High-frequency Heart Rate Variability Research Articles

Different heart rate variability profile during sleep in mid-later life adults with remitted early-onset versus late-onset depression

BackgroundIn mid-later life adults, early-onset and late-onset (i.e., onset ≥50 years) depression appear to be underpinned by different pathophysiology yet have not been examined in relation to autonomic function. Sleep provides an opportunity to examine the autonomic nervous system as the physiology changes across the night. Hence, we aimed to explore if autonomic profile is altered in mid-later life adults with remitted early-onset, late-onset and no history of lifetime depression. MethodsParticipants aged 50–90 years (n = 188) from a specialised clinic underwent a comprehensive clinical assessment and completed an overnight polysomnography study. General Linear Models were used to examine the heart rate variability differences among the three groups for four distinct sleep stages and the wake after sleep onset. All analyses controlled for potential confounders – age, sex, current depressive symptoms and antidepressant usage. ResultsFor the wake after sleep onset, mid-later life adults with remitted early-onset depression had reduced standard deviation of Normal to Normal intervals (SDNN; p = .014, d = −0.64) and Shannon Entropy (p = .004, d = −0.46,) than those with no history of lifetime depression. Further, the late-onset group showed a reduction in high-frequency heart rate variability (HFn.u.) during non-rapid eye movement sleep stage 2 (N2; p = .005, d = −0.53) and non-rapid eye movement sleep stage 3 (N3; p = .009, d = −0.55) when compared to those with no lifetime history. LimitationsCausality between heart rate variability and depression cannot be derived in this cross-sectional study. Longitudinal studies are needed to examine the effects remitted depressive episodes on autonomic function. ConclusionThe findings suggest differential autonomic profile for remitted early-onset and late-onset mid-later life adults during sleep stages and wake periods. The differences could potentially serve as peripheral biomarkers in conjunction with more disease-specific markers of depression to improve diagnosis and prognosis.

The impact of outdoor soundscapes at nursing homes on physiological indicators in older adults

This research explores the impact of outdoor soundscapes at nursing homes on the physiological health of older adults. Using virtual reality, the study recreated the outdoor environments at nursing homes for 57 seniors in a lab setting, continuously monitoring physiological indicators such as skin conductance level, heart rate, low to high-frequency heart rate variability ratio, respiratory frequency, blink frequency, and pupil diameter. The comparison of these indicators with corresponding soundscapes revealed the diverse effects of different nursing home outdoor scenarios on the physiological health of older adults. Furthermore, analysis of the temporal marginal effects of these indicators highlighted the significant influence of time on the physiological responses of seniors in various soundscapes, showing fluctuations in each indicator at different times. Finally, to understand the channels of impact, the study examined how acoustic features at nursing homes affect seniors' physiological indicators. The findings suggest that increased loudness and roughness in soundscapes elevate seniors' heart rates and cardiovascular risks, while a moderate increase in LAeq and fluctuation strength in dynamic scenarios might have positive stimulative effects on the physiological functions of the older adults.

Oscillatory Coupling Between Neural and Cardiac Rhythms.

Oscillations serve a critical role in organizing biological systems. In the brain, oscillatory coupling is a fundamental mechanism of communication. The possibility that neural oscillations interact directly with slower physiological rhythms (e.g., heart rate, respiration) is largely unexplored and may have important implications for psychological functioning. Oscillations in heart rate, an aspect of heart rate variability (HRV), show remarkably robust associations with psychological health. Mather and Thayer proposed coupling between high-frequency HRV (HF-HRV) and neural oscillations as a mechanism that partially accounts for such relationships. We tested this hypothesis by measuring phase-amplitude coupling between HF-HRV and neural oscillations in 37 healthy adults at rest. Robust coupling was detected in all frequency bands. Granger causality analyses indicated stronger heart-to-brain than brain-to-heart effects in all frequency bands except gamma. These findings suggest that cardiac rhythms play a causal role in modulating neural oscillations, which may have important implications for mental health.

The psychophysiological salience of past experiences of discrimination.

This study sought to test whether a discrimination recall task would elicit a significant parasympathetic response in multiracial undergraduate women. The study also investigated whether parasympathetic responsivity to the discrimination recall would be similar or different from that elicited by a widely used stress paradigm-the Trier Social Stress Test (TSST), and whether responses would differ for Black and White women. Multiracial undergraduate women (n = 67; Mage = 19.4 years; 32% White, 22% Black) completed the TSST and a discrimination recall task. Parasympathetic activity was assessed using high-frequency heart rate variability (HF-HRV). Women exhibited significant HF-HRV responsivity to the discrimination recall and showed smaller average decreases in HF-HRV to the discrimination recall than the TSST. However, whereas White women exhibited decreased HF-HRV in response to both tasks, Black women showed increased HF-HRV for the discrimination recall but decreased HF-HRV for the TSST. Findings complement a growing body of research suggestive that experiences of discrimination are psychophysiologically salient. Additionally, discriminatory experiences may elicit distinctive patterns of HF-HRV responsivity compared to generic social stressors. Efforts to elucidate the unique role of discrimination-specific HF-HRV responsivity may be critical for delineating discrimination-health linkages. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Dose-dependent response of prefrontal transcranial direct current stimulation on the heart rate variability: An electric field modeling study.

Transcranial direct current stimulation (tDCS) of the prefrontal cortex (PFC) modulates the autonomic nervous system by activating deeper brain areas via top-down pathway. However, effects on the nervous system are heterogeneous and may depend on the amount of current that penetrates. Therefore, we aimed to investigate the variable effects of tDCS on heart rate variability (HRV), a measure of the functional state of the autonomic nervous system. Using three prefrontal tDCS protocols (1.5, 3 mA and sham), we associated the simulated individual electric field (E-field) magnitude in brain regions of interest with the HRV effects. This was a randomized, double-blinded, sham-controlled and within-subject trial, in which healthy young-adult participants received tDCS sessions separated by 2 weeks. The brain regions of interest were the dorsolateral PFC (DLPFC), anterior cingulate cortex, insula and amygdala. Overall, 37 participants were investigated, corresponding to a total of 111 tDCS sessions. The findings suggested that HRV, measured by root mean squared of successive differences (RMSSD) and high-frequency HRV (HF-HRV), were significantly increased by the 3.0 mA tDCS when compared to sham and 1.5 mA. No difference was found between sham and 1.5 mA. E-field analysis showed that all brain regions of interest were associated with the HRV outcomes. However, this significance was associated with the protocol intensity, rather than inter-individual brain structural variability. To conclude, our results suggest a dose-dependent effect of tDCS for HRV. Therefore, further research is warranted to investigate the optimal current dose to modulate HRV.

High-Frequency Heart Rate Variability Is Prospectively Associated With Sleep Complaints in a Healthy Working Cohort.

Vagus nerve functioning, as indexed by high-frequency heart rate variability (HF-HRV), has been implicated in a wide range of mental and physical health conditions, including sleep complaints. This study aimed to test associations between HF-HRV measured during sleep (sleep HF-HRV) and subjective sleep complaints 4 years later. One hundred forty-three healthy employees (91% male; MAge = 47.8 years [time 2], SD = 8.3 years) of an industrial company in Southern Germany completed the Jenkins Sleep Problems Scale, participated in a voluntary health assessment, and were given a 24-hour ambulatory heart rate recording device in 2007. Employees returned for a health assessment and completed the Jenkins Sleep Problems Scale 4 years later. Hierarchical regression analyses showed that lower sleep HF-HRV measured in 2007 was associated with higher self-reported sleep complaints 4 years later after controlling for covariates (rab,c = -0.096, b = -0.108, 95% CI, -0.298 to 0.081, ΔR2 = 0.009, p = .050). These data are the first to show that lower sleep HF-HRV predicted worse sleep 4 years later, highlighting the importance of vagus nerve functioning in adaptability and health.

A framework for the interpretation of heart rate variability applied to transcutaneous auricular vagus nerve stimulation and osteopathic manipulation.

Reports on autonomic responses to transcutaneous auricular vagus nerve stimulation (taVNS) and osteopathic manipulative techniques have been equivocal, partly due to inconsistent interpretation of heart rate variability (HRV). We developed a mechanistic framework for the interpretation of HRV based on a model of sinus node automaticity that considers autonomic effects on Phase 3 repolarization and Phase 4 depolarization of the sinoatrial action potential. The model was applied to HRV parameters calculated from ECG recordings (healthy adult humans, both genders) before (30 min), during (15 min), and after (30 min) a time control intervention (rest, n = 23), taVNS (10 Hz, 300 μs, 1-2 mA, cymba concha, left ear, n = 12), or occipitoatlantal decompression (OA-D, n = 14). The experimental protocol was repeated on 3 consecutive days. The model simulation revealed that low frequency (LF) HRV best predicts sympathetic tone when calculated from heart rate time series, while high frequency (HF) HRV best predicts parasympathetic tone when calculated from heart period time series. Applying our model to the HRV responses to taVNS and OA-D, revealed that taVNS increases cardiac parasympathetic tone, while OA-D elicits a mild decrease in cardiac sympathetic tone.

Acceptability and Perceived Utility of Virtual Reality Among People Who Are Incarcerated Who Use Drugs.

People who are incarcerated are at heightened risk of overdose upon community reentry. Virtual reality (VR) may provide an innovative tool for overdose prevention intervention in corrections facilities. This mixed methods study sought to understand incarcerated individuals' perspectives on VR for overdose prevention and explore physiological arousal associated with use of VR equipment. Study participants were 20 individuals, stratified by gender, with an opioid use disorder at a county jail. Qualitative interviews assessed acceptability and perceived utility of VR in the jail setting. Thematic analysis indicated high levels of acceptability and potential utility in the following areas: (a) mental health and substance use interventions, (b) community reentry skills training, and (c) communication and conflict resolution skills. Heart rate variability (HRV) data were collected continuously during the interview and during VR exposure to explore whether exposure to the VR environment provoked arousal. Physiological data analyses showed a significant decrease in heart rate (HR) [b = -3.14, t(18) = -3.85, p < .01] and no arousal as measured by root mean square of successive RR interval differences (RMSSD) [b = -0.06, t(18) = -1.06, p = .30] and high frequency-HRV (HF-HRV) [b = -0.21, t(18) = -1.71, p = .10]. This study demonstrated high acceptability and decreased HR response of VR among incarcerated people who use drugs.

Childhood Maltreatment and Leukocyte Telomere Length: Cardiac Vagal Activity Influences the Relation in Older Adults.

Childhood maltreatment is associated with shorter leukocyte telomere length (LTL). However, the influence of cardiac vagal control on this relation is unknown. We examined whether cardiac vagal control at rest and in response to stress moderates or cross-sectionally mediates the relationship between childhood maltreatment and LTL. Participants were 1179 men and women (aged 65 [7.2] years) suffering from coronary artery disease or non-cardiovascular chronic disease. They completed a childhood maltreatment questionnaire and underwent a stress protocol while electrocardiogram was monitored. High-frequency heart rate variability (HF-HRV) measures were obtained at rest, during stress, and after stress in absolute and normalized units (nu). LTL was measured using quantitative polymerase chain reaction. Mediation and moderation analyses were performed. HF-HRV and HF-HRV in normalized units (HFnu) measures did not mediate the childhood maltreatment-LTL relation. However, baseline HFnu ( p = .027) and HFnu reactivity ( p = .051) moderated the relation. Specifically, maltreatment was associated with significantly lower LTL among those with baseline HFnu at ( b = -0.059, p = .003) or below the mean ( b = -0.103, p < .001), but not among those with higher baseline HFnu. It was also associated with significantly lower LTL among participants who showed either blunted ( b = -0.058, p = .004) or increased HFnu ( b = -0.099, p = .001) responses to stress but not in those with large decreases in HFnu. Childhood maltreatment was associated with lower LTL in those who showed a distinct cardiac vagal profile at baseline and in response to stress. The mechanisms and implications remain to be determined.

The Effect of Light on Negative Emotion and Cognitive Regulation in Individuals with Depressive Tendencies

ABSTRACT Light has been demonstrated to influence transient mood states in healthy populations and can be used as a treatment for clinical mood disorders. However, it is still interesting to know whether stimulus with relatively low light levels can moderate the transient mood state of people with depressive tendencies, and what are the effects respectively from light levels and light color. In this study, 10 subjects with depressive tendencies were recruited and screened to receive a typical lighting intervention, including five crossover conditions with the 300 l×-isoluminance groups (red, 6500 K-white, blue) and 6500 K-isospectral groups (50 lx, 300 lx, and 1500 lx). Negative cognitive bias, high-frequency heart rate variability, and subjective emotion were measured at different stages during the lighting intervention. Statistical results demonstrated that the lighting condition of 1500 lx-6500 K was associated with a transient positive mood state (p < 0.001) and had a significant positive moderating effect on the negative cognitive biases compared with the other groups (p = .017). Colored lights are more likely to trigger negative emotions and negative cognitive biases.

Public health nurse-delivered cognitive behavioral therapy for postpartum depression: Assessing the effects of maternal treatment on infant emotion regulation.

The effects of maternal postpartum depression (PPD) on offspring emotion regulation (ER) are particularly deleterious as difficulties with ER predict an increased risk of psychopathology. This study examined the impact of maternal participation in a public health nurse (PHN)-delivered group cognitive behavioral therapy (CBT) intervention on infant ER. Mothers/birthing parents were ≥ 18 years old with an Edinburgh Postnatal Depression Scale (EPDS) score ≥ 10, and infants were < 12 months. Between 2017 and 2020, 141 mother-infant dyads were randomized to experimental or control groups. Infant ER was measured at baseline (T1) and nine weeks later (T2) using two neurophysiological measures (frontal alpha asymmetry (FAA) and high-frequency heart rate variability (HF-HRV)), and informant-report of infant temperament. Mothers were a mean of 30.8 years old (SD = 4.7), 92.3% were married/ common-law, and infants were a mean of 5.4 months old (SD = 2.9) and 52.1% were male. A statistically significant group-by-time interaction was found to predict change in HF-HRV between T1 and T2 (F(1,68.3) = 4.04, p = .04), but no significant interaction predicted change in FAA or temperament. Results suggest that PHN-delivered group CBT for PPD may lead to adaptive changes in a neurophysiological marker of infant ER, highlighting the importance of early maternal intervention.

Concentration-effect relationships of plasma caffeine on EEG delta power and cardiac autonomic activity during human sleep.

Acute caffeine intake affects brain and cardiovascular physiology, yet the concentration-effect relationships on the electroencephalogram and cardiac autonomic activity during sleep are poorly understood. To tackle this question, we simultaneously quantified the plasma caffeine concentration with ultra-high-performance liquid chromatography, as well as the electroencephalogram, heart rate and high-frequency (0.15-0.4 Hz) spectral power in heart rate variability, representing parasympathetic activity, with standard polysomnography during undisturbed human sleep. Twenty-one healthy young men in randomized, double-blind, crossover fashion, ingested 160 mg caffeine or placebo in a delayed, pulsatile-release caffeine formula at their habitual bedtime, and initiated a 4-hr sleep opportunity 4.5 hr later. The mean caffeine levels during sleep exhibited high individual variability between 0.2 and 18.4 μmol L-1 . Across the first two non-rapid-eye-movement (NREM)-rapid-eye-movement sleep cycles, electroencephalogram delta (0.75-2.5 Hz) activity and heart rate were reliably modulated by waking and sleep states. Caffeine dose-dependently reduced delta activity and heart rate, and increased high-frequency heart rate variability in NREM sleep when compared with placebo. The average reduction in heart rate equalled 3.24 ± 0.77 beats per minute. Non-linear statistical models suggest that caffeine levels above ~7.4 μmol L-1 decreased electroencephalogram delta activity, whereas concentrations above ~4.3 μmol L-1 and ~ 4.9 μmol L-1 , respectively, reduced heart rate and increased high-frequency heart rate variability. These findings provide quantitative concentration-effect relationships of caffeine, electroencephalogram delta power and cardiac autonomic activity, and suggest increased parasympathetic activity during sleep after intake of caffeine.

Acute dissociation as part of the defense cascade: Associations with behavioral, autonomic, and experiential threat responses in posttraumatic stress disorder.

Dissociative symptoms, such as depersonalization and derealization, are experienced by about half of individuals with posttraumatic stress disorder (PTSD). Theoretical models propose that acute dissociation is accompanied by specific behavioral, physiological, and experiential alterations and contributes to unfavorable PTSD symptom course. Yet, empirical evidence is scarce. Here, we explored associations between dissociative and behavioral, physiological, and experiential threat responses as well as effects of dissociative responding on PTSD symptom course. Individuals with PTSD (N = 71) participated in a preregistered script-driven imagery study including exposure to standardized, detail-enriched trauma, and neutral scripts. Stabilometry, eye-tracking, facial electromyography, autonomic psychophysiology, and self-report data were collected. Moreover, PTSD symptoms were assessed before and 3 months after testing. Analyses did not link acute dissociation to bodily and facial immobility or staring in response to trauma scripts. However, dissociation displayed an inverted U-shaped relationship with heart rate and was linked to higher nonspecific skin conductance fluctuation and higher high-frequency heart rate variability in response to trauma scripts. Moreover, acute dissociation was linked to higher self-reported negative affect responses to trauma scripts and displayed a U-shaped relationship with unfavorable PTSD symptom course. While results did not confirm hypothesized behavioral markers of dissociation, they do support defense-cascade model assumptions of an inverted U-shaped relationship between dissociation and psychophysiological arousal resulting from a progression of parasympathetic versus sympathetic dominance with increasing dissociation. On an experiential level, results did not confirm posttraumatic dissociation-induced emotional numbing, questioning theoretical notions. The observed nonlinear associations may help explain the heterogeneity of prior findings and might inform an updated conceptualization of posttraumatic dissociation. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Asymptomatic Autonomic Dysregulation after Recovery from Mild COVID-19 Infection Revealed by Analysis of Heart Rate Variability Responses to Task Load.

(1) Background: The coronavirus disease 2019 (COVID-19) infection is often followed by various complications, which can cause disturbances in daily life after recovery from the infectious state, although etiological mechanisms are not fully elucidated. Previous studies have indicated that autonomic dysregulation is an underlying factor, and it is of interest to clarify whether autonomic dysregulation is also present in the asymptomatic subjects after COVID-19 infection (post-COVID-19) for early detection of post-COVID-19 complications. (2) Methods: In the present study, autonomic activity was assessed using heart rate variability (HRV) analysis in the workers who recovered from mild COVID-19 infection (n = 39). They took a leave of absence for an average of 11.9 days and returned to the original work without complications. HRV was measured after an average of 9.3 days from return. High-frequency (HF) and low-frequency (LF) HRV parameters and heart rate (HR) were recorded during a three-behavioral-state paradigm of approximately 5 min length composed of initial rest, task load, and post-task rest periods and were compared with the data of the workers without the history of COVID-19 infection (normal, n = 38). (3) Results: The HRV and HR scores at the initial rest in the post-COVID-19 subjects showed no difference from those in the control. It is found that the post-COVID-19 subjects exhibited an attenuation of LF/HF increment during the task load and an excessive increase of HF together with a decrease of LF, LF/HF and HR during the post-task rest period in comparison with the initial rest scores. (4) Conclusions: These abnormalities are evaluated as asymptomatic autonomic dysregulation in response to task load, are frequently present after COVID-19 infection, and could be related to the generation of complications.

I know why the caged bird sings: Distress tolerant individuals show greater resting state connectivity between ventromedial prefrontal cortex and right amygdala as a function of higher vagal tone

BackgroundIntolerance to psychological distress is associated with various forms of psychopathology, ranging from addiction to mood disturbance. The capacity to withstand aversive affective states is often explained by individual differences in cardiovagal tone as well as resting state connectivity of the ventromedial prefrontal cortex (vmPFC), a region involved in the regulation of emotions and cardio-autonomic tone. However, it is unclear which brain regions involved in distress tolerance show greater resting state functional connectivity (rsFC) as a function of resting heart rate variability (HRV). MethodsOne-hundred and twenty-six adults, aged 20 to 83.5 years, were selected from a lifespan cohort at the Nathan Kline Institute-Rockland Sample. Participants' distress tolerance levels were assessed based upon performance on the Behavioral Indicator of Resiliency to Distress (BIRD) task. Artifact-free resting-state functional brain scans collected during separate sessions were used. While inside the scanner, a pulse oximeter was used to record beat-to-beat intervals to derive high-frequency heart rate variability (HF-HRV). The relationship between HF-HRV and vmPFC to whole brain functional connectivity was compared between distress tolerant (BIRD completers) and distress intolerant (BIRD non-completers). ResultsGroups did not differ in their history of psychiatric diagnosis. Higher resting HF-HRV was associated with longer total time spent on the BIRD task for the entire sample (r = 0.255, p = 0.004). After controlling for age, gender, body mass index, head motion, and gray matter volume. Distress tolerant individuals showed greater rsFC (p < 0.005 (uncorrected), k = 20) between the vmPFC and default-mode network (DMN) hubs including posterior cingulate cortex/precuneus, medial temporal lobes, and the parahippocampal cortex. As a function of higher resting HF-HRV greater vmPFC connectivity was observed with sub-threshold regions in the right amygdala and left anterior prefrontal cortex, with the former passing small volume correction, in distress tolerant versus distress intolerant individuals. ConclusionIn a lifespan sample of community-dwelling adults, distress tolerant individuals showed greater vmPFC connectivity with anterior and posterior hubs of the DMN compared to distress intolerant individuals. As a function of greater HF-HRV, distress tolerant individuals evidenced greater vmPFC with salience and executive control network hubs. These findings are consistent with deficits in neural resource allocation within a triple network resting amongst persons exhibiting behavioral intolerance to psychological distress.

Heart Rate Variability during Slow Wave Sleep is Linked to Resting‐state Functional Connectivity in the Central Autonomic Network among Older Adults ‘at‐risk’ of Dementia

AbstractBackgroundReduced heart rate variability (HRV) can be an early sign of autonomic dysfunction in neurodegenerative diseases, and may be related to brain dysfunction in the central autonomic network (CAN). As yet, such autonomic dysfunction has not been examined during sleep – which is an ideal physiological state to study brain‐heart interaction as both the central and peripheral nervous systems behave differently compared to during wakefulness. Therefore, we aimed to examine whether nocturnal HRV, especially slow wave sleep (SWS), is associated with CAN functional connectivity in older adults ‘at‐risk’ of dementia.MethodOlder adults (n = 78; age range = 50‐88 years; 64% female) attending a memory clinic for cognitive concerns underwent resting‐state functional magnetic resonance imaging and an overnight polysomnography. From these, CAN functional connectivity strength and HRV data during sleep were derived, respectively. High‐frequency heart rate variability (HF‐HRV) was extracted to index parasympathetic activity during distinct periods of sleep, including SWS as well as secondary outcomes of non‐rapid eye movement sleep, wake after sleep onset, and rapid eye movement sleep. General linear models were used to examine associations between CAN functional connectivity and HF‐HRV.ResultAnalyses revealed that increased HF‐HRV during SWS was associated with stronger functional connectivity (F = 3.98, p = 0.022) in two core brain regions within the CAN, the right anterior insular and posterior midcingulate cortex, as well as stronger functional connectivity (F = 6.21, p = 0.005) between broader CAN brain regions – the right amygdala with three sub‐nuclei of the thalamus. There were no significant associations between HF‐HRV and CAN functional connectivity during wake after sleep onset or rapid eye movement sleep.ConclusionThese findings show that in older adults ‘at‐risk’ of dementia, parasympathetic regulation during SWS is uniquely linked to differential functional connectivity within both core and broader CAN brain regions. It is possible that dysfunctional brain‐heart interactions manifest primarily during this specific period of sleep known for its role in memory and metabolic clearance. Further studies elucidating the pathophysiology and directionality of this relationship should be conducted to determine if HRV drives neurodegeneration, or if brain degeneration within the CAN promotes aberrant HRV.

What Disrupts Flow in Office Work? The Impact of Frequency and Relevance of IT-Mediated Interruptions

Flow, the holistic sensation people experience when they act with total involvement, is a known driver for desired work outcomes like task performance. However, the increasing ubiquity of IT at work can disrupt employees’ flow. Thus, the impact of IT-mediated interruptions on flow warrants more attention in research and practice. We conducted a NeuroIS laboratory experiment focusing on a typical office work task—an invoice matching task (i.e., matching customer payments to invoices). We manipulated interruption frequency (low, high) and content relevance (irrelevant, relevant) to study the impact of interruptions on self-reported flow, its dimensions, and high-frequency heart rate variability (HF-HRV; calculated from electrocardiography recordings) as a proxy for parasympathetic nervous system (PNS) activation. We found that content relevance moderated the relationship between interruption frequency and self-reported flow and that these results vary along flow dimensions. Content relevance also moderated the relationship between interruption frequency and PNS activation. Furthermore, self-reported flow was positively associated with both perceived and objective task performance, while PNS activation was not related to either performance measure. Lastly, we found no relationship between PNS activation (measured by HF-HRV) and self-reported flow, contributing to an important debate in the NeuroIS literature on whether physiological evidence constitutes an alternative or a complement to self-reports. Overall, our findings indicate that frequent interruptions are not harmful per se. Rather, considering content relevance is critical for a more comprehensive understanding of the effects on self-reported flow, its dimensions, and the underlying physiology.

A Mindful Alternative to Screen Time: The Short-Term Effects of a Breath-Focused Mindfulness Exercise vs. Unstructured Smartphone Screen Time on Heart Rate Variability and Relaxation

Introduction: Many smartphone users spend hours daily on unstructured screen time leisure activities including social media, games, and videos. Given that many users express a desire to cut back on this habit, it is important to test the relative physiological and emotional benefits of alternative activities, such as mindfulness meditation, as daily practices for relaxation and restoration. Methods: This study tests the immediate effects of unstructured mobile phone screen time vs. practice of a brief mindful breathing meditation exercise on heart rate variability (HRV, a common measure of healthy resting physiological activity) and self-reported states of relaxation. Participants (171 female university students) were randomly assigned to 15 minutes of unstructured screen time (i.e., use phones in a manner consistent with typical daily use) or a mindfulness induction (i.e., a guided meditation recording focused on mindfulness of breathing). Results: Consistent with hypotheses, HRV showed greater increases relative to baseline in the mindfulness condition than the screen time condition (High-frequency HRV, partial η2 = .14, p &lt; .001; Root Mean Square of Successive Differences, partial η2 = .053, p = .002). Subjective relaxation increased in both conditions (partial η2 = .47, p &lt; .001); however, mindfulness produced greater increases in relaxation over time than unstructured screen time (partial η2 = .089, p &lt; .001). Conclusions: Mindfulness was superior to unstructured screen time at increasing physiological and subjective markers of relaxation. Results suggest that repurposing smartphones to facilitate mindfulness practice though guided meditation apps may be a more effective method of promoting physiological and emotional well-being than more ubiquitous unstructured smartphone use.

The Interplay of Peer Victimization and Parasympathetic Nervous System Activity on Acute Inflammatory Stress Responses in Adolescence.

This study examined the extent to which adolescent peer victimization predicted acute inflammatory responses to stress, and whether both resting parasympathetic nervous system (PNS) activity and PNS stress reactivity moderated this association. 83 adolescents (Mage = 14.89, SDage = 0.52, 48% female) reported their history of peer victimization and were exposed to a standardized social stress task before and after which dried blood spot samples were collected to assay inflammatory markers. Inflammatory responses to the stress task were assessed with a latent inflammatory change factor using the cytokines interleukin-6 (IL-6), interleukin-10 (IL-10), and tumor necrosis factor-α (TNF-α). PNS functioning, indexed by high-frequency heart rate variability, was measured at rest and during the stressor. Contrary to hypotheses, analyses revealed no direct relation between peer victimization and acute inflammatory responses, and resting PNS activity did not moderate this association. However, peer victimization predicted stronger inflammatory responses among adolescents with weaker PNS reactivity to the stress task (b = 0.63, p = .02). This association was not observed among adolescents with stronger PNS reactivity, for whom a negative but non-significant trend was found. Weaker PNS reactivity may thus indicate victimized adolescents' vulnerability for acute inflammatory responses, whereas stronger PNS reactivity may indicate adolescents' resilience to a social stressor.

Abstract 14007: Decreased Perceived Social Support and Heart Rate Variability Are Associated With Hopelessness in Patients With Ischemic Heart Disease

Introduction: Hopelessness is present in up to 52% of patients with ischemic heart disease (IHD) and associated with a 3.4 times increased risk of death and adverse outcomes. Decreased perceived social support (PSS) has been associated with hopelessness in patients with IHD reporting moderate-severe hopelessness but has not been examined in a well-powered sample with varying levels of hopelessness. Increased PSS is associated with increased high frequency (HF) heart rate variability (HRV) in adults following a stressful event, but the relationship between HRV and hopelessness has not been examined in patients with IHD. Hypothesis: The purpose of this research was to test the hypotheses that 1) lower PSS would be associated with higher hopelessness, and 2) lower HF HRV would be associated with higher hopelessness. Methods: Utilizing a cross-sectional design, 178 participants were enrolled while hospitalized for an IHD event at one large hospital in the Midwestern United States. Data collection occurred two weeks after hospital discharge using the State-Trait Hopelessness Scale, ENRICHD Social Support Inventory, Patient Health Questionnaire-9, a demographic form, and a short-term HRV measurement at rest. Linear models were used to assess association between variables in unadjusted models and models adjusted for demographic and medical history. Results: Majority of participants were male (67%), married (67%), non-Hispanic white (92%), and underwent coronary artery bypass surgery (61%). There was a moderate inverse correlation between PSS and state ( r = -0.31, p &lt; 0.001) and trait ( r = -0.28, p &lt; 0.001) hopelessness in unadjusted models. The relationships remained significant in adjusted models and did not differ between groups comparing sex, type of IHD event, and marital status. There was a moderate inverse correlation between HF HRV and state hopelessness ( r = -0.24, p = 0.023). Results remained significant in adjusted models and did not differ between groups comparing sex, type of IHD event, and beta-blocker prescription. Conclusions: There were significant inverse associations between PSS and hopelessness and HF HRV and hopelessness. Persons with low PSS and/or HF HRV may be at greater risk for experiencing hopelessness following an IHD event.