Early heart development: examining the dynamics of function-form emergence.

During early embryonic development, the heart undergoes a remarkable and complex transformation, acquiring its iconic four-chamber structure whilst concomitantly contracting to maintain its essential function. The emergence of cardiac form and function involves intricate interplays between molecular, cellular, and biomechanical events, unfolding with precision in both space and time. The dynamic morphological remodelling of the developing heart renders it particularly vulnerable to congenital defects, with heart malformations being the most common type of congenital birth defect (∼35% of all congenital birth defects). This mini-review aims to give an overview of the morphogenetic processes which govern early heart formation as well as the dynamics and mechanisms of early cardiac function. Moreover, we aim to highlight some of the interplay between these two processes and discuss how recent findings and emerging techniques/models offer promising avenues for future exploration. In summary, the developing heart is an exciting model to gain fundamental insight into the dynamic relationship between form and function, which will augment our understanding of cardiac congenital defects and provide a blueprint for potential therapeutic strategies to treat disease.

Lactate infusion elevates cardiac output through increased heart rate and decreased vascular resistance: a randomised, blinded, crossover trial in a healthy porcine model.

BACKGROUND: Lactate is traditionally recognized as a by-product of anaerobic metabolism. However, lactate is a preferred oxidative substrate for stressed myocardium. Exogenous lactate infusion increases cardiac output (CO). The exact mechanism underlying this mechanism has yet to be elucidated. The aim of this study was to investigate the cardiovascular mechanisms underlying the acute haemodynamic effects of exogenous lactate infusion in an experimental model of human-sized pigs. METHODS: In this randomised, blinded crossover study in eight 60-kg-pigs, the pigs received infusions with one molar sodium lactate and a control infusion of tonicity matched hypertonic saline in random order. We measured CO and pulmonary pressures using a pulmonary artery catheter. A pressure-volume admittance catheter in the left ventricle was used to measure contractility, afterload, preload and work-related parameters. RESULTS: Lactate infusion increased circulating lactate levels by 9.9 mmol/L (95% confidence interval (CI) 9.1 to 11.0) and CO by 2.0 L/min (95% CI 1.2 to 2.7). Afterload decreased as arterial elastance fell by  -1.0 mmHg/ml (95% CI  -2.0 to  -0.1) and systemic vascular resistance decreased by  -548 dynes/s/cm5 (95% CI  -261 to  -835). Mixed venous saturation increased by 11 percentage points (95% CI 6 to 16), whereas ejection fraction increased by 16.0 percentage points (95% CI 1.1 to 32.0) and heart rate by 21 bpm (95% CI 8 to 33). No significant changes in contractility nor preload were observed. CONCLUSION: Lactate infusion increased cardiac output by increasing heart rate and lowering afterload. No differences were observed in left ventricular contractility or preload. Lactate holds potential as a treatment in situations with lowered CO and should be investigated in future clinical studies.

Cold stimulation of the oral cavity redistributes blood towards the brain in healthy volunteers.

BACKGROUND: The aim of this study was to analyze cold stimulation-induced changes in cerebral and cardiac hemodynamics. METHODS: Upon ingestion of an ice cube, the changes in resistance index, mean flow velocity and flow index of the middle cerebral arteries (MCA) were assessed using transcranial Doppler sonography. Extracranial duplex sonography was used to measure the mean flow velocity and resistance index of the right internal carotid artery (ICA). The change in mean arterial pressure, heart rate, root mean square of successive differences (RMSSD) and end-tidal carbon dioxide pressure were analyzed additionally. These changes were compared to sham stimulation. RESULTS: Compared with sham stimulation, cooling of the oral cavity resulted in significant changes in cerebral and cardiac hemodynamics. The cold stimulation decreased the resistance index in the MCA (-4.5% ± 5.4%, p < 0.0001) and right ICA (-6.3% ± 15.6%, p = 0.001). This was accompanied by an increase in mean flow velocity (4.1% ± 8.0%, p < 0.0001) and flow index (10.1% ± 43.6%, p = 0.008) in the MCA. The cardiac effects caused an increase in mean arterial pressure (1.8% ± 11.2%, p = 0.017) and RMSSD (55% ± 112%, p = 0.048), while simultaneously decreasing the heart rate (-4.3% ± 9.6%, p = 0.0001). CONCLUSION: Cooling of the oral cavity resulted in substantial changes in cerebral and cardiac hemodynamics resulting in a blood flow diversion to the brain.

Inhaled endotoxin induces a systemic neutrophil response without affecting cardiovascular measures in a randomized cross-over exposure study.

OBJECTIVE: The gram-negative bacterial cell wall component endotoxin (lipopolysaccharide, LPS) is a key component of particulate matter (PM). PM exposure is associated with cardiovascular morbidity and mortality. However, the contribution of individual components of PM to acute and chronic cardiovascular measures is not clear. This study examines whether systemic inflammation induced by LPS inhalation causes acute changes in cardiovascular physiology measures. MATERIALS AND METHODS: In this double blinded, placebo-controlled crossover study, fifteen adult volunteers underwent inhalation exposure to 20,000 EU Clinical Center Reference Endotoxin (CCRE). Peripheral blood and induced sputum neutrophils were obtained at baseline and six hours post-exposure. Blood pressure, measures of left ventricular function (ejection fraction (LVEF) and global longitudinal strain (LVGLS)), and indices of endothelial function (flow mediated dilation (FMD) and velocity time integral during hyperemia (VTIhyp)) were measured before and after treatment. Wilcoxon sign-rank tests and linear mixed models were used for statistical analysis. RESULTS: In comparison with normal saline, LPS inhalation resulted in significant increases in peripheral blood and sputum neutrophils but was not associated with significant alterations in blood pressure, LVGLS, LVEF, FMD, or VTIhyp. DISCUSSION AND CONCLUSIONS: In healthy adults, systemic inflammation after LPS inhalation was not associated with acute changes in cardiovascular physiology. Larger studies are needed to investigate the effects of other PM components on inflammation induced cardiovascular dysfunction.

Lower-Limb Perfusion and Cardiovascular Physiology Are Significantly Improved in Non-Healthy Aged Adults by Regular Home-Based Physical Activities-An Exploratory Study.

Common daily activities including walking might be used to improve cardiovascular health in the presence of disease. Thus, we designed a specific home-based physical activity program to assess cardiovascular indicators in an older, non-active, non-healthy population. Ten participants, with a mean age of 62.4 ± 5.6 years old, were chosen and evaluated twice-upon inclusion (D0), and on day 30 (D30)-following program application. Perfusion was measured in both feet by laser Doppler flowmetry (LDF) and by polarised spectroscopy (PSp). Measurements were taken at baseline (Phase 1) immediately after performing the selected activities (Phase 2) and during recovery (Phase 3). Comparison outcomes between D0 and D30 revealed relevant differences in Phase 1 recordings, namely a significant increase in LDF perfusion (p = 0.005) and a significant decrease in systolic blood pressure (p = 0.008) and mean arterial pressure (MAP) (p = 0.037). A correlation between the increase in perfusion and the weekly activity time was found (p = 0.043). No differences were found in Phase 2, but, in Phase 3, LDF values were still significantly higher in D30 compared with D0. These simple activities, regularly executed with minimal supervision, significantly improved the lower-limb perfusion while reducing participants' systolic pressure and MAP, taken as an important improvement in their cardiovascular status.

Relationship Between Caffeine Consumption and Young Athletes' Comorbidities, Exercise-Related Symptoms, and Baseline Electrocardiogram.

BACKGROUND: Caffeine consumption causes diverse physiologic effects that can affect athletes both positively and negatively. There is a lack of research investigating the long-term effects of caffeine intake on exercise and on overall cardiovascular health in young athletes. HYPOTHESIS: Certain characteristics such as age, body mass index (BMI), race, and medical diagnoses are associated with increased caffeine use, and there is a relationship between caffeine consumption and symptoms during exercise and cardiovascular abnormalities in young athletes. STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 4. METHODS: This study utilized the HeartBytes National Youth Cardiac Registry to collect data related to demographics, caffeine use, and physical examination and electrocardiogram (ECG) findings of 7425 12- to 20-year-olds (60.6% male, 39.4% female) who attended a Simon's Heart cardiac screening event between 2014 and 2021. Univariable and multivariable logistic regression models were used for analysis. RESULTS: Persons who consumed caffeine were more likely to have attention deficit hyperactivity disorder (ADHD) (adjusted odds ratio [aOR], 1.43; CI, 1.15-1.76]; P < 0.01) and more likely to have a BMI ≥30 kg/m2 (aOR, 1.69; CI, 1.27-2.25]; P < 0.01) compared with nondrinkers. After controlling for age, gender, race, and BMI, there were no significant differences in symptoms during exercise (aOR, 1.27; CI, 0.97-1.66; P = 0.08) or abnormal ECG findings (OR, 0.93; CI, 0.66-1.31; P = 0.70) between those who consume caffeine and those who do not. CONCLUSION: Caffeine consumption was associated with increased BMI and increased likelihood of having ADHD; however, caffeine use overall was not associated with increased risk of symptoms during exercise or ECG abnormalities. CLINICAL RELEVANCE: Whereas caffeine consumption overall did not increase risk of exercise-related symptoms, soda drinkers were at higher risk for symptoms during exercise, and coffee drinkers were at higher risk of syncope with exercise. Prospective studies with longitudinal follow-up and more specific outcomes data is the next step in qualifying the impact of caffeine on young athletes.

Cardiac Output Changes during Renal Replacement Therapy: A Scoping Review.

INTRODUCTION: Renal replacement therapy (RRT) is associated with hypotension. However, its impact on cardiac output (CO) is less understood. We aimed to describe current knowledge of CO monitoring and changes during RRT. METHODS: We searched MEDLINE, Embase, and Cochrane from January 1, 2000, to January 31, 2023, using Covidence for studies of intermittent hemodialysis (IHD) and continuous RRT (CRRT) with at least three CO measurements during treatment. Two independent reviewers screened citations, and a third resolved disagreements. The findings did not allow meta-analysis and are presented descriptively. RESULTS: We screened 3,285 articles and included 48 (37 during IHD, nine during CRRT, and two during both). Non-invasive devices (electrical conductivity techniques and finger cuff pulse contour) were the most common CO measurement techniques (21 studies). The median baseline cardiac index in IHD studies was 3 L/min/m2 (95% CI, 2.7-3.39). Among the 88 patient cohorts studied, a decrease in CO occurred in 63 (72%). In 16 cohorts, the decrease was severe (>25%). Changes in blood pressure (BP) were not concordant in extent or direction with changes in CO. The decrease in CO correlated weakly with ultrafiltration rate (r = -0.3, p = 0.05) and strongly with changes in systemic vascular resistance (SVR) (r = -0.6, p < 0.001). CONCLUSION: There are limited data on CO changes during RRT. However, a decrease in CO appeared common and was marked in 1 of 5 patient cohorts. Such decreases often occurred without BP changes and were associated with increased SVR.

The vagus nerve in cardiovascular physiology and pathophysiology: From evolutionary insights to clinical medicine.

The parasympathetic nervous system via the vagus nerve exerts profound influence over the heart. Together with the sympathetic nervous system, the parasympathetic nervous system is responsible for fine-tuned regulation of all aspects of cardiovascular function, including heart rate, rhythm, contractility, and blood pressure. In this review, we highlight vagal efferent and afferent innervation of the heart, with a focus on insights from comparative biology and advances in understanding the molecular and genetic diversity of vagal neurons, as well as interoception, parasympathetic dysfunction in heart disease, and the therapeutic potential of targeting the parasympathetic nervous system in cardiovascular disease.

Commentary on: Increased stiffness of omental arteries from late pregnant women at advanced maternal age.

Worldwide, pregnancy at age 35 or older, termed 'advanced maternal age (AMA)', is increasing exponentially. As the incidence of pregnancy at AMA has increased, a growing body of evidence has suggested that AMA is also associated with increased risk for adverse maternal and fetal outcomes outside of genetic anomalies. Importantly, despite the mounting evidence and the increased global risk of adverse perinatal outcomes observed, few studies have examined the potential mechanisms underlying this elevated risk in pregnant people ≥35 years of age. Wooldridge and colleagues begin to address this gap in the literature. In their recent report, they examine vessel stiffness in omental resistance vessels obtained from pregnant individuals ≥35 years of age compared with pregnant individuals <35 years of age. Omental arteries were isolated and assessed via pressure myography (mechanical properties) and histological analysis for collagen and elastin content. Overall, the findings from this investigation report that maternal resistance arteries collected from women of AMA were less compliant and had less elastin than arteries obtained from women <35 years of age, suggesting that maternal resistance vessel stiffening in AMA may contribute to increased risk of adverse pregnancy outcomes. The authors should be commended for completing these studies in human resistance vessels, which now open new avenues for investigation and provoke a cascade of questions related to maternal cardiovascular adaptations to pregnancy in women ≥35 years of age.

Influence of Fluid Ingestion on Heart Rate, Cardiac Autonomic Modulation and Blood Pressure in Response to Physical Exercise: A Systematic Review with Meta-Analysis and Meta-Regression.

A systematic review was undertaken to investigate the involvement of hydration in heart rate (HR), HR variability (HRV) and diastolic (DBP) and systolic (SBP) blood pressure in response to exercise. Data synthesis: The EMBASE, MEDLINE, Cochrane Library, CINAHL, LILACS and Web of Science databases were searched. In total, 977 studies were recognized, but only 36 were included after final screening (33 studies in meta-analysis). This study includes randomized controlled trials (RCTs) and non-RCTs with subjects > 18 years old. The hydration group consumed water or isotonic drinks, while the control group did not ingest liquids. For the hydration protocol (before, during and after exercise), the HR values during the exercise were lower compared to the controls (-6.20 bpm, 95%CI: -8.69; -3.71). In the subgroup analysis, "water ingested before and during exercise" showed lower increases in HR during exercise (-6.20, 95%CI: 11.70 to -0.71), as did "water was ingested only during exercise" (-6.12, 95%CI: -9.35 to -2.89). Water intake during exercise only revealed a trend of avoiding greater increases in HR during exercise (-4,60, 95%CI: -9.41 to 0.22), although these values were not significantly different (p = 0.06) from those of the control. "Isotonic intake during exercise" showed lower HRs than the control (-7.23 bpm, 95% CI: -11.68 to -2.79). The HRV values following the exercise were higher in the hydration protocol (SMD = 0.48, 95%CI: 0.30 to 0.67). The values of the SBP were higher than those of the controls (2.25 mmHg, 95%CI: 0.08 to 4.42). Conclusions: Hydration-attenuated exercise-induced increases in HR during exercise, improved autonomic recovery via the acceleration of cardiac vagal modulation in response to exercise and caused a modest increase in SBP values, but did not exert effects on DBP following exercise.

The O-GlcNAc dichotomy: when does adaptation become pathological?

O-Linked attachment of ß-N-acetylglucosamine (O-GlcNAc) on serine and threonine residues of nuclear, cytoplasmic, and mitochondrial proteins is a highly dynamic and ubiquitous post-translational modification that impacts the function, activity, subcellular localization, and stability of target proteins. Physiologically, acute O-GlcNAcylation serves primarily to modulate cellular signaling and transcription regulatory pathways in response to nutrients and stress. To date, thousands of proteins have been revealed to be O-GlcNAcylated and this number continues to grow as the technology for the detection of O-GlcNAc improves. The attachment of a single O-GlcNAc is catalyzed by the enzyme O-GlcNAc transferase (OGT), and their removal is catalyzed by O-GlcNAcase (OGA). O-GlcNAcylation is regulated by the metabolism of glucose via the hexosamine biosynthesis pathway, and the metabolic abnormalities associated with pathophysiological conditions are all associated with increased flux through this pathway and elevate O-GlcNAc levels. While chronic O-GlcNAcylation is well associated with cardiovascular dysfunction, only until recently, and with genetically modified animals, has O-GlcNAcylation as a contributing mechanism of cardiovascular disease emerged. This review will address and critically evaluate the current literature on the role of O-GlcNAcylation in vascular physiology, with a view that this pathway can offer novel targets for the treatment and prevention of cardiovascular diseases.

Image Timing After COVID-19 Infection in Athletes.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has significantly impacted National Collegiate Athletic Association (NCAA) athletics, with specific concerns for cardiac involvement after infection. Pericardial abnormalities have been seen in up to 39.5% of athletes after COVID-19 infection, while myocardial involvement has been reported at a lower rate of 2.7%. To date, myocardial injury has been seen in 0.6% to 0.7% of athletes when using symptom screening and imaging as clinically indicated, which increases to 2.3% to 3.0% when all athletes with COVID-19 undergo cardiac magnetic resonance (CMR) imaging. PURPOSE: This study will examine whether there exists an ideal time from positive COVID-19 results to obtaining imaging to increase the likelihood of finding abnormalities. STUDY DESIGN: Prospective cohort study. LEVEL OF EVIDENCE: Level 3. METHODS: NCAA athletes at West Virginia University who were found to be COVID-19 positive on routine screening were required to undergo echocardiography (ECG) and CMR. These data were reviewed by cardiology and determined to be normal or abnormal. Statistical analysis with logistic regression and descriptive statistics was performed to evaluate whether a time existed where abnormalities on imaging were most likely to be found. RESULTS: A total of 41 athletes were included in this study. ECG was performed earlier on average than CMR imaging, at 18.2 days versus 27.5 days. No significant difference was found in timing from COVID-19 infection diagnosis and abnormalities seen on imaging for either ECG or CMR imaging. CONCLUSION: The risk of cardiac involvement in athletes in the setting of COVID-19 has already been documented. This study suggests that imaging timing is independent of cardiac involvement with no correlation to specific time periods where more abnormalities may be found. However, CMR imaging showing changes at day 54 after infection suggests cardiac findings can be seen months after imaging. CLINICAL RELEVANCE: Cardiac imaging for athletes after contracting COVID-19 does not show a significant relationship to time of imaging. However, given the cardiac involvement seen months after diagnosis, further examination of prolonged cardiac effects must be carried out.

Adjusting for muscle strength and body size attenuates sex differences in the exercise pressor reflex in young adults.

Females typically exhibit lower blood pressure (BP) during exercise than males. However, recent findings indicate that adjusting for maximal strength attenuates sex differences in BP during isometric handgrip (HG) exercise and postexercise ischemia (PEI; metaboreflex isolation). In addition, body size is associated with HG strength but its contribution to sex differences in exercising BP is less appreciated. Therefore, the purpose of this study was to determine whether adjusting for strength and body size would attenuate sex differences in BP during HG and PEI. We obtained beat-to-beat BP in 110 participants (36 females, 74 males) who completed 2 min of isometric HG exercise at 40% of their maximal voluntary contraction followed by 3 min of PEI. In a subset (11 females, 17 males), we collected muscle sympathetic nerve activity (MSNA). Statistical analyses included independent t tests and mixed models (sex × time) with covariate adjustment for 40% HG force, height2, and body surface area. Females exhibited a lower absolute 40% HG force than male participants (Ps < 0.001). Females exhibited lower Δsystolic, Δdiastolic, and Δmean BPs during HG and PEI than males (e.g., PEI, Δsystolic BP, 15 ± 11 vs. 23 ± 14 mmHg; P = 0.004). After covariate adjustment, sex differences in BP responses were attenuated. There were no sex differences in MSNA. In a smaller strength-matched cohort, there was no sex × time interactions for BP responses (e.g., PEI systolic BP, P = 0.539; diastolic BP, P = 0.758). Our data indicate that sex differences in exercising BP responses are attenuated after adjusting for muscle strength and body size.NEW & NOTEWORTHY When compared with young males, females typically exhibit lower blood pressure (BP) during exercise. Adjusting for maximal strength attenuates sex differences in BP during isometric handgrip (HG) exercise and postexercise ischemia (PEI), but the contribution of body size is unknown. Novel findings include adjustments for muscle strength and body size attenuate sex differences in BP reactivity during exercise and PEI, and sex differences in body size contribute to HG strength differences.

Total-Body Positron Emission Tomography: Adding New Perspectives to Cardiovascular Research.

The recent advent of positron emission tomography (PET) scanners that can image the entire human body opens up intriguing possibilities for cardiovascular research and future clinical applications. These new systems permit radiotracer kinetics to be measured in all organs simultaneously. They are particularly well suited to study cardiovascular disease and its effects on the entire body. They could also play a role in quantitatively measuring physiologic, metabolic, and immunologic responses in healthy individuals to a variety of stressors and lifestyle interventions, and may ultimately be instrumental for evaluating novel therapeutic agents and their molecular effects across different tissues. In this review, we summarize recent progress in PET technology and methodology, discuss several emerging cardiovascular applications for total-body PET, and place this in the context of multiorgan and systems medicine. Finally, we discuss opportunities that will be enabled by the technology, while also pointing to some of the challenges that still need to be addressed.

Embryonic and juvenile snakes (Natrix maura, Linnaeus 1758) compensate for high elevation hypoxia via shifts in cardiovascular physiology and metabolism.

The colonization of novel environments requires a favorable response to conditions never, or rarely, encountered in recent evolutionary history. For example, populations colonizing upslope habitats must cope with lower atmospheric pressure at elevation, and thus reduced oxygen availability. The embryo stage in oviparous organisms is particularly susceptible, given its lack of mobility and limited gas exchange via diffusion through the eggshell and membranes. Especially little is known about responses of Lepidosaurian reptiles to reduced oxygen availability. To test the role of physiological plasticity during early development in response to high elevation hypoxia, we performed a transplant experiment with the viperine snake (Natrix maura, Linnaeus 1758). We maintained gravid females originating from low elevation populations (432 m above sea level [ASL]-normoxia) at both the elevation of origin and high elevation (2877 m ASL-extreme high elevation hypoxia; approximately 72% oxygen availability relative to sea level), then incubated egg clutches at both low and high elevation. Regardless of maternal exposure to hypoxia during gestation, embryos incubated at extreme high elevation exhibited altered developmental trajectories of cardiovascular function and metabolism across the incubation period, including a reduction in late-development egg mass. This physiological response may have contributed to the maintenance of similar incubation duration, hatching success, and hatchling body size compared to embryos incubated at low elevation. Nevertheless, after being maintained in hypoxia, juveniles exhibit reduced carbon dioxide production relative to oxygen consumption, suggesting altered energy pathways compared to juveniles maintained in normoxia. These findings highlight the role of physiological plasticity in maintaining rates of survival and fitness-relevant phenotypes in novel environments.

Cardiovascular responses to mild perinatal asphyxia in growth-restricted preterm lambs.

Growth-restricted neonates have worse outcomes after perinatal asphyxia, with more severe metabolic acidosis than appropriately grown neonates. The cardiovascular physiology associated with fetal growth restriction (FGR) may alter their response to asphyxia. However, research on asphyxia in FGR is limited. Here we compared cardiovascular hemodynamics in preterm FGR and control lambs during mild perinatal asphyxia. We induced FGR in one twin at 89 days gestation (term 148 days), while the other served as a control. At 126 days gestation, lambs were instrumented to allow arterial blood pressure and regional blood flow recording, and then mild perinatal asphyxia was induced by umbilical cord clamping, and resuscitation followed neonatal guidelines. FGR lambs maintained carotid blood flow (CBF) for 7 min, while control lambs rapidly decreased CBF (P < 0.05). Fewer growth-restricted lambs needed chest compressions for return of spontaneous circulation (ROSC) (17 vs. 83%, P = 0.02). The extent of blood pressure overshoot after ROSC was similar, but it took longer for MAP to return to baseline in FGR lambs (18.83 ± 0.00 vs. 47.67 ± 0.00 min, P = 0.003). Growth-restricted lambs had higher CBF after ROSC (P < 0.05) and displayed CBF overshoot, unlike control lambs (P < 0.03). In conclusion, preterm growth-restricted lambs show resilience during perinatal asphyxia based on prolonged CBF maintenance and reduced need for chest compressions during resuscitation. However, CBF overshoot after ROSC may increase the risk of cerebrovascular injury in FGR.NEW & NOTEWORTHY Preterm growth-restricted lambs maintain carotid blood flow for longer than control lambs during asphyxia and have a lower requirement for chest compressions than control lambs during resuscitation. Preterm growth-restricted, but not control, lambs displayed an overshoot in carotid blood flow following return of spontaneous circulation.

Examining the Role of Emotion Differentiation on Emotion and Cardiovascular Physiological Activity During Acute Stress.

Emotion differentiation (ED) - the tendency to experience one's emotions with specificity - is a well-established predictor of adaptive responses to daily life stress. Yet, there is little research testing the role of ED in self-reported and physiological responses to an acute stressor. In the current study, we investigate the effects of negative emotion differentiation (NED) and positive emotion differentiation (PED) on participants' self-reported emotions and cardiac-mediated sympathetic nervous system reactivity (i.e., pre-ejection period) in response to a stressful task. Healthy young adults enrolled in a two-session study. At an initial session, participants completed a modified experience sampling procedure (i.e., the Day Reconstruction Method). At session 2, 195 completed the Trier Social Stress Test while cardiac impedance was acquired throughout. Linear regressions demonstrated that higher NED, but not PED, was associated with experiencing less intense self-reported negative, high arousal emotions (e.g., irritated, panicky) during the stressor (ß = - .15, p < .05) although people with higher NED also exhibited greater sympathetic reactivity (ß = .16, p < .05). In exploratory analyses, we tested whether the effect of NED on self-reported stress was mediated by the tendency to make internally focus (or self-focused) attributions about performance on the task but did not find a significant indirect effect (p = .085). These results both complement prior work and provide a more complex picture of the role of NED in adaptive responses to stressful life events, suggesting that people with higher NED may experience their emotions as more manageable regardless of their level of physiological arousal. Supplementary Information: The online version contains supplementary material available at 10.1007/s42761-023-00189-y.