Ethnic differences in resting heart rate variability: a systematic review and meta-analysis

Cardiac vagal control in response to acute stress during pregnancy: Associations with life stress and emotional support

Life stressors during pregnancy can disrupt maternal stress regulation and negatively impact offspring health. Despite the important role of cardiac vagal control (e.g., heart rate variability; HRV) in stress regulation, few studies have investigated how life stressors and emotional support influence vagal control during pregnancy. This study aimed to (a) characterize patterns of cardiac vagal control in response to a stressor administered in pregnancy, and (b) examine the effects of life stress and emotional support on vagal control during rest, reactivity, and recovery. Participants included 191 pregnant women (79% Black; 21% White) living in an urban U.S. city (73% receiving public assistance). Heart rate (HR) and HRV (indexed by RMSSD) were recorded continually during the preparation, task, and recovery periods of the Trier Social Stress Test (TSST). Participants reported recent life stressors (e.g., relationship problems, financial hardship) and emotional support. Piecewise growth curve modeling was used to model rates of reactivity and recovery, adjusting for gestational age at time of assessment and recent health problems. Life stress predicted greater HR and HRV reactivity to the TSST as well as greater HRV recovery (vagal rebound). However, associations were only evident for women reporting high emotional support. Results suggest that pregnant women living with frequent life stressors may exhibit more rapid autonomic responses to acute stress, including more rapid vagal rebound after stressors, potentially reflecting physiological adaptation to anticipated high-stress environments; emotional support may enhance these responses. Studies are needed to investigate long-term health outcomes related to this stress response pattern.

The Cardiovascular Conundrum in Ethnic and Sexual Minorities: A Potential Biomarker of Constant Coping With Discrimination

Background: A paradoxical profile of greater elevated sympathetic vasoconstriction (increased total peripheral resistance, TPR) and increased vagally-mediated heart rate variability (HRV) -the so-called Cardiovascular Conundrum- has been reported in African Americans (AAs) both at rest and in response to orthostasis. Whereas some authors have attributed this pattern to genetic factors, others have pointed to the potential role of coping with repeated racial discrimination.

Objective: To disentangle between these alternative explanations, we have examined the hemodynamic profile of another population that is likely to be exposed to episodes of discrimination, i.e., sexual minorities.

Methods: The first study was conducted on a sample of AAs and European Americans (EAs) with the aim of replicating previous results on the Cardiovascular Conundrum. In the second study, lesbian, gay, and bisexual (LGB) people, matched by age and sex with heterosexual participants, underwent a hemodynamic and autonomic assessment at rest and during an emotional (in the experimental group, both LGB-related and non LGB related), and a cognitive stressor.

Results: The first study confirmed a pattern of higher resting HRV, paired with higher TPR, in AAs compared to EAs. In the second study, compared to heterosexuals, the LGB group showed the Cardiovascular Conundrum pattern, characterized by greater HRV and higher TPR at baseline and a more vascular hemodynamic profile and prominent compensation deficit in response to both tasks, and particularly during the LGB-related emotional task. However, in LGB only, the vascular response was negatively correlated with perceived discrimination.

Conclusion: Present preliminary results are discussed in terms of maladaptive physiological consequences of exposure to chronic stress and the chronic use of dysfunctional emotion regulation strategies such as suppression.

The role of social vs. physical environmental nuisances in affecting stress among Jewish and Muslim women in Israel

We calculate the effects of selected social and physical environmental nuisances on the autonomic nervous system balance among Jewish and Muslim mothers. Seventy-two Jewish and Muslim young healthy mothers from an Arab and Jewish neighboring city were tested in seven urban environments. Three social mediators (social discomfort, participation in household's decision-making and freedom of movement) and three physical mediators (thermal load, carbon monoxide and noise) were considered. Mean differences between Jewish and Muslim heart rate variability (HRV) and the effects of the mediating variables were calculated by ANOVA and stepwise multiple regressions. The results suggest that HRV was predominantly affected by social discomfort. Jewish and Muslim mothers experienced similar levels of social discomfort albeit; their responses differed by type of environment. Jewish mothers experienced stronger social discomfort in outdoor environments while Muslim mothers felt stronger social discomfort at home. Crossing ethnic boundaries was associated with increase in stress in both groups. Social discomfort played a stronger role in predicting stress in inter-ethnic environments. In conclusion, the study shows that social discomfort is a predominant environmental factor in predicting stress and related risk to health as reflected in the ANS balance across ethnicities. In addition ethnic specific factors like women freedom of movement played a minor role in effecting stress. At the same time the physical environmental aspects played essential role in effecting stress.

Higher cardiac vagal activity predicts lower peripheral resistance 6 years later in European but not African Americans

African American (AA) individuals are at a greater risk for the development of cardiovascular complications, such as hypertension, compared with European Americans (EAs). Higher vagally mediated heart rate variability (HRV) is typically associated with lower blood pressure (BP) and total peripheral resistance (TPR). However, research has yet to examine the differential impact of HRV on longitudinal hemodynamic activity between AAs and EAs. We sought to rectify this in a sample of 385 normotensive youths (207 AAs, 178 EAs; mean age 23.16 ± 2.9 yr). Individuals participated in two laboratory evaluations spanning approximately 6 yr. Bioimpedance was used to assess HRV at time 1 and cardiac output at both time 1 and time 2. Mean arterial pressure (MAP) was measured at both time points via an automated BP machine. TPR was calculated as MAP divided by cardiac output. Results showed AAs to have higher BP and higher TPR at time 2 compared with EAs, independent of several important covariates. Also, higher HRV at time 1 significantly predicted both lower TPR and BP at time 2 among EAs only; these associations were attenuated and not significant in AAs. HRV did not significantly predict cardiac output at time 2 in the full sample or split by ethnicity. Our findings highlight that AAs show TPR mediated long-term increases in BP irrespective of resting HRV, providing a physiological pathway linking AAs with a greater risk for mortality and morbidity from hypertension and potentially other cardiovascular disease.NEW & NEWSWORTHY African Americans and European Americans differ in hemodynamics underlying long-term blood pressure regulation. Over 6 yr, African Americans show total peripheral resistance-mediated increases in blood pressure compared with European Americans. Higher heart rate variability predicts lower blood pressure and total peripheral resistance 6 yr later in European Americans but not African Americans.

A Close Examination of the Use of Systolic Time Intervals in the Calculation of Impedance Derived Cardiac Autonomic Balance and Regulation

Traditionally, impedance derived measures of cardiac autonomic balance (CAB) and regulation (CAR) are calculated using indices of heart rate variability (HRV) that primarily reflect parasympathetic nervous system activity (e.g., high-frequency HRV | HF-HRV) and pre-ejection period (PEP; a systolic time interval and measure of sympathetic activity). However, HF-HRV and PEP are considered measures of chronotropic and inotropic cardiac influence, respectively. Left ventricular ejection time (LVET) is a systolic time interval that reflects sympathetic chronotropic influence, and therefore may be a more appropriate measure for calculating CAB and CAR compared to PEP. Thus, the current study evaluates both PEP and LVET in the calculation of CAB and CAR. Data from 158 healthy participants (mean age = 19.09 years old, SD = 1.84 years) were available for analyses. CAB and CAR values were calculated using both HF-HRV and the root mean square of successive differences, in addition to both PEP and LVET, in accordance with previously established guidelines. Analyses showed that correlations were significantly weaker between CAB and CAR calculated using LVET for both HF (z = 5.12, p < 0.001) and RMSSD (z = 5.26, p < 0.001) than with PEP. These data suggest that LVET, compared to PEP, provides better “autonomic space” as evidenced by a lack of correlation between CAB and CAR computed using LVET. We stress that future research consider calculating CAB and CAR using chronotropic measures for both parasympathetic and sympathetic activity, as doing so may yield more accurate and independent measures of cardiac autonomic activity compared to a mixture of inotropic (i.e., PEP) and chronotropic (i.e., HF-HRV) measures.

Potassium excretion and blood pressure are associated with heart rate variability in healthy black adults: The African-PREDICT study

BACKGROUND AND AIMS

Heart rate variability (HRV) is a main determinant of autonomic function and related to the development of hypertension and cardiovascular (CV) disease. Hypertension develops in black populations at an earlier age, which could be due to differences in the autonomic nervous system activity and sodium/potassium handling in black and white populations. We investigated whether HRV is associated with 24 h urinary sodium and potassium excretion and blood pressure (BP) in a young bi-ethnic cohort.

METHODS AND RESULTS

We examined 423 black and 483 white healthy adults (aged 24.5 ± 3.1 years) for 24 h HRV, including standard deviation of normal RR intervals (SDNN) reflecting autonomic variations over time, and root mean square of successive differences (RMSSD) reflecting parasympathetic activity. We measured 24 h urinary sodium and potassium concentration and BP. The black group had lower SDNN and potassium excretion as well as higher RMSSD, sodium and Na/k ratio compared to the white group (all p < 0.05). Only in black individuals, urinary potassium excretion was independently and negatively associated with SDNN (β[95% CI];-0.26[-0.50;-0.02]ms) and RMSSD (-0.14[-0.27;-0.01]ms, p < 0.05). One unit increase in sodium/potassium (Na/K) ratio was associated with higher SDNN (β[95% CI]; 3.04[0.89; 5.19]ms) and RMSSD (1.60[0.41; 2.78]ms) in the black cohort only (both p < 0.001). In both groups elevated 24 h diastolic BP was associated with lower RMSSD (p < 0.05).

CONCLUSION

Lower potassium excretion and higher Na/K ratio related independently to higher HRV in young and healthy black adults. A better ethnic-specific understanding of sodium and potassium handling is required as part of preventive cardiology, especially in black individuals.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03292094; URL: https://clinicaltrials.gov/ct2/show/NCT03292094.

Investigating the relationship between emotional granularity and cardiorespiratory physiological activity in daily life

Emotional granularity describes the ability to create emotional experiences that are precise and context-specific. Despite growing evidence of a link between emotional granularity and mental health, the physiological correlates of granularity have been under-investigated. This study explored the relationship between granularity and cardiorespiratory physiological activity in everyday life, with particular reference to the role of respiratory sinus arrhythmia (RSA), an estimate of vagal influence on the heart often associated with positive mental and physical health outcomes. Participants completed a physiologically triggered experience-sampling protocol including ambulatory recording of electrocardiogram, impedance cardiogram, movement, and posture. At each prompt, participants generated emotion labels to describe their current experience. In an end-of-day survey, participants elaborated on each prompt by rating the intensity of their experience on a standard set of emotion adjectives. Consistent with our hypotheses, individuals with higher granularity exhibited a larger number of distinct patterns of physiological activity during seated rest, and more situationally precise patterns of activity during emotional events: granularity was positively correlated with the number of clusters of cardiorespiratory physiological activity discovered in seated rest data, as well as with the performance of classifiers trained on event-related changes in physiological activity. Granularity was also positively associated with RSA during seated rest periods, although this relationship did not reach significance in this sample. These findings are consistent with constructionist accounts of emotion that propose concepts as a key mechanism underlying individual differences in emotional experience, physiological regulation, and physical health.

Osteopathic Manipulative Treatment and Cardiovascular Autonomic Parameters in Rugby Players: A Randomized, Sham-Controlled Trial

OBJECTIVE

The purpose of this study was to investigate the effects of osteopathic manipulative treatment (OMT) on cardiovascular autonomic parameters after a rugby match.

METHODS

Resting and reactivity (ie, response to orthostasis) measures of mean arterial pressure, heart rate, and heart rate variability were assessed in 23 male players after a single session of OMT, both 18 to 20 hours after a rugby match and in a corresponding no-match condition, in a randomized, sham-controlled, crossover design.

RESULTS

Signs of reduced heart rate variability and elevated mean arterial pressure and heart rate were found 18 to 20 hours after a rugby match compared with the no-match condition. A significant increase in heart rate variability and a significant reduction in mean arterial pressure were observed after OMT in both the after-match and no-match conditions. Heart rate and heart rate variability responses to orthostasis were not affected by previous match competition, but were significantly larger after OMT compared with sham treatment.

CONCLUSION

This study suggests the presence of cardiovascular autonomic alterations in rugby players after a competitive match, which may be indicative of prolonged fatigue and incomplete recovery. In these players, favorable changes in cardiovascular autonomic parameters were observed following a single session of OMT.

Angry in America: Psychophysiological Responses to Unfair Treatment

Background

African Americans have the highest rates of hypertension-related disease of any ethnic group in the USA. Importantly, racism and discrimination have been linked to these higher rates of morbidity and mortality. Discrimination is deleterious not only to those that are the recipients of this unfair treatment but also to the partners and family members of those affected as well to those that perpetrate this bias.

Purpose

In this paper, we identify a unique pattern of physiological response to unfair treatment, we have called the “cardiovascular conundrum.” This pattern is characterized by greater heart rate variability and greater total peripheral resistance in African Americans compared to their European American counterparts.

Methods and Results

We review the evidence supporting the existence of this pattern and propose several physiological and psychological factors that might underpin it. We also propose a number of factors that might help to mitigate the deleterious effects associated with it.

Conclusions

Whereas the context of the current review is on Black/White disparities the framework we propose may be relevant to others exposed to unfair treatment. Ultimately, the systemic factors that perpetuate these inequalities will require that we first acknowledge and then face the challenges they present if we are to address the wealth and health disparities in our country.

Phenotyping stress exposures related to perinatal health disparities

Black American women living in low-resource environments are exposed to multiple stressors and are at high risk for perinatal complications. Stress exposure likely impacts pregnancy and birth complications via alterations in health systems that are engaged in regulating the stress response. Stressors may vary in terms of magnitude and pattern of effect on such health systems. In the present study, we test associations between three types of stress exposure: perceived stress, negative life events, and discrimination stress on neuroendocrine and cardiac response to a controlled laboratory stressor during the first trimester of pregnancy. In all, 100 pregnant Black women with Medicaid insurance completed a laboratory assessment during which salivary cortisol and heart rate variability (HRV) were used to measure stress response to the Trier Social Stress Test (TSST). Results revealed that only discrimination stress was significantly associated with cortisol and HRV in response to the TSST. High levels of discrimination stress were associated with lower levels of cortisol reactivity and higher levels of HRV across the visit. These results highlight the differential impact of domains of stress exposure on stress regulation during pregnancy and provide further evidence of the impact of discrimination stress on Black American women's health.

Depressive symptoms among stress-exposed youth: Relations with tonic and phasic indices of autonomic functioning

Theoretical models of adolescent depression postulate that one possible individual vulnerability factor for the development of depressive symptoms is autonomic dysregulation. However, there is limited and mixed support for these models among ethnically diverse and higher risk stress-exposed youth. Therefore, this study investigated the relations between both tonic and phasic indices of parasympathetic autonomic functioning (i.e., resting high-frequency heart rate variability [HF-HRV] and root mean square of successive differences [RMSSD]; HF-HRV and RMSSD reactivity to a mental arithmetic stressor) and depressive symptoms among 80 severely stress-exposed youth (51% female; 11-17 years of age) from diverse backgrounds (61.3% ethnic minority; caregiver-reported median family income = $20,000-$49,999 per year). Results demonstrated that lower resting HF-HRV and RMSSD, but not HF-HRV and RMSSD reactivity, was associated with greater youth depressive symptoms. Our findings suggest that lower resting parasympathetic autonomic functioning may be a potential vulnerability factor of depressive symptoms among stress-exposed youth, instead of specific emotional responses to stressors. These findings will need to be replicated in larger samples of stress-exposed youth and youth at higher risk for or exhibiting clinical levels of depressive symptoms to better elucidate relations with autonomic functioning and depressive symptoms among adolescents.

Comparison of Frequency of Atrial Fibrillation in Blacks Versus Whites and the Utilization of Race in a Novel Risk Score

Blacks have a lower prevalence of atrial fibrillation (AF) compared with Whites. We sought to confirm previously reported ethnic trends in AF in Blacks and Whites in a large database, and develop a prediction score for AF. Over 330 million hospital discharges between the years 2003 to 2013 from the National Inpatient Sample database were analyzed. All hospitalizations with a diagnosis of AF formed the study cohort. Traditional risk factors for the development of AF were compared between Blacks and Whites. Univariate and multiple logistic regression analyses were used to formulate a risk score to predict AF-CHADSAVES (Congestive heart failure, Hypertension, Age>65 years, Diabetes Mellitus, prior Stroke, Age>75 years, Vascular disease, White Ethnicity, and previous cardiothoracic Surgery). AF prevalence in Whites was 11.3% vs 4.6% in Blacks (p < 0.001). Blacks were younger (33.8% vs 14.4% patients <65 years, p < 0.01) and had less males (46.3% vs 49.4%, p < 0.01). Blacks had more hypertension (71.3% vs 64.1%, p < 0.01), congestive heart failure (24.8% vs 22.6%, p < 0.01), diabetes mellitus with (7.5% vs 4.7%, p < 0.01) or without complications (30.3% vs 23.1%, p < 0.01), renal failure (29.7% vs 17.1%, p < 0.01), and obesity (13.1% vs 8.7%, p < 0.01). CHADSAVES predicted AF in the study population (NIS 2003 to 2013) with an AUC of 0.82 and verified in a validation cohort (NIS 2014) with an AUC of 0.85. In conclusion, our data confirm a significant AF ethnicity paradox. Despite a higher prevalence of traditional risk factors for AF, Blacks had >2-fold lower prevalence of AF compared with Whites. CHADSAVES can be used effectively to predict AF in inpatients.

Early life maltreatment and resting-state heart rate variability: A systematic review and meta-analysis

Recent focus on the consequences of early life adversity (ELA) in neurobiological research led to a variety of findings suggesting alterations in several physiological systems, such as the cardiovascular system. In this systematic review and meta-analysis, we focused on the relationship between early life maltreatment (ELM), one form of ELA, and resting vagal activity indexed by resting-state heart rate variability (HRV). A systematic search of the literature yielded 1'264 hits, of which 32 studies reporting data for group comparisons or correlations were included. By quantitative synthesis of existing studies using random-effect models, we found no evidence for a relationship between ELM exposure and resting vagal activity in principal. Conducting meta-regression analyses, however, we found the relationship between ELM and resting vagal activity to significantly vary as a function of both age and the presence of psychopathology. In light of the current multitude of vastly unclear pathways linking ELM to the onset of disease, we emphasize the need for further research and outline several aspects to consider in future studies.

Assessment of baroreceptor reflex sensitivity in young obese Saudi males at rest and in response to physiological challenges

Autonomic imbalance in overweight/obese persons could lead to an increased risk of cardiovascular complications including hypertension and arrhythmias. Baroreceptor reflex sensitivity is a sensitive indicator to detect an altered sympathovagal balance in overweight/obese individuals. This study investigated the effects of overweight/obesity on baroreceptor sensitivity in young Saudi males at rest and in response to physiological challenges.

SUBJECTS AND METHODS

In this cross-sectional study, spontaneous baroreceptor sensitivity at rest and in response to deep breathing, isometric hand grip exercise and moderate intensity isotonic exercise were recorded in 20 normal weight and 20 overweight/obese subjects. Finger arterial blood pressure signal, recorded through Finometer, was used to calculate baroreceptor sensitivity through cross-correlation method. The baroreceptor sensitivity data were log transformed before application of parametric tests.

RESULTS

The spontaneous baroreceptor sensitivity was similar in both groups at baseline, but exhibited a significant increase during deep breathing only in normal weight (p < .001). Immediately after the isotonic exercise the baroreceptor sensitivity was significantly lower than baseline in both normal weight and overweight/obese and remained significantly lower in overweight/obese individuals compared to normal weight (p < .05) throughout the recovery period. There was a significant rise in baroreceptor sensitivity after isometric exercise in overweight/obese group only (p = .001). Pearson's correlation showed a significant negative correlation of baroreceptor sensitivity with body mass index during deep breathing (r = -.472, p = .004) and in post-isotonic exercise recovery period (r = -.414, p = .013).

CONCLUSION

A significantly reduced baroreceptor sensitivity response to deep breathing, reduced baroreceptor sensitivity recovery after isotonic exercise, and an exaggerated shoot up after isometric exercise in overweight/obese suggests an altered sympathovagal balance. Baroreceptor sensitivity measurements in response to physiological challenges, deep breathing, and isotonic exercise, may be more sensitive investigations for detection of early attenuation of cardiac autonomic function. This would enable timely intervention thereby delaying complications and improving the quality of life.

Resting state heart rate variability and false memories

Recent studies have shown higher resting-state vagally-mediated heart rate variability (vmHRV) to be related to greater memory retrieval. Research has not yet linked resting vmHRV with memory encoding and retrieval, as both are thought to play an important role in correctly distinguishing between true and false memories. The current study investigated this possible link in n = 71 undergraduate students. VmHRV was assessed during a 5-minute resting baseline period. Participants then completed the Deese-Roediger-McDermott (DRM) task, where they first viewed 6 word lists (12 words per list), and were later asked to identify previously shown words (true memories) and reject non-presented words. Results showed that participants with lower resting vmHRV were less able to discriminate true from false items. These data extend previous work on resting vmHRV and memory suggesting that resting vmHRV represents a psychophysiological pathway involved in both the proper encoding and retrieval of memories.

Impaired vasodilation in pregnant African Americans: Preliminary evidence of potential antecedents and consequences

Significant health disparities exist between African Americans (AA) and European Americans (EA) in hypertension and hypertension-related disorders. Evidence suggests that this is due to impaired vasodilation in AAs. Pregnancy is a potent systemic vasodilatory state. However, differences in vasodilation between AAs and EAs have not been investigated in pregnancy. We sought to examine the effects of pregnancy on vasodilation in AA and EA women and how this might be related to discrimination and low birth weight in their offspring. Hemodynamics [blood pressure (MAP), cardiac output (CO), total peripheral resistance (TPR)] and heart rate variability (HF-HRV) were examined at baseline in 40 pregnant AAs (n = 20) and EAs (n = 20) and matched nonpregnant women (n = 40). The Experiences of Discrimination scale and birth weight were also measured in the offspring of the pregnant participants. Whereas pregnancy was associated with decreased MAP independent of race, AAs showed impaired vasodilation independent of pregnancy status as indicated by greater TPR despite greater HF-HRV. In AAs, but not EAs, reports of fewer incidences of discrimination were associated with greater TPR. Finally, the HF-HRV of EA mothers was inversely related to the birth weight of their offspring but was uncorrelated in AAs. We report novel evidence of impaired vasodilation to an endogenous vasodilatory stimulus in AAs. Higher TPR was related to discrimination in AAs and higher HF-HRV was related to low birth weight in EAs. These findings have implications for understanding the intergenerational transmission of impaired vasodilation in AAs.

Heart Rate Variability with Deep Breathing in Drug-Naïve Patients with Schizophrenia

Abnormal autonomic nervous system (ANS) function may result in poor outcomes in patients with schizophrenia. Altered cardio-respiratory coupling, which indicates suppression of vagal activity, was identified as an important trait in patients with schizophrenia and their unaffected relatives. Heart rate variability (HRV) in standardized bedside reflex tests has been studied, mostly in medicated patients with schizophrenia whose ANS function could be influenced by medication. Our study aimed to explore the autonomic function differences between drug-naïve patients with schizophrenia and healthy individuals during challenge tests combining respiration and HRV analysis. Forty-two drug-naïve patients with schizophrenia were matched with 42 healthy controls in terms of age and gender. Their beat-to-beat blood pressure and heart rate were monitored in the supine position as a survey of ANS function, and the mean heart rate range (MHRR) was measured under deep-breathing challenge. A decreased MHRR, a sensitive sign indicating an impaired parasympathetic response, during the deep-breathing challenge among the drug-naïve patients with schizophrenia was found. Drug-naïve patients with schizophrenia may have a parasympathetic dysfunction in the early stages of schizophrenia before medication is introduced, which could be considered a neurobiological marker in the pathophysiology of schizophrenia.

Inverse associations between parasympathetic activity and cognitive flexibility in African Americans: Preliminary findings

Previous research suggests that vagal activity and executive function (EF) are positively associated. However, existing data exploring the relationship between HRV and EF remains limited. Though Blacks may have higher HRV, they remain underrepresented in previous research examining HRV and EF. The current study aimed to determine the relationship between EF and HRV in a sample of 92 Black undergraduates (Mean age = 20.32, SD = 2.28). Participants wore an 6‑lead ambulatory electrocardiographic impedance monitoring system to obtain the root mean square of interbeat interval differences (rMSSD) and Cardiac Sympathetic Index. After baseline autonomic activity assessment, participants completed the Berg Card Sorting Test. Utilizing hierarchical regression analyses, HRV was negatively associated with correct responses (Beta = -0.40, SE = 0.04, p=0.01) and categories experienced (Beta = -0.37, SE = 0.01, p=0.01), and positively associated with total errors (Beta = 0.39, SE =0.04, p=0.01). To further elucidate these findings, participants were assigned to coinhibition (n = 12), parasympathetically dominant (n = 34), sympathetically dominant (n = 35), or coactivation (n = 11) autonomic space subgroups. Participants in the sympathetically dominant subgroup completed more categories (M = 6.86, SD = 2.13) and committed fewer errors (M = 30.63, SD = 11.53) than their parasympathetic counterparts (M = 5.74, SD = 2.44; M = 43.29, SD = 18.83, respectively). This study suggests that a state of sympathetic arousal immediately prior to the administration of an EF task, may aid in better task performance.

Heart Rate Variability and Accelerometry as Classification Tools for Monitoring Perceived Stress Levels-A Pilot Study on Firefighters

Chronic stress is the main cause of health problems in high-risk jobs. Wearable sensors can become an ecologically valid method of stress level assessment in real-life applications. We sought to determine a non-invasive technique for objective stress monitoring. Data were collected from firefighters during 24-h shifts using sensor belts equipped with a dry-lead electrocardiograph (ECG) and a three-axial accelerometer. Levels of stress experienced during fire incidents were evaluated via a brief self-assessment questionnaire. Types of physical activity were distinguished basing on accelerometer readings, and heart rate variability (HRV) time series were segmented accordingly into corresponding fragments. Those segments were classified as stress/no-stress conditions. Receiver Operating Characteristic (ROC) analysis showed true positive classification as stress condition for 15% of incidents (while maintaining almost zero False Positive Rate), which parallels the amount of truly stressful incidents reported in the questionnaires. These results show a firm correspondence between the perceived stress level and physiological data. Psychophysiological measurements are reliable indicators of stress even in ecological settings and appear promising for chronic stress monitoring in high-risk jobs, such as firefighting.

Ethnicity Moderates the Association between Autonomic Functioning and Temperament in Preschool Children

Respiratory sinus arrhythmia (RSA) has been extensively investigated as a marker of adaptive emotional functioning in both children and adults, with studies linking RSA to temperamental dimensions such as positive affect and extraversion. However, few studies have examined the extent to which relations between RSA and temperament characteristics vary across ethnicity in childhood. We examined relations between respiratory sinus arrhythmia (RSA) and temperament dimensions (Activity Level, Task Orientation, and Affect-Extraversion) and the moderating role of ethnicity among preschoolers. Chinese- American (n = 28, M_age = 54.30 months) and European American (n = 32, M_age = 50.41 months) preschoolers were assessed for their temperament and RSA. Findings indicated higher levels of Affect-Extraversion among European American children. Ethnicity moderated the association between the baseline RSA and the Affect-Extraversion dimension of temperament, with a significant positive association found only for European American children. More research is needed to examine the effects of social-cultural experiences on the relation between children's affective regulation and autonomic functioning development.

Role of Type and Volume of Recreational Physical Activity on Heart Rate Variability in Men

The aim of this study was to investigate the effect of recreational aerobic physical activity (PA) type and volume on heart rate variability (HRV) in Arab men. This was a retrospective, cross-sectional study, and included men (n = 75, age = 37.6 ± 7.1 years, body mass index (BMI) = 26.7 ± 3.1 kg/m²) who were members of a walking group, cycling group, or were inactive controls. Monthly distances from the past three months were obtained from walking and cycling groups, and the volume of PA was classified into three subgroups (high, moderate, low). HRV was measured using a computerized electrocardiographic data acquisition device. R–R interval recordings were performed while participants rested in a motionless supine position. RR intervals were recorded for 15 minutes, and a five-minute segment with minimal ectopic beats and artifacts was selected for HRV analysis. Time-domain parameters included the mean R–R interval, standard deviation of the mean R–R interval (SDNN), and root-mean-squared difference of successive RR intervals (RMSSD). The frequency-domain parameters included high-frequency power (HF), low-frequency power (LF), and LF to HF ratio (LF/HF). Results showed that there were no significant differences between walking, cycling, and control groups for all HRV parameters. Time-domain analyses based on PA volume showed that age-adjusted SDNN for the high-active group was greater than the low-active group (P = 0.03), and RMSSD for the moderate-active group was greater than the control group (P = 0.009). For the frequency domain, LF for the high-active group was greater than the low-active and control groups (P = 0.006), and HF for the moderate-active group was greater than the low-active group (P = 0.04). These data indicate that walking >150 km per month, or cycling >100 km per month at a speed >20 km/h may be necessary to derive cardiac autonomic benefits from PA among Arab men.

Salbutamol Worsens the Autonomic Nervous System Dysfunction of Children With Sickle Cell Disease

Background

Sickle cell disease (SCD) patients with asthma have an increased rate of vaso-occlusive crisis (VOC) and acute chest syndrome (ACS) episodes when compared to those without asthma. We hypothesized that either asthma diagnosis or bronchodilator treatment might aggravate SCD via their modulating effect on the autonomic nervous system (ANS).

Methods

Cross-sectional evaluation of heart rate variability (HRV) during pulmonary function tests, including salbutamol administration, in children with SCD receiving asthma treatment or not when compared to asthmatic children without SCD matched for ethnicity.

Results

SCD children with asthma (n = 30, median age of 12.9 years old) were characterized by a reduced FEV₁/FVC ratio, an increased bronchodilator response, and a greater incidence of VOC and ACS when compared to SCD children without asthma (n = 30, 12.7 years). Children with asthma without SCD (n = 29, 11.4 years) were characterized by a higher exhaled NO fraction than SCD children. SCD children when compared to non-SCD children showed reduced HRV [total power, low (LF) and high (HF, vagal tone) frequencies], which was further worsened by salbutamol administration in all the groups: reduction in total power and HF with an increase in LF/HF ratio. After salbutamol, the LF/HF ratio of the SCD children was higher than that of the non-SCD children. The two groups of SCD children were similar, suggesting that asthma diagnosis per se did not modify ANS functions.

Conclusion

SCD children are characterized by impaired parasympathetic control and sympathetic overactivity that is worsened by salbutamol administration.

Clinical Trial Registration

www.ClinicalTrials.gov, identifier NCT04062409.

Cardiac autonomic functioning and post-traumatic stress: A preliminary study in youth at-risk for PTSD

The identification of robust, psychophysiological markers of trauma-related distress is critical for developing comprehensive, trauma-informed, mental health assessments for youth. Thus, the present study examined the clinical utility of cardiac autonomic balance (CAB) and cardiac autonomic regulation (CAR), two composite indices of the sympathetic and parasympathetic nervous system. We hypothesized that CAB/CAR would more reliably index post-traumatic stress (PTS) responses compared to measuring the parasympathetic (i.e., respiratory sinus arrhythmia; RSA) and sympathetic (i.e., pre-ejection period; PEP) nervous systems in isolation. Our sample was comprised of 88 diverse, low-income youth (40.9% African-American and 36.4% White; 60.5% girls; M_age = 12.05 years; SD_age = 1.57) who are at increased risk for adversity-exposure. RSA and PEP were measured during a 5-minute baseline period and 5-minute parent-child conflict discussion task. Adolescent-caregiver dyads completed a clinician-administered measure of the youth's lifetime trauma-exposure and current PTS. CAB represented the difference between RSA and PEP, while CAR was the summation of RSA and PEP. Analyses revealed that sympathetically-oriented CAB reactivity uniquely (a) indexed PTS, especially in the context of elevated trauma, and (b) distinguished between those with and without PTSD. Findings highlight the translational promise of using physiological markers that account for the balance between the parasympathetic and sympathetic nervous system.

The Effect of the Menstrual Cycle on Daily Measures of Heart Rate Variability in Athletic Women

Abstract. Heart rate variability (HRV) is a biomarker used to reflect both healthy and pathological state(s). The effect of the menstrual cycle and menstrual cycle phases (follicular, luteal) on HRV remains unclear. Active eumenorrheic women free from exogenous hormones completed five consecutive weeks of daily, oral basal body temperature (BBT) and HRV measurements upon waking. Descriptive statistics were used to characterize shifts in the HRV measures: standard deviation of NN intervals (SDNN), root mean square of successive difference (rMSSD), high (HF) and low frequency (LF) across the menstrual cycle and between phases. All HRV measures were assessed by medians ( Mdn), median difference of consecutive days ( Mdn∆) and variance. Seven participants ( M ±  SD; age: 28.60 ± 8.40 year) completed the study with regular menstrual cycles (28.40 ± 2.30 days; ovulation day 14.57 ± 0.98 day). Median rMSSD displayed a nonlinear decrease across the menstrual cycle and plateau around the day of ovulation. A negative shift before ovulation in Mdn∆, rMSSD, SDNN, and LF as well as peak on luteal phase Day 4 in rMSSD and SDNN was observed. Median variance increased in rMSSD (150.06 ms2) SDNN (271.12 ms2), and LF variance (0.001 sec2/Hz) from follicular to luteal phase. Daily HRV associated with the parasympathetic nervous system was observed to decrease nonlinearly across the menstrual cycle.

Racial Differences in Left Ventricular Mass and Wave Reflection Intensity in Children

The burden of heart failure is disproportionately higher in African Americans, with a higher prevalence seen at an early age. Examination of racial differences in left ventricular mass (LVM) in childhood may offer insight into risk for cardiac target organ damage (cTOD) in adulthood. Central hemodynamic load, a harbinger of cTOD in adults, is higher in African Americans. The purpose of this study was to examine racial differences in central hemodynamic load and LVM in African American and non-Hispanic white (NHW) children. Two hundred sixty-nine children participated in this study (age, 10 ± 1 years; n = 149 female, n = 154 African American). Carotid pulse wave velocity (PWV), forward wave intensity (W1) and reflected wave intensity (negative area, NA) was assessed from simultaneously acquired distension and flow velocity waveforms using wave intensity analysis (WIA). Wave reflection magnitude was calculated as NA/W1. LVM was assessed using standard 2D echocardiography and indexed to height as LVM/[height (2.16) + 0.09]. A cutoff of 45 g/m (2.16) was used to define left ventricular hypertrophy (LVH). LVM was higher in African American vs. NHW children (39.2 ± 8.0 vs. 37.2 ± 6.7 g/m (2.16), adjusted for age, sex, carotid systolic pressure and socioeconomic status; p < 0.05). The proportion of LVH was higher in African American vs. NHW children (25 vs. 12 %, p < 0.05). African American and NHW children did not differ in carotid PWV (3.5 ± 4.9 vs. 3.3 ± 1.3 m/s; p > 0.05). NA/W1 was higher in African American vs. NHW children (8.5 ± 5.3 vs. 6.7 ± 2.9; p < 0.05). Adjusting for NA/W1 attenuated racial differences in LVM (38.8 ± 8.0 vs. 37.6 ± 7.0 g/m (2.16); p = 0.19). In conclusion, racial differences in central hemodynamic load and cTOD are present in childhood. African American children have greater wave intensity from reflected waves and higher LVMI compared to NHW children. WIA offers novel insight into early life origins of racial differences in central hemodynamic load and cTOD.

Stress and Depressive Symptoms Among Demographically Diverse American Pregnant Women

Pregnancy is a sensitive period of life where mental health is of utmost importance to the mother's and child's well-being peripartum and beyond. To better prevent and treat common mental health conditions such as depressive symptoms and perceived stress (defined in this study to encompass psychological and physiological (heart rate variability (HRV)) dimensions), it is crucial to examine and report differences in mental health outcomes among demographically diverse pregnant women. Therefore, the purpose of this secondary analysis (N = 79) was to determine if there are differences in mental health outcomes between pregnant women who differ across demographic factors, as well as to determine if demographic factors predict mental health outcomes when controlling for other demographic variables. Findings indicate that there were significant differences in depressive symptoms and perceived stress by all demographic factors except age. Marital status and total household income were the only significant predictors of depressive symptoms and perceived stress, respectively, when all other factors were controlled. There were no significant differences or correlations between demographic variables and HRV. Pregnant women may be predisposed to adverse mental health outcomes, illustrating the need for more refined interventions that are sensitive to pre-existing factors.

First Evaluation of an Index of Low Vagally-Mediated Heart Rate Variability as a Marker of Health Risks in Human Adults: Proof of Concept

Multiple studies have demonstrated low vagally-mediated heart rate variability (HRV) being associated with a range of risk factors for heart disease and stroke, including inflammation, hyperglycemia, hyperlipidemia, and hypertension. Yet, no cut point exists that indicates elevated risk. In the present study we sought to identify a cut point-value for HRV that is associated with elevated risk across a range of known risk factors. Methods: A total of 9550 working adults from 19 study sites took part in a health assessment that included measures of inflammation, hyperglycemia, hyperlipidemia, and hypertension and vagally-mediated HRV (Root mean square of successive differences between normal heartbeats (RMSSD)). Multiple age and sex adjusted logistic regressions were calculated per risk factor (normal versus clinical range), with RMSSD being entered in binary at different cut points ranging from 15–39 msec with a 2 msec increment. Results: For daytime RMSSD, values below 25 ± 4 indicated elevated risk (odds ratios (OR) 1.5–3.5 across risk factors). For nighttime RMSSD, values below 29 ± 4 indicated elevated risk (OR 1.2–2.0). Conclusion: These results provide the first evidence that a single value of RMSSD may be associated with elevated risk across a range of established cardiovascular risk factors and may present an easy to assess novel marker of cardiovascular risk.

Ethnic Differences in Home-Related Maternal Stress: Muslim and Jewish Mothers

Parental stresses are normal responses to raising children. They are affected by stresses parents and children accumulate and bring to their interrelations. Background factors like economic difficulties or the relations between the parents may affect parental stresses as well as demographic and environmental factors like noise and access to urban parks. Most studies on parental stress are based on a verified psychological questionnaire. We suggest using frequency domain heart rate variability index (HRV) to measure parental stress enabling, by thus, the measurement of physiological aspects of stress and risk to health. Parental stress is measured as the difference between HRV accumulated at home while staying with the children and without the husband and HRV measured in the neighborhood while staying without the children and the husband. We use the index to compare differences among Muslim and Jewish mothers in exposure to maternal stress at their homes and to expose the factors that predict differences in maternal stress. We found that Muslim mothers suffer from home-related maternal stress while Jewish mother do not. Number of children and ethnically related environmental aspects predict differences in maternal stress between Muslim and Jewish mothers. Muslims' lower access to parks stems from lack of home garden and parks in their neighborhoods in the Arab towns but mainly by restrictions on Muslim mothers' freedom of movement to parks. Despite differences in levels of noise at home and in the status of the mother in the household, these factors did not predict differences in maternal stress. Instead, the study highlights the crucial role of greenery and freedom of movement to parks in moderating home-related maternal stress.

Sex Differences in the Impact of Racial Discrimination on Mental Health Among Black Americans

PURPOSE OF REVIEW

Greater racial discrimination is associated with poorer mental health among Black Americans; yet, there remains an incomplete understanding of sex differences in exposure to racial discrimination, and further, of how sex differences in coping with racial discrimination may heighten or diminish risk for poorer mental health.

RECENT FINDINGS

Black men may experience greater exposure to both structural and communal forms of racial discrimination, whereas Black women may face both a wider range of potential sources, as well as encounter greater variability in the subjective experience of racial discrimination. For both Black women and men, racial discrimination may be similarly associated with maladaptive coping strategies (i.e., emotional eating, rumination) that also are linked to poorer mental health; however, emerging findings suggest that mindfulness may partially buffer these deleterious effects. Overall, the recent literature reveals mixed findings with respect to sex differences in the experience and negative mental health impact of racial discrimination. Despite this heterogeneity, evidence documents sex differences in the settings, type, and qualitative experience of racial discrimination among Black Americans. Additionally, growing evidence indicating that racial discrimination is associated with physiological markers of stress reactivity and psychopathology risk further bolsters its characterization as a unique form of chronic stress among Black Americans and other minority groups in the USA.

Heart Rate Variability and Cardiac Autonomic Dysfunction: Prevalence, Risk Factors, and Relationship to Arterial Stiffness in the Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) Study

OBJECTIVE

To determine whether prior type 2 diabetes (T2D) treatment or glycemic control over time are independently associated with heart rate variability (HRV) and whether the presence of cardiac autonomic dysfunction is associated with arterial stiffness in young adults with youth-onset T2D enrolled in the Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) study.

RESEARCH DESIGN AND METHODS

Heartbeats over 10 min were measured to derive the normal R-Rs (NN intervals). Outcomes included the standard deviation of the NN intervals (SDNN), the root mean square differences of successive NN intervals (RMSSD), percent of NN beats that differ by more than 50 ms (PNN50), and the low-frequency (LF) power domain, high-frequency (HF) power domain, and their ratio (LF:HF). Autonomic dysfunction was defined as ≥3 of 5 abnormal HRV indices compared with obese controls from a separate study.

RESULTS

A total of 397 TODAY participants were evaluated 7 years after randomization. TODAY participants had reduced HRV (SDNN 58.1 ± 29.6 ms vs. controls 67.1 ± 25.4 ms; P < 0.0001) with parasympathetic loss (RMSSD 53.2 ± 36.7 ms vs. controls 67.9 ± 35.2 ms; P < 0.0001) with sympathetic overdrive (LF:HF ratio 1.4 ± 1.7 vs. controls 1.0 ± 1.1; P < 0.0001). Cardiac autonomic dysfunction was present in 8% of TODAY participants, and these participants had greater pulse wave velocity compared with those without dysfunction (P = 0.0001). HRV did not differ by randomized treatment, but higher hemoglobin A1c (HbA_1c) over time was independently associated with lower SDNN and RMSSD and higher LF:HF ratio after adjustment for age, race-ethnicity, sex, and BMI.

CONCLUSIONS

Young adults with youth-onset T2D show evidence of cardiac autonomic dysfunction with both parasympathetic and sympathetic impairments that are associated with higher HbA_1c.

Stereotype threat, trait perseveration, and vagal activity: evidence for mechanisms underpinning health disparities in Black Americans

Objective: Black Americans (BAs) are at an elevated risk for morbidity and mortality in comparison to White Americans (WAs). Racial stressors are a common occurrence in American culture and is theorized to contribute to these disparities. When race-focused, stereotype threat (ST) is considered to be a factor that is detrimental to health in BAs; however few studies have directly investigated the impact of a ST manipulation on physiological function. Furthermore, it is proposed that racial stressors such as ST may have prolonged effects when more likely to perseverate (e.g. rumination) over the stressor and thus, those with greater trait perseveration may be more affected by ST. We sought to explore the impact of ST and trait perseveration on changes in vagus nerve activity - an indication of adaptive psychological and physiological well-being - as indexed by vagally mediated heart rate variability (vmHRV). Design: Forty-three (24 females, mean age of 20, standard deviation of 3 years) apparently healthy BA individuals were randomly assigned to one of three experimental conditions in which they received either implicit (subtle), explicit (blatant), or no ST priming (control condition), prior to completing a cognitive task. Resting vmHRV was assessed both at baseline (pre-task) and recovery (post-task). Results: BAs in the explicit ST condition exhibited the greatest decrease in vmHRV in comparison to the control group from pre- to post-task. BAs with moderate to high levels of trait perseveration showed the greatest decrease in vmHRV from pre- to post-task in comparison to those with lower levels of trait perseveration and BAs in the control group. Conclusion: These data suggest that racial ST, especially when explicit and coupled with trait perseveration, can decrease vagal activity, as indexed by decreased vmHRV, which when experienced frequently can have significant consequences for health and longevity in BAs.

Resting Cerebral Blood Flow and Ethnic Differences in Heart Rate Variability: Links to Self-Reports of Affect and Affect Regulation

Reduced high-frequency heart rate variability (HF-HRV) is associated with a greater risk for cardiovascular disease (CVD). Although African Americans (AA) are at greater risk for CVD, they show greater HF-HRV compared to European Americans (EA). Previous studies suggest that differences in the association between regional cerebral blood flow (CBF) and HF-HRV in AA and EA may explain this surprising pattern of findings, termed the Cardiovascular Conundrum. Here we pooled data from a total of n = 452 EA and n = 102 AA, investigating differences in the association between CBF in 8 regions of interest (ROI), including the cingulate (anterior, mid, posterior), insula (anterior, posterior), and amygdala (basolateral, centromedial, superfical), with HF-HRV, mean heart rate (HR) and their Coefficient of Variation (CoV). Bayesian statistics illustrate that CBF - in particular in the anterior cingulate cortex (ACC) - is positively associated with HF-HRV and CoV in EA, but negatively associated in AA. Exploring the association between HF-HRV and CBF with self-reports of affect and affect regulation showed some differences as a function of ethnicity. The association between greater habitual use of reappraisal only showed a positive correlation with HF-HRV in AA. Similar, greater suppression or non-expression of angry emotions was associated with greater HF-HRV whereas greater outward direction of anger was associated with lower HF-HRV in AA only. Given the importance of the ACC in emotion and emotion regulation, we suggest that increased HF-HRV may serve a compensatory role in AA. Implications from these findings and suggestions for future studies are discussed.

The Autonomic Nervous System and Hypertension: Ethnic Differences and Psychosocial Factors

PURPOSE OF THE REVIEW

In the present paper, we overview emerging research examining the autonomic nervous system (ANS), especially the parasympathetic nervous system as indexed by heart rate variability (HRV), and the impact of psychosocial factors on hypertension-related disease in African Americans.

RECENT FINDINGS

A growing corpus of studies has shown that (1) usual patterns of compensatory sympathetic-parasympathetic regulation differ between African Americans and European Americans; (2) despite their enhanced cardiovascular disease risk profile, African Americans tend to exhibit higher HRV relative to European Americans; and (3) racial discrimination and other forms of psychosocial stress are associated with diminished HRV among African Americans. Significant disparities in hypertension-related disease exist such that African Americans have greater risk. The underlying factors associated with this increased risk are, to date, not fully understood. The present review provides evidence for a unique pattern of ANS regulation in African Americans and shows that psychosocial factors such as racial discrimination may contribute to this paradoxical situation.

Active coping moderates associations among race-related stress, rumination, and depressive symptoms in emerging adult African American women

Cross-sectional and longitudinal research has shown that race-related stress is associated with increased depressive symptoms among racial/ethnic minorities. Rumination has long been considered a maladaptive self-regulatory response to race-related stress, and growing evidence suggests that it may be an important link in the relation between race-related stress and depression. More adaptive forms of self-regulation, such as active coping, may counteract the negative impact of rumination. We examined the influence of rumination on the relation between race-related stress and depressive symptoms in a sample (N = 69) of young adult (mean age = 20 ± 1.5 years) African American women. We also considered the possible moderating effects of John Henryism, a form of persistent and determined goal striving, and vagally mediated heart rate variability, a purported biomarker of coping. Anticipatory race-related stress was indirectly associated with depressive symptoms through rumination: estimate = 0.07, 95% confidence interval [0.01, 0.16]. Both John Henryism and vagally mediated heart rate variability moderated the relationship between race-related stress and rumination; however, only John Henryism reliably influenced the indirect association between race-related stress and depression through rumination. We discuss these findings in the context of growing research examining the interplay between cultural and biological factors in the risk for poorer mental health.

In sync: Physiological correlates of behavioral synchrony in infants and mothers

Infant-mother behavioral synchrony is thought to scaffold the development of self-regulation in the first years of life. During this time, infants' and mothers' physiological regulation may contribute to dyadic synchrony and, in infants, dyadic synchrony may support infants' physiological regulation. Because the sympathetic nervous system (SNS) and parasympathetic nervous system (PNS) serve different regulatory functions, the current study aimed to elucidate relations between infants' and mothers' SNS and PNS functioning and dyadic behavioral synchrony. Skin conductance (SC; SNS index), respiratory sinus arrhythmia (RSA; PNS index), heart period (HP; index of joint SNS and PNS arousal), and behavioral synchrony were assessed in 6-month-old infants (N = 140) and their mothers during a mild social stressor, the Face-to-Face Still-Face paradigm (Tronick, Als, Adamson, Wise, & Brazelton, 1978). Synchrony was related to infants' and mothers' PNS and to mothers' broad autonomic arousal but not to SNS-specific arousal. Higher levels of behavioral synchrony were associated with lower infant RSA but with higher mother HP and RSA at baseline and in each Face-to-Face Still-Face paradigm episode. Therefore, lower RSA infants may have required more synchronous engagement with mothers to support regulation, while higher RSA, less aroused mothers may have been particularly well-attuned to infants' emotions. Findings suggest that each individual's physiological state may contribute to the behavioral functioning of the dyad. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

The effects of crossing ethnic boundaries on the autonomic nervous system in Muslim and Jewish young women in Israel

Exposure to alien inter-group environments can differently effect ethnic groups’ autonomous nervous system, measured by heart rate variability (HRV). Our aim was to evaluate the effect of crossing alien ethnic boundaries on heart rate variability in three selected types of environments. In a field experiment study, we test responses of 72 Muslim and Jewish women to exposure to alien ethnic environments. We measured their HRV in intra and inter-ethnic parks, town centers and residential neighborhoods in Arab and Jewish adjacent towns. The subjects stayed half an hour in each environment. Mixed models were used to evaluate the effects. The results show that for both groups more favorable HRV measurements were demonstrated in intra-ethnic environments as compared to their HRV once crossing ethnic boundaries. The strongest effect in frequency domain (LF/HF) in response to ethnic boundary crossing was observed in the park for Muslims (β:0.65, 95%CI: 0.60–0.70) and for Jews (β: 0.60, 95%CI: 0.57–0.63). Following the eruption of the uprising, the most significant increase in LF/HF in response to ethnic boundary crossing was demonstrated in parks (β: 0.66, 95%CI: 0.60–0.71). In conclusion, both groups are effected by boundary crossing but there are ethnic differences in the autonomic nervous system balance and in response to crossing alien ethnic boundaries. A further study is needed to understand the causes of these differences.

Perspectives on two temperamental biases

This paper describes the contribution of two infant temperamental biases to variation in behaviour and biology over the first 18 years in a sample of middle-class Caucasian children. One bias, called high reactive, is defined by frequent display of limb activity and crying in four-month-old infants to unexpected or unfamiliar events. The other, called low reactive, is defined by the opposite pair of behaviours to the same incentives. High reactive infants are likely to display cautious, avoidant responses and signs of an excitable amygdala to unexpected experiences. Low reactives are characterized by a sociable, emotionally spontaneous profile to the same experiences and a minimally excitable amygdala. However, each bias is a better predictor of the future traits that are unlikely to develop than the ones that do. The final pattern of traits is a function of the person's temperaments, life history, and current circumstances.This article is part of the theme issue 'Diverse perspectives on diversity: multi-disciplinary approaches to taxonomies of individual differences'.

Heart rate variability as a biomarker of anxious depression response to antidepressant medication

BACKGROUND

There is a need to identify biomarkers of treatment outcomes for major depressive disorder (MDD) that can be disseminated. We investigated the predictive utility of pretreatment heart rate variability (HRV) for outcomes of antidepressant medication in MDD, with pretreatment anxious depression as a hypothesized moderator of HRV effects.

METHODS

A large, randomized, multicenter practical trial (International Study to Predict Optimized Treatment in Depression) in patients with current nonpsychotic MDD (N = 1,008; 722 completers) had three arms: escitalopram, sertraline, and venlafaxine-extended release. At pretreatment, patients were defined as having anxious (N = 309) versus nonanxious (N = 413) depression and their resting high-frequency HRV (root mean square of successive differences) was assessed. Patients' usual treating clinicians managed medication. At 8 weeks, primary outcomes were clinician-rated depressive symptom response and remission; secondary outcomes were self-reported response and remission.

RESULTS

Pretreatment HRV predicted antidepressant outcomes as a function of anxious versus nonanxious depression. In anxious depression, patients with higher HRV had better outcomes, whereas patients with lower HRV had poorer outcomes. In nonanxious depression, patients with lower HRV had better outcomes, whereas patients with higher HRV had poorer outcomes. Some simple effects were not significant. Results did not differ by treatment arm and remained significant when controlling for important covariates.

CONCLUSIONS

These findings inform a precision medicine approach in which clinical and biological assessments may be integrated to facilitate treatment outcome prediction. Knowing about HRV may help determine which patients with anxious depression could benefit from antidepressants and which patients may require a different treatment approach.

Rumination Moderates the Association Between Resting High-Frequency Heart Rate Variability and Perceived Ethnic Discrimination

Abstract. Ethnic discrimination (ED) is both an unfortunate and uncontrollable phenomenon that uniquely impacts African Americans (AAs) and other individuals of ethnic minority status. Perceived ethnic discrimination (PED), defined as the degree to which an individual consciously perceives a negative event as discriminatory and threatening, largely determines the impact that ED can have on target individuals. However, research has not yet considered how individual differences in both emotion regulation abilities, as indexed by resting high-frequency heart rate variability (HF-HRV), and rumination, a maladaptive emotion regulation strategy, may predict PED in AAs. The following investigation examined this relationship in a sample of 101 college-aged students (45 AAs and 56 Caucasian Americans). Resting HF-HRV was assessed via electrocardiogram during a 5-minute-resting period. Rumination was assessed using the ruminative responses scale and everyday PED was assessed using the perceived ethnic discrimination questionnaire. Results showed a significant negative relationship between resting HF-HRV and PED in AAs only. Rumination significantly moderated this relationship, such that lower HF-HRV was related to higher PED only in AAs who reported moderate to higher, β = 0.417 (0.125), p < .01, levels of trait rumination. These results suggest that greater HF-HRV and lesser ruminative tendencies are key factors in reducing PED and therefore possibly, negative consequences associated with ED.

Hemodynamic profile and compensation deficit in African and European Americans during physical and mental stress

Increased vascular reactivity to stress has been suggested to contribute to the greater risk for developing hypertension in African Americans. Here, we examined the way (hemodynamic profile) and the extent to which (compensation deficit) cardiac output and total peripheral resistance compensate for each other in determining blood pressure responses to a physical (orthostasis) and a mental (anger recall) stress task, in normotensive African American (AA, n = 30) and European American (EA, n = 48) college students. Blood pressure stress reactivity did not differ as a function of race. However, AAs showed a prominent vascular hemodynamic profile and a significant compensation deficit in response to both tasks, while EAs showed no hemodynamic response to orthostasis and a mixed profile in response to anger recall. The present findings demonstrate a more prominent vascular hemodynamic reactivity to stress in AAs, which could contribute to the pathogenesis of hypertension in this ethnic group.

A unifying conceptual framework of factors associated to cardiac vagal control

Cardiac vagal control (CVC) reflects the activity of the vagus nerve regulating cardiac functioning. CVC can be inferred via heart rate variability measurement, and it has been positively associated to a broad range of cognitive, emotional, social, and health outcomes. It could then be considered as an indicator for effective self-regulation, and given this role, one should understand the factors increasing and decreasing CVC. The aim of this paper is to review the broad range of factors influencing CVC, and to provide a unifying conceptual framework to integrate comprehensively those factors. The structure of the unifying conceptual framework is based on the theory of ecological rationality, while its functional aspects are based on the neurovisceral integration model. The structure of this framework distinguishes two broad areas of associations: person and environment, as this reflects adequately the role played by CVC regarding adaptation. The added value of this framework lies at different levels: theoretically, it allows integrating findings from a variety of scientific disciplines and refining the predictions of the neurovisceral integration model; methodologically, it helps identifying factors that increase and decrease CVC; and lastly at the applied level, it can play an important role for society regarding health policies and for the individual to empower one's flourishing.

Breath of Life: The Respiratory Vagal Stimulation Model of Contemplative Activity

Contemplative practices, such as meditation and yoga, are increasingly popular among the general public and as topics of research. Beneficial effects associated with these practices have been found on physical health, mental health and cognitive performance. However, studies and theories that clarify the underlying mechanisms are lacking or scarce. This theoretical review aims to address and compensate this scarcity. We will show that various contemplative activities have in common that breathing is regulated or attentively guided. This respiratory discipline in turn could parsimoniously explain the physical and mental benefits of contemplative activities through changes in autonomic balance. We propose a neurophysiological model that explains how these specific respiration styles could operate, by phasically and tonically stimulating the vagal nerve: respiratory vagal nerve stimulation (rVNS). The vagal nerve, as a proponent of the parasympathetic nervous system (PNS), is the prime candidate in explaining the effects of contemplative practices on health, mental health and cognition. We will discuss implications and limitations of our model.

A comparison of the effects of selected mono-ethnic urban environments on the autonomic functions of Muslim and Jewish women in Israel

Few previous studies evaluated ethnic differences in the effects of urban environments on the autonomic balance in intra-ethnic environments and the mediation effects of environmental exposures (air pollution, noise, and thermal load). In a field experimental study, we exposed 48 Muslim and 24 Jewish women to park, town center, and residential street in Israeli mono-ethnic small towns. Heart rate variability (HRV), noise, thermal load, and carbon monoxide (CO) were measured by portable devices while visiting the environments and were analyzed using mixed models. The results highlight the restorative effect of parks on both ethnic groups with stronger effect for Jewish women compared to Muslim women (β coefficient (95% confidence interval (CI)): - 6.45(- 6.70, - 6.20); - 4.99 (- 5.15, - 4.83), respectively). However, significant differences were recorded in Muslim and Jewish coping with the environments and the environmental exposures as measured by HRV.

Autonomic nervous system functioning assessed during the Still-Face Paradigm: A meta-analysis and systematic review of methods, approach and findings

Animal and human research suggests that the development of the autonomic nervous system (ANS) is particularly sensitive to early parenting experiences. The Still-Face Paradigm (SFP), one of the most widely used measures to assess infant reactivity and emotional competence, evokes infant self-regulatory responses to parental interaction and disengagement. This systematic review of 33 peer-reviewed studies identifies patterns of parasympathetic (PNS) and sympathetic (SNS) nervous system activity demonstrated by infants under one year of age during the SFP and describes findings within the context of sample demographic characteristics, study methodologies, and analyses conducted. A meta-analysis of a subset of 14 studies with sufficient available respiratory sinus arrhythmia (RSA) data examined whether the SFP reliably elicited PNS withdrawal (RSA decrease) during parental disengagement or PNS recovery (RSA increase) during reunion, and whether results differed by socioeconomic status (SES). Across SES, the meta-analysis confirmed that RSA decreased during the still-face episode and increased during reunion. When studies were stratified by SES, low-SES or high-risk groups also showed RSA decreases during the still face episode but failed to show an increase in RSA during reunion. Few studies have examined SNS activity during the SFP to date, preventing conclusions in that domain. The review also identified multiple qualifications to patterns of SFP ANS findings, including those that differed by ethnicity, infant sex, parental sensitivity, and genetics. Strengths and weaknesses in the extant research that may explain some of the variation in findings across the literature are also discussed, and suggestions for strengthening future research are provided.

Effect of Heart Rate Variability Biofeedback on Sport Performance, a Systematic Review

Aim is to determine if the training with heart rate variability biofeedback allows to improve performance in athletes of different disciplines. Methods such as database search on Web of Science, SpringerLink, EBSCO Academic Search Complete, SPORTDiscus, Pubmed/Medline, and PROQUEST Academic Research Library, as well as manual reference registration. The eligibility criteria were: (a) published scientific articles; (b) experimental studies, quasi-experimental, or case reports; (c) use of HRV BFB as main treatment; (d) sport performance as dependent variable; (e) studies published until October 2016; (f) studies published in English, Spanish, French or Portuguese. The guidelines of the PRISMA statement were followed. Out of the 451 records found, seven items were included. All studies had a small sample size (range from 1 to 30 participants). In 85.71% of the studies (n = 6) the athletes enhanced psychophysiological variables that allowed them to improve their sport performance thanks to training with heart rate variability biofeedback. Despite the limited amount of experimental studies in the field to date, the findings suggest that heart rate variability biofeedback is an effective, safe, and easy-to-learn and apply method for both athletes and coaches in order to improve sport performance.