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

Heart Rate Variability Predicts Therapy Outcome in Anxiety Disorders: The Role of Inhibitory Learning

Exposure therapy has been shown to be useful for the treatment of anxiety disorders. However, there are individual differences in the extent to which this intervention is effective in reducing symptoms, and a substantial number of patients may experience a return of fear (ROF). The factors associated with successful therapy outcomes are an important topic of investigation as these factors might influence the nature of the interventions as well as enhance our understanding of the process associated with the disorder and its treatment. Here, we investigated the effect of resting heart rate variability (HRV) on ROF following exposure therapy in social phobics. In particular, using path modeling, we assessed the hypothesis that resting HRV prospectively predicts inhibitory learning, which, in turn, prospectively predicts ROF at follow-up. Forty adult participants (60% female) diagnosed with Social Anxiety Disorder were assigned to a single massed exposure therapy session. Self-reported behavioral and physiological responses were recorded pre-treatment, immediately following treatment, and at one-month follow-up. The Personalized Implicit Association Task (PIAT) was used as an implicit measure of inhibitory learning, and HF-HRV was taken as a measure of vagal activity. Results revealed that those with high pre-treatment HRV reported less negative implicit attitude towards public speaking after exposure (b = -0.044, p =.047) and showed reduced residual symptoms one month after treatment. (b = 2.247, p =.013). Taken together these results support exposure therapy models that emphasize the importance of inhibitory learning in extinction and are consistent with research linking HRV to inhibition.

Gritty Heart: Improved Heart Rate Variability Markers of Adaptive Physiological Response in Grit

Grit is a personality trait, conceptualized as perseverance of effort and consistency of interests in long-term goals. Previous research has shown that grit is associated with various positive outcomes, including well-being. Despite extensive research on grit, most studies relied on self-reported measures rather than objective measures. To address this gap, our study investigated the relationship between grit and physiological responses, focusing on resting-state heart rate variability (HRV)-a physiological marker of well-being and adaptability. Additionally, we examined whether this relationship was unique to grit and not explained by other related psychological constructs (i.e., conscientiousness and self-control). A total of 206 healthy college students participated in this study (Mage = 21.03, SD = 2.48, age range = 18-33; 111 women). Results of hierarchical regression analyses showed that grit significantly predicted resting-state HRV measures (i.e., RMSSD, SDNN, and HF) even after controlling for conscientiousness, self-control, age, gender, and respiration rate. These findings suggest that grit may play an important role in maintaining improved biological responses in daily life, beyond the effects of neighboring constructs.

New Mothers' Experiences of Childhood Adversity and Current Context of Economic Adversity Predict Parent and Infant RSA

This study examined the pathways from mothers' adverse childhood experiences (ACEs) to infants' respiratory sinus arrhythmia (RSA), testing potential mechanisms of current contextual risk, maternal RSA, and parenting in accounting for the intergenerational transmission of adversity. Participants were 200 first-time mothers and their infants living in low-income contexts. Mothers reported on ACEs and contextual risk (economic insecurity, cumulative risk) during their pregnancy (T1). Observed parenting behaviors and mothers' and infants' baseline RSA were obtained when the infants were 2-4 months of age (T2) and 4-6 months of age (T3). The results from path analyses showed that mothers' experiences of ACEs were related to higher current economic insecurity and cumulative risk. Higher current economic insecurity predicted lower baseline RSA at T2 in infants but not in mothers, whereas mothers' report of ACEs predicted lower maternal baseline RSA at T2. Higher maternal baseline RSA at T2 predicted relative increases in infant RSA from T2 to T3. Maternal responsiveness was unrelated to ACEs and current contextual risk but predicted relative increases in infant baseline RSA from T2 to T3, indicating an independent effect of parenting. The findings highlight potential pathways for the intergenerational transmission of experiences of adversity. Mothers' own experiences of adversity as a child may impact a psychophysiological substrate of emotion regulation of infants through current economic insecurity and maternal emotional regulation, whereas maternal parenting appears to independently support a correlate of infant regulation.

Reactivity of the Autonomic Nervous System During Visual-Physical Incongruent Walking Conditions-A Virtual Reality Study

The force of gravity critically impacts locomotion regulation while walking on inclined surfaces. To construct an updated assessment about the gravitational consequences and change gait patterns accordingly, the central nervous system (CNS) integrates multiple sensorial cues, including vestibular and proprioceptive (i.e., body-based cues) and visual. Not much is known about the contribution of the autonomic nervous system (ANS) to locomotion regulation, especially when multiple types of sensorial cues are involved. Here we examine the responsiveness of the ANS, as reflected by cardiac reactivity, for example heart rate (HR) and heart rate variability (HRV), to coherent versus non-coherent sensorimotor signaling. Fourteen healthy young participants completed level, uphill, and downhill self-paced walking trials in a virtual reality (VR) environment in which the incline of the visual scene was either congruent or incongruent with the physical incline of the walking surface. We found that during level walking, incongruent visual cues (i.e., up/downhill scenery) triggered alterations in ANS balance, reflected in HRV decrease and in a residual increase of HR. Taken together with the fact that an ultimate change in gait patterns requires alterations in cardiac resources, we speculate that ANS function and its responsive modes of action are, in fact, facilitating adaptive behavior.

Does Resting Respiratory Sinus Arrhythmia Buffer the Link from Trait Anger to Aggression in Young Adults?

From both psychological and physiological perspectives, the current study focused on investigating the moderating role of resting respiratory sinus arrhythmia (resting RSA) in the association between trait anger and aggression. One-hundred and sixteen college students (73.28 % females, Mage= 19.15, SD = 0.92) reported their trait anger and aggression. RSA data was collected during a resting period in the laboratory. The results showed that trait anger interacted with resting RSA in predicting aggression, such that a positive association between trait anger and aggression was found among participants with lower, rather than higher, resting RSA. Our findings suggested that high resting RSA may be a protective physiological factor in the relation between trait anger and aggression among college students.

Prefrontal executive function enhanced by prior acute inhalation of low-dose hypoxic gas: Modulation via cardiac vagal activity

Today, diverse psychophysiological stresses, such as severe time constraints and busy lifestyles, contribute to cardiac parasympathetic dysfunction, potentially leading to mental health issues and declines in critical executive functions. It is essential to develop accessible methods of enhancing cardiac vagal activity (CVA) to mitigate these adverse effects. We previously demonstrated that inhaling low-dose hypoxic gas (FIO₂: 13.5 %) for 10 min acts as a hormetic stressor, inducing a supercompensation effect in CVA post-hypoxia. Since CVA is a key mediator of brain-heart communication in that it influences executive functions by interacting with the left dorsolateral prefrontal cortex (L-DLPFC), increasing CVA may enhance cognitive ability. We hypothesized that acute low-dose hypoxia leads to enhanced executive function via CVA modulation. Twenty-six individuals participated in both normobaric hypoxia (NH; FIO₂: 13.5 %) and normoxia (NN; ambient air) conditions. CVA, measured through heart rate variability, was analyzed three times: pre-hypoxia/normoxia, hypoxia/normoxia, and post-hypoxia/normoxia. Executive function was assessed using the Stroop task before and after exposure, and prefrontal cortex activity during the task was monitored using multichannel functional near-infrared spectroscopy. A supercompensation of CVA occurred concomitantly with a reduction in heart rate following hypoxic gas inhalation. Stroop performance improved with increased task-related activation of the L-DLPFC in the NH condition. Causal mediation analysis revealed that the post-hypoxia enhancement of CVA mediated improvements in Stroop performance and increased L-DLPFC activation. These findings strongly support our hypothesis that the enhancement of CVA following hormetic hypoxic stress contributes to improved executive function, broadening the scope of neurocognitive approaches for effectively enhancing executive function.

Cardiac vagal modulation predicts decision-making in sacrificial and everyday moral dilemmas

Cardiac vagal modulation indicates the self-regulatory activity of the autonomic nervous system and can thus be used to assess an individual's ability to integrate physiological, cognitive, and emotional responses in the decision-making process. In this paper, cardiac vagal modulation, quantified by heart rate variability (HRV), was used to predict decision-making in two types of moral dilemmas: First, sacrificial dilemmas which create a moral conflict between utilitarian (acting to maximise aggregate well-being by sacrifice) and deontological (rejecting the sacrifice) alternatives; second, everyday dilemmas which create a conflict between altruistic (acting non-selfish) and egoistic (acting self-centered) alternatives. HRV was analysed in 112 healthy participants before, during, and after decision-making, allowing to assess not only self-regulatory ability (resting HRV) but also self-regulatory capacities (HRV during and after decision-making). HRV predicted concrete decisions, but effects were only found in women. In sacrificial dilemmas, deontological women showed a stronger vagal withdrawal but also a faster cardiac vagal recovery compared to high utilitarian women. In everyday moral dilemmas, altruism was associated with reduced vagal outflow and increased sympathetic activity. Findings suggest differences in the acquisition of self-regulatory capacities between decision-makers in both types of moral dilemmas, which can be measured by HRV.

Working memory training improves general emotion regulation: Evidence from resting HF-HRV

It has been argued that Working Memory Training (WMT) has the potential to improve emotional regulation. In this study, we investigated whether 20 days of WMT improved general emotion regulation in healthy participants using resting high-frequency heart rate variability (HF-HRV) as a physiological indicator of general emotion regulation, and examined its maintenance effect three months later. The analysis of the linear mixed-effects (LME) model revealed that after completing 20 days of WMT, there was a significant improvement in the individual's resting HF-HRV. This improvement was observed to be stable even after 3 months, and the resting HF-HRV of the training group was significantly better than that of the control group. In addition, there was a positive correlation between the gain in resting HF-HRV and the gain in working memory in the training group, which persisted from post-test to follow-up, suggesting that the greater the gain in working memory, the greater the gain in emotional regulation. Our study provides the first evidence that WMT can effectively improve general emotional regulation ability, and this improvement can last for at least three months.

Effect of deep pressure input on autonomic regulation during wisdom tooth extraction: From waiting room to surgery

Background and purpose

Tooth extraction is a common dental procedure associated with heightened anxiety, particularly during the waiting period before treatment. This stress response is regulated by the autonomic nervous system (ANS), comprising the sympathetic nervous system (SNS), which induces excitatory responses, and the parasympathetic nervous system (PsNS), which promotes relaxation. Deep pressure input, delivered through weighted vests and blankets, has been shown to shift ANS dominance from the SNS to the PsNS, facilitating stress reduction. This study investigated the effects of deep pressure input on ANS modulation using a weighted vest during the waiting phase and a weighted blanket during the tooth extraction phase.

Materials and methods

Healthy adults were randomly assigned to a control group or an experimental group. The control-group subjects underwent wisdom tooth extraction without deep pressure input, while the experimental-group subjects wore a weighted vest during the waiting phase and used a weighted blanket during the tooth extraction procedure. Heart rate (HR), low-frequency heart rate variability (LF-HRV), and high-frequency heart rate variability (HF-HRV) were measured to assess ANS activity.

Results

The control-group subjects exhibited increased HR, elevated LF-HRV, and reduced HF-HRV, indicating the stress-induced sympathetic activation. In contrast, the experimental-group subjects showed significantly lower HR and higher HF-HRV, demonstrating the enhanced parasympathetic activation that persists throughout the tooth extraction procedure.

Conclusion

Deep pressure input for high-anxiety patients can effectively reduce stress and enhances the parasympathetic activation during the wisdom tooth extraction procedure. After a large-scale clinical study, it may enter clinical application for high-anxiety patients.

Self-compassion modulates autonomic and psychological responses to stress among adults with generalized anxiety disorders

Background

Self-compassion is associated with emotional well-being, yet its benefits in generalized anxiety disorder (GAD) patients remain unclear. This study investigated the impact of self-compassion on emotional and physiological stress responses in individuals diagnosed with GAD.

Methods

Seventy-seven GAD patients were categorized into high (n = 39) and low (n = 38) self-compassion groups using the Self-Compassion Scale. Electrocardiograms were recorded during a stress-inducing task, in which negative feedback was provided on personal intelligence and career development. Participants reported state anxiety and perceived stress pre- and post-task.

Results

When exposed to a stressor, individuals with higher self-compassion had lower heart rates (t (75) = -2.06, p = 0.043), higher heart rate variability (t (75) = 2.73, p = 0.04), and lower anxiety (t (75) = -2.07, p = 0.041) compared to the lower self-compassion group. Moreover, heart rate variability was negatively correlated with anxiety across patients (r = -0.31, df = 75, p = 0.03).

Conclusion

These results highlight the role of self-compassion in managing psychological and physiological responses to stress in GAD patients and indicate the potential of self-compassion interventions in GAD treatments.

The monthly rhythm of the brain-heart connection

Integrating the menstrual cycle into heart-brain research is a crucial step toward advancing sex-specific medicine and improving outcomes for female brain and body health.

The Moderating Role of Context Processing in the Intergenerational Transmission of Posttraumatic Stress

This pilot study aimed to understand the moderating role of context processing (i.e. encoding and memorizing) when mothers are confronted with threatening stimuli and undergo physiologic monitoring in order to understand a possible mechanism favoring intergenerational transmission of posttraumatic stress. Thirty-one mothers (M age = 33.87 years, SD = 4.14) and their toddlers (M age = 22.66 months, SD = 7.01) participated in the study. Mothers reported adverse life events (ALE), their current posttraumatic stress symptoms (PTSS), as well as regulatory problems of their toddler. Mothers performed a context-encoding and -memory (CEM) task including emotional facial expressions (especially angry faces considered as threatening stimuli) embedded into photo-backgrounds, after which they were asked to recognize both the faces and contexts. Maternal heart rate variability (HRV) was measured during resting state. Maternal current PTSS, but not ALE, had impact on child dysregulation only for mothers with poor context processing (β = 0.014, p = .017). Baseline HRV was negatively correlated with the recognition of contexts previously associated with angry faces (ρ = -.53, p = .006), and marginally with the recognition of angry faces (ρ = -.37, p = .059). This pilot study identifies psychophysiological markers (i.e. CEM, HRV) that may influence the intergenerational transmission of posttraumatic stress. This may open new avenues in early identification and intervention with traumatized mothers and their toddlers.

A method for dyadic cardiac rhythmicity analysis: Preliminary evidence on bilateral interactions in fetal-maternal cardiac dynamics

Cardiac activity responds dynamically to metabolic demands and neural regulation. However, little is known about this process during pregnancy. Reports show occasional fetal-maternal heart rate couplings, but it has remained unclear whether these couplings extend to more complex oscillatory patterns of the heart rhythm. We developed a framework of time-varying measures of heart rate and rhythm, to test the presence of co-varying patterns in concurrent maternal and fetal measures (late pregnancy dataset, n = 10, and labour dataset, n = 12). These measures were derived from first and second-order Poincaré plots, with the aim to describe changes in short- and long-term rhythmicity, but also the dynamic shifts in acceleration and deceleration of heart rate. We found episodes of maternal-fetal co-varying patterns of cardiac rhythm in all the measures explored, in both datasets (at least 90% of the dataset presented a significant maternal-fetal correlation in each measure, with P < 0.001), with dynamic delays suggesting bilateral interactions at different time scales. We also found that these couplings intensify during labour (test between late pregnancy vs. labour datasets, P < 0.0015 in all second-order Poincaré plot-derived measures). While most literature suggests that the fetal heart responds to maternal breathing patterns or contractions, we propose the possibility that the fetal heart may also have a signalling function in the context of co-regulatory mechanisms and maternal inter-organ interactions. Understanding these complex visceral oscillations in utero may enhance the assessment of a healthy fetal development.

Vagally-mediated heart rate variability longitudinally predicts test anxiety in university students

BACKGROUND AND OBJECTIVES

Self-regulatory processes, namely behavioral regulation (in terms of executive functions) and emotion regulation, are assumed to be central for test anxiety. Both self-regulation components, along with vagally-mediated heart rate variability (HRV) - a proposed concomitant of top-down self-regulation - are associated with anxiety.

DESIGN

A longitudinal design was adopted to test the hypotheses that (1) higher vagally-mediated HRV, (2) adaptive emotion regulation and (3) better executive functioning (i.e., higher inhibitory control) at the semester beginning (t1) predict lower levels of test anxiety at the end of the semester (t2).

METHODS

A sample of N = 70 (58 female) university students (M [SD] age = 25.04 [7.14] years) completed a measurement of resting HRV (RMSSD), performed an affective go/no-go task, and reported on emotion regulation and test anxiety at t1. Test anxiety and certain examination characteristics were assessed at t2. A hierarchical regression analysis was conducted to test the hypotheses.

RESULTS

Supporting hypothesis 1, HRV at t1 significantly predicted test anxiety at t2, whereas emotion regulation and inhibitory control were no significant predictors.

CONCLUSIONS

As vagally-mediated HRV seems meaningful for the prediction of test anxiety, interventions designed to reduce test anxiety could benefit from incorporating HRV biofeedback training.

Substance Use is Associated With College Students' Acute Parasympathetic Nervous System Responses to Challenge

College students use substances for varied reasons, including to cope with stress. The parasympathetic nervous system (PNS) regulates bodily functions to promote energy conservation (the 'rest and digest' response), and individuals differ in their physiological sensitivity to challenge. It remains unclear whether greater PNS responses (i.e., declines in PNS activity, termed vagal withdrawal) to challenge could suggest difficulty regulating and thereby confer risk for using substances in community samples. We hypothesised that lower resting PNS activity and greater PNS responses to a challenge task would be associated with more frequent substance use (i.e., alcohol use, binge drinking, cannabis use). College students (N = 152; Mage = 20.5, SD = 3.2; 73.8% female) reported their past month frequency of substance use and completed a laboratory-based challenge task while having an electrocardiogram administered to derive respiratory sinus arrhythmia (RSA), a measure of PNS activity. They watched a 4-min neutral video (resting baseline) and then traced a star with their nondominant hand while only seeing the mirror reflection of their hand (challenge). Higher resting RSA was related to more frequent cannabis use. Individuals with larger declines in RSA from the video to the task (i.e., greater PNS responses) tended to use each substance more frequently. RSA recovery from the task was not related to substance use. Taken together, college students who are more physiologically responsive to challenge may use substances more frequently, potentially as a means of coping. Biofeedback interventions can be investigated for reducing college students' substance use risk.

Differential Analysis of Heart Rate Variability in Repeated Continuous Performance Tests Among Healthy Young Men

OBJECTIVE

Executive function correlates with the parasympathetic nervous system (PNS) based on static heart rate variability (HRV) measurements. Our study advances this understanding by employing dynamic assessments of the PNS to explore and quantify its relationship with inhibitory control (IC).

METHODS

We recruited 31 men aged 20-35 years. We monitored their electrocardiogram (ECG) signals during the administration of the Conners' Continuous Performance Test-II (CCPT-II) on a weekly basis over 2 weeks. HRV analysis was performed on ECG-derived RR intervals using 5-minute windows, each overlapping for the next 4 minutes to establish 1-minute intervals. For each time window, the HRV metrics extracted were: mean RR intervals, standard deviation of NN intervals (SDNN), low-frequency power with logarithm (lnLF), and high-frequency power with logarithm (lnHF). Each value was correlated with detectability and compared to the corresponding baseline value at t0.

RESULTS

Compared with the baseline level, SDNN and lnLF showed marked decreases during CCPT-II. The mean values of HRV showed significant correlation with d', including mean SDNN (R=0.474, p=0.012), mean lnLF (R=0.390, p=0.045), and mean lnHF (R=0.400, p=0.032). In the 14th time window, the significant correlations included SDNN (R=0.578, p=0.002), lnLF (R=0.493, p=0.012), and lnHF (R=0.432, p=0.031). Significant correlation between d' and HRV parameters emerged only during the initial CCPT-II.

CONCLUSION

A significant correlation between PNS and IC was observed in the first session alone. The IC in the repeated CCPT-II needs to consider the broader neural network.

A propensity score-adjusted HRV analysis of social avoidance and distress in patients with panic disorders

Panic disorder (PD) may accompany elevated social avoidance and distress (SAD). Higher SAD in patients with PD predicts a poorer prognosis and response to treatment. As heart rate variability (HRV) reflects the self-regulatory capacity underlying SAD, applying HRV to distinguish PD heterogeneity would be clinically beneficial in formulating personalized treatment strategies. We hypothesized that HRV would be lower in patients with PD and severe SAD (PD-SAD group) than in those without SAD (PD group). A total of 288 patients met the eligibility criteria, with complete collection of variables of interest and HRV. The inverse probability of treatment weighting (IPTW) method was used to balance the groups for the baseline characteristics of patients. Following IPTW adjustment, the average treatment effects were computed using inverse propensity weighting with regression adjustment (IPW-RA). All characteristics were similar in both groups after IPTW adjustment. The PD-SAD group showed a decreased tendency in time domain parameters, including mean heart rate, SDNN, RMSSD, and pNN50 with a nonlinear domain of SD1. However, no significant intergroup differences were observed in the frequency domain. Higher SAD in PD was associated with reduced HRV, mainly in the time domain, which may be attributed to the shared neural networks between dysfunctional self-regulation statuses, as indexed by reduced HRV. As respiratory sinus arrhythmia is mainly reflected in the frequency domain, the time domain may be more reliable for identifying heterogeneity within patients with PD, who are frequently associated with respiratory pattern abnormalities.

Effects of Exergame Training on Executive Function and Heart Rate Variability in Middle-Aged and Older Adults: A Randomized Controlled Study

Exergame has become widely popular and offers great levels of cognitive demands, thus may facilitate cognitive benefits. In addition, researchers have proposed that cardiac autonomic function, assessed via heart rate variability (HRV), is associated with cognitive executive function. However, few exergame training studies have investigated this relationship. This study aimed to investigate the effects of 10-week exergame training on executive function and HRV in middle-aged and older adults. Ninety-one participants were randomly assigned to either an exergame training group (63.73 ± 4.48 years) or a control group (62.46 ± 4.77 years). The training program was 50 min per session, twice per week for 10 weeks. The control group was instructed to maintain their usual lifestyle. All participants completed questionnaires and received assessments of executive functions and electrocardiography at baseline and postintervention. Results revealed significant group-by-time interaction effects for the three indices of the digit span test and the total initiation time of the Tower of London task with better postintervention performances achieved by the exergame group. The 6 min walk test also improved significantly in the exergame group but not in the control group. No significant change in HRV was observed for both groups. There were significant correlations between HRV and digit span test scores. Our results suggest that the 10-week exergame training program was effective in improving executive functions of working memory, inhibitory control, and planning ability as well as aerobic fitness in middle-aged and older adults. Moreover, HRV was associated with improved executive function.

Autonomic regulation and comorbid symptoms in children with attention deficit hyperactivity disorder

OBJECTIVE

Vagally-mediated heart rate variability (vmHRV) is regarded as transdiagnostic marker of emotion regulation and cognitive control capacity. We analysed vmHRV of children with attention deficit/hyperactivity disorder (ADHD). Based on previous research, we expected to find comorbid symptom dimensions (i.e. internalizing symptoms, conduct problems (CP), and callous unemotional (CU) traits) to relate to vmHRV measures.

METHODS

The sample comprised 100 (70 boys) medication naïve children with ADHD. Children were 6 to 11 years old. High frequency HRV (HF-HRV) was measured at rest and during a delay of gratification task. Additionally, sympathetic reactivity was assessed via skin conductance responses (SCR). Comorbid symptoms were assessed by parent-report questionnaires and clinical interviews.

RESULTS

The multiple correlation between CU traits and the HF-HRV scores proved statistically significant. Higher CU traits were associated with higher HRV resting-state and response scores. CP were positively associated with the SCR score.

CONCLUSION

In children with ADHD, increased CU traits might point to a comparatively less impaired self-regulation capacity in the reward-related context. The result corresponds to findings from previous studies. In the future, CU traits should be considered in analyses of autonomic regulation in ADHD.

Heart rate variability, electrodermal activity and cognition in adults: Association with short-term indoor PM2.5 exposure in a real-world intervention study

BACKGROUND

Long-term effects of ambient fine particulate matter (PM2.5) exposure on mortality and morbidity are well established. The study aims to evaluate how short-term indoor PM2.5 exposure affects physiological responses and understand potential mechanisms mediating the cognitive outcomes in working-age adults.

METHODS

This real-world randomized single-blind crossover intervention study was conducted in an urban office setting, with desk-based air purifiers used as the intervention. Participants (N = 40) were exposed to average PM2.5 levels of 18.0 μg/m3 in control and 3.7 μg/m3 in intervention conditions. Cognitive tests, heart rate variability (HRV), and electrodermal activity (EDA) measures were conducted after 5 h of exposure. Self-reported mental effort, exhaustion, and task difficulty were collected after the cognitive tests.

RESULTS

Participants in the intervention condition had significantly higher HRV during cognitive testing, particularly in the standard deviation of normal-to-normal intervals (SDNN), root mean square of successive differences (RMSSD), and high-frequency power (HF) indices. Mediation analysis revealed that elevated PM2.5 exposure reduced HRV indices, which mediated the effect on two executive function-related cognitive skills out of 16 assessed skills. No significant differences were found in EDA, self-reported task difficulty, or exhaustion, but self-reported mental effort was higher in the control condition.

CONCLUSIONS

Lower indoor PM2.5 level was associated with reduced mental effort and higher HRV during cognitive testing. Furthermore, the association between indoor PM2.5 exposure and executive function might be mediated through cardiovagal responses. These findings provide insights on the mechanisms through which fine particle exposure adversely affects the autonomic nervous system and how this in turn affects cognition. The potential cardiovascular and cognitive health benefits of PM2.5 reduction warrants further research.

Resting vagally-mediated heart rate variability in the laboratory is associated with momentary negative affect and emotion regulation in daily life

Vagally-mediated heart rate variability (vmHRV) is a physiological index reflecting parasympathetic activity that has been linked to emotion regulation (ER) capacity. However, very limited research has examined associations of physiological indices of regulation such as vmHRV with emotional functioning in daily life. The few studies that exist have small samples sizes and typically focus on only a narrow aspect of ER or emotional functioning. In this study, we examined associations between vmHRV assessed in the laboratory and emotional/mental health functioning in daily life using a 7-day ecological momentary assessment design in 303 adult community participants. We hypothesized that higher resting vmHRV would be associated with higher positive affect (PA), lower negative affect (NA), less affective variability, greater well-being, fewer dysphoria symptoms, greater use of engagement ER strategies, and less use of avoidance ER strategies, as assessed in daily life. Results revealed that higher resting vmHRV in the laboratory (as indexed by both high frequency heart rate variability, HF-HRV, and the root mean of successive square deviations between heart beats, RMSSD) was significantly associated with less frequent use of avoidance ER strategies in daily life. Theoretical and clinical implications are discussed, including the association of vmHRV with negatively valenced, rather than positively valenced, daily life experiences.

The recovery of decreased executive attention in Tibetan migrants at high-altitude

Attention is one of the basic cognitive functions sensitive to high altitude, and most studies have focussed on exposure times of approximately 3 years; however, it is unclear how attention changes in migrants who have lived and worked at high altitude for nearly 20 years. We explored the dynamics of attentional networks and neurophysiological mechanisms in migrants over 3-20 years using the Attentional Network Test combined with Electrocardiograph and Electroencephalography and found a consistent quadratic correlation between exposure and executive control efficiency, P3 amplitude and heart rate variability (HRV), with a decrease followed by an increase/relative stability, with approximately 10 years being the breakpoint. However, neither linear nor quadratic trajectories were observed for the alerting and orienting network. Mediation analysis revealed that the P3 amplitude mediated the decrease and increase in executive control efficiency with exposure time depends on the breakpoint. Correlations between HRV and executive control efficiency and P3 amplitude suggest that U-shaped changes in executive control in migrants may be related to body homeostasis maintained by the autonomic nervous system, and that P3 amplitude may serve as a neurophysiological marker of migrants' adaptation/recovery from high-altitude exposure.

Differences in Emotion Expression, Suppression, and Cardiovascular Consequences Between Black and White Americans in the Midlife in the United States (MIDUS) Study

OBJECTIVE

Recent theoretical work suggests that the expression of emotions may differ among Black and White Americans, such that Black Americans engage more frequently in expressive suppression to regulate emotions and avoid conflict. Prior work has linked expressive suppression usage with increases in cardiovascular disease risk, suggesting that racialized differences in expressive suppression usage may be one mechanism by which racism "gets under the skin" and creates health disparities.

METHOD

To examine racialized differences in expressive suppression and blood pressure (a measure of cardiovascular disease risk), we used self-report and facial electromyography (fEMG) data from two cohorts of Black and White Americans from the Midlife in the United States (MIDUS) longitudinal study (MIDUS 2, n = 271, 34.7% Black, collected from 2004 to 2009; MIDUS Refresher 1, n = 114, 31.6% Black, collected from 2012 to 2016; total N = 385, 33.9% Black).

RESULTS

Black Americans reported engaging in expressive suppression more frequently than White Americans ( t (260.95) = 2.18, p = .002) and showed less corrugator fEMG activity during negative images ( t (969) = 2.38, pFDR = .026). Less corrugator activity during negative images was associated with higher systolic blood pressure only for Black Americans ( b = -4.63, t (375) = 2.67, p = .008).

CONCLUSION

Overall, results are consistent with theoretical accounts that Black Americans engage more frequently in expressive suppression, which in turn is related to higher cardiovascular risk. Additional research is needed to further test this claim, particularly in real-world contexts and self-reports of in-the-moment usage of expressive suppression.

Premenstrual syndrome is associated with differences in heart rate variability and attentional control throughout the menstrual cycle: A pilot study

INTRODUCTION

Most persons with an active menstrual cycle suffer from a range of aversive symptoms (e.g. reduced ability to concentrate) in the days before their menstruation - the premenstrual syndrome (PMS). Biological and cognitive mechanisms of PMS are poorly understood. It has been shown that vagally mediated heart rate variability (vmHRV), a physiological marker of self-regulation, decreases during the PMS-affected cycle phase (luteal phase) only in individuals with high PMS symptomology. This study investigates the specific associations between vmHRV, PMS symptomology and cognitive self-regulation (attentional control).

METHODS

In this between-subject study, participants completed an vmHRV baseline measurement through electrocardiography, a reaction time paradigm to measure attentional control (modified attention network test revised, ANT-R) and filled out a questionnaire regarding impact of PMS as well as current menstrual phase.

RESULTS

Mixed Model analysis showed interactions effects in the hypothesized direction. VmHRV was decreased during the luteal phase only in individuals with higher PMS. Analogously, performance in the Executive Functioning of the ANT-R task was reduced in the luteal compared to the follicular phase only in individuals with increased PMS symptoms. No effects were found in the Orienting Network Score.

DISCUSSION

The results point in the direction of associations between vmHRV, PMS and self-regulation. This could hint at common underlying mechanisms. Further research, however, must be conducted to examine causal pathways to confirm these associations.

The association between perceived social functioning and heart rate variability is mediated by subclinical depressive symptomatology and moderated by gender

Chronic loneliness and low perceived social support have been recognized as risk factors for both mental and cardiovascular disorders. It has been proposed that their link to psychophysiological problems may involve changes in parasympathetic activity. However, the exact underlying psychopathological mechanisms and the moderating effects of gender are still not thoroughly examined. Thus, the present study investigated associations between perceived social functioning and resting vagal tone in the context of potential cognitive and subclinical mediators and gender differences. Three hundred twenty-five young adults (aged 18-35, 180 women) underwent an electrocardiogram measurement of 6-minute resting heart rate variability (HRV). They also completed questionnaires assessing loneliness, perceived social support, social cognitive biases, depressive and social anxiety symptoms, and general mental health. In men, HRV was significantly and negatively associated with poorer perceived social functioning, depressive symptoms, and self-reported social cognitive biases, while in women, there was a quadratic link between HRV and depressive symptoms and HRV and general mental health. Moderated mediation analysis revealed that depressive symptoms fully mediated the relationship between perceived social functioning and HRV in men. The results suggest that decreased resting vagal tone in lonely individuals is linked to depressive symptomatology rather than to specific social cognitive biases and that this association is significant only in men.

Intraindividual variability in post-stroke cognition and its relationship with activities of daily living and social functioning: an ecological momentary assessment approach

INTRODUCTION

Ecological momentary assessment (EMA) is a methodological approach to studying intraindividual variation over time. This study aimed to use EMA to determine the variability of cognition in individuals with chronic stroke, identify the latent classes of cognitive variability, and examine any differences in daily activities, social functioning, and neuropsychological performance between these latent classes.

METHODS

Participants (N = 202) with mild-to-moderate stroke and over 3-month post-stroke completed a study protocol, including smartphone-based EMA and two lab visits. Participants responded to five EMA surveys daily for 14 days to assess cognition. They completed patient-reported measures and neuropsychological assessments during lab visits. Using latent class analysis, we derived four indicators to quantify cognitive variability and identified latent classes among participants. We used ANOVA and Chi-square to test differences between these latent classes in daily activities, social functioning, and neuropsychological performance.

RESULTS

The latent class analysis converged on a three-class model. The moderate and high variability classes demonstrated significantly greater problems in daily activities and social functioning than the low class. They had significantly higher proportions of participants with problems in daily activities and social functioning than the low class. Neuropsychological performance was not statistically different between the three classes, although a trend approaching statistically significant difference was observed in working memory and executive function domains.

DISCUSSION

EMA could capture intraindividual cognitive variability in stroke survivors. It offers a new approach to understanding the impact and mechanism of post-stroke cognitive problems in daily life and identifying individuals benefiting from self-regulation interventions.

The dynamic role of the left dlPFC in neurovisceral integration: Differential effects of theta burst stimulation on vagally mediated heart rate variability and cognitive-affective processing

Adapting to the ever-changing demands of the environment requires a complex interplay between cognitive-affective, neuronal, and autonomic processes. Vagally mediated heart rate variability (vmHRV) is positively associated with both cognitive-affective functioning and prefrontal cortex (PFC) activity. Accordingly, the Neurovisceral Integration Model has posited a shared role of the PFC in the regulation of cognitive-affective processes and autonomic nervous system (ANS) activity. While there are numerous correlational findings in this regard, no study so far has investigated whether the manipulation of PFC activity induces changes in vmHRV and cognitive-affective processing in an inter-dependent manner. In a sample of 64 participants, we examined the effects of continuous (cTBS; n = 21) and intermittent theta-burst stimulation (iTBS; n = 20) compared to sham stimulation (n = 23) over the left dorsolateral PFC (dlPFC) on vmHRV and cognitive-affective processing within an emotional stop-signal task (ESST). Our results revealed that both resting vmHRV and vmHRV reactivity predicted cognitive-affective processing. Furthermore, we found a dampening effect of cTBS on resting and on-task vmHRV, as well as an enhancing effect of iTBS on ESST performance. Our results show no direct association between vmHRV changes and ESST performance alterations following stimulation. We interpret our results in the light of a hierarchical model of neurovisceral integration, suggesting a dynamical situation-dependent recruitment of higher-order cortical areas like the dlPFC in the regulation of the ANS. In conclusion, our results highlight the complex interplay between PFC activity, autonomic regulation, and cognitive-affective processing, emphasizing the need for further research to understand the causal dynamics of the underlying neural mechanisms.

Respiratory Sinus Arrhythmia, Effortful Control, and Child Social Anxiety Symptoms

Emotion dysregulation is implicated in child social anxiety and its etiology. Child emotion dysregulation has been studied via physiological indicators (e.g., respiratory sinus arrhythmia [RSA]) and behavioral indicators (e.g., effortful control). Previous work suggests that physiological indicators of regulation may predict outcomes in a non-linear manner and must be considered within the context of other intrapersonal factors, perhaps including effortful control. To this end, the current study tested effortful control as a moderator of the relation between RSA and child social anxiety, considering both linear and curvilinear patterns and controlling for inhibited temperament, an established predictor of child anxiety. Children (n = 119; 44% female) participated when they were 4 years old and entering school age (5 to 7 years). Mothers reported on children's effortful control (age 4) and social anxiety (school age). Children's RSA (age 4) was calculated from electrocardiogram data when they were at rest (i.e., baseline RSA) and when they were giving a speech. Results indicated that when children were high in effortful control, lower baseline RSA predicted higher social anxiety symptoms. Tentative evidence emerged for a relation between greater suppression of RSA during the speech compared to baseline and higher social anxiety symptoms when children were low in effortful control. Results support assessing the temperamental domain of effortful control as a contextualizing factor in the relation between psychophysiology and child anxiety outcomes.

Examining the Light Heart Mobile Device App for Assessing Human Pulse Interval and Heart Rate Variability: Validation Study

BACKGROUND

Pulse interval is a biomarker of psychological and physiological health. Pulse interval can now be assessed using mobile phone apps, which expands researchers' ability to assess pulse interval in the real world. Prior to implementation, measurement accuracy should be established.

OBJECTIVE

This investigation evaluated the validity of the Light Heart mobile app to measure pulse interval and pulse rate variability in healthy young adults.

METHODS

Validity was assessed by comparing the pulse interval and SD of normal pulse intervals obtained by Light Heart to the gold standard, electrocardiogram (ECG), in 14 young healthy individuals (mean age 24, SD 5 years; n=9, 64% female) in a seated posture.

RESULTS

Mean pulse interval (Light Heart: 859, SD 113 ms; ECG: 857, SD 112 ms) demonstrated a strong positive linear correlation (r=0.99; P<.001) and strong agreement (intraclass correlation coefficient=1.00, 95% CI 0.99-1.00) between techniques. The Bland-Altman plot demonstrated good agreement for the mean pulse interval measured with Light Heart and ECG with evidence of fixed bias (-1.56, SD 1.86; 95% CI -5.2 to 2.1 ms), suggesting that Light Heart overestimates pulse interval by a small margin. When Bland-Altman plots were constructed for each participant's beat-by-beat pulse interval data, all participants demonstrated strong agreement between Light Heart and ECG with no evidence of fixed bias between measures. Heart rate variability, assessed by SD of normal pulse intervals, demonstrated strong agreement between techniques (Light Heart: mean 73, SD 23 ms; ECG: mean 73, SD 22 ms; r=0.99; P<.001; intraclass correlation coefficient=0.99, 95% CI 0.97-1.00).

CONCLUSIONS

This study provides evidence to suggest that the Light Heart mobile app provides valid measures of pulse interval and heart rate variability in healthy young adults.

Infant emotion regulation in the context of stress: Effects of heart rate variability and temperament

Stressful events are inherently emotional. As a result, the ability to regulate emotions is critical in responding effectively to stressors. Differential abilities in the management of stress appear very early in life, compelling a need to better understand factors that may shape the capacity for emotion regulation (ER). Variations in both biologic and behavioural characteristics are thought to influence individual differences in ER development. We sought to determine the differential contributions of temperament and heart rate variability (HRV; an indicator of autonomic nervous system function) to infant resting state emotionality and emotional reactivity in response to a stressor at 6 months of age. Participants included 108 mother-infant dyads. Mothers completed a measure of infant temperament at 6 months postnatal. Mother and infant also participated in a standardized stressor (the Repeated Still Face Paradigm) at that time. Electrocardiographic data were acquired from the infant during a baseline resting state and throughout the stressor. Fast Fourier Transformation was used to analyse the high frequency (HF) domain of HRV, a measure of parasympathetic nervous system activity. Infant ER was measured via standardized coding of emotional distress behaviours from video-records at baseline and throughout the stressor. Severity of mothers' depressive symptoms was included as a covariate in analyses. Results of linear regression indicate that neither temperament nor HRV were associated significantly with an infant's emotional resting state, although a small effect size was found for the relationship between infant negative affectivity and greater emotional distress (β = 0.23, p = 0.08) prior to the stressor. Higher HF-HRV (suggesting parasympathetic dominance) was related to greater emotional distress in response to the stressor (β = 0.34, p = 0.009). This greater emotional reactivity may reflect a more robust capacity to mount an emotional response to the stressor when infants encounter it from a bedrock of parasympathetic activation. Findings may inform eventual markers for assessment of ER in infancy and areas for intervention to enhance infant management of emotions, especially during stressful events.

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

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

Dual-task improvement of older adults after treadmill walking combined with blood flow restriction of low occlusion pressure: the effect on the heart-brain axis

OBJECTIVE

This study explored the impact of one session of low-pressure leg blood flow restriction (BFR) during treadmill walking on dual-task performance in older adults using the neurovisceral integration model framework.

METHODS

Twenty-seven older adults participated in 20-min treadmill sessions, either with BFR (100 mmHg cuff pressure on both thighs) or without it (NBFR). Dual-task performance, measured through light-pod tapping while standing on foam, and heart rate variability during treadmill walking were compared.

RESULTS

Following BFR treadmill walking, the reaction time (p = 0.002) and sway area (p = 0.012) of the posture dual-task were significantly reduced. Participants exhibited a lower mean heart rate (p < 0.001) and higher heart rate variability (p = 0.038) during BFR treadmill walking. Notably, BFR also led to band-specific reductions in regional brain activities (theta, alpha, and beta bands, p < 0.05). The topology of the EEG network in the theta and alpha bands became more star-like in the post-test after BFR treadmill walking (p < 0.005).

CONCLUSION

BFR treadmill walking improves dual-task performance in older adults via vagally-mediated network integration with superior neural economy. This approach has the potential to prevent age-related falls by promoting cognitive reserves.

Cure for tantrums? Longitudinal associations between parental digital emotion regulation and children's self-regulatory skills

Introduction

Parents often use digital devices to regulate their children's negative emotions, e.g., to stop tantrums. However, this could hinder child development of self-regulatory skills. The objective of the study was to observe bidirectional longitudinal associations between parents' reliance on digital devices to regulate their child's emotions and self-regulatory tendencies (anger/frustration management, effortful control, impulsivity).

Methods

Parents (N = 265) filled out the Child Behavior Questionnaire-Short Form and the Media Assessment Questionnaire twice: the initial assessment (T1) took place in 2020 (mean child age = 3.5 years old), and follow-up (T2) occurred a year later in 2021 (mean child age = 4.5 years old).

Results

Higher occurrence of parental digital emotion regulation (PDER) in T1 predicts higher anger and lower effortful control in T2, but not impulsivity. Higher anger in T1, but not impulsivity and effortful control, predicts higher PDER in T2.

Discussion

Our results suggest that parents of children with greater temperament-based anger use digital devices to regulate the child's emotions (e.g., anger). However, this strategy hinders development of self-regulatory skills, leading to poorer effortful control and anger management in the child.

Alleviating premenstrual symptoms with smartphone-based heart rate variability biofeedback training: a pilot study

Introduction

Heart rate variability biofeedback (HRVB) is a well-studied intervention known for its positive effects on emotional, cognitive, and physiological well-being, including relief from depressive symptoms. However, its practical use is hampered by high costs and a lack of trained professionals. Smartphone-based HRVB, which eliminates the need for external devices, offers a promising alternative, albeit with limited research. Additionally, premenstrual symptoms are highly prevalent among menstruating individuals, and there is a need for low-cost, accessible interventions with minimal side effects. With this pilot study, we aim to test, for the first time, the influence of smartphone-based HRVB on depressive and premenstrual symptoms, as well as anxiety/stress symptoms and attentional control.

Methods

Twenty-seven participants with above-average premenstrual or depressive symptoms underwent a 4-week photoplethysmography smartphone-based HRVB intervention using a waitlist-control design. Laboratory sessions were conducted before and after the intervention, spaced exactly 4 weeks apart. Assessments included resting vagally mediated heart rate variability (vmHRV), attentional control via the revised attention network test (ANT-R), depressive symptoms assessed with the BDI-II questionnaire, and stress/anxiety symptoms measured using the DASS questionnaire. Premenstrual symptomatology was recorded through the PAF questionnaire if applicable. Data analysis employed linear mixed models.

Results

We observed improvements in premenstrual, depressive, and anxiety/stress symptoms, as well as the Executive Functioning Score of the ANT-R during the intervention period but not during the waitlist phase. However, we did not find significant changes in vmHRV or the Orienting Score of the ANT-R.

Discussion

These findings are promising, both in terms of the effectiveness of smartphone-based HRVB and its potential to alleviate premenstrual symptoms. Nevertheless, to provide a solid recommendation regarding the use of HRVB for improving premenstrual symptoms, further research with a larger sample size is needed to replicate these effects.

Heart rate variability biofeedback to reduce anxiety in autism spectrum disorder - a mini review

There is a reported high prevalence of anxiety in people with autism spectrum disorder. This mini review appraises existing research investigating heart rate variability biofeedback to help manage symptoms of anxiety in people with autism spectrum disorder. A thorough search of electronic databases was conducted to find relevant literature. Consultation with experts and a librarian helped develop search terms following the PICO framework. Five databases were searched, and screening was undertaken using Covidence software, with the process outlined in a PRISMA flowchart. The latest review showed positive short-term effects but there is a need for long-term follow-up. Future investigations should consider device type, training settings, and control interventions. Accurate heart rate variability assessment independent of biofeedback devices is crucial. Additional measures like cortisol assessment and user feedback are recommended for comprehensive evaluation. The findings highlight progress in the evidence base and offer insight to future directions.

The emotion paradox in the aging body and brain

With age, parasympathetic activity decreases, while sympathetic activity increases. Thus, the typical older adult has low heart rate variability (HRV) and high noradrenaline levels. Younger adults with this physiological profile tend to be unhappy and stressed. Yet, with age, emotional experience tends to improve. Why does older adults' emotional well-being not suffer as their HRV decreases? To address this apparent paradox, I present the autonomic compensation model. In this model, failing organs, the initial phases of Alzheimer's pathology, and other age-related diseases trigger noradrenergic hyperactivity. To compensate, older brains increase autonomic regulatory activity in the pregenual prefrontal cortex (PFC). Age-related declines in nerve conduction reduce the ability of the pregenual PFC to reduce hyperactive noradrenergic activity and increase peripheral HRV. But these pregenual PFC autonomic compensation efforts have a significant impact in the brain, where they bias processing in favor of stimuli that tend to increase parasympathetic activity (e.g., stimuli that increase feelings of safety) and against stimuli that tend to increase sympathetic activity (e.g., threatening stimuli). In summary, the autonomic compensation model posits that age-related chronic sympathetic/noradrenergic hyperactivity stimulates regulatory attempts that have the side effect of enhancing emotional well-being.

The neuroimmune pathway of high-altitude adaptation: influence of erythrocytes on attention networks through inflammation and the autonomic nervous system

Introduction

Many studies have shown that the functional adaptation of immigrants to high-altitude is closely related to oxygen transport, inflammatory response and autonomic nervous system. However, it remains unclear how human attention changes in response to hypoxia-induced neurophysiological activity during high-altitude exposure.

Methods

In the present study, we analyzed the relationship between hypoxic-induced neurophysiological responses and attention networks in 116 immigrants (3,680 m) using an attention network test to simultaneously record electroencephalogram and electrocardiogram in combination with specific routine blood markers.

Results

Our analysis revealed that red blood cells exert an indirect influence on the three attention networks, mediated through inflammatory processes and heart rate variability.

Discussion

The present study provides experimental evidence for the role of a neuroimmune pathway in determining human attention performance at high- altitude. Our findings have implications for understanding the complex interactions between physiological and neurocognitive processes in immigrants adapting to hypoxic environments.

Night time heart rate predicts next-day pain in fibromyalgia and primary back pain

Introduction

Primary chronic pain is pain that persists for over 3 months without associated measurable tissue damage. One of the most consistent findings in primary chronic pain is its association with autonomic hyperactivation. Yet whether the autonomic hyperactivation causes the pain or results from it is still unclear. It is also unclear to what extent autonomic hyperactivation is related to experienced pain intensity in different subtypes or primary chronic pain.

Objectives

Our first aim was to test lagged relationships between the markers of autonomic activation (heart rate) and pain intensity to determine its directionality. The main question here was whether autonomic biomarkers predict pain intensity or whether pain intensity predicts autonomic biomarkers. The second aim was to test whether this relationship is different between people with primary back pain and people with fibromyalgia.

Methods

Sixty-six patients with chronic pain were observed over an average of 81 days. Sleep heart rate and heart rate variability were measured with a wearable sensor, and pain intensity was assessed from daily subjective reports.

Results

The results showed a predictive relationship between sleep heart rate and next-day pain intensity (P < 0.05), but not between daily pain intensity and next night heart rate. There was no interaction with the type of chronic pain.

Conclusions

These findings suggest that autonomic hyperactivation, whether stress-driven or arising from other causes, precedes increases in primary chronic pain. Moreover, the present results suggest that autonomic hyperactivation is a common mechanism underlying the pain experience in fibromyalgia and chronic back pain.

The Effectiveness of Mindfulness in the Treatment of Methamphetamine Addiction Symptoms: Does Neuroplasticity Play a Role?

INTRODUCTION

Methamphetamine is a highly stimulating psychoactive drug that causes life-threatening addictions and affects millions of people around the world. Its effects on the brain are complex and include disturbances in the neurotransmitter systems and neurotoxicity. There are several known treatment methods, but their effectiveness is moderate. It must be emphasised that no drugs have been approved for treatment. For this reason, there is an urgent need to develop new, effective, and safe treatments for methamphetamine. One of the potential treatments is mindfulness meditation. In recent years, this technique has been researched extensively in the context of many neurological and psychiatric disorders.

METHODS

This review explores the use of mindfulness in the treatment of methamphetamine addiction. Searches were conducted in the PubMed/Medline, Research Gate, and Cochrane databases.

RESULTS

Ten studies were identified that used mindfulness-based interventions in the treatment of methamphetamine addiction. The results show that mindfulness is an effective form of reducing hunger, risk of relapses, stress indicators, depression, and aggression, alone or in combination with transcranial direct current stimulation (tDCS). Mindfulness also improved the cognitive function in addicts. The included studies used only behavioural measures. The potential mechanisms of mindfulness in addiction were explained, and it was proposed that it can induce neuroplasticity, alleviating the symptoms of addiction.

CONCLUSIONS

Evidence from the studies suggest that mindfulness may be an effective treatment option for methamphetamine addiction, used alone or in combination with tDCS. However, further high-quality research is required to establish the role of this treatment option in this field. The use of neuroimaging and neurophysiological measures is fundamental to understand the mechanisms of mindfulness.

Breathing Right… or Left! The Effects of Unilateral Nostril Breathing on Psychological and Cognitive Wellbeing: A Pilot Study

The impact of controlled breathing on cognitive and affective processing has been recognized since ancient times, giving rise to multiple practices aimed at achieving different psychophysical states, mostly related to mental clarity and focus, stress reduction, and relaxation. Previous scientific research explored the effects of forced unilateral nostril breathing (UNB) on brain activity and emotional and cognitive functions. Some evidence concluded that it had a contralateral effect, while other studies presented controversial results, making it difficult to come to an unambiguous interpretation. Also, a few studies specifically addressed wellbeing. In the present study, we invited a pilot sample of 20 participants to take part in an 8-day training program for breathing, and each person was assigned to either a unilateral right nostril (URNB) or left nostril breathing condition (ULNB). Then, each day, we assessed the participants' wellbeing indices using their moods and mind wandering scales. The results revealed that, after the daily practice, both groups reported improved wellbeing perception. However, the effect was specifically related to the nostril involved. URNB produced more benefits in terms of stress reduction and relaxation, while ULNB significantly and increasingly reduced mind-wandering occurrences over time. Our results suggest that UNB can be effectively used to increase wellbeing in the general population. Additionally, they support the idea that understanding the effects of unilateral breathing on wellbeing and cognition requires a complex interpretive model with multiple brain networks to address bottom-up and top-down processes.

The relationship between sustained attention and parasympathetic functioning

Sustained attention (SA) is an important cognitive ability that plays a crucial role in successful cognitive control. Resting vagally-mediated heart rate variability (vmHRV) has emerged as an informative index of parasympathetic nervous system activity and a sensitive correlate of individual differences in cognitive control. However, it is unclear how resting vmHRV is associated with individual differences in sustained attention. The primary aim of the current study was to assess if resting vmHRV was associated with individual differences in performance on a neuropsychological assessment of sustained attention. We further aimed to characterize the relationship between resting vmHRV and dispositional factors related to sustained attention, specifically attentional errors in daily life, self-regulation, mindfulness and media-multitasking. Based on previous work, we hypothesized higher resting vmHRV would be associated with better sustained attention across task-based and self-report measures. We did not find resting vmHRV to be significantly associated with performance measures on a task-based assessment of sustained attention. Further, resting vmHRV was not significantly associated with attention errors, self-regulation, mindfulness, or media-multitasking. This work stands to expand the current understanding between parasympathetic functioning, cognition, and behavior, investigating the unexplored domain of sustained attention and related dispositional factors.

Loneliness during the post-confinement period: The significance of social living conditions for stress biomarkers and memory

In the aftermath of the COVID-19 lockdown, concerns about the impact of loneliness and reduced social interactions on mental health have arisen. This study explored the repercussions of post-lockdown social restrictions across psychological (loneliness, perceived stress, and depressive symptoms), biological (hair cortisol and cardiovascular activity), and cognitive dimensions (subjective memory complaints and working, declarative, and prospective memory), with a specific emphasis on perceived loneliness and the living situation. The study included 45 students: 23 (mean age = 25.69 years) in the Alone Group (AG), who experienced significant family changes and international relocation, and 22 (mean age = 25.50 years) in the Not Alone Group (NAG), who maintained their nuclear family and did not move from their home country. We assessed heart rate variability (HRV) before, during, and after immediate memory evaluations using time-domain (the square root of the mean, RMSSD) measures. The analysis revealed no significant group differences in telematic contact with family and friends, perceived stress, or depression. However, the AG participants reported fewer face-to-face interactions and greater perceived loneliness compared to the NAG. Additionally, the AG group exhibited slightly higher hair cortisol levels and worse working memory (WM) and prospective memory (PM) performance. Importantly, no significant associations were observed between memory outcomes and stress biomarkers. However, a significant interaction effect of loneliness in the relationship between hair cortisol levels and PM was found. That is, hair cortisol concentrations were negatively related to PM when participants perceived high and moderate loneliness. This interaction was absent in the working and declarative memory domains. In summary, these findings underscore the intricate interplay between loneliness, cortisol, and memory, emphasizing the need for comprehensive research on the complex mechanisms governing these multifaceted relationships.

Emotion regulation and heart rate variability may identify the optimal posttraumatic stress disorder treatment: analyses from a randomized controlled trial

Introduction

High variability in response and retention rates for posttraumatic stress disorder (PTSD) treatment highlights the need to identify "personalized" or "precision" medicine factors that can inform optimal intervention selection before an individual commences treatment. In secondary analyses from a non-inferiority randomized controlled trial, behavioral and physiological emotion regulation were examined as non-specific predictors (that identify which individuals are more likely to respond to treatment, regardless of treatment type) and treatment moderators (that identify which treatment works best for whom) of PTSD outcome.

Methods

There were 85 US Veterans with clinically significant PTSD symptoms randomized to 6 weeks of either cognitive processing therapy (CPT; n = 44) or a breathing-based yoga practice (Sudarshan kriya yoga; SKY; n = 41). Baseline self-reported emotion regulation (Difficulties in Emotion Regulation Scale) and heart rate variability (HRV) were assessed prior to treatment, and self-reported PTSD symptoms were assessed at baseline, end-of-treatment, 1-month follow-up, and 1-year follow-up.

Results

Greater baseline deficit in self-reported emotional awareness (similar to alexithymia) predicted better overall PTSD improvement in both the short- and long-term, following either CPT or SKY. High self-reported levels of emotional response non-acceptance were associated with better PTSD treatment response with CPT than with SKY. However, all significant HRV indices were stronger moderators than all self-reported emotion regulation scales, both in the short- and long-term. Veterans with lower baseline HRV had better PTSD treatment response with SKY, whereas Veterans with higher or average-to-high baseline HRV had better PTSD treatment response with CPT.

Conclusions

To our knowledge, this is the first study to examine both self-reported emotion regulation and HRV, within the same study, as both non-specific predictors and moderators of PTSD treatment outcome. Veterans with poorer autonomic regulation prior to treatment had better PTSD outcome with a yoga-based intervention, whereas those with better autonomic regulation did better with a trauma-focused psychological therapy. Findings show potential for the use of HRV in clinical practice to personalize PTSD treatment.

Clinical trial registration

ClinicalTrials.gov identifier, NCT02366403.

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.

Respiratory sinus arrhythmia (RSA), vagal tone and biobehavioral integration: Beyond parasympathetic function

Linchpin to the entire area of psychophysiological research and discussion of the vagus is the respiratory and cardiovascular phenomenon known as respiratory sinus arrhythmia (RSA; often synonymous with high-frequency heart-rate variability when it is specifically linked to respiratory frequency), i.e. rhythmic fluctuations in heart rate synchronized to inspiration and expiration. This article aims 1) to clarify concepts, terms and measures commonly employed during the last half century in the scientific literature, which relate vagal function to psychological processes and general aspects of health; and 2) to expand upon an earlier theoretical model, emphasizing the importance of RSA well beyond the current focus upon parasympathetic mechanisms. A close examination of RSA and its relations to the vagus may 1) dispel certain commonly held beliefs about associations between psychological functioning, RSA and the parasympathetic nervous system (for which the vagus nerve plays a major role), and 2) offer fresh perspectives about the likely functions and adaptive significance of RSA, as well as RSA's relationship to vagal control. RSA is neither an invariably reliable index of cardiac vagal tone nor of central vagal outflow to the heart. The model here presented posits that RSA represents an evolutionarily entrenched, cardiovascular and respiratory phenomenon that significantly contributes to meeting continuously changing metabolic, energy and behavioral demands.

Prenatal fluoride exposure, offspring visual acuity and autonomic nervous system function in 6-month-old infants

BACKGROUND

Prenatal fluoride exposure can have adverse effects on children's development; however, associations with visual and cardiac autonomic nervous system functioning are unknown. We examined associations between prenatal fluoride exposure and visual acuity and heart rate variability (HRV) in 6-month-old infants.

METHODS

We used data from Canadian mother-infant pairs participating in the Maternal-Infant Research on Environmental Chemicals (MIREC) cohort. We estimated prenatal fluoride exposure using: i) fluoride concentration in drinking water (mg/L), ii) maternal urinary fluoride adjusted for specific gravity (MUFSG; mg/L) and averaged across pregnancy, and iii) maternal fluoride intake (µg/kg/day) from consumption of water, tea, and coffee, adjusted for maternal body weight (kg). We used multivariable linear regression to examine associations between each measure of fluoride exposure and Teller Acuity Card visual acuity scores (n = 435) and assessed HRV (n = 400) using two measures: root mean square of successive differences (RMSSD) and the standard deviation of N-N intervals (SDNN) measured at 6-months of age.

RESULTS

Median (IQR) values for water fluoride, MUFSG, and daily fluoride intake were 0.20 (IQR: 0.13-0.56) mg/L; 0.44 (0.28-0.70) mg/L and 4.82 (2.58-10.83) µg/kg/day, respectively. After adjustment for confounding variables, water fluoride concentration was associated with poorer infant visual acuity (B = -1.51; 95 % CI: -2.14,-0.88) and HRV as indicated by lower RMSSD (B = -1.60; 95 % CI: -2.74,-0.46) but not SDNN. Maternal fluoride intake was also associated with poorer visual acuity (B = -0.82; 95 % CI: -1.35,-0.29) and lower RMSSD (B = -1.22; 95 % CI: -2.15,-0.30). No significant associations were observed between MUFSG and visual acuity or HRV.

CONCLUSION

Fluoride in drinking water was associated with reduced visual acuity and alterations in cardiac autonomic function in infancy, adding to the growing body of evidence suggesting fluoride's developmental neurotoxicity.

Change in heart rate variability with increasing time-on-task as a marker for mental fatigue: A systematic review

Fatigue-specific changes in the autonomic nervous system are often assumed to underlie the development of mental fatigue caused by prolonged cognitive tasks (i.e. Time-on-Task). Therefore, several previous studies have chosen to investigate the Time-on-Task related changes in heart rate variability (HRV). However, previous studies have used many different HRV indices, and their results often show inconsistencies. The present study, therefore, systematically reviewed previous empirical HRV studies with healthy individuals and in which mental fatigue is induced by prolonged cognitive tasks. Articles relevant to the objectives were systematically searched and selected by applying the PRISMA guidelines. We screened 360 records found on 4 databases and found that 19 studies were eligible for full review in accordance with the inclusion criteria. In general, all studies reviewed (with the exception of two studies) found significant changes in HRV with increasing Time-on-Task, suggesting that HRV is a reliable autonomic marker for Time-on-Task induced fatigue. The most conclusive HRV indices that showed a consistent Time-on-Task effect were the low frequency component of HRV and the time domain indices, particularly the root mean square of successive differences. Time-on-Task typically induced an increasing trend in both type of measures.

The added value of a micro-level ecological approach when mapping self-regulatory control processes and externalizing symptoms during adolescence: a systematic review

Deficits in self-regulatory control (SRC) represent a core characteristic of externalizing (EXT) symptoms (e.g., rule-breaking behavior or aggressive behaviors) in adolescents. This review aims to specify the added value of ecologically valid assessments at a micro-level when examining the associations between SRC and EXT symptoms in adolescents. This systematic review was reported according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) 2020. The search strategy addressed the added value of (1) naturalistic assessment for the understanding of the relationship between (2) SRC and (3) EXT symptoms in (4) adolescents. We conducted comprehensive searches in bibliographic databases. An additional search was conducted in Google Scholar and supplementary studies were identified through backward and forward citation tracking. Twenty-four studies (n = 4071 adolescents) met the inclusion criteria. The methods used to assess naturalistic aspects included the experience sampling method (ecological momentary- or ambulatory assessment) and the time-course approach (i.e., real-time assessment of SRC processes referring to situations approximating real-life experience where SRC are to be engaged such as in frustrating situations). Micro-level ecological assessments, when mapping the intra-individual relationships between SRC processes and EXT symptoms over time in adolescents within their natural context (i.e., real world) of expression in real time, added a finer-grained observation alongside with a higher ecological validity. Micro-level approaches may enhance the understanding of the complex interplay between SRC and EXT symptoms in adolescence, especially in interventional studies, allowing for the acquisition of endpoints with a higher relevance for everyday functioning.

Effect of Selected Music Soundtracks on Cardiac Vagal Control and Complexity Assessed by Heart Rate Variability

Listening to music is experimentally associated with positive stress reduction effect on human organisms. However, the opinions of therapists about this complementary non-invasive therapy are still different.

PURPOSE

The aim of our study was to investigate the effect of selected passive music therapy frequencies without vocals on selected cardio-vagal and complexity indices of short-term heart rate variability (HRV) in healthy youth, in terms of calming the human.

MAIN METHODS

30 probands (15 male, averaged age: 19.7+/-1.4 years, BMI: 23.3+/-3.8 kg/m2) were examined during protocol (Silence baseline, Music 1 (20-1000 Hz), Silence 1, Music 2 (250-2000 Hz), Silence 2, Music 3 (1000-16000 Hz), and Silence 3). Evaluated HRV parameters in time, spectral, and geometrical domains represent indices of cardio-vagal and emotional regulation. Additionally, HRV complexity was calculated by approximate entropy and sample entropy (SampEn) and subjective characteristics of each phase by Likert scale.

RESULTS

the distance between subsequent R-waves in the electrocardiogram (RR intervals [ms]) and SampEn were significantly higher during Music 3 compared to Silence 3 (p=0.015, p=0.021, respectively). Geometrical cardio-vagal index was significantly higher during Music 2 than during Silence 2 (p=0.006). In the subjective perception of the healthy youths evaluated statistically through a Likert scale, the phases of music were perceived significantly more pleasant than the silent phases (p<0.001, p=0.008, p=0.003, respectively).

CONCLUSIONS

Our findings revealed a rise of cardio-vagal modulation and higher complexity assessed by short-term HRV indices suggesting positive relaxing effect music especially of higher frequency on human organism.

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

Introduction

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

Methods

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

Results

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

Discussion

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