Gender differences in personality and heart-rate variability

Impact of Sleep Apnea on Nocturnal Parasympathetic Activity in Atrial Fibrillation Patients After Catheter Ablation - Implications for Heart Rate Variability Analysis

BACKGROUND

The impact of sleep apnea (SA) on heart rate variability (HRV) in atrial fibrillation (AF) patients has not been investigated.

METHODS AND RESULTS

Of 94 patients who underwent AF ablation between January 2021 and September 2022, 76 patients who had a nocturnal Holter electrocardiography and polysomnography conducted simultaneously were included in the analysis. A 15-min duration of HRV, as determined by an electrocardiogram during apnea and non-apnea time, were compared between patients with and without AF recurrence at 12 months' postoperatively. Patients had a mean age of 63.4±11.6 years, 14 were female, and 20 had AF recurrence at 12 months' follow-up. The root mean square of the difference between consecutive normal-to-normal intervals (RMSSD, ms) an indicator of a parasympathetic nervous system, was more highly increased in patients with AF recurrence than those without, during both apnea and non-apnea time (apnea time: 16.7±4.5 vs. 13.5±3.3, P=0.03; non-apnea time: 20.9±9.5 vs. 15.5±5.9, P<0.01). However, RMSSD during an apneic state was decreased more than that in a non-apneic state in both groups of patients with and without AF recurrence (AF recurrence group: 16.7±4.5 vs. 20.9±9.5, P<0.01; non-AF recurrence group; 13.5±3.3 vs. 15.5±5.9, P=0.03). Consequently, the effect of AF recurrence on parasympathetic activity was offset by SA. Similar trends were observed for other parasympathetic activity indices; high frequency (HF), logarithm of HF (lnHF) and the percentage of normal-to-normal intervals >50 ms (pNN50).

CONCLUSIONS

Without considering the influence of SA, the results of nocturnal HRV analysis might be misinterpreted. Caution should be taken when using nocturnal HRV as a predictor of AF recurrence.

The effectiveness of an osteopathic manual technique compared with a breathing exercise on vagal tone as indicated by heart rate variability, a crossover study

INTRODUCTION

Parasympathetic nervous system (PSNS) function can be inferred by heart rate variability (HRV) providing indications about an individual's health. Manual therapy may influence PSNS function, however the research outcomes in this regard are equivocal. This study explored the PSNS effect of a measured breathing technique with suboccipital balanced ligamentous tension, an osteopathic manipulative therapy technique.

METHODS

Healthy adult participants in this crossover study (n = 18) were randomly allocated into two groups with differing order of interventions. A 1:1 breathing rate of 6 breaths per minute maintained for 5 min was compared to the osteopathic intervention. HRV was measured for 5 min before and after each intervention and analysed using the root mean square of successive differences (RMSSD) between normal heartbeats and high frequency normalised units (HFnu).

RESULTS

The RMSSD data demonstrated no significant difference between groups or within groups (p > 0.05) over time. HFnu results showed a significant between-group difference over the four time points (p = 0.004) with a medium effect size (ηp2 = 0.240), and no significant within-group difference (p > 0.05).

DISCUSSION

The osteopathic intervention raised HRV to a small extent, however measured breathing lowered HRV. In the group that received the osteopathic technique first, HFnu values continued to rise post-osteopathic treatment possibly indicating an increasing parasympathetic effect over time. Recommendations for future studies include changing the breathing ratio to ensure parasympathetic response, take into account potential delayed effects of interventions, consider outcome measures less variable than HRV, and longer follow up times.

CONCLUSION

This study suggests parasympathetic stimulation may occur with the application of suboccipital balanced ligamentous tension and sympathetic stimulation from measured breathing.

The impact of virtual reality scenes on stress response characteristics of individuals with different personality traits

Virtual reality based physical stress (VRPS) paradigms could eliminate the influence of social factors on participants, and it may be a desirable tool to explore the impact of personality traits on stress levels. In this study, we attempt to explore the effects of VRPS on stress response among individuals with different personality traits. Forty male participants with an average age of 22.79 ± 0.41 years were divided into two groups based on Harm Avoidance (HA) scores of Tridimensional Personality Questionnaire (TPQ), referred to as the Low-HA group and the High-HA group. The stress levels of the participants were assessed using salivary α-amylase (sAA) activity and heart rate variability (HRV) indices pre- and post-stress. The influence of personality traits on stress response among different groups was analyzed. VRPS significantly affected the sAA activity and HRV indicators of both groups. During and after stress, there were significant differences in sAA activity and HRV indicators between the two groups. The sAA levels and HRV indices of the Low-HA group were lower than those of the High-HA group. Furthermore, sAA levels and HRV indices were correlated with the scores of TPQ. VRPS scenarios elicit different stress responses on individuals with different harm avoidance personality traits. Stress evaluation based on VR scenarios presents potential in personality trait assessments, particularly for distinguishing between individuals with low and high HA tendencies.

Clarifying the link between psychopathologies and heart rate variability, and the sex differences: Can neuropsychological features serve as mediators?

BACKGROUND

Patients with common mental disorders (depression, anxiety, and somatic symptoms) often exhibit lower heart rate variability (HRV) than healthy individuals. Under the hypothesis that disorder status affects cognitive function, we examined whether neuropsychological features can be mediators between psychopathologies and HRV and possible sex differences.

METHODS

We recruited 359 individuals (aged 42.47 ± 12.23) with and without common mental disorders. Questionnaires were used to measure their psychopathologies. Eight tests from the Cambridge Neuropsychological Test Automated Battery were selected to measure neuropsychological functions. Resting-state HRV measurements were obtained for 5 min. The associations among these constructs were analyzed using multiple linear regression analysis and structural equation modelling.

RESULTS

Among women, Reaction Time (RTI, a task of psychomotor speed) indicator mediated the relationship between depression and low-frequency power (LF); Emotion Recognition Task (ERT, a task of emotional regulation) indicator mediated the relationship between health anxiety and high-frequency power (HF). Among men, Intra-Extra Dimensional Set Shift (IED, a task of shifting) indicator mediated the relationship between depression and LF; Match to Sample Visual Search (MTS, a task of selective attention) indicator mediated the relationship between health cognition and HF. The depression-RTI-LF pathway in women tended to lower HRV; whereas health anxiety-ERT-HF in women, depression-IED-LF and health cognition-MTS-HF in men tended to increase HRV.

LIMITATIONS

Possible medication effects; not directly measuring brain activity; only gathering resting-state HRV.

CONCLUSION

Our findings support the notion that neuropsychological features mediate the relationship between psychopathologies and HRV, and that sex differences exist.

Can peripheral biomarkers reflect the psychological condition in geriatric populations? The influence of cardiovascular comorbidities

BACKGROUND

Although previous studies indicated the association between peripheral biomarkers and psychological conditions, a higher prevalence of cardiovascular diseases (CVD) among geriatric populations may hinder the applicability of the biomarkers. The objective of this study was to assess the adequacy of the application of biomarkers to evaluate psychological conditions among geriatric populations.

METHOD

We collected information on the demographics and history of CVD in all participants. All participants completed the Brief Symptom Rating Scale (BSRS-5) and the Chinese Happiness Inventory (CHI), which are the measurement of negative and positive psychological conditions, respectively. Four indicators of the peripheral biomarkers, including the standard deviation of normal to normal RR intervals (SDNN), finger temperature, skin conductance, and electromyogram were collected for each participant during a 5-min resting state. Multiple linear regression models were conducted to evaluate the association between the biomarkers and the psychological measurements (BSRS-5, CHI) with and without the inclusion of the participants with CVD.

RESULTS

A total of 233 participants without CVD (non-CVD group) and 283 participants with CVD (CVD group) were included. The CVD group was older and with higher body mass index compared to the non-CVD group. In the multiple linear regression model with all participants, only BSRS-5 scores had a positive association with electromyogram. After the exclusion of the CVD group, the association between the BSRS-5 scores and electromyogram was more relevant, while CHI scores became positively associated with SDNN.

CONCLUSIONS

A single measurement of the peripheral biomarker may be insufficient to depict psychological conditions among geriatric populations.

Heart rate variability changes in patients with obstructive sleep apnea: A systematic review and meta-analysis

Obstructive sleep apnea is a common sleep breathing disorder related to autonomic nervous function disturbances. Heart rate variability is an important non-invasive indicator of autonomic nervous system function. The PubMed, Embase, Medline and Web of Science databases were systematically searched for English literature comparing patients with obstructive sleep apnea with controls up to May 2021. Heart rate variability outcomes, including integrated indices (parasympathetic function and total variability), time domain indices (the standard deviation of NN intervals and the root mean square of the successive differences between normal heartbeats) and frequency domain indices (high-frequency, low-frequency, very-low-frequency and the ratio of low-frequency to high-frequency) were derived from the studies. Twenty-two studies that included 2565 patients with obstructive sleep apnea and 1089 healthy controls were included. Compared with controls, patients with obstructive sleep apnea exhibited significantly reduced parasympathetic function. For the obstructive sleep apnea severity subgroup meta-analysis, patients with severe obstructive sleep apnea had significantly lower parasympathetic function, high-frequency, root mean square of the successive differences between normal heartbeats and standard deviation of NN intervals, and higher low-frequency and ratios of low-frequency to high-frequency. However, only the ratio of low-frequency to high-frequency was significantly higher in patients with moderate obstructive sleep apnea than in controls. Finally, for the collection time analysis, patients with obstructive sleep apnea had significantly higher low-frequency and ratio of low-frequency to high-frequency at night, significantly lower parasympathetic function, high-frequency, root mean square of the successive differences between normal heartbeats and standard deviation of NN intervals, and a higher ratio of low-frequency to high-frequency during the day than controls. Autonomic function impairment was more serious in patients with severe obstructive sleep apnea. During sleep, low-frequency can well reflect the impairment of autonomic function in obstructive sleep apnea, and the ratio of low-frequency to high-frequency may play an important role in obstructive sleep apnea diagnosis.

The association between heart rate variability and skin conductance: a correlation analysis in healthy individuals and patients with somatic symptom disorder comorbid with depression and anxiety

Objective

To investigate the correlations between heart rate variability (HRV) and skin conductance (SC) in two populations under three different situations.

Methods

This cross-sectional study enrolled patients with somatic symptom disorder comorbid with depression and anxiety and healthy individuals without a psychiatric history. The biological signals were measured under three conditions: resting state, during a cognitive task and during paced breathing. Pearson’s correlation analysis and the generalized estimating equation were used to examine the correlations between SC and HRV in the two populations under the three situations.

Results

The study enrolled 97 patients with somatic symptom disorder comorbid with depression and anxiety and 96 healthy individuals. In healthy individuals, the ratio of low-frequency power to high frequency power (LF/HF) and normalized LF (LF%) were significantly correlated with SC in the resting state and during a cognitive task, but the correlation coefficients were low level. In patients with somatic symptom disorder comorbid with depression and anxiety, LF/HF and LF% did not show significant correlations with SC under any situation.

Conclusions

The two different populations and three situations might have affected the significance of the LF/HF-SC and LF%-SC correlations. The generally low correlations indicate that LF/HF and LF% cannot fully reflect the sympathetic cholinergic activity represented by SC.

Cardiorespiratory Response to Moderate Hypercapnia in Female College Students Expressing Behaviorally Inhibited Temperament

Behaviorally inhibited (BI) temperament is marked by heightened behavioral sensitivity to environmental threats. The degree to which threat sensitivity is reflected in cardiorespiratory responses has been relatively unexplored. Female college students were exposed to modest hypercapnia (7.0% CO₂) or ambient air (AA) while engaging in a computerized task with cued reinforcement features. All physiological variables except for blood pressure were processed in 4 min epochs corresponding to pre-exposure, exposure, and post-exposure. Primary respiratory measures were respiratory frequency (f_b), tidal volume (V_T), and minute ventilation (V_E). Electrocardiograms (ECGs) were processed using ARTiiFACT software with resultant heart rate variability (HRV) measures in the frequency domain and time domain. Consistent with the literature, modest hypercapnia increased V_T, F_b, and V_E. No differences in respiratory parameters were detected between BI and non-behaviorally inhibited individuals (NI). For HRV in the time domain, RMSSD and NN50 values increased during CO₂ inhalation which then returned to pre-exposure levels after CO₂ cessation. Hypercapnia increased high frequency (HF) power which then recovered. BI exhibited reduced low frequency (LF) power during the pre-exposure period. For NI, LF power reduced over the subsequent phases ameliorating differences between BI and NI. Hypercapnia improved the task performance of BI. This is the largest study of female reactivity to hypercapnia and associated HRV to date. In general, hypercapnia increased time domain HRV and HF power, suggesting a strong vagal influence. Those expressing BI exhibited similar respiratory and HRV reactivity to NI despite inherently reduced LF power. Although 7% CO₂ represents a mild challenge to the respiratory and cardiovascular systems, it is nonetheless sufficient to explore inherent difference in stress reactivity in those vulnerable to develop anxiety disorders.

Cardiovascular Responses to Stress Utilizing Anticipatory Singing Tasks

Abstract. Models of psychobiological stress reactivity have a foundation in the measurement of responses to standardized stress tasks. Tasks with anticipatory phases have been proposed as an effective method of stress induction, either as a stand-alone task or replacement constituent elements for existing stressor paradigms. Tasks utilizing singing as a primary stressor have been proposed but the efficacy of these tasks have not been demonstrated while maintaining adherence to a resting/reactivity/recovery framework desirable for heart rate variability (HRV) measurement. This study examines the viability of an anticipatory sing-a-song task as a method for inducing mental stress and examines the utility of the task with specific reference to measures of cardiovascular reactivity and recovery activity, and standard protocols to examine HRV reactivity and recovery. Participants completed a dual task with a math task and an anticipation of singing component. Responses were examined according to a resting/reactivity/recovery paradigm and the findings indicate that the sing-a-song stimulus is effective in generating a stress response. Significant differences in heart rate and self-reported stress between baseline and stressor conditions were detected, with greater magnitude differences between baseline and anticipatory phases. This study has demonstrated the viability of the anticipation of singing as a standardized stressor using cardiovascular measures and has described variants of this task that may be used for repeated measures study designs.

Intranasal oxytocin increases heart-rate variability in men at clinical high risk for psychosis: a proof-of-concept study

Autonomic nervous system (ANS) dysfunction (i.e., increased sympathetic and/or decreased parasympathetic activity) has been proposed to contribute to psychosis vulnerability. Yet, we still lack directed therapeutic strategies that improve ANS regulation in psychosis or at-risk states. The oxytocin system constitutes a potential therapeutic target, given its role in ANS regulation. However, whether intranasal oxytocin ameliorates autonomic regulation during emerging psychosis is currently unknown. We pooled together two datasets, one of 30 men at clinical high risk for psychosis (CHR-P), and another of 17 healthy men, who had participated in two double-blinded, placebo-controlled, randomised, crossover MRI studies with similar protocols. All participants self-administered 40 IU of intranasal oxytocin or placebo using a nasal spray. We recorded pulse plethysmography during a period of 8 min at about 1 h post dosing and estimated heart rate (HR) and high-frequency HR variability (HF-HRV), an index of cardio-parasympathetic activity. CHR-P and healthy men did not differ at resting HR or HF-HRV under placebo. We found a significant condition × treatment effect for HF-HRV, showing that intranasal oxytocin, compared with placebo, increased HF-HRV in CHR-P but not in healthy men. The main effects of treatment and condition were not significant. In this proof-of-concept study, we show that intranasal oxytocin increases cardio-parasympathetic activity in CHR-P men, highlighting its therapeutic potential to improve autonomic regulation in this clinical group. Our findings support the need for further research on the preventive and therapeutic potential of intranasal oxytocin during emerging psychosis, where we lack effective treatments.

Heart Rate Variability is Associated with Memory in Females

Research into the association between heart rate variability (HRV) and cognitive function is scarce, particularly with regard to gender differences. HRV in 182 healthy volunteers was assessed by the root mean square of the successive difference (RMSSD) and spectrum analysis, while the Wechsler Memory Scale-Revised (WMS-R) was used to determine memory function. Robust and significant associations were found to exist between HRV (RMSSD and high-frequency HRV) and domains of the WMS-R in females. Caution should therefore be taken to control for gender when conducting studies on the relationships between HRV and cognitive variables.

Heart Rate Kinetics and Sympatho-Vagal Balance Accompanying a Maximal Sprint Test

When a maximal sprint starts, heart rate (HR) quickly increases. After the exercise ends, HR keeps high for seconds before recovering with a roughly exponential decay. Such decay and its time constant (τ_off) have been widely studied, but less attention was devoted to the time delay (t_delay) between sprint end and HR decay onset. Considering the correlation between sympatho-vagal balance and performance, as well as the occurrence of heart failure in cardiopaths during the post-exercise phase, we evaluated sympatho-vagal balance before and after sprint, trying to correlate it with both t_delay and τ_off. R-R intervals, recorded in 24 healthy adults from 5 min before to 5 min after a 60-m sprint-test (from Storniolo et al., 2017, with permission of all authors), were re-processed to extract HR variability power (LF and HF) in the low- and high-frequency ranges, respectively. The sympatho-vagal balance, evaluated in pre-test resting period (LF/HF)_REST and at steady-state recovery (LF/HF)_RECOV, was correlated with t_delay and τ_off. Both (LF/HF)_REST and (LF/HF)_RECOV had a skewed distribution. Significant rank correlation was found for (LF/HF)_REST vs. τ_off and for (LF/HF)_RECOV vs. both τ_off and t_delay. The difference (LF/HF)_RECOV-REST had a normal distribution and a strong partial correlation with t_delay but not with τ_off. Thus, a long t_delay marks a sympathetic activity that keeps high after exercise, while a high sympathetic activity before sprint leads to a slow recovery (high τ_off), seemingly accompanying a poor performance.

Autonomic reactivity during reading of a somatic distress script in patients with somatic symptom disorder

OBJECTIVE

The relationship between resting-state heart rate variability (HRV) and somatic symptom disorder (SSD) has been explored in several studies. We planned to examine HRV during the performance of psychological tasks, and assumed that it could be applied for the diagnosis of SSD.

METHODS

Fifty-three patients with SSD and 52 healthy controls were recruited. Demographic and psychological data were collected. Subjects' HRV was measured over five 5-minute blocks during which they viewed different scripts (resting state; health anxiety; somatic distress; depression; neutral topic). After each block they completed a self-assessment manikin. Generalized estimated equation analysis was used to analyze the impact of mental scripts, SSD and sex on physiological and psychological indicators.

RESULTS

In men there was a script*SSD interaction concerning high-frequency power (HF) involving the neutral script; SSD men showed significantly higher HF than healthy men when viewing neutral script. In women there were script*SSD interactions with respect to low-frequency power (LF) and HF involving the somatic distress script and a script*SSD interaction with respect to LF and emotional valence involving the neutral script; SSD women revealed significantly lower LF and HF than healthy women when viewing somatic distress script, they also showed significantly lower LF and higher valence than healthy ones during neutral script. The somatic distress script*SSD interaction still influenced LF and HF in women after adjusting for potential confounders.

CONCLUSION

In women cue-specific HRV is a better method of differentiating people with SSD from healthy individuals than resting-state HRV.

TRIAL REGISTRATION INFORMATION

The Research Ethics Committee of National Taiwan University Hospital approved this study (approval number: 201410050RINB).

Heart rate variability related to season of birth: A replication study

Low heart rate variability (HRV) has strongly been associated with an increased risk for cardiovascular disease. With cardiovascular disease being the number one cause of global deaths, factors that influence its development are relevant to understand. Season of birth has been suggested as one of the factors influencing the development of HRV. The current study was set up to replicate the finding that men born in winter have higher HRV later in life compared to those born in other seasons. To this end, we studied a sample of 1,871 healthy participants from the Brain Resource International Database during rest and during task. Furthermore, sex and age differences and associations with personality traits and psychiatric symptoms were explored. We replicated the earlier finding that men born in winter have a lower ratio of low frequency (LF) power to high frequency (HF) power during rest compared to summer and fall, and, although less pronounced, higher HF compared to summer. A difference between summer and winter for LF/HF in men was internally replicated using data recorded during task. Additionally, for both sexes, LF/HF ratio increased with age, and LF and HF both decreased. In general, LF/HF was lower in women, but heart rate was higher. In men, low HRV was associated with depression and the personality trait openness. In conclusion, results from a large multicenter data set covering the entire lifespan demonstrate that HRV changes with age in both sexes and confirm that season of birth influences HRV later in life in men.

This is a replication study, showing heart rate variability (HRV) to vary with season of birth (SoB). Since both HRV and SoB have been related to cardiovascular disease, the relationship is relevant to understand. We used an almost five times larger sample than the original sample, covering wider geographic areas and the full lifespan. Additionally, age and sex differences in HRV were found. Replicating earlier findings provides solid evidence for a relationship between SoB and HRV later in life, thereby providing insights on how HRV develops and ultimately how increased risk for cardiovascular disease can be reduced.

Salivary Alpha-Amylase and Behavior Reaction in Acute Stress and the Impact of Tridimensional Personality

BACKGROUND

Understanding individual differences of these indexes in response to stress is important for developing effective interventions. The Tridimensional Personality Questionnaire (TPQ), which has three dimensions, may reflect such individual differences. Meanwhile, there is increasing interest in the relationship between mental stress and non-invasive markers.

OBJECTIVES

We examined whether these three dimensions were associated with cognitive behavior tests and the related sAA responses.

METHODS

All subjects were divided into different groups based on the scores of the TPQ measuring temperament dimensions. Patterns of Stroop combined with mental arithmetic stress tests were presented, and the sAA responses were recorded as the index of stress responses, and compared between groups.

RESULTS

The sAA levels in the post stress test and the recovery period of the high reward-dependence (RD) group were significantly greater than in the low-RD group. The number of trials of Stroop in the high novelty-seeking (NS) group was significantly greater than in the low-NS group.

CONCLUSIONS

Individual differences in TPQ personality traits may be associated with different patterns of stress responses.

Altered Autonomic Functions and Distressed Personality Traits in Male Adolescents with Internet Gaming Addiction

Internet gaming addiction (IGA) has been associated with many negative health outcomes, especially for youth; however, few studies have examined the physiological parameters and personality features related to this addiction. This study aimed to identify differences in autonomic functions and distressed (type D) personality traits among Korean adolescent males with and without IGA. In a cross-sectional study, 68 adolescent males were recruited in a Korean city using convenience and snowball sampling methods. For each subject, heart rate variability (HRV) parameters were measured as autonomic functions and questionnaires were used to identify IGA and type D personality traits. Data were analyzed using descriptive analyses, t tests, χ² tests, and Pearson's correlation. Most HRV parameters significantly differed between the IGA and non-IGA groups (all p < 0.05). Type D personality total and subscale scores, including those for negative affectivity (NA) and social inhibition, were significantly higher in the IGA group (all p < 0.001). Of the 68 subjects, 46 were classified as having type D personality, with nearly twice as many in the IGA group as in the non-IGA group (p = 0.002). Type D personality total scores negatively correlated with the logarithmic value of total power and low frequency among the HRV parameters (both p < 0.05). Results showed that excessive Internet gaming was related to alterations in autonomic functions and distressed personality traits in male adolescents. These findings provide further understanding of the IGA phenomenon and highlight the need for interventions that address male adolescents with IGA.

Measures of Heart Rate Variability in Individuals With Somatic Symptom Disorder

OBJECTIVE

Little is known about autonomic nervous system activity in individuals with somatic symptom disorder (SSD) as defined by DSM-V criteria. The aims of this study were to investigate whether individuals with SSD differ from healthy controls in heart rate variability (HRV) measures of autonomic nervous system activity and whether sex has a moderating effect on this association.

METHODS

We recruited 168 individuals with SSD (35.1% men) and 106 healthy controls (27.4% men). Demographics, HRV, and psychological factors were measured using the Patient Health Questionnaire-15, Health Anxiety Questionnaire, Beck Depression Inventory-II (BDI-II), and Beck Anxiety Inventory. Multiple regression analysis was used to examine the association of SSD with HRV, adjusting for demographic and psychological measures.

RESULTS

Individuals with SSD had lower levels of total-power HRV and low-frequency HRV, but no differences in high-frequency (HF)-HRV were found. HRV differences between SSD and controls varied by sex and age (triple interaction TP-HRV β = -0.222, p < .001; low-frequency HRV β = -0.332, p < .001; and HF-HRV β = -0.167, p = .006). Whole-sample multiple regression analyses revealed significant sex differences in the magnitudes of the association between BDI-II with HF-HRV (β of sex*BDI-II: 0.761, p = .005) and analyses stratified by sex indicated that HF-HRV was significantly correlated with depression in men with SSD (r = -0.491, p < .001) but not in women with SSD (r = 0.057, p = .558).

CONCLUSIONS

These results suggest that patients with SSD demonstrate different patterns of HRV and the patterns of association between HRV indices and psychological factors vary between men and women.

Heart Rate Variability (HRV) Analysis: A Methodology for Organizational Neuroscience

Recently, the application of neuroscience methods and findings to the study of organizational phenomena has gained significant interest and converged in the emerging field of organizational neuroscience. Yet, this body of research has principally focused on the brain, often overlooking fuller analysis of the activities of the human nervous system and associated methods available to assess them. In this article, we aim to narrow this gap by reviewing heart rate variability (HRV) analysis, which is that set of methods assessing beat-to-beat changes in the heart rhythm over time, used to draw inference on the outflow of the autonomic nervous system (ANS). In addition to anatomo-physiological and detailed methodological considerations, we discuss related theoretical, ethical, and practical implications. Overall, we argue that this methodology offers the opportunity not only to inform on a wealth of constructs relevant for management inquiries but also to advance the overarching organizational neuroscience research agenda and its ecological validity.

Linking an Anxiety-Related Personality Trait to Cardiac Autonomic Regulation in Well-Defined Healthy Adults: Harm Avoidance and Resting Heart Rate Variability

OBJECTIVE

Anxiety trait, anxiety and depression states have all been reported to increase risks for cardiovascular disease (CVD), possibly through altering cardiac autonomic regulation. Our aim was to investigate whether the relationship between harm avoidance (HA, an anxiety-related personality trait) and cardiac autonomic regulation is independent of anxiety and depression states in healthy adults.

METHODS

We recruited 535 physically and mentally healthy volunteers. Participants completed the Beck Anxiety Inventory (BAI), Beck Depression Inventory (BDI) and Tri-dimensional Personality Questionnaire. Participants were divided into high or low HA groups as discriminated by the quartile value. Cardiac autonomic function was evaluated by measuring heart rate variability (HRV). We obtained the time and frequency-domain indices of HRV including variance (total HRV), the low-frequency power (LF; 0.05-0.15 Hz), which may reflect baroreflex function, the high-frequency power (HF; 0.15-0.40 Hz), which reflects cardiac parasympathetic activity, as well as the LF/HF ratio.

RESULTS

The BDI and HA scores showed associations with HRV parameters. After adjustment for the BDI scores and other control variables, HA is still associated with reduced variance, LF and HF power. Compared with the participants with low HA, those with high HA displayed significant reductions in variance, LF and HF power and a significant increase in their LF/HF ratio.

CONCLUSION

This study highlights the independent role of HA in contributing to decreased autonomic cardiac regulation in healthy adults and provides a potential underlying mechanism for anxiety trait to confer increased risk for CVD.

Sex differences in healthy human heart rate variability: A meta-analysis

The present meta-analysis aimed to quantify current evidence on sex differences in the autonomic control of the heart, indexed by measures of heart rate variability (HRV) in healthy human subjects. An extensive search of the literature yielded 2020 titles and abstracts, of which 172 provided sufficient reporting of sex difference in HRV. Data from 63,612 participants (31,970 females) were available for analysis. Meta-analysis yielded a total of 1154 effect size estimates (k) across 50 different measures of HRV in a cumulated total of 296,247 participants. Females showed a significantly lower mean RR interval and standard deviation of RR intervals (SDNN). The power spectral density of HRV in females is characterized by significantly less total power that contains significantly greater high- (HF) and less low-frequency (LF) power. This is further reflected by a lower LF/HF ratio. Meta-regression revealed significant effects of age, respiration control and the length of recording available for analysis. Although women showed greater mean heart rate, they showed greater vagal activity indexed by HF power of HRV. Underlying mechanisms of these findings are discussed.

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

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

Personality Correlates of Midlife Cardiometabolic Risk: The Explanatory Role of Higher-Order Factors of the Five-Factor Model

Varying associations are reported between Five-Factor Model (FFM) personality traits and cardiovascular disease risk. Here, we further examine dispositional correlates of cardiometabolic risk within a hierarchical model of personality that proposes higher-order traits of Stability (shared variance of Agreeableness, Conscientiousness, inverse Neuroticism) and Plasticity (Extraversion, Openness), and we test hypothesized mediation via biological and behavioral factors. In an observational study of 856 community volunteers aged 30-54 years (46% male, 86% Caucasian), latent variable FFM traits (using multiple-informant reports) and aggregated cardiometabolic risk (indicators: insulin resistance, dyslipidemia, blood pressure, adiposity) were estimated using confirmatory factor analysis (CFA). The cardiometabolic factor was regressed on each personality factor or higher-order trait. Cross-sectional indirect effects via systemic inflammation, cardiac autonomic control, and physical activity were tested. CFA models confirmed the Stability "meta-trait," but not Plasticity. Lower Stability was associated with heightened cardiometabolic risk. This association was accounted for by inflammation, autonomic function, and physical activity. Among FFM traits, only Openness was associated with risk over and above Stability, and, unlike Stability, this relationship was unexplained by the intervening variables. A Stability meta-trait covaries with midlife cardiometabolic risk, and this association is accounted for by three candidate biological and behavioral factors.

Is Heart Rate Variability Related to Season of Birth?

BACKGROUND

Season of birth (SOB) has been found to be related to cardiovascular mortality, but the mechanisms are unclear. It is suggested that birth in winter is a protective factor for the circulatory system, and this should be able to be observed using heart rate variability (HRV) measurements. The phenomenon may have a sex difference and is likely to be modulated by climatic factors. This study focused on this problem and investigates healthy school-age children to minimize confounding factors.

HYPOTHESIS

Birth in winter is protective to cardiovascular system via autonomic modulation. There is a gender difference in the relationship between SOB and autonomic activity. Climatic factors are the cause of SOB effects on autonomic system.

METHODS

A total of 381 healthy school-age children were recruited for this study. Their HRV profiles were measured once and climatic information related to their month of birth was gathered. The HRV profiles of the 2 sexes and 4 seasons of birth were compared. Correlation and regression analysis were performed to clarify the relationship between climatic factors and the HRV results.

RESULTS

Boys born in winter have higher high-frequency power (HF) but a lower ratio of low-frequency power to high-frequency power (LF/HF) than do males born in other seasons. This result is not found for girls. Age and the temperature of the SOB are predictive factors for HF among boys. The humidity of SOB is a predictive factor for normalized low-frequency power (LF%) and LF/HF among girls.

CONCLUSIONS

Season of birth is related to both parasympathetic and sympathetic activity among school-age children, especially boys. Temperature and humidity are potential causes of this SOB phenomenon.

The role of the harm avoidance personality in depression and anxiety during the medical internship

To determine whether physicians with harm avoidance (HA) personality traits were more prone to developing increased anxiety and depression during the medical internship. A prospective longitudinal study of 74 medical interns was carried out using repeated measures of symptoms of anxiety and depression with the Beck Anxiety and Depression Inventories (BAI and BDI) before, at the 3rd, 6th, and 12th months during the internship, and 2 weeks after the internship was completed. Baseline personality was assessed by the Tridimensional Personality Questionnaire with 3 dimensions: novelty-seeking, HA, and reward dependence (RD). Levels of both depression and anxiety increased (6.4 and 3.4 on scores for BDI and BAI, respectively) during the internship and returned to baseline 2 weeks after it ended. HA scores were significantly correlated with depression and anxiety (0.3 scores on both the BDI and the BAI) and the scores for RD were significantly correlated with anxiety but not with depression. The interaction of HA and point in internship showed no significant differences. Internship plays a major role in the increase in depression and anxiety. A HA personality was also associated with the development of both depression and anxiety.