The COVID-19 pandemic, caused by SARS-CoV-2, has had profound global impacts since its emergence in late 2019. Whilst acute symptoms are well-documented, increasing evidence suggests long-term consequences extending beyond the acute phase. This study aimed to investigate the long-term cognitive and autonomic effects of COVID-19 in young adults.

We conducted a cross-sectional study comparing young adults with a history of COVID-19 (n = 34) to matched controls (n = 34). Cognitive function was assessed using the Sternberg Task, Stroop Task, and Go/No-Go Task (GNG). Autonomic function was evaluated using heart rate variability (HRV) parameters.

The average time interval between COVID-19 infection and testing was 28.2 months. The COVID-19 group showed significantly increased reaction time in the 2-item absent condition (p = 0.044) and errors in the 4-item present condition (p = 0.012) of the Sternberg Task and increased neutral response time (p = 0.028) and the normalized time for completing the task (p = 0.022) in the Stroop Task. No significant differences were found in the GNG Task. HRV parameters did not differ significantly between groups, although trends toward higher overall HRV were observed in the COVID-19 group.

Young adults who had COVID-19 infection approximately 28 months ago show minimal long-term impact on cognitive function and autonomic regulation. However, subtle cognitive inefficiencies persist, particularly in working memory and executive function tasks. These findings suggest a generally favorable long-term prognosis for young adults following mild to moderate COVID-19 but highlight the need for further investigation into persistent subtle cognitive effects and autonomic effects.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia characterized by consistently irregular atrial and ventricular contractions. Heart rate variability (HRV) refers to the changes in the intervals between consecutive ventricular heartbeats. In sinus rhythm, HRV may be subtle and is quantitatively reflecting the dynamic interplay of the cardiac autonomic nervous system, which plays a crucial role in the onset, development, and maintenance of AF. HRV metrics, consisting of time-domain, frequency-domain, and nonlinear parameters, have been verified to vary significantly before and after AF episodes, and AF treatment-related procedures such as electrical cardioversion, ablation, and surgery of AF. Therefore, HRV may serve as a digital biomarker in predicting AF risk in long-term and acute risk period, identification of patients with AF risk in sinus rhythm and recurrence risk stratification after procedures. HRV in AF rhythm, predominantly influenced by dynamic atrioventricular node conduction under the onslaught of irregular atrial impulses, shows a huge disparity compared to that in sinus rhythm. Despite this, HRV in AF rhythm still provides valuable prognostic information, as reduced HRV may indicate a poor heart function and outcomes in patients with AF. Despite being influenced by lots of variables, HRV can still serve as an independent digital biomarker in the clinical management of AF throughout its entire lifecycle.

Cancer remains a significant global health challenge, with its progression shaped by complex and multifactorial mechanisms. Recent research suggests that the vagus nerve could play a critical role in mediating communication between the tumor microenvironment and the central nervous system (CNS). This review highlights the diversity of vagal afferent receptors, which could position the vagus nerve as a unique pathway for transmitting immune, metabolic, mechanical, and chemical signals from tumors to the CNS. Such signaling could influence systemic disease progression and tumor-related responses. Additionally, the vagus nerve's interactions with the microbiome and the renin-angiotensin system (RAS)-both implicated in cancer biology-further underscore its potential central role in modulating tumor-related processes. Contradictions in the literature, particularly concerning vagal fibers, illustrate the complexity of its involvement in tumor progression, with both tumor-promoting and tumor-suppressive effects reported depending on cancer type and context. These contradictions often overlook certain experimental biases, such as the failure to distinguish between vagal afferent and efferent fibers during vagotomies or the localized parasympathetic effects that cannot always be extrapolated to the systemic level. By focusing on the homeostatic role of the vagus nerve, understanding these mechanisms could open the door to new perspectives in cancer research related to the vagus nerve and lead to potential therapeutic innovations.

Depressive symptoms are associated with alterations in central and autonomic nervous system activity, including misperception of bodily activity (e.g., low interoception), somatic symptoms and decreased vagally mediated heart rate variability (vmHRV). However, there is a lack of studies that examine both perception of bodily activity and autonomic function in depression. The present study investigated the association between interoception, vmHRV, and subclinical depressive symptoms.

Eighty-eight students were enrolled and vmHRV was calculated from a 5-minute resting electrocardiogram. Interoceptive accuracy (heartbeat tracking task; heartbeat discrimination task), interoceptive sensibility (Body Perception Questionnaire), and depressive symptoms (Depression, Anxiety and Stress Scale - 21 Items) were assessed.

Interoceptive accuracy and sensibility positively correlated with vmHRV and negatively correlates with depressive symptoms. Cluster analysis performed on vmHRV, interoceptive accuracy, and sensibility provided two clusters: the first characterized by a pattern of low interoceptive accuracy, sensibility, and decreased resting vmHRV, the second characterized by an opposite pattern. Regression analyses showed that the first cluster was characterized by significantly higher depressive symptoms compared to the second (β = 1.97; pBonferroni = 0.04), even after controlling for sex, BMI, anxiety, and stress levels.

Subclinical depressive symptoms are associated with a consistent impairment in the perception and interpretation of bodily activity and altered regulatory function of the autonomic nervous system. The present results suggest that the alteration of brain-body communication could be involved in subclinical depressive symptoms. Early identification of such alterations could help with targeted preventive strategies.

Previous observational studies have suggested a potential association between heart rate variability (HRV) and cerebrovascular disease. However, a causal relationship between the two has not yet been established.

The objective of this study was to determine the causal relationship between heart rate variability (HRV) and stroke through a two-sample Mendelian randomization analysis.

Three genetic predictive traits of heart rate variability standard deviation of the normal-to-normal interbeat intervals (SDNN), the root mean square of the successive differences of interbeat intervals (RMSSD), and the peak-valley respiratory sinus arrhythmia or high-frequency power (pvRSA/HF) were collected from publicly available genome-wide association studies (IEU Open GWAS). Additionally, stroke (STROKE) and its sub-types: ischemic stroke (IS), cardioembolic stroke (CES), small vessel stroke (SVS), large artery stroke (LAS), lacunar stroke (LS), and intracerebral hemorrhage (ICH)were also from this database. Two-sample Mendelian randomization and various sensitivity analyses were employed to explore the causal relationship between HRV and stroke and its sub-types. Inverse-variance weighted (IVW) was the primary method via which Mendelian randomization (MR) was conducted, and for the causal estimates determined by IVW, a series of sensitivity analyses were performed to assess the reliability of the results. (i) Four additional MR methods that complement IVW were utilized; (ii) Cochran's Q-test was employed for assessing heterogeneity; (iii) the MR-Egger's intercept test and MR-PRESSO global test were applied to assess the level of multivariate validity, and (iv) the "leave-one-out" method was utilized to assess stability.

Two of the genetically predictive traits of HRV (standard deviation of the normal-to-normal interbeat intervals [SDNN]) and (the peak-valley respiratory sinus arrhythmia or high-frequency power [pvRSA/HF]) were associated with IS (OR 0.63,95 %CI 0.42-0.95, P = 0.03), (OR 0.84, 95 %CI: 0.72-1.00; P = 0.04), and LAS (OR 135.93, 95 %CI: 7.19-2569.22; P = 0.05), (OR 1.42, 95 %CI: 1.02-1.98; P = 0.04) were significantly correlated in addition to (pvRSA/HF) and LS (OR 0.84, 95 %CI: 0.72-1.00; P = 0.04) were also causally associated. Neither was causally associated with other sub-types of stroke or hemorrhagic stroke. Another genetically predictive trait of HRV (the root mean square of the successive differences of interbeat intervals [RMSSD]) was not found to be significantly associated with stroke, its subtypes, or Intracerebral hemorrhage.

This study provides genetic evidence supporting the causal effects of HRV (SDNN) on ischemic stroke (IS) and large artery stroke (LAS), as well as (pvRSA/HF) on ischemic stroke (IS), large artery stroke (LAS), and lacunar stroke (LS).

Sleep is a complex physiological state characterized by distinct stages, each exhibiting unique electroencephalographic patterns and physiological phenomena. Sleep research has unveiled the presence of intricate cyclic-periodic phenomena during both non-rapid eye movement and rapid eye movement sleep stages. These phenomena encompass a spectrum of rhythmic oscillations and periodic events, including cyclic alternating pattern, periodic leg movements during sleep, respiratory-related events such as apneas, and heart rate variability. This narrative review synthesizes empirical findings and theoretical frameworks to elucidate the dynamics, interplay and implications of cyclic-periodic phenomena within the context of sleep physiology. Furthermore, it invokes the clinical relevance of these phenomena in the diagnosis and management of sleep disorders.

Identification and continuous monitoring of relaxation/stress level through easily measurable physiological signals has become an urgent need. Relaxation/stress is mainly mediated by autonomic nervous system (ANS) which can hardly be noninvasively-measured, but can be reflected in heartbeat and respiration because the human body is a strongly coupling system. However, existing metrics based on heart rate and respiration present low accuracy for relaxation assessment. Our main objective is to propose a reliable metric for relaxation/stress monitoring.

By improving the quantification of Respiratory Sinus Arrhythmia (RSA) and introducing the phase difference between heart rate and respiration, we construct a new metric called Heart-Breath Coherence (HBC) based on heart rate and respiration collected synchronously. Firstly, its practical performance is examined by the multi-scenario experiment with 34 volunteers, which contains four scenarios: smelling odors, listening to sounds, emotional evocations, and watching videos. Then, the synthetic data are employed to test the precision of RSA quantification by HBC.

Comparing with 26 existing metrics, HBC shows the highest accuracy 91% (p-value 0.01 and effect size 0.8) in the multi-scenario experiment. The introduction of magnitude of phase difference is crucial for the success. Synthetic studies show that HBC improves the RSA quantification with the minimum error comparing to other metrics.

HBC is a reliable metric for relaxation/stress monitoring and RSA quantification.

HBC can provide the real-time monitoring of relaxation/stress level and reflect the ANS balance, which is meaningful for healthcare and may be used for psychology and clinical practice.

To assess the effects of two different body positions on the cardiovascular autonomic profile during a single bout of exercise in patients with postural orthostatic tachycardia syndrome (POTS).

Thirteen patients with POTS and thirteen healthy controls (C) participated in the study. ECG, respiration, beat-by-beat arterial pressure and O2 consumption (VO2) were continuously recorded while on a cycle ergometer in supine and upright positions, before and during exercise (6 min, 50 Watts). Spectral analysis of RR intervals and systolic arterial pressure (SAP) variability provided indexes of cardiac sympathovagal interaction (LF/HF ratio), cardiac vagal modulation (HFRR, high-frequency component of RR variability, ~ 0.25 Hz), sympathetic vasomotor control (LFSAP, low-frequency component of SAP variability, 0.1 Hz) and baroreflex sensitivity (BRS, αLF).

While supine, patients with POTS showed lower HFRR and αLF, greater heart rate (HR), LF/HF and LFSAP, compared with C, suggesting cardiovascular sympathetic over-activity and reduced BRS. While sitting upright, POTS showed greater HR and reduced HFRR and αLF compared with C. During supine exercise, SAP, HR, LF/HF increased and HFRR and αLF decreased similarly in POTS and C. In POTS, upright sitting exercise was associated with slightly higherV ˙ O 2 , a greater increase in HR whereas LFSAP was lower than in C.

Upright exercise was associated with excessive enhancement of HR and a blunted increase of the sympathetic vasomotor control in POTS. Conversely, supine exercise-induced hemodynamic and autonomic changes similar in POTS and C, thus making supine exercise potentially more suitable for physical rehabilitation in POTS.

Acute traumatic coagulopathy (ATC) is a well-described phenomenon known to begin shortly after injury. This has profound implications for resuscitation from hemorrhagic shock, as ATC is associated with increased risk for massive transfusion (MT) and mortality. We describe a large-data machine learning-based Coagulation Risk Index (CRI) to test the early prediction of ATC in bleeding trauma patients.

Coagulation Risk Index was developed using continuous vital signs (VSs) available during the first 15 minutes after admission at a single trauma center over 4 years. Data to compute the CRI were derived from continuous features of photoplethymographic and electrocardiographic waveforms, oximetry values, and blood pressure trends. Two groups of patients at risk for ATC were evaluated: critical administration threshold and patients who received an MT. Acute traumatic coagulopathy was evaluated in separate models and defined as an international normalized ratio (INR) >1.2 and >1.5 upon arrival. The CRI was developed using 2 years of cases for training and 2 years for testing. The accuracy of the models is described by area under the receiver operator curve with 95% confidence intervals.

A total of 17,567 patients were available for analysis with continuous VS data, 52.8% sustained blunt injury, 30.2% were female, and the mean age was 44.6 years. The ability of CRI to predict ATC in critical administration threshold patients was excellent. The true positive and true negative rates were 95.6% and 88.3%, and 94.9% and 89.2% for INR >1.2 and INR >1.5, respectively. The CRI also demonstrated excellent accuracy in patients receiving MT; true positive and true negative rates were 92.8% and 91.3%, and 100% and 88.1% for INR >1.2 and INR >1.5, respectively.

Using continuous VSs and large-data machine learning capabilities, the CRI accurately predicts early ATC in bleeding patients. Clinical application may guide early hemostatic resuscitation. Extension of this technology into the prehospital setting could provide earlier treatment of ATC.

Diagnostic Tests/Criteria; Level III.

Normotensive African Americans (AAs) show attenuated vascular responses and reduced nitric oxide (NO) bioavailability compared to European Americans (EAs). Few studies have used diverse measures to examine differences in macrovascular function and structure in individuals with a family history of CV disease (CVD). We assessed 150 AAs (Mage, 23.57 ± 2.73 yr) and 104 EAs (Mage, 22.70 ± 2.86) with a confirmed family history of CVD. Age, sex, body mass index, and father's education were used as covariates, hemodynamic measures (heart-rate [HR], stroke volume [SV], cardiac output [CO], total peripheral resistance [TPR], mean arterial pressure [MAP], systolic and diastolic blood pressure [SBP/DBP], and pulse pressure [PP]), high-frequency heart-rate variability [HF-HRV], and endothelial-dependent arterial dilation [EDAD] were the dependent variables. AA's had lower EDAD (11.64 vs. 13.20%) and higher HF-HRV (7.31 vs. 7.11 ms2), TPR (17.60 vs. 15.93 mmHg/L/min), TPI (33.72 vs. 30.09 mmHg/L/min/m2), MAP (83.60 vs. 78.36 mmHg), SBP (115.44 vs. 110.23 mmHg), and DBP (65.35 vs. 60.57 mmHg). Lower EDAD alongside no ethnic differences in PP, HR, or SV suggests early onset endothelial dysfunction (lower NO availability) rather than inherited pathophysiological structural characteristics (arterial stiffness) in AAs. Future prospective studies are needed and should consider measures of sympathetic activity and potential moderators, including discrimination.

Increased beat-to-beat QT interval variability (QTV) in the electrocardiogram is strongly associated with ventricular arrhythmias and sudden cardiac death, yet its origins remain poorly understood. While heart rate variability decreases with deteriorating cardiac health, QTV increases, suggesting distinct underlying mechanisms. The stochastic nature of ion channel gating is a potential source of cardiac variability. However, the law of large numbers suggests that, with billions of channels in the heart, this stochasticity should be minimized. In this study, we tested the hypothesis that dynamical instability amplifies stochastic ion channel fluctuations, leading to increased action potential (AP) variability. Using a mathematical model of ventricular myocytes, we investigated the relationship between AP variability and voltage instability. Our results demonstrate that stochastic gating alone cannot cause large AP variability, but dynamical instability significantly amplifies this variability. We found a positive correlation between voltage instability, indicated by the slope of the AP duration restitution curve, and AP duration variability. Notably, the largest variability occurred at the onset of alternans when considering every other beat. These findings provide a mechanistic explanation for increased QTV in pathological conditions and suggest that measuring QTV using every other beat may predict the onset of alternans and severity of alternans. Our study highlights the critical role of dynamical instability in cardiac electrical variability and offers new insights into the mechanisms underlying arrhythmogenesis.

Acute exercise can transiently enhance cognitive flexibility. The cognitive demand of firefighters makes it relevant to understand if on-shift exercise could produce similar improvements in cognitive performance during subsequent occupational tasks. Metrics of heart rate variability (HRV), such as time- and frequency-domain outcomes, may shed light upon the influence exercise has on cognition, as they discern information related to cardiac autonomic (sympathetic/parasympathetic) function. We aimed to determine if acute resistance and aerobic exercise impact cognitive flexibility during occupational tasks and its relation to HRV.

32 participants completed a baseline Wisconsin Card Sorting Task (WCST) and three experimental trials: resistance exercise (RE), aerobic exercise (AE), or a rested control (CON). An occupational task assessment (OTA) including four rounds of 10 deadlifts and a 0.15-mile sandbag carry in an environmental chamber (35 °C/50% humidity) was completed after each trial. The second round was followed by the WCST. Repeated measures ANOVAs were used to analyze differences by condition.

For the WCST, total, perseverative, and non-perseverative errors did not differ (ps > 0.39). Time-domain HRV metrics were not different (ps > 0.05). All frequency-domain metrics, other than low-frequency power, were not different (ps > 0.24). Low-frequency power was lower based on condition (p = 0.03). Post hoc analysis showed low-frequency power was lower following AE compared to RE and CON.

Results suggest an acute bout of on-shift aerobic or resistance exercise may not impact cognitive flexibility during subsequent simulated occupational tasks, despite depressed metrics of heart rate variability following aerobic exercise.

The prognostic significance of vagal nerve (VN) activity, as measured by heart rate variability (HRV) in cancer patients remains a subject of debate. The aim of this meta-analysis was to evaluate the association between various HRV parameters and cancer prognosis.

We conducted an extensive search of the PubMed, Embase, Cochrane, and Web of Science databases and compared the overall survival (OS) of cancer patients with high and low HRV. The data type was unadjusted hazard ratio (HR). Random or fixed-effects models were used to calculate the pooled HR along with the 95% Confidence Interval (CI). We used funnel plot analysis to evaluate potential publication bias.

A total of 11 cohort studies were included with 2539 participants. The methodological quality of the included studies is generally high. Compared with low standard deviation of normal-to-normal intervals (SDNN) group, higher SDNN was a protective factor for OS in patients with cancer (I2 = 66%, HR = 0.59, 95% CI: 0.46-0.75, P < 0.0001). Compared with low root mean square of successive differences (RMSSD) group. The prognostic value of RMSSD did not reach statistical significance (I2 = 0%, HR = 0.85, 95% CI: 0.70-1.03, P = 0.11). Among the frequency domain indicators, higher high-frequency power HRV (HF-HRV) and low-frequency power HRV (LF-HRV) were associated with significantly longer overall survival compared to the low HF-HRV and LF-HRV groups (I2 = 6%, HR = 0.59, 95% CI: 0.43-0.80, P = 0.006 and I2 = 74%, HR = 0.45, 95% CI: 0.22-0.93, P = 0.03). In the nonlinear indicators, higher maximal diagonal line length (Lmax), mean diagonal line length (Lmean), percent of recurrence (REC), and determinism (DET) were associated with poorer tumor OS. The funnel plot shows that there is no publication bias in the study.

The findings of this study demonstrate that HRV parameters, particularly SDNN, HF-HRV, and nonlinear indices, exhibit predictive value for prognosis in cancer. Furthermore, it can be inferred that elevated VN activity may predict prolonged survival outcomes. However, these findings should be interpreted with caution due to the heterogeneity observed across included studies. Future research should prioritize prospective studies with standardized measurement protocols to validate these associations.

Relations between load and acute psychophysiological responses have been widely studied in football. However, due to the large heterogeneity in contexts, operationalization, and results, the direction and strength of these relations remain unclear. In this meta-analysis, we examine the relation between load and typical acute (i.e. within one week) responses - wellbeing, recovery, and heart rate measures - in football players from all football codes (soccer, rugby, futsal, American football, and Australian rules football). We consulted PubMed, Web of Science, and CINAHL up to the 19th of June 2024, and included 62 articles and 1,474 participants in the meta-analysis. Subsequently, we estimated 12 meta-analysis models and applied meta-regression models to explore the influence of several moderators. Significant relations were found between load and overall wellbeing (r = -0.33 [95%CI: -0.48; -0.19]), muscle soreness (r = -0.36 [95%CI: -0.49; -0.24]), fatigue (r = -0.41 [95%CI: -0.56; -0.26]), sleep quality (r = -0.21 [95%CI: -0.31; -0.10]), and stress (r = -0.16 [95%CI: -0.26; -0.06]). Given the high risk of bias, inconsistency (wide prediction intervals), and imprecision, the certainty in these findings based on the GRADE assessment is very low. Additionally, the high risk of bias scores indicates that the overall quality of the included studies is low. In conclusion, this meta-analysis provides comprehensive information on the acute responses of the athlete to load, and directions for improvement of the quality of future studies.

Cardiovascular Autonomic Neuropathy (CAN) is one of the most devastating complications of Diabetes Mellitus (DM) and presents high morbidity and mortality. Its association with diabetic kidney disease (DKD) worsens the condition even further. CAN diagnosis remains a challenge and is being based on reflex tests which are laborious, risky and difficult to perform. Heart Rate Variability (HRV) tests has been suggested as having high utility in diagnosing CAN, but this issue remains controversial. The aim is to evaluate the sensitivity and specificity of HRV tests to diagnose CAN in patients with type 2 diabetes mellitus (T2DM) and DKD with severely increased albuminuria. This is a cross-sectional study in patients with T2DM and DKD with severely increased albuminuria. A total of 48 subjects were recruited and underwent laboratory and neuropathy assessment. The diagnosis of CAN was first confirmed in 75% (36/48) of patients based on cardiovascular autonomic reflex tests (CARTs). HRV tests (VLF, LF, TP and SDNN) differed between groups with and without CAN (212 vs. 522 ms2, p = 0.024; 57 vs. 332 ms2, p = 0.025; 359.5 vs. 2733 ms2, p = 0.007; 20 vs. 48 ms, p = 0.012), respectively. The best cut-off points based on ROC curve were < 1,117 ms2, < 152.5 ms2, < 1,891 ms2 and < 46.5 ms, respectively. VLF and TP reached highest sensitivity values (97% and 92%) and F1 Score of 90%, while LF had best specificity (75%) and TP had best accuracy (85%). Our best model of serial algorithm using VLF as first screening test and TP in sequency obtained a sensitivity of 97% and accuracy of 90%, reducing in 90% the need to perform CARTs. Our findings suggest that it is possible to achieve high sensitivity and accuracy using an algorithm with VLF and TP parameters analyzed in series. It could enable a simpler and early diagnosis, avoiding CARTs complications.

We conducted a study in an ecological setting to evaluate the heart rate variability (HRV) of expert communicators during a live national primetime video interview. The study involved 32 expert science communicators, all with mid- to long-term experience in public speaking and outreach work, who were evaluated by an external jury to assess their communication skills. Prior to the experiment, participants completed an online survey to gather socio-demographic data, work-related information, and psychological profiles. The six indices of communication abilities assessed by jury were: Interest, Agreement, Engagement, Authoritativeness learning, and Clarity. HRV acquisitions were divided into three phases: baseline pre-interview, during the interview, and another baseline recording after the interview. Science communicators were characterized by high levels of self-esteem and prosociality, which were positively correlated with communication indices and inversely correlated with age. Evaluation of physiological responses showed that the total power and low-frequency components of HRV were significantly higher in the post-interview phase compared to both the interview and pre-interview phases. However, when we divided the entire group according to high and low Authoritativeness and Clarity indices, significant interactive effects were detected. Indeed, for the low Authoritativeness and Clarity subgroups, significant differences among all phases were observed, with total power decreasing from the pre-interview to the interview phase and increasing in the post-interview phase. This indicates a clear pattern of stress response and recovery. In contrast, the high Authoritativeness and Clarity subgroup showed less variation across phases, suggesting better stress regulation or less perceived stress during the interview. We provided the psychophysiological basis of science communication expertise that can affect the control of stress regulation during public speaking.

IntroductionEmpathetic end-of-life (EOL) communication is important for high quality pediatric patient and family outcomes. Trainees may have limited exposure and training in caring for patients at EOL which may impact communication-related stress. This study had 2 aims: (1) describe pediatric resident physician EOL exposure and training (2) measure objective and subjective stress during simulated critical communication encounters and the impact of prior communication training/exposures on stress responses.MethodsWe performed a prospective, pilot observational cohort study measuring physician exposure to caring for patients/families at EOL and simulated communication stress. Simulated stress was measured subjectively using the state-trait anxiety inventory (STAI) and objectively using heart rate variability (HRV) during a communication training intervention.Results85.7% (18/21) of residents reported seldom/never caring for patients at EOL and universally felt ill-prepared to provide care. Subjective and objective stress increased when directly communicating with the simulated parent/patient actor compared to baseline in all HRV domains. Residents with limited exposure to patients/families at EOL had a smaller stress response than those who cared for a substantial number.ConclusionsPediatric residents report limited opportunities to communicate with patients/families at EOL, which may impact stress responses when communicating life-altering news to families. Simulated communication encounters can be designed to evoke subjective and objective stress which can be measured using novel technology and may help address limited EOL opportunities.

Maternal mental health conditions significantly contribute to pregnancy-related mortality in the United States. Approximately 20-25% of postnatal women exhibit symptoms of depressive and anxiety disorders. Mental health is influenced by stress, which affects mood, cognition, and behavior. Heart rate variability (HRV), the time interval between consecutive heartbeats, is a physiological marker for assessing stress levels, providing critical insights into the body's autonomic responses. Wearable devices measuring HRV offer a non-invasive method to monitor stress and mental health, enabling early detection of maternal stress dynamics to facilitate timely interventions. In this scoping review, we aimed to capture the current state of science on two areas of focus: (1) utilization of wearable technology for HRV monitoring in pregnant and postpartum women, (2) findings from these perinatal HRV studies, including observed HRV trends throughout pregnancy and postpartum, as well as the association between HRV, perinatal stress, and mental health. The six included perinatal HRV studies employed five fitness tracking wearables, utilizing either periodic or continuous 24-h monitoring. Findings include evidence that HRV declines during pregnancy, with a return to normal levels postpartum. Associations between HRV and stress were inconsistent across studies, with some demonstrating correlations and others reporting no relationship. Postpartum HRV measurements effectively differentiated between women with postpartum depression (PPD) versus those with adjustment disorder (AJD), demonstrating high diagnostic accuracy. In this scoping review, HRV shows promise as a stress biomarker among pregnant/postpartum people, although more work is needed to standardize optimal methods of wearable HRV measurement in this population.

BackgroundExamining the restorative effects of indoor nature exposure that can be controlled through management and design in work settings is crucial for public health. However, concerns about the external validity of existing findings persist due to insufficiency of studies with ecologically sound experimental designs.ObjectiveThrough an experiment that prioritized higher ecological validity, this study aimed to explore the effects of working in an office room vegetated with green plants on employees' physiological and psychological well-being, and their attentional performance.MethodsThis controlled experimental study employed a crossover design in real-life work environments, involving 40 working individuals. It assessed changes in perceived fatigue, psychological and physiological stress, and attentional performance after individual work in either a vegetated or plant-free office room, with other environmental factors kept constant.ResultsAfter an hour of individual work in a vegetated room, participants reported decreased perceived stress and fatigue, supported by changes in measures of systolic blood pressure and heart rates when compared to a plant-free room. Gender differences emerged, with females experiencing greater relief in perceived stress and males showing more noticeable reductions in stress-related physiological indicators. Enhanced attentional reactions were noted solely among males.ConclusionsThis study accentuated the immediate emotional well-being benefits of indoor plants at work, highlighting the importance of considering diverse user groups in indoor workspace design. It also proposes potential explanations for how indoor plants induce restorative effects on working individuals, suggesting further research.

The Autonomic Nervous System (ANS) regulates 'automatic' functions such as heart rate, and alterations may have significant impacts on health outcomes. Cardiovascular measures of autonomic function such as heart rate variability are of interest as biological markers in autism spectrum disorder (ASD). The interplay between the ANS and physical health establishes a need to examine cardiovascular autonomic functioning in youth with and without ASD over development. The current study aimed to identify change in autonomic function and balance across the parasympathetic and sympathetic branches over time as a function of diagnosis, age, pubertal development, and physical health status.

The study included 244 ASD (N = 140) or neurotypical (NT) (N = 104) youth, ages 10 to 13 years at enrollment and followed over four years. Resting state autonomic functioning was measured using respiratory sinus arrhythmia (RSA; parasympathetic) and pre-ejection period (PEP; sympathetic). Autonomic balance and regulation were also examined as outcomes. Linear mixed models tested between- and within-group differences in the primary autonomic outcomes as well as the influence of pubertal development, body weight, and medication use.

Baseline models showed diagnostic differences, with lower parasympathetic regulation, in youth with ASD, but no differences were observed for the other three outcomes. Adding body mass index (BMI) percentile and medication use removed the statistically significant diagnostic effect, while both variables were significantly related to lower RSA and overall autonomic regulation. Parasympathetic function (RSA) was stable over age and pubertal stage, while a notable decrease in sympathetic control (increased PEP) was found for age and pubertal stage. BMI percentile at enrollment significantly predicted autonomic function, while change in BMI over time did not.

Minimal research to date has explored physical health (e.g., BMI) and autonomic outcomes in ASD. The current study observed few group differences yet demonstrates important effects of physical health on ANS function in both ASD and neurotypical youth. Findings further emphasize a need to focus on individual traits such as BMI and medication use to elucidate the extent to which autonomic differences are related to health status, irrespective of diagnostic category, across the lifespan.

This study aims to investigate changes in the autonomic nervous system (ANS) by analyzing the characteristics of heart rate variability (HRV).

A portable 3-lead dynamic electrocardiogram monitoring device was used to collect HRV data from the participants. Based on the inclusion and exclusion criteria, a total of 52 volunteers from the Xinjiang Hetian area (ultra-high plateau group, approximately 5300 m altitude) and 56 volunteers from the Sichuan Chengdu area (plain group, approximately 500 m altitude) were enrolled for the 24-hour long-term HRV data collection. A cross-sectional comparison was made between the groups in terms of various HRV time-domain, frequency-domain, and nonlinear indices. The diurnal and nocturnal variations in HRV and ANS after prolonged residence in the ultra-high plateau were further explored by dividing the day into daytime and nighttime periods and calculating the ΔHRV values. Additionally, the participants' heart rate and sleep conditions were analyzed.

Compared to the plain group, the ultra-high plateau group showed a significant reduction in overall HRV, with decreased indices of vagal activity (RMSSD, NN50, pNN50, HF, HF norm, and SD1) and increased indices of sympathetic activity (LF norm). The ANS balance indices were increased (LF/HF) and decreased (SD1/SD2), respectively. More importantly, although the diurnal and nocturnal trends of various HRV indices in the ultra-high plateau group were consistent with the plain group, the △HRV value analysis indicated that the ultra-high plateau group had increased △LF (95% CI: 10.20 to 271.60, P = 0.031) and △LF/HF (95% CI: -2.23 to -0.49, P < 0.001), and decreased △HF (95% CI: -383.10 to -35.50, P = 0.012) and △S (95% CI: -12149.47 to -2759.29, P = 0.001). Additionally, in the ultra-high plateau group, both the mean and minimum heart rates were elevated compared to the plain group (84.67 ± 1.37 vs. 73.2 ± 0.93 beats/min and 52.9 ± 1.37 vs. 47.57 ± 0.73 beats/min, respectively, P < 0.001), while the maximum heart rate was reduced (135.21 ± 1.63 vs. 144.43 ± 3.22 beats/min, P = 0.012). Furthermore, the ultra-high plateau group had a significant increase in the number of awakenings (18.27 ± 1.14 vs. 15.34 ± 1.43, P = 0.046) and the Apnea-Hypopnea Index (AHI) (20.14 ± 2.47 vs. 11.36 ± 0.76, P < 0.001).

Prolonged residence in the ultra-high plateau reduces HRV, cardiac reserve capacity, and sleep quality in healthy young adults, diminishes the diurnal recovery capacity of the vagal nerve, and leads to a shift in ANS balance towards reduced vagal activity and enhanced sympathetic activity.

Despite the approval of over 200 artificial intelligence (AI) applications for radiology in the European Union, widespread adoption in clinical practice remains limited. Current assessments of AI applications often rely on post-hoc evaluations, lacking the granularity to capture real-time radiologist-AI interactions. The purpose of the study is to realise the Radiology AI lab for real-time, objective measurement of the impact of AI applications on radiologists' workflows. We proposed the user-state sensing framework (USSF) to structure the sensing of radiologist-AI interactions in terms of personal, interactional, and contextual states. Guided by the USSF, a lab was established using three non-invasive biometric measurement techniques: eye-tracking, heart rate monitoring, and facial expression analysis. We conducted a pilot test with four radiologists of varying experience levels, who read ultra-low-dose (ULD) CT cases in (1) standard PACS and (2) manually annotated (to mimic AI) PACS workflows. Interpretation time, eye-tracking metrics, heart rate variability (HRV), and facial expressions were recorded and analysed. The Radiology AI lab was successfully realised as an initial physical iteration of the USSF at a tertiary referral centre. Radiologists participating in the pilot test read 32 ULDCT cases (mean age, 52 years ± 23 (SD); 17 male; 16 cases with abnormalities). Cases were read on average in 4.1 ± 2.2 min (standard PACS) and 3.9 ± 1.9 min (AI-annotated PACS), with no significant difference (p = 0.48). Three out of four radiologists showed significant shifts (p < 0.02) in eye-tracking metrics, including saccade duration, saccade quantity, fixation duration, fixation quantity, and pupil diameter, when using the AI-annotated workflow. These changes align with prior findings linking such metrics to increased competency and reduced cognitive load, suggesting a more efficient visual search strategy in AI-assisted interpretation. Although HRV metrics did not correlate with experience, when combined with facial expression analysis, they helped identify key moments during the pilot test. The Radiology AI lab was successfully realised, implementing personal, interactional, and contextual states of the user-state sensing framework, enabling objective analysis of radiologists' workflows, and effectively capturing relevant biometrics. Future work will focus on expanding sensing of the contextual state of the user-state sensing framework, refining baseline determination, and continuing investigation of AI-enabled tools in radiology workflows.

Traumatic physical injuries can lead to psychological distress and increased risk of psychiatric disorders, often reflected in dysregulated autonomic responses measurable through heart rate variability (HRV). Slow-paced breathing has shown potential in enhancing HRV, but its effectiveness in injured survivors remains unexplored. This study investigates the effect of slow-paced breathing on HRV among injured survivors compared to non-injured individuals and explores the influence of psychological distress and spontaneous respiratory rate on this effect.

The study involved 120 injured individuals and 112 non-injured controls with similar age, sex, and education levels. Injured participants with minor-to-moderate injuries from traffic crashes were assessed 3-6 weeks post-injury. Psychological distress was defined as the risk of post-traumatic stress disorder and/or major depression. Physiological assessment (HRV) included a 2-min resting baseline and a 2-min slow-paced breathing session (6 breaths/min). Repeated measure MANCOVA assessed HRV changes between groups, while correlation analyses examined the relationship between these changes.

Injured survivors had significantly lower HRV than non-injured controls. Both groups showed notable HRV increases during slow-paced breathing. Among injured individuals, those with higher psychological distress exhibited greater HRV increases, particularly in parasympathetic activity and overall variability. Higher spontaneous respiratory rates were associated with greater HRV changes, especially in non-injured individuals.

Slow-paced breathing demonstrated significant physiological effects for injured survivors, particularly those with higher psychological distress, and supports its potential in improving stress regulation post-injury. Future research should examine the long-term effects of sustained breathing practice and clinical applicability in reducing psychological distress and disability post-injury.

Obstructive sleep apnea (OSA) is a prevalent sleep disorder with a high rate of undiagnosed patients, primarily due to the complexity of its diagnosis made by polysomnography (PSG). Considering the severe comorbidities associated with OSA, especially in the cardiovascular system, the development of early screening tools for this disease is imperative. Heart rate variability (HRV) is a simple and non-invasive approach used as a probe to evaluate cardiac autonomic modulation, with a variety of newly developed indices lacking studies with OSA patients.

We aimed to evaluate numerous HRV indices, derived from linear but mainly nonlinear indices, combined or not with oxygen saturation indices, for detecting the presence and severity of OSA using machine learning models.

ECG waveforms were collected from 291 PSG recordings to calculate 34 HRV indices. Minimum oxygen saturation value during sleep (SatMin), the percentage of total sleep time the patient spent with oxygen saturation below 90% (T90), and patient anthropometric data were also considered as inputs to the models. The Apnea-Hypopnea Index (AHI) was used to categorize into severity classes of OSA (normal, mild, moderate, severe) to train multiclass or binary (normal-to-mild and moderate-to-severe) classification models, using the Random Forest (RF) algorithm. Since the OSA severity groups were unbalanced, we used the Synthetic Minority Over-sampling Technique (SMOTE) to oversample the minority classes.

Multiclass models achieved a mean area under the ROC curve (AUROC) of 0.92 and 0.86 in classifying normal individuals and severe OSA patients, respectively, when using all attributes. When the groups were dichotomized into normal-to-mild OSA vs. moderate-to-severe OSA, an AUROC of 0.83 was obtained. As revealed by RF, the importance of features indicates that all feature modalities (HRV, SpO2, and anthropometric variables) contribute to the top 10 ranks.

The present study demonstrates the feasibility of using classification models to detect the presence and severity of OSA using these indices. Our findings have the potential to contribute to the development of rapid screening tools aimed at assisting individuals affected by this condition, to expedite diagnosis and initiate timely treatment.

Self-compassion is associated with emotional well-being, yet its benefits in generalized anxiety disorder (GAD) patients remain unclear. This study investigated the impact of self-compassion on emotional and physiological stress responses in individuals diagnosed with GAD.

Seventy-seven GAD patients were categorized into high (n = 39) and low (n = 38) self-compassion groups using the Self-Compassion Scale. Electrocardiograms were recorded during a stress-inducing task, in which negative feedback was provided on personal intelligence and career development. Participants reported state anxiety and perceived stress pre- and post-task.

When exposed to a stressor, individuals with higher self-compassion had lower heart rates (t (75) = -2.06, p = 0.043), higher heart rate variability (t (75) = 2.73, p = 0.04), and lower anxiety (t (75) = -2.07, p = 0.041) compared to the lower self-compassion group. Moreover, heart rate variability was negatively correlated with anxiety across patients (r = -0.31, df = 75, p = 0.03).

These results highlight the role of self-compassion in managing psychological and physiological responses to stress in GAD patients and indicate the potential of self-compassion interventions in GAD treatments.

The beat-by-beat fluctuation of heart rate (HR) in its temporal sequence (HR dynamics) provides information on HR regulation by the autonomic nervous system (ANS) and its dysregulation in pathological states. Commonly, linear analyses of HR and its variability (HRV) are used to draw conclusions about pathological states despite clear statistical and translational limitations.

The main aim of this study was to compare linear and nonlinear HR measures, including detrended fluctuation analysis (DFA), based on ECG recordings by radiotelemetry in C57BL/6N mice to identify pathological HR dynamics.

We investigated different behavioral and a wide range of pharmacological interventions which alter ANS regulation through various peripheral and/or central mechanisms including receptors implicated in psychiatric disorders. This spectrum of interventions served as a reference system for comparison of linear and nonlinear HR measures to identify pathological states.

Physiological HR dynamics constitute a self-similar, scale-invariant, fractal process with persistent intrinsic long-range correlations resulting in physiological DFA scaling coefficients of α~1. Strongly altered DFA scaling coefficients (α ≠ 1) indicate pathological states of HR dynamics as elicited by (1) parasympathetic blockade, (2) parasympathetic overactivation and (3) sympathetic overactivation but not inhibition. The DFA scaling coefficients are identical in mice and humans under physiological conditions with identical pathological states by defined pharmacological interventions.

Here, we show the importance of tonic vagal function for physiological HR dynamics in mice, as reported in humans. Unlike linear measures, DFA provides an important translational measure that reliably identifies pathological HR dynamics based on altered ANS control by pharmacological interventions. Central ANS dysregulation represents a likely mechanism of increased cardiac mortality in psychiatric disorders.

Arterial stiffness and cardiac autonomic function are crucial indicators of cardiovascular health. Acute exercise and age impact these parameters, but research often focuses on specific exercise activities, lacking ecological validity.

We examined the acute effects of commercially available group fitness classes (indoor cycling, resistance training, combined exercise) on arterial stiffness and vagal-related heart rate variability (HRV) indices in twelve young and twelve middle-aged adults. Participants attended four sessions, including exercise and control conditions, with measurements taken at rest and during recovery.

Middle-aged, but not young adults, showed reductions in central and peripheral systolic blood pressure 20-min into recovery across all exercise modalities (range: -7 to -8 mmHg p < 0.05). However, arterial stiffness remained unchanged. Similarly, vagal-related HRV indices (range: -0.51 to -0.90 ms, p < 0.05) and BRS (-4.03, p < 0.05) were reduced immediately after exercise, with differences persisting 30 min into recovery only after indoor cycling. Resistance and combined exercise elicited similar cardiovagal modulation and delayed baroreflex sensitivity recovery to cycling exercise, despite higher energy expenditure during indoor cycling (+87 to +129 kcal, p < 0.05).

Acute group fitness classes induce age-dependent alterations in blood pressure, but not in arterial stiffness or cardiovagal modulation. While the overall cardiovascular effects were generally consistent, differences in autonomic recovery were observed between exercise modes, with prolonged effects seen after indoor cycling. This suggests that exercise prescription should consider both age and exercise modality, as well as recovery time. The findings also emphasize the importance of ecological validity in exercise interventions, highlighting that acute effects on cardiovascular health in real-world settings may differ from those observed in controlled laboratory environments (ID: NCT06616428).

This study aimed to investigate the effectiveness of electroencephalographic (EEG) biofeedback therapy in reducing anxiety levels and improving overall well-being among patients diagnosed with rectal cancer. A randomised controlled trial was conducted with 150 patients with rectal cancer who were randomly assigned to either the intervention group (n = 75) or the control group (n = 75). The intervention group received 16 sessions of EEG biofeedback therapy over 8 weeks, whereas the control group received standard care. Anxiety levels were assessed using the State-Trait Anxiety Inventory at baseline, post-intervention, 3-month follow-up, 6-month follow-up and 12-month follow-up. Secondary outcomes, including quality of life, sleep quality, treatment adherence, cortisol levels and heart rate variability (HRV), were also evaluated. The intervention group showed significant reductions in state anxiety (p < 0.001) and trait anxiety (p < 0.001) compared with the control group at all post-intervention time points. Significant improvements were also observed in the intervention group for quality of life (p < 0.001), sleep quality (p < 0.001), treatment adherence (p < 0.001), cortisol levels (p < 0.01) and HRV (p < 0.01). The effects were maintained at the 12-month follow-up. Electroencephalographic biofeedback therapy is an effective non-pharmacological intervention for reducing anxiety levels and improving overall well-being in patients with rectal cancer. The findings suggest that incorporating EEG biofeedback therapy into the standard care of patients with rectal cancer may enhance their psychological well-being, quality of life, sleep quality, treatment adherence, physiological stress responses and autonomic function. Long-term benefits were observed, indicating the sustainability of the intervention's effects. Further research is warranted to investigate the underlying mechanisms and potential applications of EEG biofeedback therapy in other cancer populations.

Military personnel are exposed to a high level of operational stress that degrades their psychophysiological and cognitive performance and could impact the mission. Commando training is a unique opportunity to assess psychological, physiological, and cognitive performance in an ecological setting.

Psychological, physiological, and cognitive performance were evaluated at baseline, and before and after a 1-week commando training course consisting of exercises and night walks. Psychological factors (anxiety, subjective stress), physiological measures (heart rate variability, electrodermal conductance), cognitive behavior (cognitive bias, risk-taking, decision-making), and cognitive performance (the MindPulse neurophysiological test) were assessed. Volunteers were 39 young (mean age 21.6 years) French army officers.

Blind spot bias was found in all participants before training, except for the action-inaction bias. We observed a deterioration in parasympathetic functioning (Root Mean Square of Successive Differences, P = .05), an increase in subjective fatigue (P < .001), and impaired cognitive performance: reaction time (P = .02, F = 5.77), errors (P = .03, F = 4.97). Post-training, we observed an emerging group dynamic, notably an increase in avoidance (buck-passing) (P = .002, F = 10,43), a reduction of the action-inaction bias (P = .009, F = 7.59), ostrich effect (P = .008, F = 7.83) and stereotyping bias (P = .03, F = 5.11).

Commando training increases stress and impacts the cognitive performance of military personnel. Pre-deployment preparation could consider the need for physiological recovery, and the impact of deployment on cognitive performance.

Although encephalopathy and encephalitis are uncommon complications of SARS-CoV-2 infection in children, they can lead to significant morbidity and mortality. Therefore, the aim of the study is to assess heart rate variability in children with SARS-CoV-2 infection and determine those at risk of progressing to SARS-CoV-2-associated encephalopathy.

Children with confirmed SARS-CoV-2 infection between September 1, 2022 and December 8, 2023 were prospectively enrolled and divided into encephalopathic and non-encephalopathic groups. The non-encephalopathic group was further classified into mild, moderate, and severe/critical disease groups. One-minute electrocardiography was recorded on the first day of admission. Heart rate variability indices were compared between the encephalopathic and non-encephalopathic groups.

A total of 72 children (30 girls [41.7 %] and 42 boys [58.3 %]) with SARS-CoV-2 infection were enrolled, with age ranging from 1 month to 18 years. Of these children, 15 (20.8 %) were classified into the encephalopathic group, and 57 (79.2 %) were classified into the non-encephalopathic group. We compared heart rate variability indices and found that both time domain analysis (SDNNc and RMSSDc) and nonlinear Poincaré plot analysis (SD1/SD2 ratio) were lower in the encephalopathic group and severe/critical disease group than in the mild and moderate severity non-encephalopathic groups.

Heart rate variability parameters were significantly lower in the severe/critical disease group and the encephalopathic group compared to the mild to moderate severity groups. The implications of heart rate variability, particularly when considering neurological symptoms, as a predictor of disease progression to encephalopathy require further evaluation.

Distress detection in virtual reality systems offers a wealth of opportunities to improve user experiences and enhance therapeutic practices by catering to individual physiological and emotional states.

This study evaluates the performance of two wearable devices, the Empatica E4 wristband and the Faros 360, in detecting distress in a motion-controlled interactive virtual reality environment. Subjects were exposed to a baseline measurement and two VR scenes, one non-interactive and one interactive, involving problem-solving and distractors. Heart rate measurements from both devices, including mean heart rate, root mean square of successive differences, and subject-specific thresholds, were utilized to explore distress intensity and frequency.

Both the Faros and E4 sensors adequately captured physiological signals, with Faros demonstrating a higher signal-to-noise ratio and consistency. While correlation coefficients were moderately positive between Faros and E4 data, indicating a linear relationship, small mean absolute error and root mean square error values suggested good agreement in measuring heart rate. Analysis of distress occurrence during the interactive scene revealed that both devices detect more high- and medium-level distress occurrences compared to the non-interactive scene.

Device-specific factors in distress detection were emphasized due to differences in detected distress events between devices.

Metro drivers are more likely to trigger accidents if they suffer from cognitive distractions during manual driving. However, identifying metro drivers' cognitive distractions faces challenges as generally no obvious behavior can be found during the distractions. To address the challenge, this paper identifies metro drivers' cognitive distractions based on Electrocardiogram (ECG) signals collected by wearable devices in simulated driving experiments. The ECG signals are processed to generate ultra-short-term heart rate and heart rate variability (HR-HRV) features. The HR-HRV features are extracted by 30-s and 60-s time-windows in driving phase, and 25-s time-windows in parking phase, respectively. Machine learning approaches are developed to identify distractions (binary) and distinguish the degrees of distractions (multi-class). The optimal input features are determined by a random forest and recursive feature elimination (RF-RFE) algorithm. Results show that the DT with only one HR-HRV feature extracted from 30-s time-windows and XGBoost with 20 h-HRV features extracted from 60-s time-windows are optimal models for binary and multi-class classification for distractions during driving phase, respectively. The features including NN20, pNN20, SD1/SD2, Max-HR, Min-HR, and MEDNN are the most critical HR-HRV features associated with distractions. Cognitive distractions in parking phase are difficult to be detected using HR-HRV features.

Stress is a pervasive issue in modern society, manifesting in various forms such as emotional, physical, and work-related stress, each with distinct impacts on individuals and society. Traditional stress studies often rely on psychological, performance, or social tests; however, recently, immersive virtual reality (VR), which provides a sense of presence and natural interaction, offers the opportunity to simulate real-world tasks and stressors in controlled environments. Despite its potential, the use of VR to investigate the multifaceted manifestations of stress has not been thoroughly explored.

This study aimed to explore the feasibility of using a VR-based platform, bWell, to elicit multifaceted stress responses and measure the resulting behavioral and physiological changes. Specifically, we aimed to design various VR stress exercises based on neurocardiac models to systematically test cardiac functioning within specific contexts of self-regulation (executive functioning, physical efforts, and emotional regulation).

The development process adhered to guidelines for VR clinical trials and complex health interventions, encompassing 3 phases: preparation, development, and verification. The preparation phase involved a comprehensive literature review to establish links between stress, the heart, and the brain, leading to the formulation of a conceptual model based on the Neurovisceral Integration Model (NVIM) and Vagal Tank Theory (VTT). The development phase involved designing VR exercises targeting specific stressors and integrating physiological sensors such as photoplethysmography (PPG) and electromyography (EMG) to capture heart rate variability (HRV) and facial expressions. The verification phase, conducted with a small number of trials, aimed to design a study and implement a workflow for testing the feasibility, acceptability, and tolerability of the VR exercises. In addition, the potential for capturing physiological measures along with subjective ratings of stress for specific dimensions was assessed.

Verification trials demonstrated that the VR exercises were well tolerated, with negligible cybersickness and high user engagement. The different VR exercises successfully elicited the intended stress demands, along with the physiological responses.

The study presents a novel VR-based experimental setup that allows a systematic and individualized assessment of stress responses, paving the way for future research to identify features that confer stress resilience and help individuals manage stress effectively. While our conceptual model highlights the role of HRV in providing valuable insights into stress responses, future research will involve multivariate and machine learning analyses to predict individual stress responses based on comprehensive sensor data, including EMG and the VR-based behavioral data, ultimately guiding personalized stress management interventions.

Recent studies have suggested that adverse outcomes of postterm birth (≥42 completed weeks of gestation), including increased cardiometabolic risk factors, impaired glucose metabolism, and obesity, may extend into adulthood. We studied interconnected determinants of cardiovascular health, including physical activity (PA; based on accelerometry for 2 weeks), muscular strength (measured by handgrip strength), cardiorespiratory fitness (CRF; measured by 4-min step test), and cardiac autonomic function (heart rate [HR] recovery, HR variability, and baroreflex sensitivity) among 46-year-old adults from the Northern Finland Birth Cohort born postterm (n = 805) and at term (n = 2645). Adults born postterm undertook vigorous PA 2.0 min day-1 (95% CI, 0.4-3.7) less than term-born adults when adjusted for sex, age, and maternal- and pregnancy-related covariates in multiple linear regression. Postterm birth was associated with reduced CRF, based on a higher peak HR (2.1 bpm; 95% CI, 0.9-3.4) and slower HR recovery 30 s after the step test (-0.7 bpm; 95% CI, -1.3 to -0.1). Postterm birth was associated with less PA of vigorous intensity and CRF and slower HR recovery in middle age. Our findings reinforce previous suggestions that postterm birth should be included as a perinatal risk factor for adult cardiometabolic disease.

Military personnel are repeatedly exposed to multiple stressors, and are sometimes characterized by high levels of anger. Evidence suggests that this anger can become dysfunctional, and impact the health status of populations chronically exposed to stress. In particular, rumination (understood as perseverative thoughts about a past event), provides a theoretical framework for investigating how anger may impact stress regulation abilities in military personnel declared fit for deployment. This exploratory study aimed therefore to examine the impact of the anger profile on psychological suffering in terms of burnout and post-traumatic stress disorder (PTSD), along with the reactivity of the autonomic nervous system, measured as cardiac variability. One hundred and seventeen French soldiers were tested before deployment to Operation BARKHANE. Anger rumination, burnout, and PTSD symptoms were assessed using questionnaires, and cardiac variability was measured as the questionnaires were completed. The results revealed two profiles related to anger trait and anger rumination. Burnout and PTSD scores were higher among military personnel with high levels of anger trait and rumination, and this group also had lower parasympathetic activity and flexibility after completing the questionnaires. These results suggest that there may be a link between an angry profile and psychological suffering, notably burnout and PTSD. Rumination could be involved in this link, as it is associated with poor adaptation to stress in a military context. Prospective researches including post-deployment will establish whether this ruminative response can account for the relationship between problematic anger, stress regulatory capacities and psychological health in military populations.

Brief behavioral treatment for insomnia is an effective short-term therapy focusing on stimulus control and sleep restriction to enhance sleep quality. As a crucial part of this therapy, diaphragmatic breathing is often recommended when patients fail to fall asleep within 30 minutes. With the rise of health apps and gamification, these tools are increasingly seen as effective ways to boost self-efficacy and user engagement; however, traditional games tend to increase attention, which can negatively impact sleep and contradicts the aim of sleep therapy. This study thus explored the potential for gamification techniques to promote relaxation without disrupting sleep processes.

The study developed 4 breathing guidance mechanisms, ranging from concrete to abstract: number countdown, zoom-in/out, up/down, and color gradients. The objective was to explore the relationship between game mechanics, cognitive load, relaxation effects, and attention as well as to understand how different designs impact users with varying levels of insomnia.

The study was conducted in 2 phases. The first phase involved a questionnaire on the 4 guidance mechanisms. In the second phase, 33 participants classified by insomnia severity completed a Sleep Self-Efficacy Scale. They then engaged in 5 minutes of diaphragmatic breathing using each of the 4 interfaces. Relaxation effects were measured using heart rate variability via a smartwatch, attention and relaxation levels via an electroencephalogram device, and respiratory rate via a smartphone. Participants also completed the Game Experience Questionnaire and NASA Task Load Index, followed by user interviews.

The results indicated that competence, immersion, and challenge significantly influenced cognitive load. Specifically, competence and immersion reduced cognitive load, while challenge, negative affect, and positive affect were correlated with relaxation. Negative affect showed a positive correlation with the mean root mean square of successive differences, while positive affect exhibited a negative correlation with the mean root mean square of successive differences. Cognitive load was found to affect both relaxation and attention, with a negative correlation between mental demand and attention and a positive correlation between temporal demand and respiratory rate. Sleep self-efficacy was negatively correlated with temporal demand and negative affect and positively correlated with competence and immersion.

Interfaces offering moderate variability and neither overly abstract nor too concrete guidance are preferable. The up/down interface was most effective, showing the best overall relaxation effect. Conversely, the number countdown interface was stress-inducing, while the zoom-in/out interface had a significant impact on insomnia-related issues, making them less suitable for insomnia-related breathing exercises. Participants showed considerable variability in their response to the color gradient interface. These findings underscore the importance of carefully considering game design elements in relaxation training. It is essential that breathing guidance designs account for the impact of the game experience to effectively promote relaxation in users.

There is sufficient proof that static magnetic fields (SMFs) of different parameters have a significant effect on the cardiovascular system. The sometimes contradictory, opposite-directional nature of SMF's hemodynamic effect generates uncertainty; therefore, an explanation of the underlying mechanisms is required. Following SMF selective carotid baroreceptors or microvascular net exposure, both high and low blood pressure (BP)/vascular tone starting conditions showed a return to normal. Beyond the previous descriptions of SMF's simple hemodynamic results, the current study aims to clarify the physiology of the SMF BP/vascular tone normalizing effects. The examination of available literature and hemodynamic tracings provided strong evidence that mechanoreceptor magnetic activation is concealed behind SMF vascular tone adjustment (increasing or decreasing as needed), filling in the knowledge gap regarding SMF opposite directional vascular tone normalizing outcomes. It has been proposed that cytoskeletal actin filament rearrangement, mechanically-gated Ca2+ influx, and nitric oxide (NO) activity may strengthen SMF's vascular mechanoreceptor sensing/regulation ability, modifying BP and vascular tone features in a hemodynamic normalizing pattern. It is suggested that baro/mechanoreceptor magnetic activation physiology is a unique mechanism of the magneto-cardiovascular interaction with substantial potential for cardiovascular protection.

Proprioceptive accuracy is an important aspect of motor functioning thus understanding how the stress response affects it can broaden our knowledge about the effects of stress on motor performance. There has been published only one quasi-experimental study on this topic to date, reporting a negative association between stress and proprioceptive accuracy. The aim of the present study was to explore whether the stress response influences proprioceptive accuracy in a randomized and controlled experimental setting.

Participants (Mage =  20.4 yrs, SDage =  1.91 yrs) were randomly assigned to a stress (n =  29) and a control (n =  28) group. Psychological stress was induced via an online quiz involving time pressure and instant feedback on performance. Participants' perceived (state anxiety) and physiological (heart rate, heart rate variability, skin conductance level) stress response and proprioceptive accuracy (the active and passive version of the Joint Position Reproduction test for the elbow joint) were measured before and after the experimental manipulation.

The quiz substantially increased only participants' perceived stress however, proprioceptive accuracy was not impacted by the experimental manipulation.

Perceived stress does not impact proprioceptive accuracy.

The neural and cardiovascular systems are pivotal in regulating human physiological, cognitive and emotional states, constantly interacting through anatomical and functional connections referred to as the brain-heart axis. When this axis is dysfunctional, neurological conditions can lead to cardiovascular disorders and, conversely, cardiovascular dysfunction can substantially affect brain health. However, the mechanisms and fundamental physiological components of the brain-heart axis remain largely unknown. In this Review, we elucidate these components and identify three primary pathways: neural, mechanical and biochemical. The neural pathway involves the interaction between the autonomic nervous system and the central autonomic network in the brain. The mechanical pathway involves mechanoreceptors, particularly those expressing mechanosensitive Piezo protein channels, which relay crucial information about blood pressure through peripheral and cerebrovascular connections. The biochemical pathway comprises many endogenous compounds that are important mediators of neural and cardiovascular function. This multisystem perspective calls for the development of integrative approaches, leading to new clinical specialties in neurocardiology.

Impairments in decision-making have been reported in brain-damaged (stroke/traumatic brain injury) patients with a wide range of lesion sites. Here, we propose that the performances of patients in complex sequential decision-making (DM) tasks can be explained by their negative affectivity, leading to deliberative processing associated with poor DM performances. We assumed that a slow-paced breathing (SPB) training, by reducing negative affectivity would improve performances in a complex DM task. For 24 days, 34 brain-damaged patients (16 males and 18 females; 12 had a hemorrhagic stroke, 17 with an ischemic stroke and 5 with a TBI), practiced either daily SPB or sham trainings for five min, three times a day. Before and after training, we assessed their vagal tone (electrocardiogram-ECG), affectivity (Positive and Negative Affect Schedule-PANAS) and certainty level (Dimensional Ratings Questionnaire-DRQ) and their performance on the Iowa Gambling Task. All participants showed initial weak performance, which improved only for patients in the SPB training condition. These results suggest that DM disorders in brain-damaged patients can be the consequence of their poor information processing strategy rather than an impairment in their DM abilities. Second, we showed that SPB could be efficient to normalize DM processes in brain injury patients.

Surgeon stress can influence technical and nontechnical skills, but the consequences for patient outcomes remain unknown.

To investigate whether surgeon physiological stress, as assessed by sympathovagal balance, is associated with postoperative complications.

This multicenter prospective cohort study included 14 surgical departments involving 7 specialties within 4 university hospitals in Lyon, France. Exclusion criteria consisted of patient age younger than 18 years, palliative surgery, incomplete operative time-stamping data, procedures with a duration of less than 20 minutes, and invalid surgeon heart rate variability (HRV) data. Data were accrued between November 1, 2020, and December 31, 2021, with 30-day follow-up completed on May 8, 2022. Analyses were performed from January 1 to May 31, 2024.

Sympathovagal balance of the attending surgeon in the first 5 minutes of surgery.

Major surgical complications, extended intensive care unit stay, and mortality within 30 days, after adjustment via mixed-effects multivariable logistic regression for surgeon age, professional status, the time of incision, the random effect of the surgeon, and a composite risk score incorporating patient comorbidities and surgery characteristics. Sympathovagal balance was quantified by the low frequency to high frequency (LF:HF) ratio derived from HRV data measured by chest monitors worn intraoperatively. The LF:HF ratio was normalized at the surgeon level to the median value observed for each surgeon during the study period to control for baseline differences.

A total of 793 surgical procedures performed by 38 attending surgeons were included in the analysis. Median patient age was 62 (IQR, 47-72) years, and 412 (52.0%) were female, with a median of 2 (IQR, 1-4) comorbidities. Median surgeon age was 46 (IQR, 39-52) years, 39 (78.9%) were male, and 22 (57.9%) were professors. Median surgeon heart rate was 88 (IQR, 77-99) beats per minute. Median surgeon LF:HF ratio was 7.16 (IQR, 4.52-10.72) before and 1.00 (IQR, 0.71-1.32) after normalization. Increased surgeon sympathovagal balance during the first 5 minutes of surgery was associated with significantly reduced major surgical complications (adjusted odds ratio [AOR], 0.63; 95% CI, 0.41-0.98; P = .04), though not with reduced intensive care unit stay (AOR, 0.34; 95% CI, 0.11-1.01; P = .05) or mortality (AOR, 0.18; 95% CI, 0.03-1.03; P = .05).

Increased surgeon stress at the beginning of a procedure was associated with improved clinical patient outcomes. The results are illustrative of the complex relationship between physiological stress and performance, identify a novel association between measurable surgeon human factors and patient outcomes, and may highlight opportunities to improve patient care.

Exercise training improves heart rate variability, and evidence suggests it can mitigate the detrimental effects of stress. This study aims to evaluate the relationship between surgeons' physical activity habits and their stress, assessed as heart rate variability, at the start of surgery.

This multispecialty prospective cohort study included surgeons from fourteen cardiac, endocrine, digestive, gynecologic, orthopedic, thoracic, and urologic surgical departments of four university hospitals. Surgeons wore accelerometers 24/7 from 1 November 2020 to 31 December 2021 to quantify the mean daily step counts and daily sedentary time for 7 days prior to each operation. RMSSD, the root mean square of successive differences between normal heart beats, is a heart rate variability (HRV) metric that reflects cardiac vagal tone. We evaluated RMSSD during the first 5 minutes of surgeries performed over five 15-day periods. Data were analyzed using a multivariable linear mixed model with a random effect for surgeons.

We analyzed 722 surgeries performed by 37 surgeons (median age = 47 (IQR 42-55); 29 (78.4%) male). On average (SD), surgeons walked 9762 (2447) steps and were sedentary 391 (102) minutes daily. The model showed a positive relationship between steps and cardiac vagal tone, with an increase in lnRMSSD (0.028, 95% CI 0.003 to 0.053, P = 0.026) for every 1000 more steps per day, but not for sedentary behavior. Surgeon professors presented lower lnRMSSD (-0.437, -0.749 to -0.126, P = 0.006), as did surgeons who spent less total time operating over the study period (-0.337, -0.646 to -0.027, P = 0.033), compared to their counterparts.

Higher daily step counts the week before surgery were associated with increased cardiac vagal tone, indicating lower stress levels at the beginning of surgery. This relationship highlights the influence of physical activity on surgeons' stress in the operating room.

As a prevalent and severe complication of systemic lupus erythematosus (SLE), cardiovascular autonomic neuropathy (CAN) has garnered increasing attention. Reports suggested that CAN may be related to the disease activity of SLE. This study aims to explore whether Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) is associated with CAN and to evaluate its diagnostic value for CAN.

Altogether, 144 patients with SLE from the Rheumatology Department of Nanjing Drum Tower Hospital were included. Each patient underwent assessment with the SLEDAI and cardiovascular reflex tests (CARTs). Patients were classified into three groups: non-CAN, early-CAN and diagnosed-CAN based on the CARTs results. The relationship of CARTs and SLEDAI were analyzed using SPSS 26.0.

After being divided into three groups, there were significant differences in SLEDAI among them. With increasing SLEDAI score (P < 0.05), both CARTs scores and four individual parameters score increased significantly, both before and after adjusting for influencing factors (P < 0.05). Besides, in Logistic regression analysis, it identified that SLEDAI as an independent risk factor for CAN (OR = 1.227, 95%CI = 1.143-1.316, P < 0.001). Finally, after accounting for the influence of glucocorticoids, a significant positive correlation between CARTs and SLEDAI remained (P < 0.05).

As the gold standard in the diagnosing CAN, CARTs and four parameters are significantly correlated with SLEDAI. Furthermore, SLEDAI is also an independent risk factors for its development. In conclusion, this research demonstrated that SLEDAI is a dependable indicator for the onset and progression of CAN. Key Points • This study is the first to demonstrate a strong association between SLEDAI and cardiovascular autonomic neuropathy, identifying SLEDAI as a risk factor for CAN in SLE patients. • This study offers a convenient and rapid method for the clinical evaluation of CAN in SLE patients, providing significant value in assessing cardiovascular complications.