Heart Rate Variability Indices Research Articles

Relationship between heart rate variability and echocardiography indices of cardiac function in healthy individuals.

This study evaluated the relationship between HRV and echocardiography indices of cardiac function. Healthy individuals (N = 30) aged 33 ± 10 years old, underwent short-term resting HRV assessment and transthoracic echocardiography with speckle tracking analysis. Time domain - (i.e. R-R interval, root mean square of successive RR interval difference (RMSSD), standard deviation of normal RR intervals (SDNN) and frequency domain-measures of HRV (i.e. high-frequency power (HF), low-frequency power (LF), high-frequency normalised (HFnorm) and low-frequency normalised (LFnorm)). Echocardiography indices of cardiac function included; Left ventricular ejection fraction (LVEF), left- and right-ventricular global longitudinal strain (LV-GLS, and RV GLS), left atrial strain: left atrial reservoir (LAres), left atrial conduit (LAcon) and left atrial contraction (LACT). The mean values for HRV time-domain measures were: R-R (991 ± 176 ms), SDNN (50.9 ± 21.5 ms), and RMSSD (46.8 ± 29.4 ms); and frequency-domain: LF (727 ± 606 ms2), HF (415 ± 35 ms2), LFnorm (56 ± 19.4) and HFnorm (36.5 ± 18.8). Mean values for indices of cardiac function were LVEF (59.9% ± 2.8%), LV-GLS (19.2% ± 1.4%), RV-GLS (21.7% ± 2.7%), LAres (36.8% ± 6.99%), LAcon (26.2% ± 6.95%) and LACT (12.3% ± 3.56%). There was a significant negative relationship between HF and LV-GLS (r = -0.47, p = 0.01) and RMSSD and LVEF (r = -0.39, p = 0.03) respectively. Heart rate variability measures such as high frequency power and RMSSD are associated with left ventricle systolic function in healthy individuals.

Дослідження впливу фаз менструального циклу на функціональний стан кваліфікованої ветеранки спорту з дзюдо

Purpose: to investigate the influence of menstrual cycle phases on the functional status of a qualified female veteran judo athlete. Material and methods. The following methods were used in the study: analysis of scientific and methodological information and Internet sources; generalization of advanced practical experience; measurement of sensorimotor reactions and determination of heart rate variability indices; methods of mathematical statistics. A qualified veteran female judo athlete (Master of Sports of Ukraine) in the age category F2 (1983-1979) took part in the study. We performed 84 measurements of heart rate variability (n=42, HRV in the supine position; n=42, heart rate variability during the test task dedicated to measuring the choice reaction). The measurement was performed using two computer programs for mobile devices running iPadOS «Research HRV» and «HRV SR+CR» during morning hours (7-8 hours) and afternoon hours (17-18 hours). Results: analysis of the dynamics of changes in heart rate variability parameters obtained in the supine position indicates an increase in sympathetic activity in the follicular phase of the menstrual cycle. Analysis of comparisons of heart rate variability parameters in different phases of the menstrual cycle indicates that the greatest number of statistically significant (p<0,05) differences is observed in the first half of the day. These changes indicate the dynamics of the decrease in the tone of the sympathetic part of the autonomic nervous system in the follicular phase when performing test tasks provided by the computer program «HRV SR+CR». Analysis of the study results indicates that the indicators of heart rate variability are also influenced by the measurement conditions. The test tasks of the computer program «HRV SR+CR» provide cognitive load and concentration of attention, especially in the second stage, where it is necessary to choose the sought-after figure. During cognitive tasks there is an increase in the activity of the parasympathetic nervous system, which leads to an increase in heart rate variability. High level of heart rate variability is associated with better cognitive functions and adaptive response to stress. Consequently, these differences in heart rate variability obtained using the «Research HRV» and «HRV SR+CR» programs may be the result of interactions between physiological changes during the menstrual cycle as well as the influence of measurement conditions. Understanding the changes in heart rate variability indices during test tasks related to the manifestation of the choice reaction provides information about the influence of cognitive load and attention concentration on the functional state of the female athlete. This will allow to plan the training process of wrestling taking into account the phases of the menstrual cycle and functional capabilities that are inherent in high-skilled female athletes. Conclusions. The parameters of heart rate variability and sensorimotor reaction time provide information about the functional state of martial artists. Understanding of metabolic and hormonal processes in different phases of the menstrual cycle of qualified wrestlers will allow to optimize their training loads and recovery measures.

Cognitive Behavioral Therapy for Paroxysmal Atrial Fibrillation: Heart Rate Variability, Physical Activity, and Sleep

BackgroundCognitive behavioral therapy for symptom preoccupation in paroxysmal atrial fibrillation (AF-CBT) significantly improved AF-specific quality of life in a recent trial. To what extent this may this may be associated with changes in physiological parameters is yet to be determined. ObjectivesThe purpose of this study was to assess the effects of AF-CBT on heart rate variability (HRV), physical activity, and sleep. MethodsPatients with symptomatic paroxysmal AF on optimal medical therapy (mean ± standard deviation 65.4 ± 8.3 years, 58% females, 61% on beta-blockers) were randomized to a 10-week online AF-CBT (n = 65) or AF education (n = 62). AF-CBT was therapist-led and focused on social and physical avoidance. A 5-day Patch-Holter with an integrated accelerometer was applied at baseline, post-treatment, and at 3-month follow-up to assess AF burden, HRV, physical activity, and sleep duration. Subjective assessments were made by the International Physical Activity (IPAQ) and Insomnia Severity Index questionnaires. ResultsAt baseline, participants walked on average 8040 ± 2600 steps/day and slept 8.0 ± 1.1 hours. Objective and subjective physical activity and sleep duration remained unchanged after treatment, with no significant difference between the groups. The Insomnia Severity Index score went from subclinical insomnia (12.2 ± 6.7) to near normal values (8.1 ± 5.6), a significant change compared to controls (P = 0.032). No changes were found in AF burden or HRV indices at rest during the day or at night. ConclusionsIn this select cohort, AF-CBT decreased insomnia severity but had no impact on HRV or physical activity. Thus, AF-CBT may operate through psychological and behavioral factors that are not targeted by current medical and lifestyle interventions.

Dynamics of Respiratory Rate and Heart Rate Variability when Performing a Cognitive Task of Two Levels of Complexity

The study examined heart rate variability (HRV) and respiratory rate during a cognitive task (reading) at two difficulty levels. Time, frequency and nonlinear analysis of HRV was used. It has been shown that both some indicators of HRV (HR, SDNN, RMSSD, SD2, SD2/SD1) and respiratory rate change with increasing mental load, however, they do not separately demonstrate significant differences at all three stages of the study. Therefore, for the first time for cognitive studies, an integral indicator was used that links the parameters of the heart with respiration – the physiological cost of activity (PhysCost), which was previously used in work with athletes when they performed physical exercises to failure. Changes in the PhysCost showed that differences between a simple and a complex task are observed at all stages of the study. Thus, it has been established that the difference in the functional state of a person in the process of performing a continuous task of two levels of complexity is most reliably revealed when using an integrative indicator connecting the activity of the respiratory system and the circulatory system.

A Cross-Sectional Study on the Effect of Stress on Short-Term Heart Rate Variability and Muscle Strength Among Construction Site Workers

This cross-sectional study investigates the immediate impact of occupational stress on short-term heart rate variability (HRV) and muscle strength among 200 construction workers in Chennai. The Perceived Stress Scale (PSS) was employed to assess stress levels, while HRV was measured using a portable ECG device, focusing on time-domain (RMSSD) and frequency-domain (HF Power) parameters. Muscle strength was evaluated using a MicroFET 2 dynamometer. Pearson correlation and multivariate regression analyses were applied to determine the associations between stress, HRV, and muscle strength, adjusting for confounding factors such as age, body mass index (BMI), and work duration. Results revealed a significant negative correlation between perceived stress and both HRV indices (RMSSD: r=-0.45, p<0.01; HF Power: r=-0.50, p<0.01) as well as muscle strength (r=-0.40, p<0.01). Higher stress levels were associated with reduced HRV and diminished muscle strength. Regression analyses confirmed that stress independently predicted lower HRV (RMSSD: ?=-0.35, p<0.01; HF Power: ?=-0.42, p<0.01) and decreased muscle strength (?=-0.32, p<0.01). These findings suggest that elevated stress negatively impacts both cardiovascular and muscular functioning, potentially increasing the health risks among construction workers. The study highlights the importance of implementing stress management interventions to improve both the physical well-being and productivity of workers in the construction industry.

Heart rate variability-based prediction of early cardiotoxicity in breast-cancer patients treated with anthracyclines and trastuzumab

Abstract Background Cardiotoxicity is a recognized complication in breast cancer (BC) patients undergoing chemotherapy with anthracyclines with or without trastuzumab. However, the prognostic value of heart rate variability (HRV) indexes for early cardiotoxicity development remains unknown. Purpose This study aimed to investigate cardiac autonomic responses to physiological stimuli in BC patients treated with anthracyclines with or without trastuzumab, and to evaluate the predictive value of transthoracic echocardiography (TTE) findings and HRV indexes for early cardiotoxicity. Methods A prospective cohort study involving 50 BC patients was conducted at a tertiary hospital with TTE assessments performed before and three months after chemotherapy. HRV indexes were obtained from continuous electrocardiograms in supine position with spontaneous breathing, active standing, and supine position with controlled breathing. The magnitude of change (Δ) between supine-standing and supine-controlled breathing was calculated. Variables were compared using t-test or ANOVA. Cardiotoxicity predictive value was assessed by ROC curve analysis. A p value of < 0.05 was considered significant. Results In our cohort, the mean age was 50 ± 8 years, and reported comorbidities included diabetes (n= 9), hypertension (n= 17), and dyslipidemia (n= 11). Twenty-three patients fulfilled echocardiographic and troponin cardiotoxicity criteria or both. TTE revealed reduced left atrial conduit strain in the cardiotoxicity group. Mean heart rate increased during all maneuvers at follow-up, with no differences in HRV indexes between patients with or without cardiotoxicity. However, a lower Δ in supine-controlled breathing of several HRV indexes predicted early cardiotoxicity identified by echocardiography (e.g. SDNN ≤ -8.44 ms: Sensitivity = 75%, Specificity = 69%). Conclusion BC patients treated with chemotherapy maintain cardiac autonomic responses to physiological stimuli after 3 months of chemotherapy. However, a lower Δ during active standing and controlled breathing before chemotherapy may predict early cardiotoxicity.Table 1.ROC curve analysisFigure 1.HRV-indexes

Cognitive behavioral therapy for symptomatic paroxysmal atrial fibrillation: effects on physical activity, sleep and heart rate variability

Abstract Background We have devised a novel psychological intervention, cognitive behavioral therapy for paroxysmal atrial fibrillation (AF-CBT), that targets symptom preoccupation and avoidance behaviour. AF-CBT significantly improved cardiac anxiety and quality of life (QoL) in a randomized trial. To what extent this may be attributed to changes in physiological parameters is yet to be determined. Purpose A) to assess changes in objective and subjective measures of physical activity and sleep. B) to evaluate potential treatment effects on heart rate variability (HRV). Methods Patients with paroxysmal AF on optimal medical therapy (65.4±8.3 years, 58% women) and European Heart Rhythm Association Symptom Score ≥2b were randomized to a 10-week therapist-led online AF-CBT (n=65) or a control group (n=62), with the primary outcome of Atrial Fibrillation Effect on Quality-of-life (AFEQT). A Patch-Holter with an integrated accelerometer was applied for five days at baseline, post-treatment, and at three months follow-up. Each recording was divided into day and night (sleep time) based on posture, heart rate, and activity. HRV was analysed in both time and frequency domains, excluding AF episodes and aberrant beats. Results AFEQT increased from 62.4±14.3 to 83.7± 13.8 points in the AF-CBT group at the 3-month follow-up with a relative difference of 15.0 points. At baseline, the participants walked 8040±2600 steps/day and slept 8.0 ± 1.1 hours. AF-CBT did not increase physical activity, and there were no significant changes in objective sleep duration. The Insomnia Severity Score went from subclinical (12.2±6.7) to near normal values (8.1±5.6), which was significant as compared to controls (p=0.032). AF burden increased from 5.3% to 7.3% in the AF-CBT group and 5.0% to 9.2% in the control group, with no difference between the groups (p=0.59). We did not observe any change in heart rate or HRV indices at rest during the day or at night. Conclusion AF-CBT did not mediate its effects on QoL by improving objective physiological variables. Thus, our findings underline the importance of subjective, psychological, and behavioural aspects and indicate that AF-CBT might fill a void beyond medical and lifestyle interventions in comprehensive AF care.

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.

Effects of six antipsychotic drug treatment regimens on short-term heart rate variability in patients with schizophrenia.

Many antipsychotic drugs have cardiac side effects due to their pharmacological actions. Heart rate variability (HRV) analysis can be used as a potential indicator of cardiotoxicity in cases where a decrease in HRV occurs after the administration of antipsychotics such as clozapine. The purpose of this study was to explore the effects of 6 antipsychotic drug regimens on short-term HRV in patients with schizophrenia. Data from 164 patients with schizophrenia between January 2018 and June 2023 were retrospectively analysed. Based on the drug used for treatment, the patients were categorised into clozapine combination (clozapine combined with aripiprazole, risperidone or ziprasidone), clozapine alone, olanzapine, aripiprazole, ziprasidone or risperidone groups. Heart rate variability indices were calculated using time domain analysis, including the standard deviation of the RR intervals (SDNN), the root mean square of successive RR interval differences (RMSSD) and the percentage of successive RR intervals over 50ms (PNN50). Compared with the pretreatment period, the SDNN, RMSSD and PNN50 were significantly lower in the clozapine combination, clozapine, olanzapine and aripiprazole groups at the end of weeks 2 and 4 of treatment (P < 0.05). However, these indicators in ziprasidone and risperidone groups did not show this significant decrease (P > 0.05). The effects of clozapine combination and clozapine on HRV were greater than for olanzapine, aripiprazole, ziprasidone or risperidone. Attention should be paid to controlling the dosage of clozapine combination and clozapine and monitoring the patient's electrocardiogram during administration.

Heart rate variability indices for predicting cardiorenal outcomes: A lesson from the PERL and ACCORD cohorts.

This commentary highlights the role of heart rate variability (HRV) indices in predicting diabetic kidney disease (DKD) progression, based on findings from the PERL and ACCORD trials. HRV-derived measures from routine ECGs are shown to be strong predictors of rapid kidney function decline in both type 1 and type 2 diabetes, suggesting their potential utility in identifying individuals at high risk for DKD and guiding early preventive interventions.

Normative data on measures of cardiovascular autonomic neuropathy and the effect of pretest conditions in a large Danish non-diabetic CVD-free population from the Lolland-Falster Health Study.

Cardiovascular autonomic neuropathy (CAN) is a common diabetic complication associated with excess morbidity and mortality. CAN is also seen in conditions such as Parkinson's disease. Normative reference data for cardiovascular autonomic function are used to stratify individuals into those with and without CAN. However, reference thresholds for both cardiovascular autonomic reflex tests (CARTs) and heart rate variability (HRV) are scarce and based on small sample sizes. The aim of the study was to establish contemporary normative reference thresholds based on a large non-diabetic population free of cardiovascular disease (CVD). Cardiovascular autonomic function, CARTs and 5-min HRV indices were assessed in individuals without diabetes and CVD from the Lolland-Falster Health Study (2018-2020) by applying the point-of-care device Vagus™. Age-specific normative reference thresholds were estimated by using log-transformed quantile regression models at the 5th and 10th percentile, with adjustments made for sex. Models assessing the association between age and HRV indices were further adjusted for heart rate. We present age-specific normative reference thresholds for cardiovascular autonomic function, including CARTs and HRV, for 875 individuals (48% females) aged 15-85years. The reference thresholds are presented for both the 5th and 10th lower percentile. Higher age was inversely associated with all outcomes. Females tended to have a higher parasympathetic drive compared to males. Pre-test conditions did not affect CARTs significantly. The presented age-related normative reference thresholds for both CARTs and HRV indices based on a large Danish cohort may facilitate improved quality of research and treatment.

Measuring psychological immersion through cardiovascular response measures in subtitled films

Abstract This paper presents a conceptual replication of Kruger et al.’s (2017a) study, investigating the utility of heart rate (HR) and heart rate variability (HRV) indicators as objective measurements of psychological immersion in subtitled audiovisual products. The study employed a quasi-experimental design in ten participants viewing video clips with and without subtitles, while their physiological responses were monitored. Results suggest lower arousal levels in both conditions compared to baseline, with statistically significant differences observed in mean HR, mean RR, and RMSSD for the subtitles condition. While most inferential tests did not yield significant outcomes, descriptive trends indicate decreased arousal relative to the baseline. They also show increased arousal throughout the clip for most indicators and opposing trends for Mean HR, RMSSD and LF/HF between the two conditions. Methodological suggestions include using multiple data points for HR and HRV analysis, exploring ultra short-term measurements, selecting self-contained clips for viewing, and considering post-task baselines for a more accurate resting state representation. Despite limitations due to the small sample size, this study underscores the potential of HR and HRV as measures of immersion in translated audiovisual products, emphasising the need for larger sample sizes in future research to enhance statistical power and generalizability.

HEART RATE VARIABILITY IN FOOTBALL PLAYERS AND TRACK AND FIELD ATHLETES

Objective of the study: To investigate the state of the autonomic nervous system in athletes based on heart rate variability indicators. Materials and methods: The study was conducted on 142 male athletes (67 football players and 75 track and field athletes) aged 17-20 years, with an average age of 18.5±1.5 years. Depending on the type of higher nervous activity, athletes were divided into 4 groups: sanguine (41.55%), choleric (28.87%), phlegmatic (19.01%), and melancholic (10.56%). Heart rate variability (HRV) was studied using the "BioMouse" system. A t-test for independent samples (Welch's t-test) was used to analyze the significance of differences between the groups. Results of the study: It was found that the highest adaptive capabilities were observed in phlegmatic athletes, who demonstrated high SDNN and HF values, as well as a low tension index (IN). Their calm temperament allows for better adaptation to physical exertion and maintaining a balance between sympathetic and parasympathetic activity. The lowest adaptive capabilities were observed in melancholics, who showed high IN and LF values, as well as low SDNN and HF, indicating an imbalance in the autonomic nervous system and lower resilience to physical stress. Overall, beginner athletes tended to have slightly higher heart rates and lower HRV indicators (SDNN), LF, and HF compared to more experienced athletes of the 2nd-3rd ranks. This is due to the fact that first-year athletes have not yet fully adapted to physical loads, leading to more pronounced dominance of the sympathetic nervous system and less parasympathetic activity. KEYWORDS: variability, heart rate, athletes, football players, track and field athletes, autonomic nervous system, physical exertion

Psychophysiological markers of athlete burnout: a call to arms.

Burnout is a growing problem in high-performance sport and has negative consequences for athletes (e.g., mental ill-health). It is therefore important to effectively monitor athlete burnout to aid intervention efforts. While self-report measures are available (e.g., athlete burnout questionnaire), the limitations associated with these measures (e.g., social desirability bias) means that objective physiological markers may also be useful. Thus, this article critically discusses potential biomarkers of athlete burnout, drawing on research inside and outside of sport to offer an overview of the current state-of-the-art in this research area. First, it outlines what athlete burnout is, its deleterious consequences, and discusses existing psychological assessments. The article then critically discusses literature on hypothalamic-pituitary-adrenal axis (e.g., salivary cortisol) and autonomic nervous system (e.g., heart rate variability) indices of burnout, highlighting some promising biomarkers for future research (e.g., salivary cortisol at bedtime, vagally-mediated heart rate variability at rest). Finally, the article concludes by highlighting key considerations and offering recommendations for future research (e.g., use of more homogenous methods in assessing burnout and physiological parameters). As a result, the intention of this article is to spark more higher quality research on the psychophysiology of athlete burnout, thereby helping tackle this prominent issue in high-performance sport.

Impact of slouching on heart rate variability and cardiovascular health among medical students

Background: Medical students frequently adopt poor postures such as slouching potentially impacting health. Heart rate variability (HRV) serves as an indicator of autonomic nervous system function, correlated with cardiovascular health. Aims and Objectives: The objective of the study was to compare HRV parameters among medical students in three postures: Sitting erect, easy pose (cross-legged), and slouching (stooping head and shoulders). Materials and Methods: A comparative cross-sectional study enrolled 26 male medical students. Participants were instructed to maintain each posture for 5 min while HRV was recorded using a Polar V800. Time domain and frequency domain parameters among different postures were analyzed using Friedman’s test and post hoc tests for pairwise comparisons. P&lt;0.05 was considered significant. Data were expressed as median interquartile range. Results: Significant differences were observed in HRV parameters between postures. The easy pose demonstrated a significantly higher median value of root mean square of differences of successive RR intervals (48.28 ms vs. 35.35 ms) and pNN50% (24.40% vs. 13.62%) compared to slouching. Frequency domain analysis revealed a significantly higher median value of high-frequency (HF) power in easy pose (626.56 ms² vs. 378.15 ms²) and HF normalized unit (33.78 vs. 22.55) compared to slouching. A lower low frequency (LF)/HF ratio and (1.96 vs. 3.43) lower LF normalized unit (66.18 vs. 77.30) was also seen in easy pose. Although statistically not significant, the parasympathetic indicators of HRV were higher in erect sitting compared to slouching posture. Conclusion: Among medical students, adopting the easy pose (cross-legged sitting) appeared to enhance HRV and thus increase parasympathetic activity, whereas adopting slouching postures decreased it.

Влияние регуляторного пептида тафтцин-pro-gly-pro на показатели вариабельности ритма сердца крыс в условиях различной физической активности

Background: The cardiotropic effects of a synthetic peptide with the anxiolytic activity of taftsinPro-Gly-Pro (taftsin-PGP) under stress was investigated. Previously, the effect of this peptide on the state of the cardiovascular system, which plays an important role in the adaptive reactions of the body under stress, has not been studied. The aim of the study: To study the effect of the regulatory peptide taftsin-Pro-Gly-Pro on the heart rate variability (HRV) indices of rats under conditions of various motor activity. Materials and methods: The study was performed on 48 Wistar rats. HRV indices were recorded using the Physiobelt 2.5.1 complex (Neurobotics, Russia) and analyzed by statistical, geometric and spectral indicators. Taftsin-PGP was administered intraperitoneally at doses of 80, 250 and 750 μg/kg once in a volume of 1 μg/kg. The study was performed in 4 stages: 1 – after adaptation to the device (before the introduction of the peptide), 2 – 15 minutes after the introduction of the peptide, 3 – after physical exertion (2-minute treadmill run), 4 – after a 15-minute rest. Results: At a dose of 80 μg/kg, taftsin-PGP had a pronounced adaptogenic effect in the form of maintaining the initial level of functioning of regulatory mechanisms both during physical exertion and during recovery. At a dose of 250 μg/kg, taftcin-PGP led to disorganization of autonomic regulation at the level of the autonomous and central circuits of heart rate regulation. The introduction of the peptide at a dose of 750 μg/kg stabilized the mechanisms of regulation of heart rate with increased physical activity, but caused an imbalance in the regulation of heart rate during recovery. Conclusion: Intraperitoneal administration of taftsin-PGP to Wistar rats had a dose-dependent and multidirectional effect on the regulation of heart rate at all stages of the experiment: at rest (15 minutes after administration), after physical exertion and during recovery.

Effect of Heart Rate Variability Biofeedback on Cardiac Autonomic Activation and Diabetes Self-Care in Patients with Type II Diabetes Mellitus.

In type 2 diabetes mellitus (T2DM), decreased autonomic activation and heightened negative emotions may worsen glycemic control. This study investigated the effects of heart rate variability biofeedback (HRVB) on autonomic activation, negative emotions, diabetes self-care, and glycemic control in patients with T2DM. A total of 61 participants with T2DM were assigned to either the HRVB group (n = 30; 62.67 ± 7.28years; 14 females) or the control group (n = 31; 63.39 ± 6.96years; 14 females). Both groups received the treatment as usual, and the HRVB group received 60min of HRVB sessions weekly for 6weeks. Participants completed psychological questionnaires, a resting electrocardiogram (ECG), and breathing rate assessments at pre- and post-tests. Heart rate variability (HRV) indices were derived from ECG data, and glycated hemoglobin (HbA1c) levels were collected from the electronic medical records. The analysis revealed significant Group × Time interaction effects on HRV indices, breathing rate, depression symptoms, and diabetes self-care behavior. The HRVB group demonstrated higher HRV indices, lower breathing rate, and improved diabetes self-care behavior compared to the control group. Moreover, the HRVB group showed enhanced HRV indices and diabetes self-care behavior, as well as reduced breathing rate and depression in the post-test compared to the pre-test. However, there was no significant interaction effect on HbA1c levels. Six sessions of HRVB proved effective as a complementary therapy for T2DM, enhancing HRV indices, alleviating depressive symptoms, and promoting better diabetes self-care behaviors.

Effects of adipose tissues on the relationship between type 2 diabetes mellitus and reduced heart rate variability: mediation analysis.

Type 2 diabetes mellitus (T2DM) is associated with decreased heart rate variability (HRV) with an unclear intermediate mechanism. This study aimed to conduct mediation analysis to explore the impact of various adipose tissues on the relationship between T2DM and HRV. A total of 380 participants were enrolled for analysis, including 249 patients with T2DM and 131 non-diabetic controls. The thicknesses of four adipose tissues (subcutaneous, extraperitoneal, intraperitoneal, and epicardial) were measured by abdominal ultrasound or echocardiography respectively. HRV was assessed by 24-hour Holter for monitoring both frequency domain indices (LF, HF, and LF/HF) and time domain indices (SDNN, SDANN, SDNN index, rMSSD and pNN50). Mediation analysis was used toexamine whether adipose tissues mediated the relationship between T2DM and each index of HRV. Then, a latent variable - HRV burden - was constructed by structural equation model with selected HRV indices to comprehensively assess the whole HRV. Compared to non-diabetic controls, patients with T2DM exhibited a significant reduction in indices of HRV, and a remarkable increase in the thicknesses of extraperitoneal, intraperitoneal, and epicardial adipose tissues. Mediation analysis found significant indirect effects of T2DM on six indices of HRV, including HF, SDNN, SDANN, SDNN index, rMSSD, and pNN50, which was mediated by epicardial adipose tissue rather than other adipose tissues, with the mediation proportions of 64.21%, 16.38%, 68.33%, 24.34%, 24.10% and 30.51%, respectively. Additionally, epicardial adipose tissue partially mediated the relationship between T2DM and reduced HRV burden (24.26%), which composed by SDNN, SDNN index, rMSSD, and pNN50. Epicardial adipose tissue partially mediated the relationship between T2DM and reduced HRV, which reinforces the value of targeting heart-specific visceral fat to prevent cardiac autonomic neuropathy in diabetes.

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.

Orienteering Is More than Just Running! Acute Effect of Competitive Pressure on Autonomic Cardiac Activity among Elite Orienteering Athletes.

Background and Objectives: Orienteering is a sport characterized by high physical exertion and intense mental demands, which increase susceptibility to errors. Understanding the impact of such errors on psychophysiological responses, particularly on heart rate variability (HRV), is essential. This study aimed to investigate the relationship between psychophysiological indicators and checkpoint errors made by elite orienteers during official competition. Materials and Methods: Fifty-three orienteers participated in this study, and their performance was continuously monitored and recorded by using a global positioning system (GPS) and HRV data. Errors made during the orienteering events were identified and analyzed. HRV data were examined in three temporal segments: before, during, and after the identified and standardized errors. Results: The analyses indicated that errors significantly impacted HRV indices across multiple domains: the time domain, frequency domain, and nonlinear domain. Additionally, a significant effect of sex on the normalized the root mean square of successive differences (r-MSSD) before and after the error was observed. Conclusions: The findings of this study underscore the significant impact of errors made by orienteers on cardiovascular responses, as evidenced by measurable alterations in HRV metrics. Cardiovascular activity, represented by the HRV, can provide useful information for coaches and sport psychologists to adopt effective training programs for athletes.