Parasympathetic Activity Research Articles

Neurobiological and Anti-Inflammatory Effects of a DeepDiaphragmatic Breathing Technique Based on Neofunctional Psychotherapy: A Pilot RCT.

We examined the feasibility of using the neofunctional deep breathing (NDB) technique to reduce the allostatic load following the Trier Social Stress Test (TSST). Forty-four healthy subjects were randomised into experimental and control groups. Following the TSST procedure, participants underwent either a single session of NDB or an attention control intervention. The Procomp Infinity Biofeedback system measured breath per minute (BPM), respiratory amplitude, HRV linear domains, skin conductance, and trapezius muscle electromyographic activity. Cortisol and cytokine salivary concentrations, perceived stress, and anxiety levels were also assessed. These parameters were combined into an allostatic load index (ALI) to measure the intervention's effect. This pilot RCT demonstrated the feasibility of the study design and practicality of the intervention. The NDB group showed reduced ALI, increased respiratory abdominal amplitude, decreased BPM, increased HRV indicating parasympathetic activation, and decreased cortisol and inflammatory cytokines. This study highlighted the feasibility of testing the NDB technique in reducing allostatic load through a neurobiological and anti-inflammatory response after exposure to psychosocial stress. This protocol can represent a non-invasive therapeutic adjutant in disorders related to a dysregulation of the HPA axis or to an inflammatory state. Trial Registration: NCT04102813.

Effects of urination process on heart rate variability.

Heart rate variability (HRV) is used for the assessment of activity of the autonomic nervous system (ANS). As urination is also under the control of the ANS, this study aimed to investigate the usefulness of HRV in the assessment of ANS during the peri-urination period. The psychological effects of sitting on a chair or on the toilet during pre- and post-urination periods were also assessed. Electrocardiogram was used to measure HRV in male participants (n = 40, aged 18-30). They were allowed to drink water to ease urination. At the stage close to voiding, six measurements (each for 90s) were taken sequentially in sitting position (pre-urination chair, pre-urination toilet, urination, post-urination toilet, post-urination chair, and basal post-urination chair). HRV indices included standard deviation of R-R intervals (SDNN), root mean square of successive differences in R-R intervals (RMSSD), percentage of successive R-R intervals differing more than 50ms (pNN50), total power (TP), very-low-frequency (VLF), low-frequency (LF), and high-frequency (HF) bands together with the ratio of LF/HF. HR, SDNN, TP, LF, and LF/HF increased during urination process (P < 0.05), whereas RMSSD, pNN50, and HF increased before urination on toilet (P < 0.05) compared to sitting on a chair before and after urination. HRV indices dynamically reflected the physiological stages of urination. Parasympathetic activity (revealed by pNN50, RMSSD, and HF) increased before urination, whereas sympathovagal balance (revealed by LF/HF) increased during urination. Thus, HRV appears to be a suitable technique for studying physiological and pathological aspects of urination.

Heart rate variability in schizophrenia: A comparative analysis before and after electroconvulsive therapy

AbstractAimThe aim of this study was to investigate autonomic nervous system imbalance in schizophrenia by comparing heart rate variability (HRV) between patients with schizophrenia and healthy controls, and to assess changes in HRV in patients before and after electroconvulsive therapy (ECT).MethodsHRV was compared between patients with schizophrenia (n = 17) and age‐ and gender‐matched healthy controls (n = 34). Changes in HRV were also assessed in patients pre‐ and post‐ECT. Additionally, the relationship between HRV and Positive and Negative Symptom Scale (PANSS) scores in patients with schizophrenia was investigated.ResultsPatients with schizophrenia showed significantly lower high‐frequency (HF) and low‐frequency (LF) power compared with healthy controls, with a trend towards a higher LF/HF ratio. Following ECT, HF power increased significantly while the LF/HF ratio decreased significantly, resulting in no significant differences between patients and controls for these HRV parameters. The associations between HRV and symptoms observed before ECT were largely diminished after ECT, with only changes in the LF component correlating with changes in PANSS scores.ConclusionFollowing ECT, we observed a shift in autonomic balance from sympathetic dominance towards increased parasympathetic activity and a state more closely resembling that in healthy controls.

The effectiveness of cryostimulation exposure on sleep and recovery in male athletes: Timing considerations.

The objectives of the study were (i) to evaluate the effects of whole-body cryostimulation (WBC) after training as an effective tool to improve sleep and recovery and (ii) to determine which exposure schedule for WBC (immediately after training vs. 1h before bedtime) is the most appropriate to improve sleep and recovery. Twenty-two well-trained male athletes or triathletes (23.1±3.5-years) were recruited in this controlled crossover protocol. Each participant completed the three experimental sessions, each composed of a running training session and one night of sleep analysis. Depending on the experimental condition, subjects were exposed-or not (CONT)-to WBC immediately after training (CRYO 7 p.m.) or 1h before going to bed (CRYO 10 p.m.). All participants were randomly assigned to each condition, spaced seven days apart. Sleep was monitored via actimetry, cerebral activity recordings, heart rate variability, body core temperature, and perceptual measurements. WBC after training did not modify subjective or objective sleep parameters compared to the control condition. However, WBC significantly improved cardiac parasympathetic activity. More specifically, it was more activated during the night following the CRYO 10 p.m. condition than in the other experimental conditions. Core body temperature (CBT) 1h after bedtime was the lowest in the CRYO 10 p.m. condition. This study confirmed the effectiveness of WBC as a recovery technique after intense evening training. We suggest that WBC may exhibit the most significant benefit on recovery if the session is performed 1h before bedtime, acting on subsequent parasympathetic activation and CBT drop.

PECULIARITIES OF ORTHODONTIC TREATMENT FOR PATIENTS WITH GENERALIZED PERIODONTITIS AND PREDOMINANCE OF PARASYMPATHETIC NERVOUS SYSTEM ACTIVITY

The use of orthodontic treatment for patients with generalized periodontitis enhances the effectiveness of comprehensive care. However, it is important to consider the reduced capacity for alveolar bone regeneration in these patients. Therefore, as part of the complex treatment of generalized periodontitis, the inclusion of medications to support alveolar bone regeneration is essential. The course of various diseases can be influenced by the state of the patient’s autonomic nervous system. In this study, medications were administered to normalize parasympathetic nervous system activity in patients with generalized periodontitis undergoing orthodontic treatment. The objective of the study was to evaluate the effectiveness of orthodontic treatment in patients with generalized periodontitis, particularly those with a predominance of parasympathetic autonomic nervous system activity. This was assessed by the supplementary use of a combination of drugs designed to stimulate alveolar bone formation and regulate parasympathetic nervous system function. Materials and methods. This study involved 35 young patients (aged 18-35) with generalized periodontitis and a predominance of parasympathetic autonomic nervous system activity, all of whom presented with displacement of the maxillary frontal teeth. These patients underwent orthodontic treatment. To correct the state of the autonomic nervous system over the treatment of generalized periodontitis, patients were prescribed to take a complex of medicines including the preparation “Calcinova” for stimulating osteogenesis. A comprehensive periodontal examination, including the assessment of hygienic indices, was conducted to evaluate periodontal status throughout the treatment. Results. The periodontal examination revealed that almost all patients demonstated an improvement in oral health. Noticeable dynamics in the pathological process were observed as a result of the complex treatment. The analysis of these findings underscores the importance of orthodontic treatment for patients with generalized periodontitis, particularly when combined with methods to correct parasympathetic nervous system activity and promote osteogenesis. This approach was shown to positively affect periodontal tissues and enhance the effectiveness of generalized periodontitis treatment. Conclusions. Correction of parasympathetic autonomic nervous system function enhances the effectiveness of therapy. In this study, a complex of medications was used to improve parasympathetic nervous system activity. The addition of “Calcinova” to stimulate osteogenesis further contributed to achieving more stable treatment outcomes in patients with generalized periodontitis.

Cardiovascular reactivity during conversations about discrimination is buffered by social support among U.S. Latines

Racial discrimination is conceptualized as an acute and chronic stressor. Like other acute stressors, lab-based studies demonstrate acute effects of discrimination-related stressors on stress-related cardiovascular outcomes, including total cardiac output, blood pressure, and indices of sympathetic and parasympathetic nervous system activity. Critically, it is important to understand how individual and social factors buffer the experience of race-related acute stress. The current study extends existing work by measuring cardiovascular indices of stress during conversations about racial/ethnic discrimination and examines the moderating role of social support. Latine/Hispanic participants (N = 97) talked about personal discrimination experiences with either a close other or a research assistant they had never previously met. Participants in both conditions exhibited cardiovascular reactivity indicative of stress during the conversation. Additionally, patterns of reactivity reflected a more adaptive stress response and recovery profile when participants talked about discriminatory experiences with a close other relative to a stranger (less parasympathetic withdrawal during the stressor and more parasympathetic rebound during recovery). These patterns are consistent with a stress buffering account of social support, which suggests social bonds and community-level support are critical to consider in interventions to mitigate the harms of experiencing discrimination and prevent chronic health disparities.

Effectiveness of Facial Massage and Exercise in Alleviating Visual Fatigue: A Systematic Review

Background: With the widespread use of electronic devices, visual fatigue has become a prevalent issue in modern society. Non-pharmacological interventions, such as facial massage and exercise, have been proposed as effective methods for alleviating visual fatigue. However, the specific effects and mechanisms behind these interventions require further exploration. Objectives: This systematic review aims to evaluate the effectiveness of facial massage and exercise in reducing visual fatigue and to explore the underlying mechanisms of these interventions. Methods: A comprehensive search was conducted across multiple databases, including PubMed, Web of Science, Scopus, and the Cochrane Library. Randomized controlled trials and crossover experiments were included for both quantitative and qualitative analyses of relevant studies. Results: The findings suggest that both facial massage and exercise can reduce visual fatigue. Facial massage alleviates eye strain by stimulating the parasympathetic nervous system, reducing stress and anxiety, relaxing muscles, and improving blood circulation. Exercise alleviates visual fatigue through two mechanisms: (1) enhancing overall blood circulation, reducing stress, improving sleep quality, and overall health; (2) directly exercising eye muscles through eye yoga, which helps relieve visual fatigue. Conclusions: Preliminary research indicates that facial massage, full-body exercise, and eye yoga hold potential as non-pharmacological interventions for visual fatigue. Eye yoga has experimental support for its ability to strengthen eye muscles and improve focus. Massage stimulates parasympathetic activity and boosts blood circulation, while full-body exercise enhances systemic circulation to relieve eye fatigue. Future research should focus on investigating the mechanisms of these interventions in more detail and comparing the effects of various types, intensities, and durations to provide more precise clinical recommendations.

Heart rate variability as a biomarker for transdiagnostic depressive and anxiety symptom trajectory in adolescents and young adults.

Internalizing psychopathology is associated with abnormalities in heart rate variability (HRV). Lower HRV that reflects reduced parasympathetic nervous system activity has been observed in depressive and anxiety disorders. Existing studies predominantly used categorical rather than dimensional approaches, the latter of which better addresses clinical comorbidity and heterogeneity. Moreover, there is little evidence on the role of HRV in longitudinal symptom trajectory in adolescents and young adults. The current study examined the association between HRV and internalizing symptom trajectory using a dimensional approach-the tri-level model of depression and anxiety. Adolescents and young adults (N = 362) were recruited in a 3-year longitudinal study, where they completed electrocardiogram recordings and self-report symptom questionnaires. Multilevel modeling was conducted with high-frequency power bands (HF power) of interbeat intervals at baseline as the predictor, and tri-level symptom factors over 3 years as the outcome. HF power significantly predicted the trajectory of the broad General Distress symptom factor, but not the intermediate Fears or Anhedonia-Apprehension symptom factors. Higher HF power was associated with a decline in General Distress over time. This association was held when neuroticism, other tri-level symptom factors, and demographic variables were covaried. That is, greater parasympathetic nervous system activity at baseline was significantly associated with a greater decline in the broad internalizing symptom factor, but not symptom factors that are more specific to depressive or anxiety disorders. Parasympathetic activity, therefore, may be a transdiagnostic biomarker for internalizing symptoms in adolescents and young adults. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Interpersonal Stressors Predicting Inflammation in Adolescents: Moderation by Emotion Regulation and Heart Rate Variability?

This study assessed interpersonal stressors (peer adversity and parental rejection) as predictors of adolescents’ circulating inflammatory markers, while examining emotion regulation and parasympathetic nervous system activity (at rest, reactivity, and recovery) as potential protective moderators. Data were collected in a Belgian cohort of adolescents in 2017 (n=185, 51.4% boys, 10-18y) and 2018 (n=98), and included serum inflammatory markers (CRP, TNFα, IFNγ, IL-6, IL-8 and IL-10), peer adversity, parental rejection, emotion regulation and heart rate variability (RMSSD-HRV, at rest and in 2018 also in response to a Trier Social Stress Test). Contrary to the hypothesis, interpersonal stressors were negatively related to TNFα (in 2017 and 2018), IFNγ (in 2017 and longitudinally) and IL-6 (in 2018). In 23% of the tested associations, HRV at rest was a significant moderator: the negative stressor-inflammation associations were present only among adolescents with low HRV resting values. No significant moderation by HRV reactivity or recovery was detected. After correction for multiple testing, all above-mentioned significant findings disappeared. These unexpected findings may suggest that the positive association between stress exposure and circulating markers of inflammation is not yet detectable in adolescence and perhaps becomes evident only later in life.

Heart rate variability in chronic ischemic stroke: analysis during the sleep-wake cycle.

Alterations of the autonomic nervous system (ANS) in the chronic stage of ischemic stroke (IS) are not well understood. Heart rate variability (HRV) provides a noninvasive approach to assess autonomic function. To compare the HRV parameters during the sleep-wake cycle between patients with IS in the chronic stage and healthy subjects. We conducted a retrospective transversal study based on clinical records and 24-hour electrocardiogram (EKG) monitoring registries of 179 patients with a confirmed IS diagnosis and 184 age- and sex-matched healthy subjects. Circadian variation was calculated according to the variation of the total autonomic activity (VTAI) and the parasympathetic activity (VPAI) indexes. Comparisons were performed using nonparametric tests. Multivariable analyses were performed with canonical discriminant analysis (CDA) and a three-way analysis of variance (ANOVA). Statistical significance was established with a confidence level of 95%. During waking hours, the healthy group exhibited higher variability in the time domain and frequency domain parameters: standard deviation of NN intervals (SDNN, p < 0.001) and of the average NN intervals (SDANN, p < 0.001), as well as low-frequency (LF) band (p < 0.001). During sleep, the difference was higher in the high-frequency (HF) band (p < 0.001), and lower in the low-/high-frequency ratio (LF/HF, p < 0.001). Both VPAI and VTAI showed less significant difference in IS patients (p < 0.001). There was diminished heart vagal activity among IS patients, as measured through HRV. During sleep, this is likely caused by an imbalance in the sympathetic and parasympathetic systems shifting through the sleep phases. These imbalances could persist over time in patients with IS, lasting months after the initial injury.

Effect of a yoga and naturopathy-based lifestyle intervention with nine-month follow-up on heart rate variability in patients with hypertension: A randomized controlled trial

PurposeHypertension is associated with autonomic nervous system (ANS) dysregulation. Heart rate variability (HRV) monitoring is frequently used as a gauge of the ANS balance. The aim of the present study was to assess the effects of yoga and naturopathy on the autonomic variables in patients with hypertension. Methods262 hypertensive patients were randomly allocated to the study group (SG) or control group (CG) in a randomized controlled trial. For ten days, the SG (n = 131) group got received naturopathic treatments and yoga, whereas the CG (n = 131) group did not. HRV which was examined at the beginning and end of the 10-day intervention period and again after 9 months, served as the study's main endpoint. ResultThere was a significant change in the frequency domain of heart rate variability with a significant increase in High frequency (HF) and a significant decrease in low frequency (LF) and LF/HF (all p < 0.05) were observed after follow-up in both SG and CG, but the magnitude of change was more in SG with a significant difference in LF/HF between group. ConclusionResults of this study suggest that 10 days of integrated yoga and naturopathy intervention produces a shift of vagal activity towards parasympathetic activity. Clinical trial registration numberCTRI/2019/01/016883.

Cardiac autonomic dysfunction in Takotsubo cardiomyopathy: an observational study

Abstract Takotsubo syndrome (TTS), commonly perceived as a benign and reversible condition has received attention due to emerging registry data revealing its prognosis to be comparable to acute coronary syndrome (ACS). Following ACS, a notable subset of patients develops autonomic dysfunction, whith unfavourable prognostic implications. Periodic repolarization dynamics (PRD) and deceleration capacity (DC), derived from ECG signals, are parameters capable of quantifying cardiac autonomic function. In this study, we aimed to assess autonomic dysfunction in patients with TTC in comparison to ST-elevation myocardial infarction (STEMI) patients. Consecutive patients diagnosed with TTS were prospectively recruited into an observational, single-centre cohort study. All patients underwent a 30-minute high-resolution ecg recording. Subsequent recordings were conducted at 4 and 12 months post-acute event. PRD and DC as markers for sympathetic and parasympathetic activity, respectively, were assessed using established methods. The control group comprised patients with STEMI. Statistical comparisons between groups were performed using the Mann-Whitney U-test, with a corrected significance level for multiple testing of α&amp;lt; .017. Between July 2021 and December 2023, 57 patients diagnosed with TTS were recruited (interquartile range [IQR]) 69.0 years (62.0-78.0), 98.3% women. A control group was derived from a pre-existing cohort of STEMI patients, matched through propensity score matching to adjust for age and sex (median age [IQR]: 69.0 [59.0-76.0] years, 98.3% women). At baseline, there was no significant difference in PRD between TTS patients and controls (median [IQR]: TTS: 5.28deg² [3.43-9.93], STEMI: 4.40deg² [2.24-7.21]; p = .04). However, at 4 months post-acute event, PRD was notably higher in TTS patients compared to controls (median [IQR]: TTS: 5.20deg² [2.71-8.17], STEMI: 2.63deg² [1.86-4.92]; p = .011). Interestingly, at 12-month follow-up, PRD in TTS patients did not differ from that of controls (median [IQR]: TTS: 4.55deg² [2.89-8.40], STEMI: 4.15deg² [2.42-6.85]; p = .68). Regarding DC, no significant differences were observed between TTS and STEMI patients at any time point (baseline: median [IQR]: TTS: 3.95 ms [2.27-5.51], STEMI: 3.52 ms [2.30-7.24], p = .51; 4 months: median [IQR]: TTS: 6.63 ms [4.59-8.64], STEMI: 7.41 ms [4.63-9.25], p = .39; 12 months: median [IQR]: TTS: 4.98 ms [4.19-6.67], STEMI: 7.48 ms [4.92-10.28], p = .17). Patients with TTS show substantial signs of cardiac autonomic dysfunction, similar or even higher than acute STEMI patients. This dysfunction persists even up to 4 months after the acute event, whereas STEMI patients show recovery of autonomic function in this 4 month period. DC remained consistent between TTS and STEMI patients across all time points. Further research elucidating the long-term implications of these autonomic alterations is warranted to refine risk stratification and therapeutic strategies in TTS management.

A Study on the Physiological Diversity of Hand Bathing under Different Conditions

Achieving the best outcomes and ensuring patients are as comfortable as possible are crucial goals for healthcare professionals. Hospital stress has been linked to worsening patient outcomes and so it is important to implement methods for keeping patients calm. Targeting the autonomic nervous system through hand bathing could provide answers. Associate Professor Hajime Nakano and his collaborators at the Faculty of Nursing, Josai International University, Japan, used precise tools to measure the heart rates of patients bathing their hands in waterbaths maintained at carefully controlled temperatures. The researchers used a probe to non-invasively measure brain activation and found that hand bathing decreased sympathetic nervous system activity, increased parasympathetic nervous system activity and produced feelings of relaxation. Nakano and the team conducted another study in which they activated the sympathetic nervous system in volunteers with mental arithmetic and found that hand bathing significantly suppressed the activation. This led them to posit that thermal stimulation has the potential to impact the stress responses in patients and their motivation in a bidirectional manner, which indicated significant possibilities for clinical applications. The researchers are keen to explore how altering the temperature of the hand bath can positively impact patients and an optimum temperature be selected. The team wants to ensure that interventions are tailored to the unique needs of patients and, as such, observed responses under different conditions and collected vast data that has enabled them to consider a research design that accommodated individual differences.

No improvement in atrial arrhythmia rates in patients on baroreflex activation therapy

Abstract Background Atrial arrhythmias encompass a wide range of abnormal cardiac rhythms including atrial fibrillation, atrial flutter, and atrial tachycardia. Patients with heart failure with reduced ejection fraction (HFrEF) have increased risk of atrial arrhythmias, ultimately leading to increased morbidity. Baroreflex Activation Therapy (BAT) employs an implantable device to increase parasympathetic nervous system activity by stimulating the carotid baroreceptors thereby reducing afterload and heart failure symptoms. In our prior study, BAT therapy has been shown to reduce hospitalization rates in patients with HFrEF. However, the effects of BAT on atrial arrhythmia has never been studied. Objective In this study, we analyzed the effects of BAT on atrial arrhythmia rates in patients with HFrEF. Methods Patients with HFrEF with BAT therapy for at least 12-months at a hospital were retrospectively studied. Inclusion criteria includes implantable cardioverter-defibrillator (ICD) placement of at least 12-months pre- and post-BAT therapy. Additionally, patients diagnosed with atrial arrhythmias prior to the study timeline were excluded. Atrial arrhythmia rates 6 and 12-months pre-BAT therapy and 6 and 12-months post-BAT therapy were compared. Atrial arrhythmia episodes were recorded through ICD interrogation every 1-3 months in the clinic. Of the 31 identified patients on BAT therapy, 11 patients fit the inclusion criteria. For the 11 patients in the study, 3 identified as female and 8 identified as male, 6 identified as white, 4 identified as Hispanic, and 1 identified as African-American with a mean age of 59.8 ± 17.4 years. The average left ventricular ejection fraction pre-BAT therapy was 23.8 ± 10.8%. Results The mean average atrial arrhythmia rates for 6-month pre-BAT therapy and 6-month post-BAT therapy were 0.12/month ± 0.40 and 1.32/month ± 2.76 respectively (p=0.18), suggesting no differences in atrial arrhythmia rates at 6-months with BAT therapy. The mean average atrial arrhythmia rates for 12-month pre-BAT therapy and 12-month post-BAT therapy were 0.11/month ± 0.35 and 2.40/month ± 5.84 respectively (p=0.22), suggesting no differences in atrial arrhythmia rates at 12-months with BAT therapy. Conclusion Although BAT therapy has been shown to decrease hospitalization rates, BAT therapy is not associated with decreased atrial arrhythmia rates at 6 months and 12 months.

Can HRV Biofeedback Training Improve the Mental Resilience of Icelandic Police Officers?

High heart rate variability (HRV) is increasingly recognized as an indicator of a healthy regulatory system, reflecting the dynamic balance between sympathetic (SNS) and parasympathetic (PSNS) nervous system activity. According to the neurovisceral integration model, this balance is managed by the central autonomic network (CAN), comprised of specific brain regions involved in emotional, attentional, and autonomic regulation. HRV thus reflects the performance of the cognitive, affective, and autonomic regulation system. Numerous studies support the relationship between HRV and the CAN, including research on HRV biofeedback training (HRVBF). Studies on the effectiveness of HRVBF for professions such as police officers have shown improvements in self-regulation, decision-making, and performance. However, few studies have specifically explored HRVBF's influence on HRV metrics in police officers, highlighting a need for further research. This study addresses this gap by randomly assigning 27 Icelandic police officers to intervention or wait-list control groups. The intervention group underwent a five-week HRVBF program, including group and individual training sessions. Results showed significant increases in HRV metrics for the intervention group, indicating improved autonomic function and stress resilience. Mental resilience increased significantly as measured by subjective measures of attentional control, mindful awareness, and reduced fatigue. These findings support the efficacy of HRVBF in enhancing HRV and mental resilience for police officers, suggesting its applicability and potential for integration into existing training programs.

Autonomic Modulation in Parkinson’s Disease Using Whole-Body Cryostimulation: A Pilot Study

Background: Parkinson’s disease (PD) is a multifaceted neurodegenerative disorder that progressively affects both the central and peripheral nervous systems. This pilot study aimed to examine the effects of repeated whole-body cryostimulation (WBC) sessions on the sympathovagal balance in PD patients and correlate heart rate variability (HRV) indexes with peripheral biomarkers of the autonomic nervous system (ANS). Methods: Seventeen PD patients with mild to moderate motor severity underwent a 10-session WBC cycle over 5 consecutive days. Thirteen patients (6 males, 7 females; mean age 64.5 ± 9.01 years; mean disease duration 5.4 ± 2.3 years) completed the protocol. Cardiac autonomic activity was assessed through HRV measures including RR interval variability (RR mean, RR min, RR max), power density of high and low frequencies (HF, LF), RMSSD, and the LF/HF ratio. Systemic sympathetic activity was evaluated via circulating blood catecholamine levels. Results: Significant increases were observed in RR mean, RR min, RR max, RMSSD, and HF spectrum, indicating enhanced parasympathetic activity. Blood pressure remained stable, suggesting safety. Conclusions: These findings provide initial support to WBC as a potential “rehabilitation booster” in PD, enhancing sympathovagal balance. Further research is needed to explore the long-term benefits of WBC in PD management.

The Effects of a Single Vagus Nerve's Neurodynamics on Heart Rate Variability in Chronic Stress: A Randomized Controlled Trial.

The modulation of the autonomic nervous system's activity, particularly increasing its parasympathetic tone, is of significant interest in clinical physiotherapy due to its potential benefits for stress-related conditions and recovery processes. This study evaluated the effectiveness of the addition of neurodynamics in enhancing parasympathetic activation in subjects with chronic stress. A clinical trial randomly assigned participants to a group with neurodynamics (6 bpm breathing protocol + manual therapy + neurodynamic technique) or a group without neurodynamics (6 bpm breathing protocol + manual therapy only). Metrics of heart rate variability (HRV), including the Mean Heart Rate (Mean HR), standard deviation of intervals between consecutive heartbeats (SDNN), Heart Rate Difference (Diff. HR), Root Mean Square of Successive Differences (RMSSD), number of intervals differing by more than 50 ms (NN50), percentage of consecutive NN intervals that differed by more than 50 ms (pNN50), and the high-frequency component measured in standardized units (HF), were assessed before, during, and after the intervention. During the intervention, the group with neurodynamics showed significant changes in all variables except in the pNN50 and HF while the group without neurodynamics only showed improvements in the Mean HR, SDNN, and RMSSD. In the post-intervention phase, the group with neurodynamics maintained an increase in HRV while the group without neurodynamics experienced a decrease, suggesting an increase in sympathetic activity. Vagal nerve neurodynamics appear to represent an effective method for enhancing parasympathetic activation in patients with chronic stress. The results highlight the importance of a more comprehensive analysis of HRV variables in order to obtain a correct picture of the impact of interventions on the complex and multifaceted functioning of the autonomic nervous system.

Prior exposure to racial discrimination and patterns of acute parasympathetic nervous system responses to a race-related stress task among Black adults.

Black adults' prior exposure to racial discrimination may be associated with their acute parasympathetic reactivity to and recovery from a new race-related stressor. Existing analytical approaches to investigating this link obscure nuances in the timing, magnitude, and patterns of these acute parasympathetic nervous system (PNS) responses. In a re-analysis of a prior study, we utilize an hidden Markov model (HMM) approach to examine how prior experiences of racial discrimination are associated with intraindividual patterns of (1) physiological states of PNS activity and (2) patterns of and variability in transitions between these physiological states. Participants (N = 118) were Black young adults (range 18-29 years; Mage = 19.67, SDage = 2.04) who completed an online survey to index prior racial discrimination exposure, followed by an in-person lab visit during which their PNS activity in response to a race-related stress task was measured via electrocardiogram and converted into respiratory sinus arrhythmia. HMMs indicated evidence for two states: baseline and a second state representing a significant reduction in respiratory sinus arrhythmia. Most participants (93.22%) demonstrated a blunted response to the task, indicating that they did not transition from baseline during the procedure. Prior racial discrimination was not associated with HMM states or state transition parameters. Blunted physiological responses may be an important area of future investigation that could inform early life course mental and physical health screenings.

Effects of a 30-min rest with a nap chair on task performance, sleepiness, and neurophysiological measures in men with suspected brain fatigue: a randomized controlled crossover trial

BackgroundIt has been suggested that a short nap in the afternoon may improve sleepiness, alertness, and task performance. The present study evaluated the effects of a 30-min rest with a new nap chair on task performance, sleepiness, and neurophysiological measures.MethodsA randomized controlled crossover trial with a 1-week interval was carried out at the BOOCS Clinic Fukuoka in Japan. The subjects were male workers aged 20 to 64 years with suspected brain fatigue, which was defined by the Profile of Mood Status 2. The intervention was a 30-min rest with an office chair or a nap chair. The primary outcome was the performance in the Uchida-Kraepelin test. The secondary outcomes included the Karolinska Sleepiness Scale and 15-min heart rate variability (HRV). The changes after the nap-chair rest and office-chair rest were compared. Repeated measures analysis of variance with nesting was used in the statistical analysis.ResultsTwenty participants were eligible and entered the crossover trial. The overall 15-min score in the Uchida-Kraepelin test improved after the nap-chair rest and after the office-chair rest to almost the same extent (5.9 vs. 5.5 points, P = 0.68). The Karolinska Sleepiness score significantly decreased after the nap-chair rest, and the between-treatment difference in the decrease was highly significant (P = 0.0004). The average duration of sleep during rest was prominently longer in the nap-chair rest than in the office-chair rest (19.0 vs. 7.6 min, P = 0.002). No participants experienced REM sleep during the rest. LF and HF powers of the HRV were greater during the nap-chair rest than during the office-chair rest, the difference in the HF power being substantial.ConclusionA 30-min rest with the nap chair did not appreciably improve the performance in the Uchida-Kraepelin test as compared with the office-chair rest. The nap-chair rest induced a substantially longer sleep accompanied with a parasympathetic activation, thereby resulting in a material improvement in sleepiness after the rest.

Magnetic Garments Promote Parasympathetic Dominance and Improve Sleep Quality in Male Long-Distance Runners Following a 30 km Run.

This study aimed to investigate the effects of high-intensity running on the autonomic nervous system and sleep quality of male long-distance runners and to examine the impact of wearing magnetic garments on these parameters. Fifteen highly trained male collegiate long-distance runners participated in a randomized, double-blind crossover study. Participants completed two 30 km runs (30k-RUN) during a 10-day training camp. After each run, they wore either magnetic (MAG) or non-magnetic control (CTRL) garments. Sleep quality and heart rate variability (HRV) were assessed using a wrist-worn device before and after each 30k-RUN. Wearing MAG garments post-30k-RUN resulted in significantly longer deep sleep duration compared to CTRL. HRV analysis revealed that the MAG condition led to a significantly higher root mean square of successive RR interval differences and high-frequency power, indicating enhanced parasympathetic activity. The low-frequency to high-frequency ratio was significantly lower in MAG than in CTRL. Perceived recovery scores were significantly higher in MAG than in CTRL. The findings of this study suggest that wearing magnetic garments following high-intensity endurance running may promote parasympathetic dominance and improve sleep quality in male long-distance runners. These findings indicate that magnetic garments may be a practical method for enhancing recovery in athletes following intense training.