Vagal Tone Research Articles

This study aims to explore the relationship between psychological resilience, vagal tone (heart rate variability [HRV]), and social adaptation, with a focus on the mediating role of HRV in the impact of psychological resilience on social adaptation. It also seeks to provide theoretical support for mental health interventions for left-behind children from a non-pharmacological perspective. This study employed a cross-sectional design with cluster sampling to select 2 middle schools in the urban-rural fringe of Zaoqiang County, Hebei Province, with a total of 312 left-behind children as the research subjects. Of these, 156 children were in the high-resilience group and 156 were in the low resilience group. The Youth Resilience Scale and the Adolescent Social Adaptation Scale were used to assess resilience and social adaptation. HRV was measured using portable equipment to assess high-frequency power (HF) and pNN50. Data analysis included descriptive statistics, analysis of covariance (ANCOVA), Pearson correlation analysis, mediation effect testing, logistic regression, and multiple linear regression. The high-resilience group showed significantly better HRV (HF and pNN50) and social adaptation compared to the low resilience group (all P <.001). Psychological resilience was significantly positively correlated with HRV (R = 0.59-0.81) and social adaptation (R = 0.95). Mediation analysis revealed that both HRV-HF and HRV-pNN50 partially mediated the relationship between psychological resilience and social adaptation (indirect effects = 0.25, 95% CI did not include 0). Logistic and multiple regression analyses further confirmed that psychological resilience (B = 2.12, P <.001) and HRV-pNN50 (B = 0.14, P = .005) were important positive predictors of social adaptation. Psychological resilience is significantly associated with better social adaptation among left-behind children, and this relationship may be partially explained by vagal tone (HRV), which plays a potential mediating role. This study provides physiological support for HRV-based non-pharmacological psychological interventions and holds significant theoretical and practical value.

Cardioneuroablation (CNA) is increasingly used worldwide in the treatment of functional bradyarrhythmia mediated by excessive vagal tone. However, a potential early or long-term complication is the development of postprocedural inappropriate sinus tachycardia (IST), which remains difficult to manage. Recent data suggest that sinus node (SN)-sparing hybrid ablation may offer promising long-term outcomes in patients with IST and postural orthostatic tachycardia syndrome (POTS). We present what is, to our knowledge, the first documented case of such a procedure performed for IST/POTS following an uncomplicated CNA for symptomatic vagally mediated sinus bradycardia (SB). The comprehensive treatment strategy included on-site cardiac rehabilitation, a home-based telerehabilitation program, and evaluation using cardiovascular autonomic functional testing (CAFT) and the Malmö POTS scoring system. We present a 33-year-old woman with a 6-month history of dizziness, palpitations, exercise and orthostatic intolerance, dyspnea, presyncope, and one syncope episode. Symptoms of IST (130-170bpm) appeared within 1 week after CNA for symptomatic SB. Despite the diagnosis of IST, CAFT have confirmed POTS. Other causes of sinus tachycardia (ST) were excluded according to guidelines. Nonpharmacological and pharmacological treatment proved ineffective. Following shared decision-making, the patient was referred for SN-sparing hybrid ablation with right-sided video-assisted thoracoscopic surgery (VATS). The patient subsequently participated in hybrid cardiac rehabilitation. At the 3-month follow-up, she was drug free and maintained a normal sinus rhythm. No evidence of bradycardia, IST/POTS, or vasovagal syncope (VVS), including CAFT, was documented during the follow-up. The serial MALMO POTS scoring system before and 3, 6, 9, 12 and 18 months after SN-sparing hybrid ablation demonstrated consistent and significant improvement, with scores decreasing from 46 to 13, 10, 6 and 12 points, respectively, values comparable to those observed in the healthy population. This is the first reported case of SN-sparing hybrid ablation for IST/POTS that developed after primary, uncomplicated CNA. Although not yet included in guidelines, the implementation of both procedures for cardiovascular autonomic dysfunction (CVAD) requires comprehensive and multidisciplinary heart team management. The MALMO POTS scoring system might be a useful tool for assessing CVAD before and after cardioneuromodulation procedures and further comprehensive evaluation.

Threat experiences and adolescent non-suicidal self-injury: Role of negative cognitive processing bias and vagal regulation.

Background: Postural Orthostatic Tachycardia Syndrome (POTS) is characterized by exaggerated heart rate increase upon standing, often accompanied by disabling symptoms such as palpitations, lightheadedness, fatigue and ‘brain fog’. As awareness of POTS has grown, its diagnosis has become more frequent; however, symptom overlap with other conditions such as orthostatic hypotension, vasovagal syncope, long-COVID, and anxiety raises the possibility of overdiagnosis and misclassification. Objective: To assess the frequency with which comprehensive autonomic testing confirms the diagnosis in patients referred with a presumptive clinical diagnosis of POTS Methods: The study population comprised 36 patients with presumed clinical diagnoses of POTS who were referred for autonomic testing between 2023 and 2025. All patients underwent standardized autonomic evaluation including active stand (AS), tilt table testing, Valsalva maneuver, and respiratory sinus arrhythmia. Laboratory confirmation of POTS was established by a baseline heart rate (HR) &gt;60 bpm, a HR increase ≥30 bpm (or ≥40 bpm in those &lt;20 years) on orthostatic challenge without hypotension and ultimate HR &gt;100 bpm within 10 minutes. Results: The cohort was predominantly female (94%) with a median age of 31 years [21–48]. Common presenting symptoms included lightheadedness (55%), palpitations (50%), syncope or near-syncope (30%), and fatigue (5%). Notably, 75% had documented anxiety or depression, 22% had Ehlers-Danlos Hypermobility syndrome, and 36% had prior COVID-19 infection. Autonomic testing confirmed a diagnosis of POTS in 11% (4/36) of patients. Normal autonomic testing was observed in 61% (22/36), and 27% (10/36) were reclassified with alternative diagnoses such as orthostatic hypotension or vasovagal syncope. The mean HR increase for POTS patients with AS was 34.33±25 bpm, the maximum HR achieved was 124±17 bpm, and the average orthostatic systolic blood pressure drop was 23±17 mmHg. Conclusion: In this cohort of patients referred for suspected POTS, only 11% met diagnostic criteria during autonomic testing, while the majority either had normal results or were reclassified with alternative autonomic conditions. These findings suggest that overdiagnosis of POTS is common in the referral population and highlight the role of formal autonomic testing to improve diagnostic accuracy. Testing may help prevent misdiagnosis, reduce unnecessary treatment, and support more precise assessment of prognosis.

Hypothesis: The concurrent implementation of time restricted eating (TRE) and a Mindfulness intervention yields superior outcomes in cardiovascular disease risk markers and stress response when compared with each intervention individually and control. Methods: We conducted an 8-week randomized controlled parallel arm pilot study evaluating TRE ( ad libitum eating between 12-8pm) and Mindfulness (“Mindfulness for Beginners” from Calm.com®) among young adults (18-39 years old) with obesity (BMI ≥ 30 and ≤ 49.9 kg/m 2 ) and a Perceived Stress Scale (PSS) ≥14 indicating moderate to severe perceived stress. Individuals were randomized to the following: TRE; Mindfulness; TRE&amp;Mindfulness; or Control. We explored changes in body weight, body composition, cardiovascular disease risk markers and stress. Results: Forty-three participants were randomized. Participants in the TRE group lost a mean -0.38 (95% CI -2.49, 1.73) kg; Mindfulness group lost a mean -2.10 (95% CI -5.21,1.02) kg; TRE&amp;Mindfulness group lost mean -1.89 (95% CI -4.32, 0.55) kg; and Control group lost a mean of -0.0.9 (95% CI -1.15,0.98) kg from baseline to post-intervention. The Mindfulness group showed the largest decrease in body fat mass (-2.20; 95% CI -4.64, 0.23 kg) while the TRE&amp;Mindfulness group demonstrated the largest decrease in visceral fat mass (-315.4; 95% CI -965.13, 334.33 g). For cardiovascular disease risk markers, the TRE&amp;Mindfulness group presented the largest decrease in diastolic blood pressure (-3.20; 95% CI -8.77, 2.37 mmHg) and a statistically significant decrease in heart rate (-1.93; 95% CI -3.70, -0.16 beats/min). For estimated heart rate variability (Root Mean Square of Successive Differences - RMSSD), all intervention arms demonstrated an increase in RMSSD, which is indicative of increased cardiac vagal tone, with the Mindfulness arm presenting the highest mean change from baseline (mean 7.61; 95% CI -1.5, 16.71 milliseconds). PSS scores decreased significantly within all arms except for Control. There was a statistically significant decrease in high sensitivity C-reactive protein from baseline to post-intervention in the TRE arm only (-1.58; 95% CI: -3.08, -0.09 mg/L). Conclusion: Results from this pilot study indicated a potential positive combined effect of TRE&amp;Mindfulness for improving anthropometric and cardiovascular disease risk markers measures among young adults with obesity and moderate to severe perceived stress compared to either intervention alone.

Intermittent high-grade atrioventricular (AV) block is a rare bradyarrhythmia in the young. In the absence of structural conduction system disease, it may result from heightened vagal tone. We present a unique case of a young adult with coexisting incessant atrial tachycardia (AT) and high-grade AV block, both of which resolved following catheter ablation targeting the AT arising in the left atrial appendage (LAA). Description of Case: A 25-year-old obese male with a 10-year history of exertional fatigue, palpitations, and presumed sinus tachycardia was referred for evaluation. Baseline ECG showed AT at 103 bpm with negative P waves in I and aVL. Ambulatory monitoring for 13 days revealed frequent tachycardia to a max of 181, average 99 bpm, but also 277 episodes of high-grade AV block up to 3 nonconducted P waves, including daytime pauses up to 2.5 seconds. An electrophysiology study for symptomatic “near incessant” AT demonstrated a focal AT arising from the base of the LAA with epinephrine infusion. Radiofrequency ablation at this site (6 lesions) rendered the AT non-inducible. AV nodal function and His-Purkinje conduction were normal. Follow-up ECGs and 2 week monitors immediately and at 6 months post-ablation revealed inappropriate sinus tachycardia (IST), and no AT nor AV block. Discussion: This case illustrates a rare co-occurrence of focal LAA AT, intermittent high-grade AV block, and IST, for which LAA ablation targeting AT also eliminated AV block. Whether all the findings are linked due to an autonomic mechanism or whether the AT was serendipitously located near ganglionated plexi that were responsible for the AV block is uncertain. These findings support the emerging role of autonomic modulation with ablation in the management of high-grade AV block in the young.

Understanding temper loss in young children: Interactions among family violence, respiratory sinus arrhythmia, and frontal asymmetry.

Newborn neurobehavior is a critical indicator of early childhood development. Therefore, we examined perinatal predictors of neurobehavioral patterns among healthy, medically low-risk infants. Participants include 385 mothers and infants. Self-reported emotion dysregulation and respiratory sinus arrhythmia (RSA) data were collected during the third trimester. Infant neurobehavior was measured approximately 24-h after birth (M = 3.61, SD = 8.39, range = 1-61 days) using the NICU Network Neurobehavioral Scale (NNNS). Latent profile analysis identified three NNNS profiles. Infants in the high-arousal, high-stress profile (P3) demonstrated more dysregulated neurobehavior than infants in the high-attention, moderate-regulation profile (P1) or the low-arousal, high-lethargy profile (P2). There were no differences between profiles on infant sex, head circumference, or APGAR scores. Differences in birth gestational age were minimal. Expectant mothers with lower emotion dysregulation were more likely to have infants in P3 than P2. Mothers with more flexible autonomic responses-RSA decreases to a stress task and better recovery-were more likely to have infants in P1 and P2 than P3. We successfully replicated low-risk NNNS profiles, suggesting that the NNNS is a reliable assessment tool for healthy, term infants. Our findings also underscore unexpected and varied associations between maternal emotional wellbeing and fetal development.

Cardiac vagal activity dynamics during anxiety induction and the effects of short-term biofeedback training.

IntroductionCardiovascular autonomic neuropathy (CAN) is a severe complication of diabetes that impairs the regulation of the cardiovascular system. This can cause hemodynamic instability, arrhythmias, and silent ischemia. Despite its clinical significance, routine testing is not widely implemented. Therefore, this study investigated the performance of a novel screening tool, the ProCVT smart-sheet, based on electrocardiography (ECG)-derived cardiac vagal tone (CVT), compared to standardized methods in type 2 diabetes (T2D).MethodsForty individuals with T2D (aged 45–75) with varying degrees of CAN and 20 age-matched controls were included in this cross-sectional study. Autonomic profiling included cardiovascular autonomic reflex tests, short-term CVT, 72-hour blood pressure monitoring, and three nights of home monitoring with the ProCVT smart-sheet. Receiver operating characteristics assessed the performance of long-term and short-term CVT to detect any, early-stage, and manifest CAN.ResultsA total of 164 recordings were obtained, with an average of 93% of each recording classified as very high signal quality before artifact removal. Short- and long-term mean CVT were the best-performing parameters, identifying any and manifest CAN with AUCs of 0.64–0.79. Suggested cut-offs were 2.7 linear vagal scale (LVS) units for short-term and 5.0 LVS for long-term recordings.ConclusionThe ProCVT smart-sheet offers a feasible, non-invasive alternative to traditional ECGs that rely on surface electrodes. CVT shows promise as a biomarker for identifying manifest CAN in T2D. However, long-term recordings of CVT were not superior to short-term recordings. Further research is warranted to assess its value in the detection of early-stage CAN.

Individualized paced deep breathing training with autonomic nervous function as rehab targets in patients with chronic heart failure: a randomized clinical trial

ABSTRACTAimOpioid‐induced respiratory depression (OIRD) is the primary cause of death in opioid overdose, resulting from both suppressed respiratory rhythm and increased airway and thoracic rigidity that compromise ventilation and resuscitation. While the effect(s) of opioids on central rhythm‐generating circuits are well documented, the mechanisms leading to airway obstruction remain poorly understood. Here, we investigated the hypothesis that enhanced vagal parasympathetic output contributes to fentanyl‐induced airway disruption.MethodsIn urethane‐anesthetized mice, diaphragm electromyography (EMG), respiratory airflow, and vagus nerve activity were recorded in‐vivo before and after intraperitoneal fentanyl administration (500 μg/kg). The effects of bilateral vagotomy, atropine administration, and intracisternal naloxone were evaluated to determine the contribution of vagal pathways and central opioid receptor mechanisms.ResultsFentanyl caused a characteristic slowing of respiratory rate accompanied by a compensatory increase in tidal volume, but also produced a transient delay between diaphragm activation and airflow onset, consistent with airway obstruction. This delay was abolished by bilateral vagotomy or atropine and reversed by intracisternal naloxone, implicating central vagal mechanisms. Vagal electroneurograms showed increased tonic multiunit activity and enhanced large‐amplitude single‐unit firing, particularly within efferent fibers, together with a loss of normal inspiratory phase‐locking. The magnitude of tonic vagal activation strongly correlated with the severity of airway disruption.ConclusionsFentanyl disrupts respiratory‐autonomic integration by enhancing parasympathetic vagal drive, producing a central, opioid receptor‐mediated mechanism of airway constriction. Targeting vagal pathways may therefore represent a promising adjunctive strategy for improving airway patency and ventilatory recovery during opioid overdose reversal.

Inflammatory bowel disease (IBD), comprising Crohn’s disease and ulcerative colitis, represents the two predominant clinical entities within this spectrum of gastrointestinal disorders. Current evidence indicates that the etiology of IBD is multifactorial, involving a complex interplay between host genetic susceptibility and environmental determinants. In recent years, non-pharmacological strategies such as physical exercise and vagus nerve stimulation have gained increasing attention as adjunctive therapeutic approaches. Vagus nerve stimulation has emerged as a promising therapeutic modality, particularly in conditions characterized by autonomic dysfunction and diminished vagal tone. Conversely, vagotomy, by disrupting vagal control, abolishes parasympathetic reflexes and may potentiate inflammatory responses and exacerbate IBD symptomatology under stress conditions. Physical exercise has likewise been investigated as a non-pharmacological intervention in Crohn’s disease and ulcerative colitis. Although the precise mechanisms remain to be fully elucidated, accumulating evidence suggests that skeletal muscle contractions promote the secretion of myokines, with recognized anti-inflammatory properties. These myokines act on the intestinal microenvironment, conferring protection against malignant transformation and modulating the composition and function of the gut microbiota. In this review, we critically examine the interplay between physical exercise, vagus nerve stimulation, and vagotomy in the pathophysiology and management of IBD, with particular emphasis on their immunomodulatory and therapeutic potential.

A 6-year-old spayed female Goldendoodle was presented as a referral for bradycardia and collapse. An electrocardiogram revealed a high-grade second-degree atrioventricular block (HG2AVB) with atrial flutter. The patient was hospitalized overnight with the intention of pacemaker placement the following morning. Following bolus administration of atropine and lidocaine to rule out high vagal tone, the patient was placed on an atropine continuous rate infusion (CRI) to increase heart rate overnight. This resulted in an acute onset of suspected delirium, which lasted several hours following cessation of the CRI. The patient proceeded with pacemaker placement the following day. No further neurological events were noted at 1 year after pacemaker placement. Atropine-associated delirium should be considered in any patient where high cumulative doses of atropine are being considered.

PurposeThe purpose of this study was to investigate vagal nerve function and correlation to CD4+ T-cell population in patients with neovascular age-related macular degeneration (nvAMD) and healthy individuals.MethodsThis study is a prospective case-control study including 36 patients with nvAMD and 40 healthy individuals. We measured the proxy of vagus nerve activity, the resting heart rate variability (HRV). Freshly sampled venous blood was prepared to measure CD4+ T-cell populations regulated by the vagal tone (regulatory T cells [Tregs], recently thymic emigrant Tregs, naïve Tregs, and effector memory T cells).ResultsCompared with healthy individuals, patients with nvAMD had significantly lower HRV (low frequency/high frequency [LF/HR] ratio, P = 0.037 and standard deviation [SD] ratio, P = 0.011), indicating impaired vagal function. HRV measures negatively correlated to the proportion of Tregs (square root of the mean squared difference of successive NN intervals [RMSSD], P = 0.046) and memory T cells (RMSSD, P = 0.046) in healthy individuals, suggesting an intact regulatory capacity. These correlations were not found in patients with neovascular AMD, suggesting an impaired vagus nerve-regulatory T cell axis. Patients with nvAMD had significantly higher Tregs (P = 0.0005), naïve Tregs (P = 0.016), and recent thymic emigrant Tregs (P = 0.015).ConclusionsVagal tone is impaired in patients with nvAMD which disharmonizes with increased Tregs in the systemic circulation. These altered regulators may be the key to increased systemic inflammation, present in patients with nvAMD.

Autonomic imbalance is a key driver of cardiovascular disease progression, arising from disrupted interactions between sympathetic and parasympathetic signaling. This review explores the molecular mechanisms underpinning autonomic dysfunction, emphasizing the roles of β-adrenergic receptor (βAR) signaling, cyclic AMP (cAMP) compartmentation, and cholinergic regulation. Dysregulated cAMP nanodomain signaling, βAR desensitization, impaired vagal tone, and maladaptive autonomic nerve remodeling collectively promote structural, electrophysiological, and functional deterioration. Advances in high-resolution imaging and molecular mapping have revealed previously unrecognized pathways governing second-messenger compartmentation and neuromodulatory feedback loops. These insights are driving the development of next-generation therapeutics designed to selectively restore autonomic balance. Promising strategies include isoform-specific phosphodiesterase (PDE) inhibitors, vagus nerve stimulation (VNS), and axonal modulation therapy (AMT), which target norepinephrine (NE) and acetylcholine (ACh) pathways while preserving physiological responsiveness. Integrating pharmacological, neuromodulatory, and molecular approaches represents an evolving frontier for cardiovascular therapeutics. Future strategies will benefit from precision mapping of autonomic circuits, patient-specific profiling, and optimization of therapeutic timing. By linking fundamental molecular signaling with translational advances, this review highlights opportunities to improve treatment precision and efficacy for autonomic dysfunction in cardiovascular disease.

Ventricular arrhythmias are associated with sympathoexcitation and increased co-transmitter neuropeptide Y (NPY) levels. Vagal nerve stimulation (VNS) has been reported to decrease release of norepinephrine, while NPY has been reported to decrease acetylcholine release ex-vivo by binding Y2 receptors on parasympathetic nerves. We hypothesized that VNS reduces NPY levels via a muscarinic receptor (MR) mediated mechanism in-vivo and that, in turn, blockade of presynaptic Y2R can further enhance the effects of VnS and decrease the effects of sympathoexcitation by increasing vagal tone. Single-cell RNA sequencing of rat stellate ganglia and immunohistochemistry were performed and identified the M2 receptor as the predominant subtype on NPY-expressing sympathetic neurons. Ex-vivo field stimulation of rat stellate ganglia, before and after application of carbamylcholine (CCH; muscarinic agonist) and atropine (muscarinic blocker) showed that CCH reduced NPY release, while the addition of atropine increased NPY levels. Subsequently, to validate ex-vivo findings, in-vivo effects of VNS during bilateral stellate ganglia stimulation (BSS) on NPY release with and without atropine were evaluated and hemodynamic and electrophysiological parameters, including ventricular activation recovery intervals (ARIs, a surrogate for action potential duration), and real-time in-vivo interstitial NPY levels were measured. Post-atropine, suppression of NPY by VNS was significantly diminished, confirming a muscarinic receptor mediated mechanism in-vivo. Finally, in a porcine model in-vivo, effects of VNS on NPY levels and of the Y2R blocker, BIIE0246, during BSS were tested. These studies demonstrated that Y2R blockade significantly reduced the cardiac effects of BSS on systolic pressure, inotropy, and ARIs. While the ventricular effects of VNS, including suppression of interstitial NPY levels, hemodynamic, and electrophysiological parameters were enhanced by Y2R blockade, heart rate remained unaffected. Vagal activation reduces interstitial NPY levels via a presynaptic sympathetic M2R mechanism.Y2R inhibition reduces effects of sympathoexcitation and enhances the effects of VNS in-vivo. These findings highlight the role of NPY in sympathovagal crosstalk and suggest Y2R as a potential target to modulate autonomic balance.

The white coat functions as medicine’s most powerful symbol, yet its role as both sacred vestment and neurobiological disruptor remains critically underexamined. While conventional analysis focuses on the “white coat effect” as simple anxiety response, deeper investigation reveals systematic disruption of healing networks at neurological, psychological, and spiritual levels. To expose the white coat as false sacred object that fundamentally compromises therapeutic relationships through neurobiological disruption, cultural colonization, and the perpetuation of harmful medical hierarchies. This heretical analysis challenges medicine’s denial of its ritual nature while proposing revolutionary alternatives. This radical theological and neuroscientific critique synthesizes findings from functional neuroimaging, autonomic physiology, mirror neuron research, and epigenetic studies, integrated with phenomenological analysis and clinical experience. The investigation draws upon Kabbalistic concepts, postcolonial theory, and embodied theology to reveal medicine’s hidden religious dimensions. Neuroimaging reveals that white coats simultaneously activate nociceptive (pain) networks while hijacking placebo responses, creating neurological double-binds that prevent authentic healing states. The garment disrupts the default mode network essential for selfhood, suppresses vagal tone necessary for parasympathetic healing, and may create lasting neuroplastic changes resembling trauma responses. These effects operate below conscious awareness, creating “iatrogenic neural injury” that compounds across clinical encounters. Cultural analysis reveals the coat as instrument of colonial domination, enforcing Western medical hegemony while excluding traditional healing wisdom. The white coat constitutes a systematic barrier to authentic therapeutic relationship, functioning as both liturgical costume in medicine’s denied religious system and neurobiological disruptor of healing networks. Revolutionary “therapeutic undressing” the contextual abandonment of formal medical attire represents necessary iconoclasm against false sacred authority. Post-coat medicine would prioritize vulnerable competence over performative authority, enabling the neural synchrony and spiritual presence essential for genuine healing encounter.

Emotion regulation begins to develop early in childhood and has important implications for optimal development. Individual regulatory factors, such as effortful control and baseline respiratory sinus arrhythmia (bRSA), have been demonstrated as markers that influence the development of emotion regulation across childhood. The aim of this present study was to examine the stability and the direct and indirect associations of these regulatory factors from early to middle childhood in predicting emotion regulation in late childhood. Children (n = 230) visited the lab when they were 3, 6, and 9 years old. At ages 3 and 6, mothers reported on child effortful control, and bRSA was assessed, and at age 9, mothers reported on child emotion regulation. Using cross lagged path modeling, we demonstrated that both effortful control and bRSA exhibited stability from early to middle childhood. Our results highlighted two distinct longitudinal pathways to emotion regulation: indirect effects of effortful control and bRSA at age 3 on emotion regulation at age 9, mediated through their respective measures at age 6. Cross-lagged mediation paths and alternate models, however, did not support the roles of effortful control and bRSA at age 6 as mediators in the relationship between each other's early measures and later emotion regulation. In other words, neither effortful control nor bRSA at age 6 indirectly predicted emotion regulation at age 9 through each other. These results are discussed in light of their clinical and prevention applications, as well as the developmental trajectories of these regulatory factors across childhood. (PsycInfo Database Record (c) 2025 APA, all rights reserved).

Background: Persistent symptoms after COVID-19, known as long COVID, may involve cardiac and autonomic dysfunction. However, there is limited data on cardiovascular alterations, body composition changes, and lingering symptoms in young adults recovering from mild COVID-19, as well as how these factors affect heart rate variability (HRV). Considering these gaps, this study examines HRV parameters, investigates alterations in body composition, and characterizes the persistence of symptoms approximately one month after mild Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection in young adults, in comparison with a group of healthy controls. Methods: This cross-sectional observational study assessed participants diagnosed with mild COVID-19 one-month post-infection at the University Hospital of Federal University of São Carlos. Assessments included: (I) clinical evaluation; (II) RR interval (iRR) recording at rest and during the respiratory sinus arrhythmia maneuver (M-RSA) using a heart rate monitor with an elastic transmitter band (Polar H10, Polar, Finland); and (III) body composition analysis via bioelectrical impedance (InBody® 720, Biospace Co. Ltd., South Korea). HRV indices were derived using Kubios software. Results: A total of 62 participants were assessed – 31 in the COVID-19 group and 31 in the control group. Participants with prior mild COVID-19 had significantly higher body fat percentages and a higher prevalence of persistent symptoms, such as fatigue and dysgeusia (p &lt; 0.05). HRV analysis showed lower root mean square of successive differences (rMSSD) values in the COVID-19 group both at rest (25.49 ± 15.45 ms) and during M-RSA (15.88 ± 0.10 ms) (p &lt; 0.0001), indicating reduced parasympathetic activity. In addition, significant negative correlations were found between total body fat mass and mean iRR (p = 0.009; r = –0.32), as well as between fat mass, body fat percentage, and rMSSD at rest (p = 0.02; r = –0.28). Conclusion: Young adults recovering from mild COVID-19 demonstrate impaired autonomic heart rate control, persistent post-infection symptoms, and increased body fat. These findings suggest subtle but detectable cardiovascular and metabolic alterations, even in mild cases of COVID-19.