Standard Deviation Of NN Intervals Research Articles

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.

Factor analysis on the performance of elite male fencing athletes.

We analyzed how stress and heart rate variability affect the performance of male fencing athletes expected to compete in various international events representing Korea. This study included 72 fencing athletes who participated in training and competition from January 2020 to December 2023. The stress was analyzed using the Sports Competition Anxiety Test (SCAT). Heart rate variability (HRV) was measured using an autonomous neurodiagnostic device (SA-6000). Heart rate variability measurement items were time domain analysis (heart rate, standard deviation of NN interval, and root mean square of the successful differences) and frequency domain analysis (total power, low frequency, and low frequency/high-frequency ratio). All athletes were classified into two categories: victory (high performance) and defeat (low performance) groups in the recent national championships. In SCAT, there was no significant difference between high and low performance. After comparing HRV, it was found that there is a significant difference in heart rates (P=0.030) and low frequency/high-frequency ratio (P=0.006) between high and low performance. heart rates and low-frequency/high-frequency ratio during the high performance were observed to be higher than during low performance. In our study, we found that SCAT does not affect performance, while HRV has been shown to have an impact on performance. These findings can be valuable for coaches and athletes in developing strategies to improve performance results, particularly for elite male fencing athletes.

Heart rate variability, electrodermal activity and cognition in adults: Association with short-term indoor PM2.5 exposure in a real-world intervention study

BackgroundLong-term effects of ambient fine particulate matter (PM2.5) exposure on mortality and morbidity are well established. The study aims to evaluate how short-term indoor PM2.5 exposure affects physiological responses and understand potential mechanisms mediating the cognitive outcomes in working-age adults. MethodsThis real-world randomized single-blind crossover intervention study was conducted in an urban office setting, with desk-based air purifiers used as the intervention. Participants (N = 40) were exposed to average PM2.5 levels of 18.0 μg/m3 in control and 3.7 μg/m3 in intervention conditions. Cognitive tests, heart rate variability (HRV), and electrodermal activity (EDA) measures were conducted after 5 h of exposure. Self-reported mental effort, exhaustion, and task difficulty were collected after the cognitive tests. ResultsParticipants in the intervention condition had significantly higher HRV during cognitive testing, particularly in the standard deviation of normal-to-normal intervals (SDNN), root mean square of successive differences (RMSSD), and high-frequency power (HF) indices. Mediation analysis revealed that elevated PM2.5 exposure reduced HRV indices, which mediated the effect on two executive function-related cognitive skills out of 16 assessed skills. No significant differences were found in EDA, self-reported task difficulty, or exhaustion, but self-reported mental effort was higher in the control condition. ConclusionsLower indoor PM2.5 level was associated with reduced mental effort and higher HRV during cognitive testing. Furthermore, the association between indoor PM2.5 exposure and executive function might be mediated through cardiovagal responses. These findings provide insights on the mechanisms through which fine particle exposure adversely affects the autonomic nervous system and how this in turn affects cognition. The potential cardiovascular and cognitive health benefits of PM2.5 reduction warrants further research.

Heart rate variability biofeedback for critical illness polyneuropathy: a randomized sham-controlled study.

Critical illness polyneuropathy (CIP) has been linked to neurocardiac dysfunction mediated by autonomic nervous system dysregulation, which increases mortality. We aimed to assess if heart rate variability (HRV) biofeedback could improve neurocardiac function in CIP. We randomly allocated (1:1) patients with electrophysiologically confirmed CIP undergoing early inpatient neurological rehabilitation to additional HRV or sham biofeedback over 14 days. We evaluated neurocardiac function via standard deviation of normal-to-normal intervals (SDNN) as the primary outcome, as well as HRV frequency domains, sympathetic cutaneous sudomotor and vasomotor functions and disability at baseline, post intervention and 4 weeks later. The study is registered on the German Clinical Trials Register (DRKS00028911). We included 30 patients with CIP (40% females, median [interquartile range] age 64.6 [56, 72] years). We observed an increase in SDNN and the predominantly parasympathetic high frequency domain post intervention (ß = 16.4, 95% confidence interval [CI] 0.2, 32.6 [p = 0.047] and ß = 1179.2, 95% CI 119.9, 2158.5 [p = 0.018]), which was sustained at the 4-week follow-up (ß = 25.7, 95% CI 6.0, 45.4 [p = 0.011] and ß = 25.7, 95% CI 6.0, 45.4 [p = 0.011]). Patients who underwent HRV biofeedback displayed a higher adjusted Barthel index, indicating less severe disability 4 weeks after the intervention compared to those in the sham group (ß = 23.3, 95% CI 5.5, 41.1 [p = 0.014]). Low frequency and sympathetic skin functions did not differ between groups (p = nonsignificant). Our study provides pilot data suggesting that, in patients with CIP, HRV biofeedback can improve neurocardiac function with a predominant effect on the parasympathetic nervous system and has a beneficial effect on functional recovery.

Educational Level Modifies the Relationship between Standard Deviation of NN Intervals and Post-traumatic Stress Disorder Development over Two-years

Educational Level Modifies the Relationship between Standard Deviation of NN Intervals and Post-traumatic Stress Disorder Development over Two-years

Hypertension and its correlation with autonomic nervous system dysfunction, heart rate variability and chronic inflammation

Objective This study investigates the relationship between hypertension, dysregulation of the autonomic nervous system, heart rate variability (HRV), and chronic inflammation. Methods We analysed a cohort of 50 hypertensive patients treated at the affiliated Hospital of Jianghan University. The average systolic and diastolic blood pressures (BPs) in this group were 155.26 and 95.32 mmHg, respectively. A control group of 50 healthy volunteers, undergoing routine physical examinations at the same hospital, was also analysed. Results The average systolic BP of the control group was 115.64 ± 10.27 mmHg, and the average diastolic BP was 75.33 ± 8.25 mmHg. In contrast, the experimental group exhibited an average systolic BP of 155.26 ± 20.13 mmHg and an average diastolic BP of 95.32 ± 12.16 mmHg. Both systolic and diastolic BPs were significantly higher in the hypertensive group (p < 0.05). The experimental group also demonstrated reduced HRV and skin conductance response, alongside increased BP variability (BPV), urinary epinephrine levels and prolonged pupillary light reaction time compared to controls (p < 0.05). Notably, Standard Deviation of Normal to Normal Intervals (SDNN) and Root Mean Square of Successive Differences (RMSSD) values were significantly lower in the experimental group (p < 0.05). Furthermore, levels of inflammatory markers such as CRP, TNF-α, IL-6 and IL-1β were markedly elevated in hypertensive patients (p < 0.05). Negative correlations were observed between systolic and diastolic BP with HRV metrics, while positive correlations were found between BP and BPV as well as urinary adrenaline levels. Conclusions The findings indicate that hypertension is closely associated with autonomic nervous system dysfunction, reduced HRV and increased chronic inflammation. A comprehensive approach to hypertension management should integrate these interrelated physiological and pathological mechanisms, with potential therapeutic interventions targeting autonomic function and inflammatory states.

Elevated correlations in cardiac–neural dynamics: An impact of mantra meditation on stress alleviation

Mantra meditation is a widely practiced technique with a demonstrated ability to promote relaxation and alleviate stress. This study aims to evaluate the impact of regular mantra meditation practice on electroencephalogram (EEG) patterns and heart rate variability (HRV) in young adults grappling with increased stress levels. Furthermore, the study explored possible correlations between these two physiological markers. Thirty-eight participants practiced mantra meditation for eight weeks, and their EEG and HRV were recorded before and after. The pre-post analysis evaluated brain activity and autonomic nervous system regulation alterations by examining EEG and HRV in the time, frequency, and nonlinear domains. Data analysis revealed significant correlations between EEG patterns and HRV indices following mantra meditation, suggesting a potential interconnection between neural and cardiovascular regulation. A notable increase in Root Mean Square of Successive Differences (RMSSD) and Standard Deviation of NN intervals (SDNN) within HRV, along with a decrease in Heart Rate (HR) and Stress Index (SI) and an increase in EEG alpha and theta power, accompanied by a reduction in their ratio, was observed. Three pivotal correlations consistently increased during eight weeks: Alpha/Theta Ratio (ATR) with Low-Frequency/High-Frequency Ratio (LHR), ATR with SD2/SD1 Ratio (SDR), and Relaxation Index (RI) with Stress Index (SI). After eight weeks, these correlations attained statistical significance, optimizing the balance between calmness and vigilance, boosting parasympathetic activity, and reducing chaos between the parasympathetic and sympathetic systems. The study elucidates the scientific mechanisms of mantra meditation, enriching research on its stress-reducing effects and emphasizing mental and physical well-being.

Impact of yoga-based interventions on cognitive and autonomic functions in major depressive disorder population.

Cognitive and autonomic dysfunction is increasingly being recognized as an important clinical dimension in major depressive disorder. The aim of this study is to evaluate the effect of a combined approach of yoga and diet intervention on cognitive and autonomic functions in individuals with major depressive disorders. This experimental observational study was conducted at RUHS College of Medical Sciences and Associated Hospitals, Jaipur, on the major depressive disorder population of either sex cognitive function (mini-mental score, Montreal cognitive protocol A and B, P300 latency and amplitude) and autonomic function parameters (frequency and time domain) were recorded at baseline and after three months of a combined approach of yoga and diet intervention. This study compared cognitive and autonomic function parameters at baseline and after three months of yoga and diet intervention in a major depressive disorder population. Analysis revealed a significant decrease in body mass index (<0.05), systolic blood pressure (<0.001), Hamilton rating scale for depression (<0.001), P300 latency (<0.001), standard deviation of NN interval (SDNN) (<0.001), and mean heart rate (<0.001), whereas there was a significant increase in mini-mental score (<0.001), Montreal cognitive protocol A and B (<0.001), high frequency (HF) (<0.001), root mean square standard deviation (RMSSD) (<0.001), and PNN50 (<0.001) after a combined approach of yoga and diet in the study group as compared to control group participants. Yoga and diet combined may be an effective adjunct therapy for improving brain health and mental performance, lowering the risk of depression by affecting the neurotransmitter system and raising vagal tone which contributes to learning and memory.

Intra- and Inter-Rater Reliability of Linear and Nonlinear Measures of Short-Term Heart Rate Variability Following Combat-Related Traumatic Injury.

Heart rate variability (HRV) is a marker of autonomic function. However, the reliability of short-term HRV measurement in individuals with combat-related traumatic injury (CRTI) remains undetermined. An intra- and inter-rater reliability study was conducted using a subsample (n = 35) of British servicemen with CRTI enrolled in the ongoing ADVANCE study. A five-minute epoch of single-lead electrocardiogram data collected during spontaneous breathing was used to measure HRV. HRV analyses were independently performed by two examiners using Kubios. Intraclass correlation coefficient (ICC), standard error of measurement (SEM), minimum detectable change (MDC), and coefficient of variance were calculated for linear [root mean square of successive difference (RMSSD), standard deviation of NN interval, low-frequency, high-frequency, total power] and nonlinear (SD1-2, acceleration and deceleration capacities, sample entropy) measures. Bland-Altman %plots were used to assess bias in intra- and inter-rater HRV data. The mean age of participants was 39.3 ± 6.3 years. An excellent ICC score of 0.9998 (95% CI 0.9997, 0.9999) was observed for intra-rater analyses of RMSSD, and similar excellent ICC scores were seen for all other HRV measures. The inter-rater reliability analyses produced an excellent ICC score (range 0.97-1.00). Comparatively, frequency-domain measures produced higher MDC% and SEM% scores than time-domain and nonlinear measures in both inter- and intra-rater analyses. The Bland-Altman plots revealed relatively higher bias for frequency-domain and nonlinear measures than time-domain measures. ECG-related short-term HRV measures were reliable in injured servicemen under spontaneous breathing. However, the reliability appeared better with the time-domain measure than frequency-domain and nonlinear measures in this sample.

Autonomic Nervous System and Sarcopenia in Elderly Patients: Insights from Long-Term Heart Rate Variability Monitoring in a Hospital Setting.

Emerging evidence suggests a link between muscle health and the autonomic nervous system, but research is scarce. This study examines the connection between long-term heart rate variability (HRV) measured autonomic function and sarcopenia in the elderly, focusing on muscle mass and strength. This retrospective cross-sectional study comprised 132 elderly hospitalized patients. Sarcopenia was defined according to the European Working Group on Sarcopenia in Older People (EWGSOP2) criteria, involving reduced muscle mass and strength. HRV was assessed using standard deviation of NN intervals (SDNN), with values below 100 milliseconds indicating reduced HRV. Multivariate logistic regression and Pearson's correlation analyses were conducted to explore the associations between sarcopenia, muscle metrics, and HRV parameters. Among elderly hospitalized patients, 45.45% had reduced HRV, with sarcopenia patients showing a fivefold higher risk (OR: 5.042; p = 0.034). Grip strength and SARC-CalF scores were independent factors associated with reduced HRV. Moderate correlations were noted between grip strength and HRV indices, particularly with SDNN (r = 0.393, p = 0.001) and the triangular index (r = 0.385, p < 0.001), while a weaker correlation was found with very low frequency power (VLF) (r = 0.283, p = 0.006). No significant correlations were identified between HRV and muscle mass. Regression analyses revealed significant independent associations between HRV parameters and the decline in muscle strength and the onset of sarcopenia. Reduced HRV is closely linked to sarcopenia and diminished muscle strength in the elderly, with the triangular index and SDNN as key indicators, highlighting HRV's potential in muscle health assessment.

Heart Rate Variability Biofeedback Training Reduces Early Maternal Stress, Anxiety, and Depression in Women Undergoing Cesarean Delivery: A Randomized Controlled Trial.

Women who undergo cesarean delivery have reported experiencing mood distress related to the surgery and postoperative pain. Heart rate variability biofeedback (HRVB) training is known to have positive effects on mental health, but its effects on women undergoing cesarean delivery have not yet been determined. This study evaluated the effects of an HRVB training intervention on stress, anxiety, and depression in women undergoing cesarean delivery. We hypothesized that 10 sessions of HRVB training could cumulatively improve emotion regulation in participants. This study was designed as a double-blinded randomized controlled trial involving a total of 86 enrolled women who were then divided into two groups: intervention and control. During their hospitalization, the intervention group underwent HRVB training daily, while both groups received standard perinatal care. Heart rate variability (HRV) was assessed using root mean square of successive differences (RMSSD), standard deviation of normal-to-normal intervals (SDNN), high-frequency power (HF) and low-frequency power (LF). HRV parameters, stress, anxiety, and depression were evaluated at baseline and on the fifth day after childbirth. Intention-to-treat (ITT) analyses examined change over time between groups. Although no significant effects were found for the RMSSD and HF, a significant increase was observed in SDNN (F = 13.43, p = < 0.001, ƞ2 = 0.14), and LF at post-assessment (F = 4.26, p = .04, ƞ2 = 0.05) compared to the control group. Except for the depression variable, stress (F = 6.11, p = .02, ƞ2 = 0.07) and anxiety (F = 8.78, p = .004, ƞ2 = 0.10) significantly decreased compared to the control group on the fifth postpartum day. Furthermore, post-hoc analysis showed that HRVB was more effective in decreasing mild to severe depressive symptoms (F = 7.60, p = .001, ƞ2 = 0.27). The intervention program successfully decreased self-perceived stress and anxiety in the postpartum period and relieved symptoms in more severely depressed participants. Our findings suggest that this program is suitable and beneficial for application in women during the early postpartum period following cesarean delivery.

Heart rate variability and mortality in critically ill COVID-19 pneumonia patients

BackgroundHeart rate variability (HRV) has prognostic value for predicting mortality in both cardiovascular and sepsis patients. Decreased HRV has been associated with increased mortality and morbidity. However, the prognostic significance of HRV in critically ill patients COVID-19 pneumonia still remains unknown. The current study aimed to (1) evaluate prognostic utility of HRV parameters on outcomes in patients with severe COVID-19 pneumonia and (2) assess the correlation between HRV parameters and inflammatory markers. MethodsConsecutive critically ill patients with COVID-19 pneumonia admitted to a tertiary referral intensive care unit from October 2021 to June 2022 in Bangkok, Thailand were enrolled. HRV parameters over the 24 h following intensive care unit admission were recorded using telemetry and analyzed using the Holter program (Philips Holter 2010 Plus/1810 Series). Receiver-operating characteristic (ROC) curve analysis was used to determine optimum threshold cutoffs of various HRV parameters. Formal comparisons of in-hospital mortality between patients with and without a decrease in HRV were performed using Cox regression after adjusting for potential confounders. ResultsA total of 65 patients were enrolled in the study. Patients were classified into two groups: survivors (n = 44, 68 %) and non-survivors (n = 21, 32 %). The standard deviation of normal-to-normal intervals (SDNN) was significantly lower in non-survivors than in survivors (70.30 vs. 105.95; p = 0.03). The SDNN predicted in-hospital mortality with an area under the ROC curve of 0.67 (95 % CI 0.55–0.79). At a cutoff of 70 ms, the SDNN showed a sensitivity and specificity of 0.48 and 0.86. The low SDNN group (<70 ms) demonstrated higher median ferritin, IL-6, and hs-C-reactive protein levels than did the normal SDNN group, although such differences did not reach statistical significance (1139.0 vs. 508.4; p = 0.137 and 91.2 vs. 64.4; p = 0.352, respectively). After adjusting for potential confounders in the multivariable model, the adjusted hazard ratio for in-hospital mortality in those with SDNN <70 ms was 3.70 (95 % CI 1.34–10.24). ConclusionA decrease in SDNN, a commonly used HRV parameter, was associated with mortality and inflammatory biomarkers in critically ill patients with COVID-19 pneumonia.

Prediction of Micro- and Macrovascular Complications in Type 2 Diabetes Mellitus using Heart Rate Variability.

To explore the utility of heart rate variability (HRV), a noninvasive marker of cardiac autonomic activity, as a prescreening tool for the prediction of micro- and macrovascular complications in type 2 diabetes mellitus (T2DM). Consenting type 2 diabetic patients of both genders between 30 and 70 years, without known micro- and macrovascular complications of diabetes, were enrolled. Patients with medications affecting the HRV were excluded. Prior to other screening tests, 15 minutes of resting electrocardiogram (ECG) (1 kHz) was recorded in enrolled patients, followed by an exercise stress test and assessment for nephropathy, retinopathy, and peripheral neuropathy. The patients with positive stress tests were referred for coronary angiography to confirm coronary artery disease. Based on screening test results, patients were grouped as Group I-T2DM without complications (n = 31) and Group II-T2DM with micro/macrovascular complications (n = 29), (total = 60). Group comparison and test for association were employed, and p-value of <0.05 was considered significant. Significantly reduced HRV (decreased standard deviation of NN interval) between groups and a strong association of HRV indices with complications of diabetes were observed. Logistic regression to classify complicated vs noncomplicated group was used, and an accuracy of 0.78 with 85% sensitivity, 74% specificity with area under the curve (AUC) of 0.83 was observed. Significantly reduced HRV, stronger association with complications, and 85% sensitivity, 74% specificity, and 78% accuracy of classification make HRV indices a promising prescreening tool to predict micro- and macrovascular complications in type 2 diabetes.

Are Wearable Photoplethysmogram-Based Heart Rate Variability Measures Equivalent to Electrocardiogram? A Simulation Study.

Traditional electrocardiography (ECG)-derived heart rate variability (HRV) and photoplethysmography (PPG)-derived "HRV" (termed PRV) have been reported interchangeably. Any potential dissociation between HRV and PRV could be due to the variability in pulse arrival time (PAT; time between heartbeat and peripheral pulse). This study examined if PRV is equivalent to ECG-derived HRV and if PRV's innate error makes it a high-quality measurement separate from HRV. ECG data from 1084 subjects were obtained from the PhysioNet Autonomic Aging dataset, and individual PAT dispersions for both the wrist (n = 42) and finger (n = 49) were derived from Mol et al. (Exp Gerontol. 2020; 135: 110938). A Bayesian simulation was constructed whereby the individual arrival times of the PPG wave were calculated by placing a Gaussian prior on the individual QRS-wave timings of each ECG series. The standard deviation (σ) of the prior corresponds to the PAT dispersion from Mol et al. This was simulated 10,000 times for each PAT σ. The root mean square of successive differences (RMSSD) and standard deviation of N-N intervals (SDNN) were calculated for both HRV and PRV. The Region of Practical Equivalence bounds (ROPE) were set a priori at ± 0.2% of true HRV. The highest density interval (HDI) width, encompassing 95% of the posterior distribution, was calculated for each PAT σ. The lowest PAT σ (2.0 SD) corresponded to 88.4% within ROPE for SDNN and 21.4% for RMSSD. As the σ of PAT increases, the equivalence of PRV and HRV decreases for both SDNN and RMSSD. The HDI interval width increases with increasing PAT σ, with the HDI width increasing at a higher rate for RMSSD than SDNN. For individuals with greater PAT variability, PRV is not a surrogate for HRV. When considering PRV as a unique biometric measure, SDNN may have more favorable measurement properties than RMSSD, though both exhibit a non-uniform measurement error.

The clinical effectiveness of sivelestat in treating sepsis patients with both acute respiratory distress syndrome and septic cardiomyopathy

BackgroundWe aimed to assess the efficacy of the neutrophil elastase inhibitor, sivelestat, in the treatment of sepsis-induced acute respiratory distress syndrome (ARDS) and septic cardiomyopathy (SCM).MethodsBetween January 2019 and December 2021, we conducted a randomized trial on patients who had been diagnosed with sepsis-induced acute respiratory distress syndrome (ARDS) and septic cardiomyopathy (SCM) at Wuhan Union Hospital. The patients were divided into two groups by random envelop method, the Sivelestat group and the Control group. We measured the serum concentrations of Interleukin (IL)-6, IL-8, Tumor necrosis factor-α (TNF-α), and High-mobility group box 1 (HMGB1) at five time points, which were the baseline, 12 h, 24 h, 48 h, and 72 h after admission to the ICU. We evaluated the cardiac function by sonography and the heart rate variability (HRV) with 24-hour Holter recording between the time of admission to the intensive care unit (ICU) and 72 h after Sivelestat treatment.ResultsFrom January 2019 to December 2021, a total of 70 patients were included in this study. The levels of IL-6, IL-8, and TNF-α were significantly lower in the Sivelestat group at different time points (12 h, 24 h, 48 h, and 72 h). HMGB1 levels were significantly lower at 72 h after Sivelestat treatment (19.46 ± 2.63pg/mL vs. 21.20 ± 2.03pg/mL, P = 0.003). The stroke volume (SV), tricuspid annular plane systolic excursion (TAPSE), early to late diastolic transmitral flow velocity (E/A), early (e’) and late (a’) diastoles were significantly low in the Control group compared with the Sivelestat group. Tei index was high in the Control group compared with the Sivelestat group (0.60 ± 0.08 vs. 0.56 ± 0.07, P = 0.029). The result of HRV showed significant differences in standard deviation of normal-to-normal intervals (SDNN), low frequency (LF), and LF/HF (high frequency) between the two groups.ConclusionsSivelestat can significantly reduce the levels of serum inflammatory factors, improve cardiac function, and reduce heart rate variability in patients with Sepsis-induced ARDS and SCM.

Effects of Exercise Training on Heart Rate Variability in Healthy Adults: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

This meta-analysis was conducted to investigate the effects of exercise training on heart rate variability (HRV) parameters associated with the autonomic nervous system (ANS) activity. Randomized controlled trials (RCTs) involving healthy adults (aged ≥ 18 years) were included. We searched PubMed, Scopus, Web of Science, and EBSCO databases to identify relevant studies. A random-effects meta-analysis was performed using the standardized mean difference (SMD) and 95% confidence interval (CI). Sixteen RCTs with a total of 623participants were selected for the final analysis. The analysis showed that exercise training improved the standard deviation of normal-to-normal intervals (SDNN) (SMD: 0.58 (0.16, 1.00); p = 0.007), the root mean square of successive differences in heart period series (RMSSD) (SMD: 0.84 (0.36, 1.31); p = 0.0005), and the absolute power of high-frequency band (HF) (SMD: 0.89 (0.27, 1.51); p = 0.005) parameters compared to the control group. Analysis of the moderator variables showed that the effect of exercise on HRV indices may be influenced by sex, age, and type of exercise used, specifically in HF band, absolute power of low-frequency band (LF), and LF/HF ratio parameters. Despite the limited number of existing RCTs related to the subject, the results suggest that exercise training enhances HRV parameters associated with vagal-related activity (RMSSD and HF) and both sympathetic and parasympathetic activities (SDNN). This study overcomes the lack of meta-analyses on the effects of exercise training on autonomic modulation among healthy adults and may bridge the gap in understanding the potential physiological underpinnings of the acknowledged positive health benefits of exercise.

The Effect of Stress-Reducing Interventions on Heart Rate Variability in Cardiovascular Disease: A Systematic Review and Meta-Analysis.

Stress is recognized as a significant trigger and exacerbator of various medical conditions, particularly in the field of cardiovascular disease (CVD). Given that heart rate variability (HRV) offers insight into the functioning of the autonomic nervous system and has been identified as a predictive factor for increased cardiovascular mortality, exploring the correlation between stress and HRV is pertinent. We systematically reviewed trials where researchers investigated the effects of stress-reducing interventions on biomarkers and time-domain/frequency-domain parameters of HRV in CVD. Eligible studies underwent meta-analysis utilizing a random-effects model. The meta-analysis showed overall beneficial effects of stress-reducing interventions on HRV for the standard deviation of Normal-to-Normal intervals (SDNN) in short-term and 24 h assessments, as well as for the low-frequency power (LF) in short-term assessment. Overall effect sizes were notably high and showed significant p-values (short-term SDNN: MD = 6.43, p = 0.01; 24 h SDNN: MD = 10.92, p = 0.004; short-term LF: MD = 160.11, p < 0.001). Our findings highlight the significant impact of stress-reducing interventions in modulating HRV by influencing short-term SDNN and LF parameters, as well as the 24 h assessment of SDNN. These results emphasize the importance of stress-reducing measures in lowering the risk of further progression in CVD and improving patient outcomes.

Altered cardiac autonomic functioning associates with self-disorders in schizophrenia

Elevated resting heart rate (RHR) and reduced heart rate variability (HRV) are signs of autonomic nervous system dysfunction identified in schizophrenia (SCZ). This dysfunction has been found to manifest prior to the onset of the clinical diagnosis. Yet whether such autonomic dysfunction is associated with vulnerability to schizophrenia remains unknown.This case-control study included recent onset SCZ patients (n = 35) and healthy controls (HC) (n = 33). Patients were scored for self-disorders (SD's) using the EASE manual and all participants underwent a 5-minute resting state electrocardiogram (ECG) recording. Patients were included from outpatient clinics in Denmark. The main measures comprised EASE total scores (SDs), RHR (beats per minute) and three standard HRV measures usually included in testing autonomic nervous system dysfunction: root mean squared of successive differences (RMSSD), standard deviation of normal-to-normal interval (SDNN) and high-frequency/ low frequency ratio (HF/LF). Pearson correlations and linear regression models adjusted for age, sex and medication were used in the SCZ group.The main finding was a positive moderate association between SDs and RHR (r = 0.463; p = 0.005) and a negative association between SDs and HRV (RMSSD) (r = −0.440; p = 0.008) in the SCZ group. Linear regression models found SDs to explain 22 % of the variance of RHR and 19 % in RMSSD. SDs correlated with LF/HF (r = 0.434; p = 0.009), but non-significantly with SDNN.The study provides evidence of an intriguing link between SDs as a susceptibility trait for schizophrenia spectrum disorders and altered cardiac autonomic functioning.

안마의자를 활용하는 마사지가 성인 남녀의 자율신경균형도에 미치는 즉각적 영향: 전향적 관찰연구

Objectives The aim of this study was to examine the immediate impact of a massage chair intervention on homeostasis and the balance of the autonomic nervous system in individuals aged 20 to 64. Methods This study was a single-center, prospective, single-arm, investigator-initiated observational study. Non-underweight adults without significant health concerns underwent a 40-minute massage chair intervention. Measurements of heart rate variability, functional near-infrared spectroscopy, and vital signs were conducted before and after the intervention. Additionally, participants completed the Mibyeong questionnaire and a satisfaction survey. Results A 40-minute massage chair session led to a notable decrease in average heart rate and low frequency to high frequency (LF/HF) ratio, coupled with an increase in root mean square of the successive differences (RMSSD) and standard deviation of NN interval (SDNN). No adverse reactions were noted. Subjects with elevated sympathetic nerve activity exhibited a reduction in LF/HF ratio, whereas those with heightened parasympathetic activity demonstrated an increase in LF/HF ratio post-intervention. Conclusions The findings indicate that the massage chair intervention has the potential to activate the parasympathetic nervous system, promote blood pressure homeostasis and autonomic nervous system balance. However, further research over a more extended period is crucial to validate these conclusions.

Association of sex with heart rate variability in atrial fibrillation patients

Abstract Background Sex-specific differences in cardiac autonomic tone have not been thoroughly investigated in patients with atrial fibrillation (AF) but may play a relevant role. Purpose We aimed to investigate cardiac autonomic function of female compared to male AF patients by means of short-term heart rate variability (HRV) analysis. Methods In this cross-sectional analysis, we enrolled 1150 patients from the Swiss-AF cohort study with 5-minute resting ECG recordings in sinus rhythm. We calculated the following HRV parameters: HRV triangular index (HRVI), standard deviation of NN intervals (SDNN), root mean square of successive differences, mean heart rate, power in the high frequency and low frequency range. We fitted linear regression models to analyze the association between gender and HRV variables adjusted for age, intake of betablockers, hypertension, diabetes and heart failure. Results 361 patients (29%) were female (mean age 72.9±7.8 years), 789 (68.6%) were male (mean age 69.8±8.5 years). In the multivariable adjusted models, female sex was associated with significantly lower values of HRVI (β = -0.74; 95% CI -1.44- -0 04, p=0.039) and SDNN (β = 8.95; 95% CI 0.162-17.7, p=0.046). This association persisted in all three age tertiles (&amp;lt;68 years, 68-75 years and ≥ 75 years of age). Conclusions In an elderly AF cohort, female sex is associated with reduced global autonomic activity. Whether this is associated with an adverse prognosis has to be investigated.