Autonomic Nervous System Activity Research Articles

Autonomic nervous system activity correlates with peak experiences induced by DMT and predicts increases in well-being.

Non-ordinary states of consciousness induced by psychedelics can be accompanied by so-called "peak experiences," characterized at the emotional level by their intensity and positive valence. These experiences are strong predictors of positive outcomes following psychedelic-assisted therapy, and it is therefore important to better understand their biology. Despite growing evidence that the autonomic nervous system (ANS) plays an important role in mediating emotional experiences, its involvement in the psychedelic experience is poorly understood. The aim of this study was to investigate to what extent changes in the relative influence of the sympathetic (SNS) and parasympathetic nervous systems (PNS) over cardiac activity may reflect the subjective experience induced by the short-acting psychedelic N,N-Dimethyltryptamine (DMT). We derived measures of SNS and PNS activity from the electrocardiograms of 17 participants (11 males, mean age = 33.8 years, SD = 8.3) while they received either DMT or placebo. Results show that the joint influence of SNS and PNS ("sympathovagal coactivation") over cardiac activity was positively related to participants' ratings of "Spiritual Experience" and "Insightfulness" during the DMT experience, while also being related to improved well-being scores 2 weeks after the session. In addition, we found that the state of balance between the two ANS branches ("sympathovagal balance") before DMT injection predicted scores of "Insightfulness" during the DMT experience, as well as subsequent sympathovagal coactivation. These findings demonstrate the involvement of the ANS in psychedelic-induced peak experiences and may pave the way to the development of biofeedback-based tools to enhance psychedelic therapy.

Alleviation of physiological stress response by apple aroma

ABSTRACT Objective The study evaluated the potential of apple aroma to alleviate physiological stress response induced by a short-term cognitive stressor. It investigated the effects of apple aroma on cardiac and peripheral autonomic nervous system activity under stressful conditions. Methods Within-subject experiments were conducted with 25 healthy male university students with a 30-minute calculation task under three conditions: Apple, Chamomile (CHA), and Di propylene glycol (DPG) (scentless air). The aroma administration was precisely controlled and counterbalanced. Cardiac activity on electrocardiograms and nose tip temperature were recorded throughout the experiment. A visual analog scale and a scent questionnaire were subjective measures. Results Apple aroma demonstrated a significantly smaller increase in heart rate (t [24] = 3.36, p = 0.008 vs. DPG, t [24] = 4.06, p = 0.001 vs. CHA), and a decrease in the high-frequency component of heart rate variability (t [24] = 2.81, p = 0.029 vs. DPG, t [24] = 3.48, p = 0.006 vs. CHA) compared to the other conditions, representing a smaller enhancement of cardiac sympathetic nervous system activity and smaller suppression of cardiac parasympathetic nervous system activity respectively. Conclusion Apple aroma showed efficacy in alleviating the physiological stress response in terms of cardiac activity. Apple was also considered significantly preferable and comfortable compared to the other conditions, which would be beneficial in the context of aromatherapy.

Role and mechanism of autonomic nervous system regulation in primary glaucoma

The regulation of blood flow in the human eye, aqueous humor production, and the outflow channels of aqueous humor are all controlled by the autonomic nervous system (ANS), encompassing both sympathetic and parasympathetic nerves. Patients with primary glaucoma often exhibit autonomic nervous system dysfunctions, which may exacerbate visual impairment. The homeostasis of the autonomic nervous system is influenced by circadian rhythms, physical exercise, emotional states, medications, and other factors. Previous studies have indicated that activities such as aerobic exercise, yoga breathing, and meditation can promote the restoration of autonomic nervous system balance, thereby reducing intraocular pressure. However, further evidence is required to substantiate the efficacy of ANS activity regulation as an effective adjunct therapy for primary glaucoma. This review examines the role and mechanisms of autonomic nervous system regulation in the context of primary glaucoma.

The Impact of Stimulation Parameters on Cardiovascular Outcomes in Chronic Stroke Patients Following Transcranial Direct Current Stimulation-A Pilot Controlled, Randomized, Double-Blind Crossover Trial.

Stroke survivors often experience autonomic nervous system (ANS) dysfunction. While Transcranial Direct Current Stimulation (tDCS) has been shown to modulate the ANS when applied to the left hemisphere, its effects on the right hemisphere remain unexplored. We aimed to compare the effects of tDCS applied to both the injured and the contralateral hemispheres on heart rate variability (HRV) and functional capacity in individuals post-stroke. Twenty individuals with cerebral hemisphere lesions (ten with right-hemisphere lesions and ten with left-hemisphere lesions) were randomized into four groups: anodal and sham tDCS on the left temporal cortex (T3) and anodal and sham tDCS on the right temporal cortex (T4). HRV was assessed before the intervention, after the six-minute walk test (6MWT), and following tDCS. HRV data were categorized into frequency ranges: low frequency (LF), high frequency (HF), and sympathovagal balance. The 6MWT (meters) was conducted both pre- and post-tDCS. In individuals with right-hemisphere lesions, a higher global LF value was observed (right side: 71.4 ± 16.8 nu vs. left side: 65.7 ± 17.3 nu; p = 0.008), as well as lower values of the HF component (right side: 29.5 ± 18.9 nu vs. left side: 34.0 ± 17.4 nu; p = 0.047), consequently exhibiting higher global values of the low/high-frequency ratio (right side: 3.9 ± 2.8 vs. left side: 2.9 ± 2.4). Regarding the stimulation site, tDCS over T3 led to a lower overall value of the low/high-frequency ratio (left hemisphere: 3.0 ± 2.2 vs. right hemisphere: 3.7 ± 2.9; p = 0.040) regardless of the lesion location. A significant increase in the distance covered in the 6MWT was observed for individuals with lesions in both hemispheres after tDCS at T3. Participants with right-hemisphere lesions exhibited superior global sympathetic autonomic nervous system activity. When the tDCS was applied on the left hemisphere, it maintained lower sympathovagal balance values and improved functional capacity regardless of the hemisphere affected by the stroke.

The dynamic role of the left dlPFC in neurovisceral integration: Differential effects of theta burst stimulation on vagally mediated heart rate variability and cognitive-affective processing.

Adapting to the ever-changing demands of the environment requires a complex interplay between cognitive-affective, neuronal, and autonomic processes. Vagally mediated heart rate variability (vmHRV) is positively associated with both cognitive-affective functioning and prefrontal cortex (PFC) activity. Accordingly, the Neurovisceral Integration Model has posited a shared role of the PFC in the regulation of cognitive-affective processes and autonomic nervous system (ANS) activity. While there are numerous correlational findings in this regard, no study so far has investigated whether the manipulation of PFC activity induces changes in vmHRV and cognitive-affective processing in an inter-dependent manner. In a sample of 64 participants, we examined the effects of continuous (cTBS; n = 21) and intermittent theta-burst stimulation (iTBS; n = 20) compared to sham stimulation (n = 23) over the left dorsolateral PFC (dlPFC) on vmHRV and cognitive-affective processing within an emotional stop-signal task (ESST). Our results revealed that both resting vmHRV and vmHRV reactivity predicted cognitive-affective processing. Furthermore, we found a dampening effect of cTBS on resting and on-task vmHRV, as well as an enhancing effect of iTBS on ESST performance. Our results show no direct association between vmHRV changes and ESST performance alterations following stimulation. We interpret our results in the light of a hierarchical model of neurovisceral integration, suggesting a dynamical situation-dependent recruitment of higher-order cortical areas like the dlPFC in the regulation of the ANS. In conclusion, our results highlight the complex interplay between PFC activity, autonomic regulation, and cognitive-affective processing, emphasizing the need for further research to understand the causal dynamics of the underlying neural mechanisms.

Stress Response Profiles and Physical Aggression in Early Childhood

This study examined the applicability of the four stress response patterns proposed by the Adaptive Calibration Model (ACM; Del Giudice et al., 2011) in 12-month-old children (N = 214; 116 boys) and their associations with physical aggression at 12, 20, and 30 months of age. Salivary alpha-amylase (sAA) and pre-ejection period (PEP) served as indices of the sympathetic nervous system, respiratory sinus arrhythmia as an index of the parasympathetic nervous system, salivary cortisol as an index of the hypothalamic-pituitary-adrenal axis, and heart rate as a measure of overall autonomic nervous system activity. A fear challenge was administered at 12 months to measure baseline, response, and recovery levels of the stress systems, while maternal reports were used to evaluate physical aggression at the various time points. Through latent profile analysis, three stress response profiles were identified: (1) ANS Responders, (2) Moderate Responders (across all stress systems), and (3) Hormonal Responders. Despite some deviations, each profile could be associated with a corresponding ACM stress response pattern, primarily due to the inclusion of both sAA and PEP as measures of sympathetic activity. At 12 months, ANS Responders showed higher levels of physical aggression, whereas Hormonal Responders exhibited higher levels of physical aggression at 20 months. The findings confirm that differences in stress response patterns can be observed as early as 12 months of age. Moreover, this study emphasizes the importance of using multiple indices of stress responsivity to identify such distinct patterns. Finally, stress response profiles that differ from the most common (moderate) profile, are associated (albeit not consistently) with higher levels of physical aggression at different ages during early childhood.

Effect of Cereal Consumption (Frugra®) on Autonomic Nervous System Function in Healthcare Workers Who Skip Breakfast.

In this study, we aimed to clarify the effects of breakfast intervention on autonomic nerve function in healthcare workers who skip breakfast. This cross-sectional, interventional study was conducted between January 2020 and December 2021. All participants were full-time healthcare workers who completed a self-administered questionnaire on fatigue and subjective symptoms and underwent noninvasive autonomic nerve function tests. "Skippers" were defined as individuals who ate breakfast <4 times per week, and "eaters" were those who ate breakfast >4 times per week. We introduced a cereal, Frugra (Calbee, Inc.), to skippers who opted for the breakfast intervention. Subsequently, they completed the questionnaire again and repeated the autonomic nerve function tests. Among 196 participants (age [mean±SD]: 29.8±7.8 y; 177 women and 19 men), 120 were categorized as skippers and 76 as eaters. In the skipper group, more participants were nurses, lived alone, and worked the night shift than in the eater group. The Chalder Fatigue Scale (CFS) score in the skipper group was higher than that in the eater group, although not significantly. Regarding autonomic nerve function, no significant differences were observed between the groups. In 50 skippers who opted for the breakfast intervention, the CFS score significantly decreased after 4 wk. Log low frequency and log coefficient of component variance total power significantly increased, whereas log high frequency increased, but not significantly, after the intervention. In conclusion, for healthcare workers who were breakfast skippers, the consumption of breakfast cereal reduced their fatigue level and improved their autonomic nervous system activity.

Preterm birth risk stratification through longitudinal heart rate and HRV monitoring in daily life

Preterm birth (PTB) remains a global health concern, impacting neonatal mortality and lifelong health consequences. Traditional methods for estimating PTB rely on electronic health records or biomedical signals, limited to short-term assessments in clinical settings. Recent studies have leveraged wearable technologies for in-home maternal health monitoring, offering continuous assessment of maternal autonomic nervous system (ANS) activity and facilitating the exploration of PTB risk. In this paper, we conduct a longitudinal study to assess the risk of PTB by examining maternal ANS activity through heart rate (HR) and heart rate variability (HRV). To achieve this, we collect long-term raw photoplethysmogram (PPG) signals from 58 pregnant women (including seven preterm cases) from gestational weeks 12–15 to three months post-delivery using smartwatches in daily life settings. We employ a PPG processing pipeline to accurately extract HR and HRV, and an autoencoder machine learning model with SHAP analysis to generate explainable abnormality scores indicative of PTB risk. Our results reveal distinctive patterns in PTB abnormality scores during the second pregnancy trimester, indicating the potential for early PTB risk estimation. Moreover, we find that HR, average of interbeat intervals (AVNN), SD1SD2 ratio, and standard deviation of interbeat intervals (SDNN) emerge as significant PTB indicators.

Analysis of perioperative autonomic nervous system activity to visualize stress in pediatric patients undergoing alveolar bone graft surgery.

Perioperative stress in pediatric patients is often difficult to assess via interviews; thus, an objective measure to assess perioperative stress is needed. To visualize perioperative stress, we observed autonomic nervous system (ANS) activity, circulatory dynamics, and psychological status in pediatric patients undergoing alveolar bone grafting under general anesthesia. This prospective observational study included 40 patients aged 8-12 years who were scheduled for alveolar bone grafting in our hospital. ANS activity was analyzed using heart rate variability the day before surgery, during general anesthesia, 2h postoperatively, 24h postoperatively, and the day before discharge. ANS assessment included LF/HF (sympathetic nervous system activity) and HF (parasympathetic nervous system activity). Additionally, heart rate (HR), systolic blood pressure (SBP), face scale (FS) score were recorded. Data from 31 patients, excluding dropouts, were analyzed. The ratio of change to the preoperative value was compared. After surgery, the LF/HF, HR, SBP, and FS score significantly increased (P < 0.01) and HF significantly decreased (2h postoperatively: P < 0.05, 24h postoperatively, before discharge: P < 0.01). SBP recovered to preoperative values 24h postoperatively, and HR and FS scores recovered to preoperative values before discharge. However, even before discharge, LF/HF remained significantly higher than preoperative values, and HF remained significantly lower than preoperative values (P < 0.01). Conclusion We observed perioperative stress from multiple perspectives. Circulatory dynamics and psychological status recovered by the day before discharge; however, ANS activity did not. Therefore, evaluating ANS activity may be useful in visualizing potential perioperative stress in pediatric patients.

The Effects of Prolonged Indoor Inhalation of Nature-Derived Odors on Menopausal Women.

This study aimed to investigate the effects of prolonged inhalation of nature-derived odors indoors on humans. Twenty-six women participated in this study. Heart rate variability, heart rate, blood pressure, pulse rate, estradiol, testosterone, and cortisol were used as indicators of autonomic nervous system and endocrine system activities. Profile of mood state, state-trait anxiety inventory, menopause rating scale and general sleep disturbance scale were used as psychological indicators. The order was as follows: After the participants relaxed in a chair for 5 min, their heart rate variability and heart rate were measured for 3 min with their eyes closed. Subsequently, blood pressure and pulse rate were measured, salivary samples were collected for estradiol, testosterone, and cortisol analyses, and a subjective assessment was conducted. The participants received a diffuser containing fir essential oil and were instructed on its usage and precautions. Subsequently, they returned home and inhaled the fir oil for a week. After 7 days, participants revisited the laboratory for posttest measurements, conducted at the same time as the pretest. Prolonged inhalation of the fir essential oil resulted in increased estradiol concentration, decreased systolic and diastolic blood pressure, relief of menopausal symptoms, reduced anxiety levels, improved sleep quality and mood states. Prolonged inhalation of the fir essential oil induced physiological and psychological relaxation on menopausal women.

Electrophysiological correlates of why humans deviate from rational decision-making: A registered replication study.

In contrast to rational choice theory predicting humans to optimize expected utilities of choices, humans deviate from rational behavior in decision-making paradigms. Hewig etal. (2011) explored affective correlates of decision-making in the ultimatum game (UG) and the dictator game (DG). They found that feedback-related negativity (FRN), subjective valence ratings, and autonomic nervous system activity predicted rejection of monetary offers. This registered replication aimed to validate and extend these findings. Although behavioral patterns and results of subjective ratings closely matched the original study, not all psychophysiological effects were successfully replicated. Firstly, we could not replicate the reported effects of autonomic nervous system activity. Secondly, a quadratic instead of the originally proposed linear relation between the offer and the FRN emerged, possibly driven by the offer evaluation in economic games and the rewarding anticipation of successful punishment for low offers. Thirdly, P3 amplitudes mirrored the quadratic offer response pattern, generally peaking for the lowest offer. In contrast to the original study, P3 responses were larger in the UG compared with the DG. Finally, our findings indicate that participant-related higher midfrontal theta activation predicted lower acceptance behavior in the UG, with a systematic dampening effect for fairer offers. This highlights cognitive control as a crucial mechanism in economic decision-making to overcome behavioral defaults. Overall, our results conceptually support the original conclusion that decision-making in economic games is non-rational and dependent on the objective situation as well as emotional and neural markers, though not precisely as suggested by Hewig etal. (2011).

(Invited) Electrodermal Activity Sensing at Scale

Electrodes have emerged as powerful tools for sensing various physiological signals, paving the way for a new era of wearable consumer devices that offer in situ measurement and analysis. Electrodermal activity (EDA) sensors are used for evaluating autonomic nervous system activity, wherein changes in EDA are associated with physiological excitation reflecting stress, arousal, and emotional changes. The Fitbit Sense 2 and Pixel Watch 2 are two wearable commercial devices that passively measure EDA using wrist-facing electrodes powering a stress management feature. Descriptive findings of the Fitbit Sense 2 across 10 million hours of continuous EDA data collected from over 16,000 people are herein reported, including real-time population response to Thanksgiving 2022 and the 2023 Super Bowl.

Momentary autonomic engagement during parent-adolescent conflict: Coping as a moderator of associations with emotions.

Regulatory efforts are hypothesized to affect associations between emotions and physiology (i.e., concordance) to facilitate adaptive functioning. Assessing the role of coping on physiological-emotional concordance during ecologically relevant scenarios can elucidate whether concordance can serve as a biomarker of risk or resilience. The present study assessed self-reported coping as a moderator of minute-to-minute associations between autonomic nervous system activity and emotions (i.e., physiological-emotional concordance) in caregivers (N = 97) and adolescents (N = 97; ages 10-15) during a dyadic conflict task. Models included physiological variables (sympathetic, skin conductance level [SCL]; and parasympathetic, respiratory sinus arrhythmia [RSA]) and their interaction (SCL × RSA) as predictors of emotions, with coping variables as moderators. Caregivers' use of primary control coping (e.g., problem solving and emotional expression) and secondary control coping (e.g., cognitive reappraisal and acceptance) use in response to family stress predicted more positive emotional experiences during the laboratory conflict task. Adolescents' use of secondary control coping moderated the SCL-emotion association, such that increases in momentary SCL were associated with more positive emotion ratings for youth reporting higher secondary control coping. For youth who report more adaptive trait-level coping skills, momentary changes in SCL may reflect active engagement and attentiveness to facilitate more positive emotional experiences. Findings advance our understanding of the interrelationships between physiological responses and psychological experiences during relevant, interactive scenarios. Autonomic responses are differentially related to affective states depending on the coping strategies that adolescents employ, suggesting that concordance may be associated with intervention targets (i.e., coping skills).

Autonomic assessment at the intersection of psychosocial and gastrointestinal health.

Wearable technology is increasingly used in clinical practice and research to monitor functional gastrointestinal symptoms and mental health. This article explores the potential of wearable sensors to enhance the understanding of the autonomic nervous system (ANS), particularly its role in linking psychological and gastrointestinal function. The ANS, facilitates brain-gut communication and is responsive to psychosocial conditions. It is implicated in disorders related to psychological stress and gut-brain interaction. Wearable technology enables tracking of the ANS in daily life, offering complementary and alternative methods from traditional lab-based measures. This review places focus on autonomic metrics such as respiratory sinus arrhythmia, vagal efficiency, and electrodermal activity as well as self-reports of autonomic symptoms. Potential applications include use of wearable sensors for tracking autonomic activity in disorder of gut-brain interaction such as cyclic vomiting syndrome, in which ANS dysregulation may be triggered by psychosocial factors. Considerations for data interpretation and contextualization are addressed, acknowledging challenges such as situational confounders of ANS activity and accuracy of wearable devices.

Circadian disruptions and their role in the development of hypertension.

Circadian fluctuations in physiological setpoints are determined by the suprachiasmatic nucleus (SCN) which exerts control over many target structures within and beyond the hypothalamus via projections. The SCN, or central pacemaker, orchestrates synchrony between the external environment and the internal circadian mechanism. The resulting cycles in hormone levels and autonomic nervous system (ANS) activity provide precise messages to specific organs, adjusting, for example, their sensitivity to approaching hormones or metabolites. The SCN responds to both photic (light) and non-photic input. Circadian patterns are found in both heart rate and blood pressure, which are linked to daily variations in activity and autonomic nervous system activity. Variations in blood pressure are of great interest as several cardiovascular diseases such as stroke, arrhythmias, and hypertension are linked to circadian rhythm dysregulation. The disruption of normal day-night cycles, such as in shift work, social jetlag, or eating outside of normal hours leads to desynchronization of the central and peripheral clocks. This desynchronization leads to disorganization of the cellular processes that are normally driven by the interactions of the SCN and photic input. Here, we review autonomic system function and dysfunction due to regulation and interaction between different cardiorespiratory brain centers and the SCN, as well as social, lifestyle, and external factors that may impact the circadian control of blood pressure.

Assessing Children's Autonomic Nervous System Activity During Structured Tasks: A Feasibility and Reliability Study in Ghana.

The significance of physiological regulation in relation to behavioral and emotional regulation is well documented, but primarily in economically advantaged contexts. Few studies have been conducted in low- and middle-income countries. We investigated the feasibility and reliability of measuring autonomic nervous system (ANS) activity and behavior during challenge tasks in 30 children aged 8-10 years in Ghana during two visits, 1 week apart. Completeness of ANS data ranged from 80% to 100% across all tasks. There was low-to-moderate test-retest reliability of video mood induction (VMI) emotion ratings and balloon analog risk task (BART) pumps (r=0.34-0.52). VMI elicited higher targeted emotion ratings in Visit 2 than Visit 1. Respiratory sinus arrhythmia (RSA) was higher, and pre-ejection period (PEP) was longer at Visit 2 than Visit 1 for baseline and both tasks. RSA was higher at baseline than during the VMI anger scene at Visit 1, whereas PEP was shorter at baseline than during all VMI emotion scenes at Visit 2. RSA was higher at baseline than during BART at both visits. In conclusion, ANS data collection within evocative and arousing challenge tasks was feasible in Ghana, and the tasks were generally reliable and effective in eliciting target emotions and risk-taking behavior in this sample.

Hypertension and Device-Based Therapies for Resistant Hypertension: An Up-to-Date Review.

Hypertension is the most prevalent modifiable risk factor associated with cardiovascular mortality. The World Health Organization (WHO) estimates that hypertension directly or indirectly causes the death of at least nine million people globally every year. The number of people living with hypertension (blood pressure (BP) of ≥140 mmHg systolic or ≥90 mmHg diastolic or on medication) doubled between 1990 and 2019, from 650 million to 1.3 billion. Despite a plethora of antihypertensivedrugs widely available, a sizable part of the antihypertensive population stays uncontrolled. The unmet need of controlling BP in this population may be addressed, in part, by developing new drugs and devices/procedures to treat hypertension and its comorbidities. Several device-based approaches have been introduced to lower BP, and most of these strategies aim to modulate autonomic nervous system activity. Importantly, when considering a device-based treatment, each patient's underlying pathophysiology is considered, and the procedural risks are weighed against the cardiovascular risk attributed to the elevated BP.In November 2023, the FDA approved two renal denervation (RDN) devices. This manuscript discusses current interventional devices and procedures recently approved (RDN) and others in the clinical testing stage for arterial hypertension intervention or management.As we list below, all others have shown promising results and are being evaluated on a larger clinical trial.The new device-based classes are as follows: catheter-based RDN, baroreflex amplification, arteriovenous (AV) malformation, carotid body (CB) ablation, pacemaker-based cardiac neuromodulation, electro-acupuncture, and deep brain stimulation. Baroreflex amplification uses peripheral neuromodulation, while AV malformation leverages AV anastomosis. CB ablation modulates chemoreceptors, and pacemaker-based neuromodulation adjusts atrioventricular intervals. Electro-acupuncture proves potential, and deep brain stimulation offers central nervous system intervention.

Hormones, autonomic nervous system activity, and criminal behavior

ABSTRACT Evidence that hormones and autonomic nervous system activity exert a joint influence on antisocial behavior suggests that they may work together to explain risk for criminal behavior. Thus, the current study explored the interactive effects of hormones (testosterone, cortisol) and ANS activity (heart rate, skin conductance) on impulsive and violent criminal behavior in a large sample of university students (n = 495). Initial analyses found positive direct associations between impulsive and violent crime and both testosterone and cortisol and a negative direct association between heart rate reactivity and impulsive and violent crime. Subsequent analyses revealed a statistically significant interaction between testosterone and heart rate in association with impulsive and violent criminal behavior. The positive association between testosterone and crime became statistically significant at −.29 standard deviations below the mean (HR = 76.44) and grew stronger as heart rate decreased from this point. The interaction between testosterone and heart rate remains statistically significant after the inclusion of controls for constructs that feature prominently in contemporary criminological theories. Other interactions between hormones and ANS activity were present but were not consistent across alternative model specifications.

Analysis of heart rate variability and anthropometric measurements to compare obesity classes II and III in patients undergoing bariatric surgery

Introduction: obesity is an important public health problem worldwide. It is believed that obese candidates for bariatric surgery present cardiac autonomic dysfunction and that weight reduction achieved through surgical treatment of obesity may promote improvement in autonomic nervous system activity, minimizing cardiovascular risks. Objective: thus, the objective of this study is to assess the impact of surgical bariatric weight reduction on HRV and on anthropometric measurements (BMI, WHtR, and WC) comparing obesity classes II and III. Method: the study included 25 obese individuals who underwent a preoperative assessment. Anthropometric measurements and heart rate varability (HRV) were collected preoperatively. The participants were then divided into two groups: obesity class II and obesity class III (class II: BMI from 35 to 39 k/m2, and class III: BMI from &gt; 40 kg/m2). Thirty days after surgery, a postoperative assessment was performed and the data were compared. Results: our results confirm that both class II and III obesity groups presented altered HRV preoperatively and that the participants in the obesity II group showed a statistically significant increase in the HRV index when compared to the obesity III group, through the mean RR, PNN50, SNS, and stress index. Conclusion: the findings confirmed the important contribution that bariatric surgery makes to improving metabolic health and lowering important obesity indices. The varying alterations in heart rate variability indicate subtle advantages concerning autonomic function, especially for individuals classified as obese II

Intrinsic Motivational States Can Be Classified by Non-Contact Measurement of Autonomic Nervous System Activation and Facial Expressions

Motivation is a primary driver of goal-directed behavior. Therefore, the development of cost-effective and easily applicable systems to objectively quantify motivational states is needed. To achieve our goal, this study investigated the feasibility of classifying high- and low-motivation states by machine learning based on a diversity of features obtained by non-contact measurement of physiological responses and facial expression analysis. A random forest classifier with feature selection yielded modest success in the classification of high- and low-motivation states. Further analysis linked high-motivation states to the indices of autonomic nervous system activation reflective of reduced sympathetic activation and stronger, more intense expressions of happiness. The performance of motivational state classification systems should be further improved by incorporating different varieties of non-contact measurements.