and depression questionnaires. FMR1 genetic indices (i.e., CGG repeat, quantitative FMRP, FMR1 mRNA, activation ratio) were obtained for the premutation group.

Results

Respiratory sinus arrhythmia was reduced in the FMR1 premutation group relative to controls. While depression symptoms were associated with reduced respiratory sinus arrhythmia among control women, these variables were unrelated in the FMR1 premutation. Elevated FMR1 mRNA was associated with higher respiratory sinus arrhythmia.

Conclusions

Women with the FMR1 premutation demonstrated autonomic dysregulation characterized by reduced vagal tone. Unlike patterns observed in the general population and in study controls, vagal activity and depression symptoms were decoupled in women with the FMR1 premutation, suggesting independence between autonomic regulation and psychopathological symptoms that is atypical and potentially specific to the FMR1 premutation. The association between vagal tone and mRNA suggests that molecular variation associated with FMR1 plays a role in autonomic regulation.

Objectively-Measured Free-Living Physical Activity and Heart Rate Recovery

The purpose of this study was to examine the association of free-living, objectively-measured physical activity on treadmill-based heart rate recovery (HRR), a parameter known to associate with morbidity and mortality. Data was used from 2003 to 2004 NHANES. Physical activity was assessed via accelerometry, with HRR recovery assessed from a treadmill-based test. Heart rate recovery minute 1 (HRR₁) and minute 2 (HRR₂) were calculated. After adjustment, light and vigorous-intensity free-living physical activity, respectively, were associated with HRR₁ (β_adjusted = 0.69, 95% CI 0.22-1.14; β_adjusted 1.94, 95% CI 0.01-3.9) and HRR₂ (β_adjusted = 0.99, 95% CI 0.35-1.62; β_adjusted = 5.88, 95% CI 2.63-9.12). Moderate physical activity was not associated with HRR₁ (β_adjusted = 0.60, 95% CI -0.41 to 1.62), but was with HRR₂ (β_adjusted = 2.28, 95% CI 1.27-3.28). As free-living physical activity intensity increased, there was a greater association with HRR. This finding may provide mechanistic insight of previous research observations demonstrating intensity-specific effects of physical activity on various health outcomes.

Electrical Grounding Improves Vagal Tone in Preterm Infants

BACKGROUND

Low vagal tone (VT) is a marker of vulnerability to stress and the risk of developing necrotizing enterocolitis in preterm infants. Electric fields produced by equipment in the neonatal intensive care unit (NICU) induce an electric potential measurable on the skin in reference to ground. An electrical connection to ground reduces the skin potential and improves VT in adults.

OBJECTIVES

We aimed to measure the electric field strengths in the NICU environment and to determine if connecting an infant to electrical ground would reduce the skin potential and improve VT. We also wished to determine if the skin potential correlated with VT.

METHODS

Environmental magnetic flux density (MFD) was measured in and around incubators. Electrical grounding (EG) was achieved with a patch electrode and wire that extended to a ground outlet. We measured the skin potential in 26 infants and heart rate variability in 20 infants before, during, and after grounding. VT was represented by the high-frequency power of heart rate variability.

RESULTS

The background MFD in the NICU was below 0.5 mG, but it ranged between 1.5 and 12.7 mG in the closed incubator. A 60-Hz oscillating potential was recorded on the skin of all infants. With EG, the skin voltage dropped by about 95%. Pre-grounding VT was inversely correlated with the skin potential. VT increased by 67% with EG. After grounding, the VT fell to the pre-grounding level.

CONCLUSION

The electrical environment affects autonomic balance. EG improves VT and may improve resilience to stress and lower the risk of neonatal morbidity in preterm infants.

The Place of Stress and Emotions in the Irritable Bowel Syndrome

Our emotional state can have many consequences on our somatic health and well-being. Negative emotions such as anxiety play a major role in gut functioning due to the bidirectional communications between gut and brain, namely, the brain-gut axis. The irritable bowel syndrome (IBS), characterized by an unusual visceral hypersensitivity, is the most common disorder encountered by gastroenterologists. Among the main symptoms, the presence of current or recurrent abdominal pain or discomfort associated with bloating and altered bowel habits characterizes this syndrome that could strongly alter the quality of life. This chapter will present the physiopathology of IBS and explain how stress influences gastrointestinal functions (permeability, motility, microbiota, sensitivity, secretion) and how it could be predominantly involved in IBS. This chapter will also describe the role of the autonomic nervous system and the hypothalamic-pituitary axis through vagal tone and cortisol homeostasis. An analysis is made about how emotions and feelings are involved in the disruption of homeostasis, and we will see to what extent the balance between vagal tone and cortisol may reflect dysfunctions of the brain-gut homeostasis. Finally, the interest of therapeutic treatments focused on stress reduction and vagal tone enforcement is discussed.

[Hypotension and bradycardia before spinal anesthesia]

I report a case of hypotension and bradycardia before spinal anesthesia in a pregnant woman with mild to moderate hypertension treated with nifedipine and methyldopa, scheduled for an elective cesarean delivery. She had the history of neurally-mediated syncopes. Two main factors (increased vagal tone and adverse effects of antihypertensive drugs) could explain the hypotension and bradycardia before spinal anesthesia. Monitoring allowed recognizing the problem and corrected it. Thus, it was avoided a disaster in anesthesia, as hemodynamic changes after spinal anesthesia, they would have joined to previous hypotension and bradycardia, which would have caused even a cardiac arrest.

Intersections between cardiac physiology, emotion regulation and interpersonal warmth in preschoolers: Implications for drug abuse prevention from translational neuroscience

BACKGROUND

Early childhood is characterized by dramatic gains in emotion regulation skills that support social adjustment and mental health. Understanding the physiological substrates of healthy emotion regulation may offer new directions for altering trajectories toward initiation and escalation of substance abuse. Here, we describe the intersections between parasympathetic and sympathetic tone, emotion regulation and prosocial behavior in a high-risk sample of preschoolers.

METHOD

Fifty-two 3-6 year old children completed an assessment of attention regulation in response to affective stimuli. Cardiac respiratory sinus arrhythmia, an index of parasympathetic tone, and pre-ejection period, a marker of sympathetic activation, were recorded at rest and while children engaged in social interactions with their mothers and an unfamiliar research assistant. Mothers reported on children's emotional reactivity and prosocial behavior.

RESULTS

Controlling for age and psychosocial risk, higher parasympathetic tone predicted better attention regulation in response to angry emotion and higher levels of prosocial behavior, whereas a reciprocal pattern of higher parasympathetic tone and lower sympathetic arousal predicted better attention in response to positive emotion and lower emotional reactivity. Children exposed to fewer risk factors and higher levels of maternal warmth were more able to sustain a high level of parasympathetic tone during interaction episodes.

CONCLUSIONS

Findings suggest that autonomic measures represent biomarkers for socio-emotional competence in young children. They also point to the importance of early experiences in the establishment of physiological regulation and the promise of family-based intervention to promote healthy emotion regulation and prevent substance dependence in high-risk populations.

Immediate Effects of Bhramari Pranayama on Resting Cardiovascular Parameters in Healthy Adolescents

INTRODUCTION

In yoga, Pranayama has a very important role in maintaining sound health. There is some strong scientific basis on constant physiological changes produced when pranayama is practiced for long duration. Still, there exists a dearth of literature on the effect of Bhramari pranayama (Bhr.p) on physiological systems.

AIM

To assess the immediate effect of Bhramari pranayama (Bhr.P) practice on the resting cardiovascular parameters in healthy adolescents.

MATERIALS AND METHODS

Sixty apparently healthy adolescents of both sex participated in the study. They were randomly divided into Bhr.P (n-30) and control (n-30) group. Informed consent was obtained after explaining the detailed procedure of the study. Bhr.P group practiced Bhramari pranayama for 45 min (5 cycles) and control group was allowed to do normal breathing (12-16 breath /min). Heart rate (HR) was assessed by radial artery palpation method and blood pressure was recorded in supine position after 5 minutes of rest by sphygmomanometer.

RESULTS

The HR reduced significantly (p-0.001) in Bhr.P group. BP indices, Pulse Pressure (PP), Mean Arterial Pressure (MAP), Rate Pressure Product (RPP) and Double Product (DoP) significantly decreased after Bhr.p practice compared with control. Pre and Post inter group analysis also showed that significant reduction in HR and BP indices in Bhr.P group.

CONCLUSION

Present study showed that Bhr.P practice produces relaxed state and in this state parasympathetic activity overrides the sympathetic activity. It suggests that Bhramari pranayama improves the resting cardiovascular parameters in healthy adolescents.

An investigation of vago-regulatory and health-behavior accounts for increased inflammation in posttraumatic stress disorder

OBJECTIVE

Posttraumatic stress disorder (PTSD) has been linked to chronic inflammation, a condition that poses a risk for cardiovascular disease. Attenuated vagal activity has been proposed as a potential mediator of PTSD and inflammation, although associated behavioral health risks-namely cigarette smoking and alcohol dependence-might also account for that link.

METHODS

Inflammation was quantified by fasting serum concentrations of C-reactive protein (CRP), tumor necrosis factor (TNF)-α, interleukin (IL)-10, and thymus- and activation-regulated chemokine (TARC)/CCL17 collected from 85 participants with PTSD and 82 without PTSD. Latent variable modeling was used to assess the relationship between PTSD symptom severity and inflammation along with potential mediators vagal activity (respiratory sinus arrhythmia; RSA), smoking status, and lifetime alcohol dependence.

RESULTS

PTSD symptom severity was associated with increased inflammation (β=.18, p=.02). However, this association was reduced in models that adjusted for RSA, smoking status, and lifetime alcohol dependence. Independent mediation effects were deemed significant via bootstrapping analyses. Together, RSA, smoking status, and lifetime alcohol dependence accounted for 95% of the effect of PTSD symptom severity on inflammation.

CONCLUSION

Although RSA accounted for a modest proportion of the association between posttraumatic stress and pro-inflammatory responses, behavioral factors-specifically cigarette smoking and alcohol dependence-proved to be larger mediators. The benefits of PTSD treatment may be enhanced by additional interventions aimed at modifying these health behaviors.

Resting vagal tone is negatively associated with suicide ideation

BACKGROUND

The present study aimed at investigating whether resting vagally mediated heart rate variability (HRV) as a trait-like biomarker of cognitive inhibitory control capacity is related to suicide ideation in a sample without suicide attempt history.

METHODS

Thirty-seven healthy students participated voluntarily (18 to 34 years, M=24.5, SD=4.1; 73.0% female). Time and frequency measures of HRV were derived from an electrocardiogram that was recorded using Einthoven's Triangle lead II. Participants filled in the Rasch-based Depression Screening and four questions concerning lifetime suicide ideation (SI). Bivariate Pearson's and partial (controlling for depression severity) correlation coefficients were calculated between SI and measures of vagally mediated HRV.

RESULTS

A significant correlation between the ln10-transformed high-frequency band of resting vagally mediated HRV and SI was found (r=-.33, p<.05). Correlations did not change substantially when controlling for depression. Mean heart rate as a time domain measure also significantly correlated with SI while controlling for depression (r=.36, p<.05). A trend correlation between SI and Root Mean Square of Successive Differences between interbeat intervals emerged.

LIMITATIONS

SI was assessed with a composite score of four items measuring SI. Future studies should consider using more comprehensive assessment instruments.

CONCLUSIONS

The relation between resting vagally mediated HRV and suicide ideation may be interpreted as indicating that reduced inhibitory cognitive control capacity may be a risk factor for suicidality. It may act already early in the suicidal process, before suicidal behavior develops and should be further investigated as potentially clinically important physiological predictor of suicidality.

Cardiorespiratory responses in an Antarctic fish suggest limited capacity for thermal acclimation

Polar fishes are at high risk from increasing seawater temperatures. Characterising the physiological responses to such changes may both clarify mechanisms that permit life under extreme conditions and identify limitations in the response to continued global warming. We hypothesised that Notothenia coriiceps would show physiological compensation after an acute exposure to 5°C, and following 6 weeks warm acclimation, compared with ambient temperature (0°C). However, initial tachycardia (22.4±2.8 versus 12.8±1.1 min(-1); P<0.01) was not reversed by acclimation (21.0±1.9 min(-1)). Hyperventilation (45.5±3.1 versus 21.4±2.4 breaths min(-1); P<0.001) showed a modest reduction following acclimation (38.0±2.9 min(-1); P<0.05), while resting oxygen consumption (0.52±0.08 mmol kg(-1) h(-1)) was acutely increased at 5°C (1.07±0.10 mmol kg(-1) h(-1); P<0.001) but unchanged with acclimation. Autonomic blockade showed initial responses were mainly of vagal origin, with little subsequent withdrawal or recovery in long-term heart rate variability after 6 weeks. Given the limited cardiorespiratory capacity to withstand sustained warming, effective physiological compensation probably requires a more prolonged acclimation period.

A yoga & exercise randomized controlled trial for vasomotor symptoms: Effects on heart rate variability

OBJECTIVES

Heart rate variability (HRV) reflects the integration of the parasympathetic nervous system with the rest of the body. Studies on the effects of yoga and exercise on HRV have been mixed but suggest that exercise increases HRV. We conducted a secondary analysis of the effect of yoga and exercise on HRV based on a randomized clinical trial of treatments for vasomotor symptoms in peri/post-menopausal women.

DESIGN

Randomized clinical trial of behavioral interventions in women with vasomotor symptoms (n=335), 40-62 years old from three clinical study sites.

INTERVENTIONS

12-weeks of a yoga program, designed specifically for mid-life women, or a supervised aerobic exercise-training program with specific intensity and energy expenditure goals, compared to a usual activity group.

MAIN OUTCOME MEASURES

Time and frequency domain HRV measured at baseline and at 12 weeks for 15min using Holter monitors.

RESULTS

Women had a median of 7.6 vasomotor symptoms per 24h. Time and frequency domain HRV measures did not change significantly in either of the intervention groups compared to the change in the usual activity group. HRV results did not differ when the analyses were restricted to post-menopausal women.

CONCLUSIONS

Although yoga and exercise have been shown to increase parasympathetic-mediated HRV in other populations, neither intervention increased HRV in middle-aged women with vasomotor symptoms. Mixed results in previous research may be due to sample differences. Yoga and exercise likely improve short-term health in middle-aged women through mechanisms other than HRV.

Structural brain correlates of heart rate variability in a healthy young adult population

The high frequency component of heart rate variability (HRV) has reliably been shown to serve as an index of autonomic inhibitory control and is increasingly considered as a biomarker of adaptability and health. While several functional neuroimaging studies identified associations between regional cerebral blood flow and HRV, studies on structural brain correlates of HRV are scarce. We investigated whether interindividual differences in HRV are related to brain morphology in healthy humans. Thirty participants underwent HRV recording at rest subsequent to structural magnetic resonance imaging. Cortical reconstruction and subcortical volumetry were performed with the Freesurfer image analysis suite. The amount of resting HRV was positively correlated with the cortical thickness of an area within the right anterior midcingulate cortex (aMCC). Consistent with existing studies implicating forebrain regions in cardiac regulation, our findings show that the thickness of the right aMCC is associated with the degree of parasympathetic regulation of heart rate. Evidence for the neural correlates of interindividual differences in HRV may complement our understanding of the mechanisms underlying the association between HRV and self-regulatory capacity.

Assessment of cardiac autonomic tone in conscious rats

Cardiac autonomic tone can be assessed either by estimating separately vagal and sympathetic tones or by evaluating the net effect of their interaction, the so-called sympathovagal balance (SVB). To compare the most commonly used methods in rats, telemetric recordings of the electrocardiogram were performed in normotensive WKY rats, and in groups of spontaneously hypertensive (SHR) rats that were either untreated or chronically treated with the cholinesterase inhibitor, pyridostigmine, to enhance vagal tone. Cardiac autonomic blockers were administered alone and in combination, so that heart rate (HR) could be measured (1) under resting conditions, (2) with either autonomic branch blocked, and (3) with both branches blocked (which provided intrinsic HR, iHR). SVB was assessed as the ratio of resting HR to iHR. This calculation pointed to a sympathetic predominance in untreated SHRs and even more so in WKY rats, and to a marked vagal predominance in pyridostigmine-treated SHRs. By contrast, the ratio between low and high frequency components (LF/HF) of RR interval spectra did not significantly differ between the groups. Each autonomic tone was quantified as the HR change induced by its selective blocker or as the difference between iHR and HR after blockade of its counterpart. Both pharmacological methods indicated vagal enhancement in treated SHRs, but provided opposite results in terms of vagal vs. sympathetic predominance. These data seriously question the use of the LF/HF ratio as an index of SVB, and the possibility to reliably estimate vagal and sympathetic tones separately through current pharmacological approaches in conscious rats.

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.

Autonomic nervous system functioning associated with psychogenic nonepileptic seizures: Analysis of heart rate variability

OBJECTIVE

Psychogenic nonepileptic seizures (PNESs) resemble epileptic seizures but originate from psychogenic rather than organic causes. Patients with PNESs are often unable or unwilling to reflect on underlying emotions. To gain more insight into the internal states of patients during PNES episodes, this study explored the time course of heart rate variability (HRV) measures, which provide information about autonomic nervous system functioning and arousal.

METHODS

Heart rate variability measures were extracted from double-lead electrocardiography data collected during 1-7days of video-electroencephalography monitoring of 20 patients with PNESs, in whom a total number of 118 PNESs was recorded. Heart rate (HR) and HRV measures in time and frequency domains (standard deviation of average beat-to-beat intervals (SDANN), root mean square of successive differences (RMSSD), high-frequency (HF) power, low-frequency (LF) power, and very low-frequency (VLF) power) were averaged over consecutive five-minute intervals. Additionally, quantitative analyses of Poincaré plot parameters (SD1, SD2, and SD1/SD2 ratio) were performed.

RESULTS

In the five-minute interval before PNES, HR significantly (p<0.05) increased (d=2.5), whereas SDANN (d=-0.03) and VLF power (d=-0.05) significantly decreased. During PNES, significant increases in HF power (d=0.0006), SD1 (d=0.031), and SD2 (d=0.016) were observed. In the five-minute interval immediately following PNES, SDANN (d=0.046) and VLF power (d=0.073) significantly increased, and HR (d=-5.1) and SD1/SD2 ratio (d=-0.14) decreased, compared to the interval preceding PNES.

CONCLUSION

The results suggest that PNES episodes are preceded by increased sympathetic functioning, which is followed by an increase in parasympathetic functioning during and after PNES. Future research needs to identify the exact nature of the increased arousal that precedes PNES.

Thinking about breathing: Effects on respiratory sinus arrhythmia

Respiratory sinus arrhythmia (RSA), the increase and decrease in instantaneous heart rate (HR) with inspiration and expiration, is commonly evaluated as function of breathing frequency f. However, to the extent that RSA plays a role in the efficiency of gas exchange, it may be expected to correlate better with HR/f ('breathing specific heart rate') than with f, because the former is a better reflection of the cardio-respiratory coupling. We measured RSA breath-by-breath in 209 young men and women during spontaneous breathing and during volitional breathing under auditory cues at vastly different f. In either case, and for both genders, RSA correlated better with HR/f than with f. As HR/f increased so did RSA, in a linear manner. When compared on the basis of HR/f, RSA did not differ significantly between spontaneous and volitional breathing. It is proposed that RSA is a central mechanism that ameliorates the matching between the quasi-continuous pulmonary blood flow and the intermittent airflow, irrespective of the type of ventilatory drive (cortical or autonomic).

Supine effect of passive cycling movement induces vagal withdrawal

[Purpose] The purpose of this study was to examine changes in vagal tone during passive exercise while supine. [Subjects and Methods] Eleven healthy males lay supine for 5 min and then performed passive cycling for 10 min using a passive cycling machine. The lower legs moved through a range of motion defined by 90° and 180° knee joint angles at 60 rpm. Respiratory rates were maintained at 0.25 Hz to elicit respiratory sinus arrhythmia. Heart rate variability was analyzed using the time domain analysis, as the root mean squared standard differences between adjacent R-R intervals (rMSSD), and spectrum domain analysis of the high frequency (HF) component. [Results] Compared to rest, passive cycling decreased rMSSD (rest, 66.6 ± 92.6 ms; passive exercise, 53.5 ± 32.5 ms). However, no significant changes in HR or HF were observed (rest, 68.2 ± 6.9 bpm, 65.6 ± 12.0 n.u.; passive exercise, 70.2 ± 7.2 bpm, 67.9 ± 10.0 n.u.). [Conclusion] These results suggest that passive exercise decreases rMMSD through supine-stimulated mechanoreceptors with no effect on HR or HF. Therefore, rMSSD is not affected by hydrostatic pressure during passive cycling in the supine position.