Mental Stress Task Research Articles

Anger recall mental stress decreases 123I-metaiodobenzylguanidine (123I-MIBG) uptake and increases heterogeneity of cardiac sympathetic activity in the myocardium in patients with ischemic cardiomyopathy

BackgroundAcute psychological stressors such as anger can precipitate ventricular arrhythmias, but the mechanism is incompletely understood. Quantification of regional myocardial sympathetic activity with 123I-metaiodobenzylguanidine (123I-mIBG) SPECT imaging in conjunction with perfusion imaging during mental stress may identify a mismatch between perfusion and sympathetic activity that may exacerbate a mismatch between perfusion and sympathetic activity that could create a milieu of increased vulnerability to ventricular arrhythmia. MethodsFive men with ischemic cardiomyopathy (ICM), and five age-matched healthy male controls underwent serial 123I-mIBG and 99mTc-Tetrofosmin SPECT/CT imaging during an anger recall mental stress task and dual isotope imaging was repeated approximately 1 week later during rest. Images were reconstructed using an iterative reconstruction algorithm with CT-based attenuation correction. The mismatch of left ventricular myocardial 123I-mIBG and 99mTc-Tetrofosmin was assessed along with radiotracer heterogeneity and the 123I-mIBG heart-to-mediastinal ratios (HMR) were calculated using custom software developed at Yale. ResultsThe hemodynamic response to mental stress was similar in both groups. The resting-HMR was greater in healthy control subjects (3.67 ± 0.95) than those with ICM (3.18 ± 0.68, P = .04). Anger recall significantly decreased the HMR in ICM patients (2.62 ± 0.3, P = .04), but not in normal subjects. The heterogeneity of 123I-mIBG uptake in the myocardium was significantly increased in ICM patients during mental stress (26% ± 8.23% vs. rest: 19.62% ± 9.56%; P = .01), whereas the 99mTc-Tetrofosmin uptake pattern was unchanged. ConclusionMental stress decreased the 123I-mIBG HMR, increased mismatch between sympathetic activity and myocardial perfusion, and increased the heterogeneity of 123I-mIBG uptake in ICM patients, while there was no significant change in myocardial defect size or the heterogeneity of 99mTc-Tetrofosmin perfusion. The changes observed in this proof-of-concept study may provide valuable information about the trigger–substrate interaction and the potential vulnerability for ventricular arrhythmias.

Abstract P184: Racial Differences In Mental Stress-induced Transient Endothelial Dysfunction And Its Association With Cardiovascular Outcomes

Background: An established link exists between acute mental stress and the development of transient endothelial dysfunction (TED) as assessed by brachial artery flow-mediated vasodilation (FMD). Black individuals have a high burden of cardiovascular (CV) risk factors and social disadvantages, which may result in adverse vascular responses to stress. We investigated differences in TED with mental stress in Black and non-Black individuals with coronary artery disease (CAD), and whether TED is associated with CV outcomes in both groups. Methods: We enrolled 812 patients with stable CAD between June 2011 and March 2016 and followed them through February 2020. Study participants were subjected to a public-speaking mental stress task and FMD (derived from % vasodilation with brachial artery hyperemia testing) was assessed by ultrasound before and 30 minutes after mental stress. TED was defined as a lower post-stress FMD than pre-stress FMD. We compared pre-stress FMD, post-stress FMD, and TED between Black and non-Black participants. In both groups, we examined the association of TED with an adjudicated composite end point of CV death and myocardial infarction (MI) after adjusting for demographic, clinical, and socioeconomic factors. Both first and recurring events were counted and multivariable models for repeated events were used for analysis. Results: The mean (SD) age was 59 (10) years, and 328 (40%) were Black. Pre-stress FMD was lower in Black than non-Black participants [3.7 (2.8) vs. 4.9 (3.8) p<0.001], and significantly declined with mental stress in both groups. TED occurred more often in Black (76%) than non-Black patients (67%), age- and sex-adjusted OR, 1.6, 95% CI, 1.4-1.7). Race related differences in TED persisted after adjustment for demographic factors, CAD risk factors and medications (Black vs. non-Black OR, 1.6, 95% CI, 1.5-1.7). After further adjusting for socioeconomic indicators (education, income, and employment status), TED remained elevated in Black patients (OR, 1.4 (95% CI, 1.3-1.6). Over a median (interquartile range) follow-up period of 75 (65-82) months, 142 (18%) patients had at least one event. Development of TED with mental stress was associated with an increased risk for the study outcome both in Black (age- and sex-adjusted HR, 3.0; 95% CI, 1.3-6.8) and non-Black participants (HR, 1.7, 95% CI, 0.96-3.0), p=0.26 for interaction. Adjustment for demographic, clinical and socioeconomic factors did not diminish these associations. Conclusions: Among CAD patients, Black individuals are more likely than non-Black individuals to develop endothelial dysfunction with mental stress, which in turn is associated with an increased risk of adverse cardiovascular events. Endothelial dysfunction in response to psychological stress may represent an important mechanism for the disproportionate risk of adverse CV outcomes in Black patients.

Effect of Positive Mental Imagery Stimuli on Anhedonic Depressive Symptoms

This study aimed to investigate the effect of the intervention of positive mental imagery on anhedonia and the underlying reward mechanism in depression, and to explore the sustainability of the impact of the intervention following stress induction. Participants reporting anhedonic depressive symptoms (N=54) were randomly assigned to either a positive mental imagery condition or a verbalization condition, the former utilizing positive imagery stimuli only, and the latter utilizing language-based on meaning. Participants in both the conditions completed a computerized picture-word task for imagery generation and mental arithmetic stress task for stress induction. The results showed that both intervention conditions significantly reduced anhedonia and negative affect and that the mental imagery intervention was not superior to verbalization intervention. After stress induction, there was no significant difference between the two conditions in terms of the sustainability of the impact of the intervention on mood, reward subcomponents, and anhedonia. These findings provide preliminary evidence of the effectiveness of positive mental imagery in improving anhedonia. Furthermore, this study emphasizes the importance of repetitive imagery intervention due to the unsustainable impact of brief interventions after stress induction.

Комп’ютерна оцінка результатів психоемоційного навантажувального тестування для виявлення патологічних гемодинамічних реакцій

Один із алгоритмів Data Mining — дерево класифікації і регресії — використаний для аналізу результатів психоемоційного навантажувального тестування з метою діагностики функціональної реактивності кровообігу пацієнта. Використаний алгоритм дозволив визначити 5 типів гемодинамічної реакції на психоемоційний стрес, у тому числі 3 відомі — нормальну, гіперреактивну і гіпертензивну, а також дві додаткові — гіпертензивну релаксацію при нормальній реакції на стрес і атипову — з відсутністю підвищення артеріального тиску у відповідь на стрес. Комп’ютерний алгоритм оцінки навантажувальної реакції і запропонована класифікація функціональної реактивності кровообігу дозволяють спростити аналіз та об’єктивізувати виявлення функціональних регуляторних порушень гемодинаміки, характерних для артеріальної гіпертензії, а також інших, що потребують клінічної інтерпретації.

Early life stress and autonomic response to acute mental stress in individuals with coronary heart disease.

Early life stress (ELS) has been associated with an increased risk of cardiovascular disease. We examined whether ELS was associated with autonomic function and stress reactivity among individuals with coronary heart disease (CHD). We included patients with stable CHD from two parallel studies, the Mental Stress Ischemia Prognosis Study (MIPS) and the Myocardial Infarction and Mental Stress Study 2 (MIMS2), and assessed ELS using the Early Trauma Inventory-Self-Report-Short Form. Participants underwent a laboratory-based mental stress task while undergoing ambulatory electrocardiographic monitoring. We used multivariate linear regression models to estimate the associations between ELS and heart rate variability (HRV; low frequency [LF], high frequency [HF], and LF and HF [LH] ratio). The analytic sample included 405 MIPS and 284 MIMS2 participants. Most participants endorsed at least one experience of ELS (92.2%). Although we did not observe associations between ELS and HRV outcomes in the overall sample, ELS was associated with lower LH ratio HRV during recovery in the posttraumatic stress disorder (PTSD) subgroup, ELS x PTSD interaction, p=.041. In the MIMS2 subgroup, ELS was associated with lower resting period LF HRV, =-0.16 ln ms2 ; 95% CI [-0.31, -0.02]. Exposure to physical trauma was associated with decreased HF HRV overall reactivity only among participants with high to moderate depressive symptoms, =-0.52 ln ms2 vs. =0.01 ln ms2 , p=.013. Overall, heterogeneous associations between ELS and HRV emerged, suggesting the need for additional research regarding longer-term ambulatory HRV.

The stress, salt excretion, and nighttime blood pressure (SABRE) study: Rationale and study design

BackgroundAbnormal diurnal patterns of blood pressure (BP) on ambulatory BP monitoring (ABPM), defined by reduced BP dipping or elevated nighttime BP, are associated with increased risk for adverse cardiovascular events. Psychological stress is associated with abnormal diurnal patterns of BP. Exposure to an acute stressor (e.g., mental stress task) normally increases urinary sodium excretion. However, some individuals have sodium retention after stress provocation, revealing substantial between-person variability in the degree of stress-induced sodium excretion. Prior research suggests urinary sodium excretion that does not occur during the daytime may shift toward the nighttime, accompanied by an increase in nighttime BP. Associations between psychological stress and the diurnal patterns of sodium excretion and BP are not yet fully understood. DesignThe study is conducted in both the laboratory and naturalistic environment with a multi-racial/ethnic sample of 211 healthy adults. In the laboratory, change in urinary sodium excretion in response to mental stress tasks is examined with pre-/post-stress assessments of sodium excretion. Changes in angiotensin-II, catecholamines, BP, heart rate, endothelin-1, and cortisol are also assessed. In the 24-hour naturalistic environment, the diurnal patterns of sodium excretion and systolic BP are assessed as daytime-to-nighttime ratio of sodium excretion and ABPM, respectively. Ecological momentary assessments of perceived stress are also collected. SummaryThe SABRE study investigates previously unexplored associations between stress-induced urinary excretion in the laboratory, diurnal patterns of sodium excretion and BP in the naturalistic environment, and ecological stress. It has high potential to advance our understanding of the role of psychological stress in hypertension.

Vasoconstriction Response to Mental Stress in Sickle Cell Disease: The Role of the Cardiac and Vascular Baroreflexes

Recent studies have shown that individuals with sickle cell disease (SCD) exhibit greater vasoconstriction responses to physical autonomic stressors, such as heat pain and cold pain than normal individuals, but this is not the case for mental stress (MTS). We sought to determine whether this anomalous finding for MTS is related to inter-group differences in baseline cardiac and vascular autonomic function. Fifteen subjects with SCD and 15 healthy volunteers participated in three MTS tasks: N-back, Stroop, and pain anticipation (PA). R–R interval (RRI), arterial blood pressure and finger photoplethysmogram (PPG) were continuously monitored before and during these MTS tasks. The magnitude of vasoconstriction was quantified using change in PPG amplitude (PPGa) from the baseline period. To represent basal autonomic function, we assessed both cardiac and vascular arms of the baroreflex during the baseline period. Cardiac baroreflex sensitivity (BRSc) was estimated by applying both the “sequence” and “spectral” techniques to beat-to-beat measurements of systolic blood pressure and RRIs. The vascular baroreflex sensitivity (BRSv) was quantified using the same approaches, modified for application to beat-to-beat diastolic blood pressure and PPGa measurements. Baseline BRSc was not different between SCD and non-SCD subjects, was not correlated with BRSv, and was not associated with the vasoconstriction responses to MTS tasks. BRSv in both groups was correlated with mean PPGa, and since both baseline PPGa and BRSv were lower in SCD, these results suggested that the SCD subjects were in a basal state of higher sympathetically mediated vascular tone. In both groups, baseline BRSv was positively correlated with the vasoconstriction responses to N-back, Stroop, and PA. After adjusting for differences in BRSv within and between groups, we found no difference in the vasoconstriction responses to all three mental tasks between SCD and non-SCD subjects. The implications of these findings are significant in subjects with SCD since vasoconstriction reduces microvascular flow and prolongs capillary transit time, increasing the likelihood for vaso-occlusive crisis (VOC) to be triggered by exposure to stressful events.

Self-reported emotional eaters consume more food under stress if they experience heightened stress reactivity and emotional relief from stress upon eating

Group data means from individuals who self-assess as emotional eaters do not reliably show increased food intake in response to stress or negative emotions. This inconsistency in predictive validity of self-reported emotional eating (EE) could be attributable to unconsidered moderation of the relationship between self-reported EE and behavioral measures of EE. Greater emotional relief from stress by eating may provide enhanced negative reinforcement and promote future EE in response to stress as a form of self-medication. Thus, we predicted that greater emotional relief from stress by eating (decrease in negative affect from stress to post-eating) would moderate the extent to which heightened stress reactivity (measured by systolic blood pressure, SBP) moderates the relationship between self-reported EE and food intake post-stress. We also hypothesized that self-reported EE would not predict greater food consumption on the rest day. 43 undergraduate women completed online assessments of eating behaviors. Participants were given snacks to eat after a mental stress task (TSST) or rest period on separate days in counterbalanced order. Our prediction was supported, as the moderated moderation model (PROCESS model 3) was highly significant on the stress day. Self-reported EE predicted increased food intake post-stress only under conditions of high stress reactivity and high emotional relief. On the rest day, self-reported EE predicted greater snack food intake only when SBP was high. This conditional increased intake substantiates stress as a promoter of snack food consumption for women with greater EE. Overall, our findings identified factors that may distinguish the subset of self-reported emotional eaters who are more likely to display EE behaviors in a laboratory setting, yet further studies are needed to directly test whether negative reinforcement via emotional relief from stress by eating drives enhanced EE following stress.

Perceived control and reactivity to acute stressors: Variations by age, race and facets of control

Greater perceived control is associated with better health and well-being outcomes, possibly through more adaptive stress processes. Yet little research has examined whether facets of perceived control (personal mastery and perceived constraints) predict psychological and physiological stress reactivity. The present study evaluated the associations of personal mastery and perceived constraints with changes in subjective stress and cortisol in response to acute laboratory stressors, with age and race as potential moderators. In the Midlife in the United States Refresher Study (N=633 adults aged 25-75), participants completed a baseline perceived control measure and were subsequently recruited to participate in the laboratory stress protocol. The protocol consisted of completing two mental stress tasks (mental arithmetic and Stroop) as well as providing saliva samples and subjective stress ratings. Race moderated the association between perceived constraints and subjective stress reactivity, such that higher constraints predicted greater subjective stress responses in White participants, but no association was observed in Black participants. Higher personal mastery and perceived constraints each predicted greater increases in cortisol in response to the stress tasks (AUCi ) among younger but not older adults. These findings suggest that older adults were buffered against the association between facets of control and cortisol stress reactivity. Discussion on potential racial differences in the link between constraints and stress reactivity are elaborated further, as well as considerations for future work to distinguish between facets of control and examine age and racial differences.

Examining the influence of mental stress on balance perturbation responses in older adults.

Reach-to-grasp responses following balance perturbations are important to fall prevention but are often ineffective in older adults. The ability to shift attention from an ongoing cognitive task to balance related processes has been shown to influence reach-to-grasp effectiveness in older adults. However, the added influence of stress and anxiety - known to negatively affect attention shifting ability - has not yet been explored in relation to recovery from balance perturbations. Given that fear and anxiety over falling is a key fall risk factor, an understanding of how such a negative mental state may affect postural reactions is important. This study aimed to investigate the effect of varied induced emotional states on reach-to-grasp balance responses in older adults. Healthy older adults (mean age 70.5±5.38years) stood laterally between 2 handrails with contact sensors. A safety harness with an integrated loadcell was worn to prevent falls and measure the amount of harness assistance (expressed as percent body weight). With instructions to grasp one rail to restore balance, participants' balance was laterally disturbed using surface translations under three randomized conditions: no cognitive task, neutral (verb generation) task, and mental stress task with negative prompts (paced auditory serial addition). The primary outcome was frequency of protective grasps. Secondary outcomes included frequency of harness assistance during trials with grasp errors as well as wrist movement time, trajectory distance, and peak velocity. Perceived level of distress was highest for the mental stress task compared to no task (p<0.001) and neutral task conditions (p=0.008). The mental stress task resulted in the lowest percentage of protective grasps (p<0.001) in response to balance perturbations. Closer examination of trials that resulted in grasp errors (i.e., collisions or overshoots), revealed increased harness assistance and reduced peak velocity of wrist movement (p<0.001) under the mental stress condition compared to grasp errors that occurred under the no task or neutral task condition. Distressing mental thoughts immediately prior to a balance perturbation lead to reduced effectiveness in reach-to-grasp balance responses compared to no or neutral cognitive tasks and should be considered as a possible fall risk factor.

Effect of Laboratory Mental Stressors on Cardiovascular Reactivity in Young Women During Different Phases of Menstrual Cycle: An Observational Study.

Introduction: Excessive cardiovascular reactivity to mental stress may be a risk factor for cardiovascular disease. However, there is inconsistent report in the literature regarding change in cardiac autonomic tone with the phase of the menstrual cycle and how it is affected by mental stress. Therefore, the present study was aimed at determining the cardiovascular reactivity to different laboratory mental stressors during follicular and luteal phase of menstrual cycle using heart rate variability (HRV).Methods: Thirty-three regularly cycling young females (19–35 years of age) were exposed to four cognitive tasks (Stroop test, Mental Rotation test, n-back test, and Mental Arithmetic Stress Test [MAST]) employed as laboratory mental stressors. HRV of the study participants were recorded before, during, and after each cognitive task and the recording was done in both phases of menstrual cycle for each individual.Results: A significant difference was observed in time domain parameters and nonlinear parameters of HRV in pretest versus during-test condition and during-test versus post-test conditions, but not in frequency domain parameters. No phase difference was found in time domain or frequency domain analysis of HRV in baseline or during performance of task. MAST performance (score out of 50) was significantly higher in luteal than follicular phase, while other tests showed no such difference.Conclusion: All four mental stress tasks used in the present study were able to elicit significant decrease in parasympathetic tone during performance of task as compared with baseline values of HRV. The present study did not elicit any phase difference in cardiovascular reactivity.

Heightened Stress Reactivity in Response to an Attachment Related Stressor in Patients With Medically Treated Primary Hypertension.

Background: A heightened stress reactivity to mental stress tasks has been shown in hypertensive patients and might contribute to a higher disease risk. We investigated this hyperreactivity with regard to an attachment related stressor that focuses on emotions instead of performance and we examined whether this effect can also be found in patients on antihypertensive drugs.Materials and Methods: Fifty patients with primary hypertension, treated with at least one antihypertensive drug, were compared with 25 healthy individuals. After 10 min of rest, they participated in an attachment-related interview (Adult Attachment Projective picture system, AAP) and were exposed to an attachment-related stressor (Separation Recall, SR), a short-time stressor which activates attachment-related emotions and thoughts by talking 5 min about a personal experience of loneliness. Blood samples to measure adrenocorticotrope hormone (ACTH), cortisol, norepinephrine, epinephrine, and dopamine were taken. Blood pressure, heart rate and arterial stiffness were measured at rest, after AAP, after SR and 10 min after recovery. Standard deviation of normal-to-normal intervals (SDNN) and root mean square of successive differences (RMSSD) were calculated. Parameters were compared using Mann Whitney U-test and linear mixed-effects regression models controlling for age and body mass index (BMI) after logarithmic transformation if appropriate.Results: Healthy test persons were younger and had lower BMI than patients. Comparing the two groups there were no significant differences in blood pressure and heart rate at rest. Both stressors provoked a significant response in almost all parameters. Results of the post-estimation of contrasts from linear mixed-effects regression models showed a steeper rise in systolic BP and arterial stiffness as well as a more pronounced decline in SDNN in hypertensive patients than in healthy controls. Levels of cortisol rose earlier and higher in hypertensive patients than in healthy controls.Conclusion: Vascular, autonomic, and hypothalamic pituitary adrenal axis response is heightened in medicated subjects with hypertension in response to attachment-focused stressors compared to healthy subjects. We conclude that the remaining hyper-reactivity even with sufficient antihypertensive medication still poses a substantial risk for affected patients. New ways to diminish this risk should be developed.

Effect of short-term mental stress on time- domain indices of heart rate variability in obese individuals – A case- control study

&#x0D; Introduction and Aim: Mental stress may impact dramatically on dynamic autonomic control on heart. Many studies have demonstrated association of high body mass index (BMI) with greater risk for cardiovascular disease with disturbance in autonomic neuronal activity. Analysis of Heart rate variability (HRV)during acute mental stress assesses the autonomic status of the individual. Hence, we aimed to study the effect of acute mental stress on time domain measures in obese adults.&#x0D; &#x0D; Materials and Methods:Sixty male volunteers of 30 each in study group (obese individuals) and control group (non-obese individuals) were recruited for the study. A basal recording of ECG in lead II was done on all the individuals. Then they underwent mental arithmetic stress task for 5 minutes during which again ECG was recorded. The change in time domain measures of HRV during rest and stress task was analyzed and compared between both the groups.&#x0D; &#x0D; Results: Analysis of time domain measures of HRV revealed a statistically significant increase (p ? 0.001) in mean heart rate in both obese and non-obese individuals, while rMSSD(root mean square differences of successive RR interval) and SDNN (standard deviation of all NN intervals) showed a statistically significant (p? 0.001) decrease in obese individuals and non-obese individuals did not show any statistically significant change during the mental stress task.&#x0D; &#x0D; Conclusion: In response to acute mental stress there was increased heart rate in both the groups. But the autonomic neuronal activity differed by way of sympathetic dominance in non-obese individuals and parasympathetic withdrawal in obese individuals.&#x0D;

Cocoa Flavanols Improve Vascular Responses to Acute Mental Stress in Young Healthy Adults.

Mental stress has been shown to induce cardiovascular events, likely due to its negative impact on vascular function. Flavanols, plant-derived polyphenolic compounds, improve endothelial function and blood pressure (BP) in humans, however their effects during stress are not known. This study examined the effects of acute intake of cocoa flavanols on stress-induced changes on vascular function. In a randomised, controlled, double-blind, cross-over intervention study, 30 healthy men ingested a cocoa flavanol beverage (high-flavanol: 150 mg vs. low-flavanol < 4 mg (−)-epicatechin) 1.5 h before an 8-min mental stress task). Forearm blood flow (FBF), BP, and cardiovascular activity were assessed pre- and post-intervention, both at rest and during stress. Endothelial function (brachial flow-mediated dilatation, FMD) and brachial BP were measured before the intervention and 30 and 90 min post-stress. FMD was impaired 30 min post-stress, yet high-flavanol cocoa attenuated this decline and remained significantly higher compared to low-flavanol cocoa at 90 min post-stress. High-flavanol cocoa increased FBF at rest and during stress. Stress-induced cardiovascular and BP responses were similar in both conditions. Flavanols are effective at counteracting mental stress-induced endothelial dysfunction and improving peripheral blood flow during stress. These findings suggest the use of flavanol-rich dietary strategies to protect vascular health during stress.

Validity of the Polar V800 Monitor for Assessing Heart Rate Variability in Elderly Adults under Mental Stress and Dual Task Conditions.

Background: Aging may result in autonomic nervous dysfunction. Heart rate variability (HRV) is a non-invasive method to measure autonomic nervous activities. Many studies have shown that HRV contributes to the risk assessment of diseases. A Polar V800 heart rate monitor is a wearable device that measures R-R intervals, but has only been validated in younger adults under limited testing conditions. There is no validation of the V800 under mental stress or in dual task testing conditions. Therefore, this study investigated the validity of the Polar V800 heart rate monitor for assessing R-R intervals and evaluated if there were differences on HRV parameters under different situations in community-dwelling elderly adults. Methods: Forty community-dwelling elderly adults were recruited. Heart rates were recorded via electrocardiogram (ECG) and the V800 under sitting, during an arithmetic test, during a naming test, a self-selected walking velocity test (SSWV), and dual tasks (SSWV performing mental arithmetic test and SSWV performing naming test). Indices of time and frequency domains of HRV were calculated afterwards. The intra-class correlation coefficient (ICC) analysis and effect size were calculated to examine the concurrent validity between the V800 and the ECG. Results: All HRV indices from the V800 were highly correlated with the ECG under all tested conditions (ICC = 0.995–1.000, p < 0.001) and the effect size of bias was small (<0.1). Conclusion: Overall, the V800 has good validity on the assessment of HRV in community-dwelling elderly adults during sitting, mental arithmetic test, naming test, SSWV, and dual tasks.

Transcutaneous vagal nerve stimulation blocks stress-induced activation of Interleukin-6 and interferon-γ in posttraumatic stress disorder: A double-blind, randomized, sham-controlled trial

Posttraumatic stress disorder (PTSD) is a highly disabling condition associated with alterations in multiple neurobiological systems, including increases in inflammatory function. Vagus nerve stimulation (VNS) decreases inflammation, however few studies have examined the effects of non-invasive VNS on physiology in human subjects, and no studies in patients with PTSD. The purpose of this study was to assess the effects of transcutaneous cervical VNS (tcVNS) on inflammatory responses to stress. Thirty subjects with a history of exposure to traumatic stress with (N ​= ​10) and without (N ​= ​20) PTSD underwent exposure to stressful tasks immediately followed by active or sham tcVNS and measurement of multiple biomarkers of inflammation (interleukin-(IL)-6, IL-2, IL-1β, Tumor Necrosis Factor alpha (TNFα) and Interferon gamma (IFNγ) over multiple time points. Stressful tasks included exposure to personalized scripts of traumatic events on day 1, and public speech and mental arithmetic (Mental Stress) tasks on days 2 and 3. Traumatic scripts were associated with a pattern of subjective anger measured with Visual Analogue Scales and increased IL-6 and IFNγ in PTSD patients that was blocked by tcVNS (p ​< ​.05). Traumatic stress had minimal effects on these biomarkers in non-PTSD subjects and there was no difference between tcVNS or sham. No significant differences were seen between groups in IL-2, IL-1β, or TNFα. These results demonstrate that tcVNS blocks behavioral and inflammatory responses to stress reminders in PTSD.

Snacking on Whole Almonds for Six Weeks Increases Heart Rate Variability during Mental Stress in Healthy Adults: A Randomized Controlled Trial.

Cardiac autonomic regulation can be indirectly measured by heart rate variability (HRV). Low HRV, which can be induced by mental stress, is a predictor of risk of sudden cardiac death. Few studies have investigated cause-and-effect relationships between diet and HRV. Nut consumption is associated with CVD risk reduction, but the impact on HRV, particularly in response to stress, is unclear. Men and women (30–70 y) with above average risk of developing CVD were randomly assigned in a 6-week randomized, controlled, parallel arm trial to consume either whole almond or isocaloric control snacks (20% of daily estimated energy requirement). Control snacks contained the average nutrient profile of UK snacks. Five-minute periods of supine heart rate (HR) and HRV were measured at resting and during mental stress (Stroop color-word test) at baseline and six weeks. High frequency (HF) power, which reflects parasympathetic regulation of HR, was increased following almonds during the mental stress task relative to control (mean difference between groups 124 ms2; 95% CI 11, 237; p = 0.031, n = 105), but other indices were unaffected. Snacking on whole almonds instead of typical snacks may reduce risk of CVD partly by ameliorating the suppression of HRV during periods of mental stress.

Effects of Daily Intake of Almonds on Cardiac Autonomic Functions Measured by Heart Rate Variability in Response to Acute Stress: A Randomized Controlled Trial

Abstract Objectives Stress is inversely associated with heart rate variability (HRV), an indicator of cardiac autonomic function and a predictor of risk of sudden cardiac death. At times of stress, people tend to favor high sugar and fatty foods, often as snacks, with potential adverse effects on cardiometabolic health. Dietary recommendations for cardiovascular disease (CVD) prevention emphasize fruits, vegetables, wholegrains and nuts. There is evidence that consumption of nuts can reduce LDL cholesterol and blood pressure and help with weight management, however the impact of nuts on HRV in response to stress is unknown. The ATTIS dietary intervention study investigated the HRV response to acute stress following 6-week substitution of almonds for typical snacks high in refined starch, free sugars and saturated fats, and low in fibre. The study population comprised adults aged 30–70 y, who were habitual snack consumers, and at moderate risk of developing CVD. It was hypothesized that snacking on almonds would increase HRV during stress tasks, when HRV is expected to be reduced due to increased sympathetic activity. Methods A 6-week randomized controlled parallel trial was conducted. Participants were randomized to 1) control snacks (mini-muffins formulated to follow the average UK snack nutrient profile), or 2) dry-roasted whole almonds, both providing 20% estimated energy requirement. Supine HRV was measured (Mega Electronics Emotion Faros 180°, 2-leads wearable ECG-HRV monitor) during resting (5 min), physical stress (blood pressure monitor cuff inflation 200 mmHg, 5 min) and mental stress (Stroop colour-word test, 5 min) tasks pre- and post-intervention. A total of 105 participants (73 females and 32 males; mean age 56.2 y, SD 10.4) completed the trial. Results Almonds significantly increased the beat-to-beat HRV parameter, high-frequency power, during the mental stress test (mean difference 124 ms2; 95% CI 11, 237; P = 0.031) relative to control, indicating increased parasympathetic regulation. There were no treatment effects during resting and the physical stress task. Conclusions Snacking on whole almonds as a replacement for typical snacks increases HRV during mental stress, indicating an increased resilience in cardiac autonomic function and a novel mechanism whereby nuts may be cardioprotective. Funding Sources Almond Board of California.

0162 Mental Stress Compromises Human Sleep Through a Biological, Not Psychological, Pathway

Abstract Introduction The extent to which mental stress causes sleep disturbance is unknown as experimental studies of stress and sleep have yielded mixed results. Potential mechanisms linking stress to poor sleep are also poorly characterized. The current study aimed to 1) assess the impact of experimentally-induced mental stress on daytime sleep and 2) test candidate mechanisms including physiological and emotional stress reactivity, stress rumination, attentional threat bias, and insensitivity to future consequences. Methods Participants (N=30) were randomized to a control (n=14) or stress group (n=16). Both groups were given a 60-minute nap opportunity at midday (≈13:30). Prior to sleep, participants in the stress group completed a socially evaluative mental arithmetic stress task and were instructed that they would be required to give a brief speech upon awakening. Sleep was monitored with polysomnography and scored according to standard AASM criteria. Measures of heart rate (HR), blood pressure (BP) and self-reported stress were recorded during the stress task. Self-reported stress rumination was measured upon awakening. Attentional threat bias was measured using an emotional dot probe and performance on the Iowa Gambling Task quantified insensitivity to future consequences. Results Acute mental stress significantly increased HR and BP (all p&amp;lt;.001, all Cohen’s d&amp;gt;1.24) and participants reported significant increases in self-reported stress (p&amp;lt;.001). The stress group exhibited longer sleep latency (p=.038, d=.82), shorter sleep duration (p=.044, d=.78), and worse sleep continuity (p=.045, d=.79). Subjective sleep quality was not different across groups (p=.39, d=.32). Of all candidate mechanisms, physiological reactivity was the only one significantly related to sleep measures. Greater HR reactivity predicted longer sleep latency (r=.37), shorter sleep duration (r=-.59), and worse sleep continuity (r=-.59). Conclusion Acute mental stress caused significant disturbances in a single episode of daytime sleep. The degree of disturbance was, to an extent, predicted by the amount of physiological reactivity to stress. Support This work was supported a Washington and Lee University Summer Lenfest Grant and the Summer Research Scholars Program.

Neural Correlates of Stress and Abdominal Obesity in Patients With Coronary Artery Disease.

This study aimed to investigate the relationship between waist circumference as a measure of abdominal obesity and brain responses to stress among patients with coronary artery disease (CAD). Patients with CAD (N = 151) underwent acute mental stress tasks in conjunction with high-resolution positron emission tomography and radiolabeled water imaging of the brain. Brain responses to mental stress were correlated with waist circumference. Waist circumference was positively correlated with increased activation in the right and left frontal lobes (β values ranging from 2.81 to 3.75 in the paracentral, medial, and superior gyri), left temporal lobe, left hippocampal, left amygdala, left uncus, and left anterior and posterior cingulate gyri (β values ranging from 2.93 to 3.55). Waist circumference was also negatively associated with the left and right parietal lobes, right superior temporal gyrus, and right insula and precuneus (β values ranging from 2.82 to 5.20). Increased brain activation in the brain regions involved in the stress response and autonomic regulation of the cardiovascular system during psychological stress may underlie stress-induced overeating and abdominal obesity in patients with CAD.