Autonomic Nervous System Activity Research Articles

Autonomic nervous system responses to hypo- and hyperglycemia in type 2 diabetes and prediabetes.

Previous research points to a role of the brain in the regulation of glucose and pathogenesis of type 2 diabetes (T2D) via modulation of counter-regulatory hormone secretion and activity in the autonomic nervous system (ANS). The aim of this study was to investigate glucose-dependent responses of catecholamines and ANS activity in individuals with T2D, prediabetes (PD) and normoglycemia (NG). Cross-sectional. Individuals with T2D (n=19, 7 men, HbA1c 49 mmol/mol), prediabetes (PD, n=18, 8 men) and normoglycemia (NG, n=17, 3 men) underwent one stepwise hyperinsulinemic-euglycemic-hypoglycemic and one hyperglycemic clamp with repeated measurements of catecholamines, symptoms, heart rate variability (HRV) and hemodynamics. The hypoglycemic response of adrenaline was augmented in T2D and PD vs NG (both p<0.05) and there was a strong association with insulin resistance (p<0.05 for M-value). In relation to achieved glucose levels in both clamps, noradrenaline exhibited a steeper rise during hypoglycemia in T2D vs NG and PD (both p<0.05). There were trends toward more marked autonomic hypoglycemic symptoms in T2D vs PD and NG. By contrast, insulin resistance was associated with attenuated responses of heart rate and HRV-indices PLF and PHF at the target glucose plateau of 2.7 mmol/l (p<0.05), independent of BMI and HbA1c. Alterations in glucose-dependent responses of counter-regulatory hormones and the autonomic nervous system appear before, and probably contribute to, the onset of T2D. Together with other reported alterations in neuroendocrine pathways, the findings suggest that a maladaptation of the brain's responses to glucose fluctuations is important in T2D progression.

Potential Mechanisms of Covid-19 Related Nervous System Damage and Effects on Female Fertility.

Signs and symptoms that persist or worsen beyond the "acute COVID-19" stage are referred to as long-COVID. These patients are more likely to suffer from multiple organ failure, readmission, and mortality. According to a recent theory, long-lasting COVID-19 symptoms may be caused by abnormal autonomic nervous system (ANS) activity, such as hypovolemia, brain stem involvement, and autoimmune reactions. Furthermore, COVID-19 can also cause impaired fertility in women, which may also be related to inflammation and immune responses. Currently, few treatments are available for long-COVID symptoms. This article reviews the major effects of COVID-19 on the nervous system and female fertility, as well as offers potential treatment approaches.

Remote Monitoring of Sympathovagal Imbalance During Sleep and Its Implications in Cardiovascular Risk Assessment: A Systematic Review.

Nocturnal sympathetic overdrive is an early indicator of cardiovascular (CV) disease, emphasizing the importance of reliable remote patient monitoring (RPM) for autonomic function during sleep. To be effective, RPM systems must be accurate, non-intrusive, and cost-effective. This review evaluates non-invasive technologies, metrics, and algorithms for tracking nocturnal autonomic nervous system (ANS) activity, assessing their CV relevance and feasibility for integration into RPM systems. A systematic search identified 18 relevant studies from an initial pool of 169 publications, with data extracted on study design, population characteristics, technology types, and CV implications. Modalities reviewed include electrodes (e.g., electroencephalography (EEG), electrocardiography (ECG), polysomnography (PSG)), optical sensors (e.g., photoplethysmography (PPG), peripheral arterial tone (PAT)), ballistocardiography (BCG), cameras, radars, and accelerometers. Heart rate variability (HRV) and blood pressure (BP) emerged as the most promising metrics for RPM, offering a comprehensive view of ANS function and vascular health during sleep. While electrodes provide precise HRV data, they remain intrusive, whereas optical sensors such as PPG demonstrate potential for multimodal monitoring, including HRV, SpO2, and estimates of arterial stiffness and BP. Non-intrusive methods like BCG and cameras are promising for heart and respiratory rate estimation, but less suitable for continuous HRV monitoring. In conclusion, HRV and BP are the most viable metrics for RPM, with PPG-based systems offering significant promise for non-intrusive, continuous monitoring of multiple modalities. Further research is needed to enhance accuracy, feasibility, and validation against direct measures of autonomic function, such as microneurography.

Heart Rate Variability and Interoception in Periodic Limb Movements in Sleep: Interference with Psychiatric Disorders?

Periodic limb movements in sleep (PLMS) are a prevalent disorder characterized by rhythmic, involuntary movements of the lower limbs, such as dorsiflexion of the ankle and extension of the big toe, occurring in periodic intervals during sleep. These movements are often linked to disrupted autonomic nervous system (ANS) activity and altered interoception. Interoception involves perceiving internal bodily states, like heartbeat, breathing, hunger, and temperature, and plays a crucial role in maintaining homeostasis and the mind-body connection. This review explores the complex relationships between PLMS, heart rate variability (HRV), ANS dysregulation, and their impact on psychiatric disorders. By synthesizing the existing literature, it provides insights into how ANS dysregulation and altered interoceptive processes, alongside PLMS, contribute to psychiatric conditions. The review highlights the potential for integrated diagnostic and therapeutic approaches and presents a cause-and-effect model illustrating the mutual influence of psychiatric disorders, ANS dysregulation, PLMS, and interoception.

Effects of long-term transcutaneous auricular vagus nerve stimulation on circadian vagal activity in people with Prader-Willi Syndrome: A case-series

BackgroundPrader-Willi Syndrome (PWS) is a genetic neurodevelopmental disorder marked by disruptions in circadian rhythms and autonomic nervous system (ANS) activity, hyperphagia, and episodes of emotional outbursts. Previous trials suggest that both invasive and non-invasive vagus nerve stimulation (VNS) can reduce emotional outbursts in PWS, potentially through its effects on vagal activity. AimThis case series investigated the effects of transcutaneous auricular VNS (taVNS) on cardiac markers of circadian vagal activity, specifically heart rate variability (HRV) and heart rate (HR), and their potential links to improvements in emotional outbursts. MethodsFive individuals with PWS (mean age: 26.9 years; 3 males, 2 females) received four hours of daily taVNS for 12 months, followed by one month of two-hour daily sessions. Outcome measures included daily recording of emotional outbursts and every three months 24-h HRV and HR recordings. Mixed cosinor models were applied to analyze changes in circadian rhythms of HRV and HR. A linear mixed model was used to assess the predictive value of cardiac vagal activity on emotional outbursts. ResultsCircadian amplitudes of HRV and HR were significantly higher at the end of the treatment compared to baseline (all p’s < .01). There was a significant increase in the rhythm-adjusted mean of HRV (p < .01), while the rhythm-adjusted HR mean significantly decreased, both indicating increased cardiac vagal activity. Higher rhythm-adjusted mean HRV predicted a lower number of emotional outbursts. ConclusionThe results suggest that taVNS may be effective by targeting ANS activity in individuals with PWS, contributing to improvements in behavioral regulation.

Childhood Maltreatment and Electrodermal Reactivity to Stress Among Pregnant Women.

There are competing theoretical hypotheses regarding the consequences of early adversity, such as childhood maltreatment, for individuals' autonomic nervous system activity. Research examining potential implications of child maltreatment for sympathetic nervous system activity, specifically, is scarce. In this preregistered study, we examined whether childhood maltreatment history is associated with pregnant adults' sympathetic responses to different stressors. This population is particularly relevant, given potential intergenerational consequences of pregnant individuals' physiological responses to stress. Pregnant women's (N=162) electrodermal levels were recorded while completing the Trier Social Stress Test (TSST), which elicits social-evaluative threat, and while watching a video of an unfamiliar infant crying, which was intended to activate the attachment system. Pregnant women's retrospective reports of childhood maltreatment were negatively associated with their electrodermal reactivity to the TSST and to the video of the infant crying. Follow-up analyses indicated that these associations were specific to reported experiences of childhood abuse and not childhood neglect. Altogether, these findings indicate that self-reported childhood maltreatment experiences, and childhood abuse in particular, may result in blunted activity of the sympathetic nervous system in response to multiple types of stressors.

Investigating the Impact of Garden Plant Smellscapes on Human Well-Being: A Case Study of Pine Forests

The smellscape of garden plants plays a crucial role in promoting human well-being. Despite this, empirical data on the specific effects of distinct stimulation methods on public health remain insufficient. The objective of this research is to investigate the influence of three distinct sensory modalities, olfactory, visual, and their combined effect, on both physiological and psychological reactions to a pine forest’s smellscape. A sample of 95 college students was selected, with data collected through both physiological and psychological measurements. The analysis focused on variables such as blood pressure (BP), pulse rate (P), pulse pressure (PP), skin conductance (SC), brainwave patterns (α, β), the odor emotion semantic differential (SD), and the State Anxiety Inventory (S-AI) scale. The results reveal that in the pine forest aroma environment, the central nervous system shows a compromise effect during olfactory–visual interaction, with greater autonomic nervous system (ANS) activation compared with either stimulus alone, suggesting cumulative effects. Psychologically, the influence of olfactory interaction on anxiety fell between that of visual and olfactory stimulation. Participants consistently reported that the combination of both the sight and scent of a pine forest was the most invigorating. Furthermore, research revealed that combining olfactory and visual stimuli led to a more profound amplification of positive environmental perceptions compared with when each sense was engaged individually. These findings lay the groundwork for understanding how garden plant aromas contribute to human well-being.

Investigating the effects of artificial baroreflex stimulation on pain perception: A comparative study in no-pain and chronic low back pain individuals.

The autonomic nervous system (ANS) and pain exhibit a reciprocal relationship, where acute pain triggers ANS responses, whereas resting ANS activity can influence pain perception. Nociceptive signalling can also be altered by 'top-down' processes occurring in the brain, brainstem and spinal cord, known as 'descending modulation'. By employing the conditioned pain modulation (CPM) paradigm, we previously revealed a connection between reduced low-frequency heart rate variability and CPM. Individuals with chronic pain often experience both ANS dysregulation and impaired CPM. Baroreceptors, which contribute to blood pressure and heart rate variability regulation, may play a significant role in this relationship, although their involvement in pain perception and their functioning in chronic pain have not been sufficiently explored. In the present study, we combined artificial 'baroreceptor stimulation' in both pressure pain and CPM paradigms, seeking to explore the role of baroreceptors in pain perception and descending modulation. In total, 22 individuals with chronic low back pain (CLBP) and 29 individuals with no-pain (NP) took part in the present study. We identified a differential modulation of baroreceptor stimulation on pressure pain between the groups of NP and CLBP participants. Specifically, NP participants perceived less pain in response to baroreflex activation, whereas CLBP participants exhibited increased pain sensitivity. CPM scores were associated with baseline measures of baroreflex sensitivity in both CLBP and NP participants. Our data support the importance of the baroreflex in chronic pain and a possible mechanism of dysregulation involving the interaction between the ANS and descending pain modulation. KEY POINTS: Baroreflex stimulation has different effects on pressure pain in participants with chronic pain compared to matched individuals with no-pain. Baroreceptor activation decreases pain in participants with no-pain but increases pain perception in participants with chronic pain. Baroreflex sensitivity is associated with conditioned pain modulation in both groups of chronic pain and no-pain participants. The reactivity of the baroreflex during autonomic stress demonstrated a positive correlation with Pain Trait scores in participants with chronic back pain.

Evaluating the Effects of Different Cognitive Tasks on Autonomic Nervous System Responses: Implementation of a High-Precision, Low-Cost Complementary Method.

We developed a low-cost, user-friendly complementary research tool to evaluate autonomic nervous system (ANS) activity at varying levels of cognitive workload. This was achieved using visual stimuli as cognitive tasks, administered through a specially designed computer-based test battery. To assess sympathetic stress responses, skin conductance response (SCR) was measured, and electrocardiograms (ECG) were recorded to evaluate heart rate variability (HRV), an indicator of cardiac vagal tone. Twenty-five healthy adults participated in the study. SCR and ECG recordings were made during both tonic and phasic phases using a computer-based system designed for visual stimuli. Participants performed a button-pressing task upon seeing the target stimulus, and the relationship between reaction time (RT) and cognitive load was evaluated. Analysis of the data showed higher skin conductance levels (SCLs) during tasks compared to baseline, indicating successful elicitation of sympathetic responses. RTs differed significantly between simple and cognitive tasks, increasing with mental load. Additionally, significant changes in vagally mediated HRV parameters during tasks compared to baseline highlighted the impact of cognitive load on the parasympathetic branch of the ANS, thereby influencing the brain-heart connection. Our findings indicate that the developed research tool can successfully induce cognitive load, significantly affecting SCL, RTs, and HRV. This validates the tool's effectiveness in evaluating ANS responses to cognitive tasks.

Feasibility of Early Assessment for Psychological Distress: HRV-Based Evaluation Using IR-UWB Radar.

Mental distress-induced imbalances in autonomic nervous system activities adversely affect the electrical stability of the cardiac system, with heart rate variability (HRV) identified as a related indicator. Traditional HRV measurements use electrocardiography (ECG), but impulse radio ultra-wideband (IR-UWB) radar has shown potential in HRV measurement, although it is rarely applied to psychological studies. This study aimed to assess early high levels of mental distress using HRV indices obtained using radar through modified signal processing tailored to reduce phase noise and improve positional accuracy. We conducted 120 evaluations on 15 office workers from a software startup, with each 5 min evaluation using both radar and ECG. Visual analog scale (VAS) scores were collected to assess mental distress, with evaluations scoring 7.5 or higher classified as high-mental distress group, while the remainder formed the control group. Evaluations indicating high levels of mental distress showed significantly lower HRV compared to the control group, with radar-derived indices correlating strongly with ECG results. The radar-based analysis demonstrated a significant ability to differentiate high mental distress, supported by receiver operating characteristic (ROC) analysis. These findings suggest that IR-UWB radar could be a supportive tool for distinguishing high levels of mental stress, offering clinicians complementary diagnostic insights.

Monitoring surgical nociception using multisensor physiological models

Monitoring nociception, the flow of information associated with harmful stimuli through the nervous system even during unconsciousness, is critical for proper anesthesia care during surgery. Currently, this is done by tracking heart rate and blood pressure by eye. Monitoring objectively a patient's nociceptive state remains a challenge, causing drugs to often be over- or underdosed intraoperatively. Inefficient management of surgical nociception may lead to more complex postoperative pain management and side effects such as postoperative cognitive dysfunction, particularly in elderly patients. We collected a comprehensive and multisensor prospective observational dataset focused on surgical nociception (101 surgeries, 18,582 min, and 49,878 nociceptive stimuli), including annotations of all nociceptive stimuli occurring during surgery and medications administered. Using this dataset, we developed indices of autonomic nervous system activity based on physiologically and statistically rigorous point process representations of cardiac action potentials and sweat gland activity. Next, we constructed highly interpretable supervised and unsupervised models with appropriate inductive biases that quantify surgical nociception throughout surgery. Our models track nociceptive stimuli more accurately than existing nociception monitors. We also demonstrate that the characterizing signature of nociception learned by our models resembles the known physiology of the response to pain. Our work represents an important step toward objective multisensor physiology-based markers of surgical nociception. These markers are derived from an in-depth characterization of nociception as measured during surgery itself rather than using other experimental models as surrogates for surgical nociception.

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.

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.