The Relationship between Heart Rate Variability and Adiposity Differs for Central and Overall Adiposity

Direct and indirect effects of adiposity on markers of autonomic nervous system activity in older adults

Several cardiovascular disease (CVD) risk factors (e.g., hypertension, poor glycemic control) can affect and be affected by autonomic nervous system (ANS) activity. Since excess adiposity can influence CVD development through its effect on hypertension and diabetes mellitus, it is important to determine how adiposity and altered ANS activity are related. The present study employed structural equation modeling to investigate the relation between adiposity and ANS activity both directly and indirectly through biological variables typically associated with glycemic impairment and cardiac stress in older adults. Utilizing the Atherosclerosis Risk in Communities (ARIC) dataset, 1,145 non-smoking adults (74±4.8 yrs, 62.8% female) free from known CVD, hypertension, and diabetes and not currently taking beta-blockers were evaluated for fasting blood glucose (FBG), insulin, and HbA1c concentrations, waist circumference (WC), blood pressure (BP), and markers of ANS activity. WC was recorded just above the iliac crest and was used to reflect central adiposity. Resting 2-minute electrocardiograph recordings, pulse wave velocity, and ankle-brachial index data were used to assess the root mean square of successive differences in RR intervals (RMSSD) and the pre-ejection period (PEP), markers of parasympathetic and sympathetic activity, respectively. FBG, insulin, and HbA1c inferred a latent variable termed glycemic impairment (GI), whereas heart rate and diastolic BP inferred a latent variable termed cardiac stress (CS). The structural equation model fit was acceptable [root mean square error of approximation = 0.050 (90% CI = .036, .066), comparative fit index = .970, Tucker Lewis Index = 0.929], with adiposity having both significant direct (β = 0.208, p = 0.018) and indirect (β = -.217, p = .041) effects on PEP through GI. Adiposity displayed no significant direct effect on RMSSD. CS displayed a significant pathway (β = -0.524, p = 0.035) on RMSSD, but the indirect effect of WC on RMSSD through CS did not reach statistical significance (β = -0.094, p = 0.137). These results suggest that adiposity's relation to ANS activity is multifaceted, as increased central adiposity had opposing direct and indirect effects on markers of sympathetic activity in this population of older adults.

Assessment of Cardiac Autonomic Function in Women With Polycystic Ovary Syndrome Through Ewing's Battery, Heart Rate Variability Analysis, and Composite Autonomic Symptom Score-31 Scale

Introduction Polycystic ovary syndrome (PCOS) is a frequently occurring endocrine condition prevalent in women of reproductive age characterized by chronic anovulation, hyperandrogenism, insulin resistance, and a low-grade inflammatory state. Patients with PCOS are more vulnerable to developing cardiac and metabolic co-morbidities. Sympathetic overactivity is also reported in PCOS patients. Objective This study aimed to assess cardiac autonomic function in PCOS by Heart Rate Variability Analysis, Ewing's Test, and Composite Autonomic Symptom Scale-31 (COMPASS-31). Methods Thirty female PCOS patients and 30 age-matched control females were enrolled in the study. Both cases and controls were subdivided into sub-groups based on body mass index (BMI) and waist-to-hip ratio (WHR). The cardiac autonomic functions were assessed by the COMPASS-31 questionnaire, Ewing's battery tests, and short-term heart rate variability analysis. Results There was no significant difference in age, BMI, and WHR of both groups. Additionally, cases had a significantly higher low frequency to high frequency (LF/HF) ratio and COMPASS-31 score and also reported more derangement in Ewing's battery test, indicating cardiac autonomic dysfunction in PCOS patients. Conclusion Patients with PCOS are more prone to developing cardiac and metabolic co-morbidities. Early assessment of cardiac autonomic function can prevent future complications with timely interventions. Altered autonomic function in PCOS patients can be due to hyperandrogenism and insulin resistance.

Association of body indices and risk of mortality in patients with type 2 diabetes

INTRODUCTION

A body shape index (ABSI) is independently associated with mortality in general population, but studies on the predictability of ABSI in the risk of mortality in patients with type 2 diabetes (T2D) are limited. We aimed to examine the independent and joint association of ABSI, body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), and body roundness index (BRI) with mortality in patients with T2D.

RESEARCH DESIGN AND METHODS

The study included 11 872 patients (46.5% women) aged 30 years and older and who took part in diabetes care management program of a medical center in Taiwan. Body indices were evaluated by anthropometric measurements at baseline between 2001 and 2016, and their death status was followed up through 2021. Multivariate Cox regression models were used to assess the effect of body indices on mortality.

RESULTS

During a mean follow-up of 10.2 years, 560 cardiovascular disease (CVD) deaths and 3043 deaths were recorded. For ABSI, WC, WHR, WHtR and BRI, all-cause mortality rates were statistically significantly greater in Q4 versus Q2. For BMI and WHtR, all-cause mortality rates were also statistically significantly greater in Q1 versus Q2. The combination of BMI and ABSI exhibited a superiority in identifying risks of all-cause mortality and CVD mortality (HRs: 1.45 and 1.37, both p<0.01).

CONCLUSIONS

Combined use of ABSI and BMI can contribute to the significant explanation of the variation in death risk in comparison with the independent use of BMI or other indices.

Body fat and muscle in relation to heart rate variability in young-to-middle age men: a cross sectional study

BACKGROUND

While obesity is recognisably associated with changes in heart rate variability (HRV), the association between skeletal muscle mass and HRV is less clear.

AIMS

In this cross sectional study, we analysed the association of body fat (four parameters) and muscle mass (five parameters) with indicators of HRV activity.

SUBJECTS AND METHODS

Assessment of body composition and HRV was performed in n = 180 young-to-middle age healthy men exposed to high occupational physical activity, using the multi-frequency bioelectrical impedance device and the PPG-StressFlow® HRV photoplethysmography device, respectively.

RESULTS

Mean values of parameters of fat tissue were above normal/reference values. Muscle tissue indicators were higher or within the reference ranges. Fat tissue parameters were significantly higher in participants with lower parasympathetic nervous system (PNS) indicators. Weight-adjusted skeletal muscle index (wSMI) was significantly lower in men with reduced PNS parameters. Fat tissue parameters were negatively correlated with PNS parameters, while wSMI was positively correlated with PNS parameters.

CONCLUSIONS

Participants with higher fat mass and lower muscle mass had poorer parasympathetic activity. Since mean values of HRV parameters indicated mild parasympathetic dominance, we conclude that physical activity and consequently good muscle mass potentially compensated for the negative interaction between fat tissue and HRV.

Two-dimensional and three-dimensional multiple object tracking learning performance in adolescent female soccer players: The role of flow experience reflected by heart rate variability

Three-dimensional multiple object tracking (3D-MOT) has been used in various fields to mimic real-life tracking, especially in perceptual-cognitive skills training for soccer. Yet, the learning efficiency in 3D-MOT tasks has not been compared with 2D-MOT. Further, whether the advantage can be reflected by heart rate variability (HRV) based on the neurovisceral integration model should also be examined. Therefore, we used both 2D- and 3D-MOT in a brief adaptive task procedure for adolescent female soccer players with HRV measurement. A faster tracking speed threshold of participants was found in the 3D- compared to 2D-MOT, as well as average tracking speed in the last training period of 3D-MOT. Moreover, lower low frequency (LF) components of HRV in the 3D-MOT indicated a flow experience, demonstrating the provision of more attentional resources. Therefore, we observed that adolescent female soccer players demonstrated higher learning efficiency in 3D-MOT tasks in virtual reality (VR) through a higher flow experience. This study examined the learning efficiency between the two MOT tasks in the soccer domain using evidence from HRV and highlighted the utility and applicability of 3D-MOT application.

Toolkit article: Approaches to measuring social inequities in health in human biology research

Across populations, human morbidity and mortality risks generally follow clear gradients, with socially-disadvantaged individuals and groups tending to have higher morbidity and mortality at all life stages relative to those more socially advantaged. Anthropologists specialize in understanding the proximate and ultimate factors that shape variation in human biological functioning and health and are therefore well-situated to explore the relationships between social position and health in diverse ecological and cultural contexts. While human biologists have developed sophisticated methods for assessing health using minimally-invasive methods, at a disciplinary level, we have room for conceptual and methodological improvement in how we frame, measure, and analyze the social inequities that might shape health inequities. This toolkit paper elaborates on some steps human biologists should take to enhance the quality of our research on health inequities. Specifically, we address: (1) how to frame unequal health outcomes (i.e., inequalities vs. disparities vs. inequities) and the importance of identifying our conceptual models of how these inequities emerge; (2) how to measure various axes of social inequities across diverse cultural contexts, and (3) approaches to community collaboration and dissemination. We end by discussing (4) future directions in human biology research of health inequities, including understanding the ultimate causes of sensitivity to social inequities and transitioning from research to action.

Heart Rate Variability and Laboratory-Based Loss-of-Control Eating in Children and Adolescents

Among youth, greater heart rate (HR) and lesser HR variability (HRV) are precursors to loss-of-control (LOC) eating episodes in the natural environment. However, there are limited data examining whether pre-meal HR and HRV are associated with greater LOC-eating in the laboratory setting. We therefore examined temporal relationships between pre-meal HR, frequency- and time-based metrics of pre-meal HRV, perceived LOC-eating, and energy intake during a meal designed to simulate a LOC-eating episode. Among 209 participants (54.5% female, 12.58 ± 2.72 years, 0.52 ± 1.02 BMIz), 19 reported LOC-eating in the prior month. Perceived LOC-eating during the laboratory meal was not significantly linked to pre-meal HR (p = 0.37), but was positively related to pre-meal HRV (ps = 0.02–0.04). This finding was driven by youth with recent LOC-eating, as these associations were not significant when analyses were run only among participants without recent reported LOC-eating (p = 0.15–0.99). Pre-meal HR and HRV were not significantly related to total energy intake (ps = 0.27–0.81). Additional research is required to determine whether early-stage pediatric LOC-eating is preceded by a healthy pre-meal stress response. Longitudinal studies could help clarify whether this pattern becomes less functional over time among youth who develop recurrent LOC-eating episodes.

Heart rate variability as a function of menopausal status, menstrual cycle phase, and estradiol level

Low estradiol status is associated with increased cardiovascular risk. We sought to determine the association between heart rate variability (HRV), a marker of cardiovascular risk, at baseline and in response to stressor as a function of menopausal status, menstrual cycle phase and estradiol level. Forty-one healthy women (13 postmenopausal, 28 premenopausal) were studied. Eleven premenopausal women were additionally studied in the high and low estradiol phases of the menstrual cycle. HRV was calculated by spectral power analysis (low Frequency (LF), high frequency (HF) and LF:HF) at baseline and in response to graded Angiotensin II (AngII) infusion. The primary outcomes were differences in HRV at baseline and in response to AngII. Compared to premenopausal women in the low estradiol phase, postmenopausal women demonstrated lower baseline LF (p = 0.01) and HF (p < 0.001) measures, which were not significant after adjustment for age and BMI. In response to AngII, a decrease in cardioprotective HRV (ΔHF = -0.43 ± 0.46 ln ms² , p = 0.005 vs. baseline) was observed in postmenopausal women versus premenopausal women. Baseline HRV parameters did not differ by menstrual phase in premenopausal women. During the low estradiol phase, no differences were observed in the HRV response to AngII challenge. In contrast, women in the high estradiol phase were unable to maintain HRV (ΔLF = -0.07 ± 0.46 ln ms² , p = 0.048 response vs. baseline, ΔHF = -0.33 ± 0.74 ln ms2, p = 0.048 response vs. baseline). No association was observed between any measure of HRV and estradiol level. Menopausal status and the high estradiol phase in premenopausal women were associated with reduced HRV, a marker of cardiovascular risk. Understanding the role of estradiol in the modulation of cardiac autonomic tone may help guide risk reduction strategies in women.

Sleep quality and heart rate variability in adolescents with type 1 or type 2 diabetes

INTRODUCTION

Decreased sleep quality and lower heart rate variability (HRV) have both independently been associated with diabetes and may contribute to risks for cardiovascular disease. Although poor sleep quality has been associated with lower HRV in adults with type 2 diabetes (T2D), studies of sleep quality in adolescents with (T2D) or studies examining the possible association of poor sleep quality with lower HRV in adolescents with T2D or T1D are not available.

AIM

Thus, we conducted a secondary analysis of data from an existing study to determine if there were associations between sleep quality and HRV in adolescents with T1D or T2D.

METHODS

Adolescents with T1D (n = 101) or T2D (n = 37) completed 24-h HRV Holter monitoring and analysis and a self-reported global measure of sleep quality.

RESULTS

Poor sleep quality was significantly associated with lower HRV, a known predictor for CV risk. Those with T2D had lower measures of HRV.

CONCLUSIONS

The evaluation of sleep quality and early signs of cardiovascular autonomic changes should be considered in routine assessments of adolescents with diabetes. Future research is warranted to examine more robust measures of sleep and HRV in adolescents with diabetes.

Influence of Obesity on Heart Rate Variability in Nurses with Age and Shift Type as Moderators

Obesity is a risk factor of cardiovascular disease-related mortality and may be associated with changes in the autonomic nerve activity. Nurses working shifts and caring for patients are under great mental and physical pressure, and research has proven that these can negatively affect the body. The objective of this study was to examine the influence of obesity in nurses on their heart rate variability (HRV) and determine whether age or shift type moderates this influence. A questionnaire survey and HRV measurements were conducted on nurses at a hospital in Taiwan during a routine employee health checkup. HRV analysis was conducted using a noninvasive HRV monitor for five minutes. A total of 242 nurses with a mean age of 28.98 ± 6.56 years were enrolled in this study. An overly large waist circumference (WC) had a negative impact on high frequency (HF), low frequency (LF), and standard deviation of normal-to-normal interval (SDNN), while an overly high body mass index (BMI) had a negative impact on very low frequency (VLF) and SDNN. The interaction term “overly large WC × age” had a negative impact on HF (β = −0.21, p = 0.010) and LF (β = −0.18, p = 0.030), whereas the interaction term “overly high BMI×age” had a negative impact on HF (β = −0.27, p = 0.001), LF (β = −0.19, p = 0.023), and VLF (β = −0.17, p = 0.045). The interaction terms “overly large WC × shift type” and “overly high BMI × shift type” did not influence any HRV parameters. As age increased, so did the degree to which the HF and LF of nurses with an overly large WC were lower than normal, and so did the degree to which the HF, LF, and VLF of nurses with an overly high BMI were lower than normal.

Influence of Chronic Exposure to Exercise on Heart Rate Variability in Children and Adolescents Affected by Obesity: A Systematic Review and Meta-Analysis

Background: Sedentary lifestyles are increasingly common amongst children, and insufficient physical activity is a global epidemic estimated to contribute to future incapacities and potential deaths. Objective: We aimed to increase the amount of evidence concerning the effect of chronic exposure to exercise on heart rate variability in children and adolescents affected by obesity. Methods: A systematic review commenced following the PRISMA guidelines developed by Web of Science, Virtual Health Library, PubMed, Cochrane Library, Embase, Ovid, Medline Complete, and Scopus using keywords obtained from the Descriptors in Health Sciences and Medical Subject Headlines (MeSH) terms. We considered (1) Population: Pediatric individuals affected by obesity; (2) Intervention: Exercise; (3) Control: Pre-intervention and sedentary; (4) Outcomes: Clearly presented primary parameters; and (5) Studies: Clinical trials, case controls, case reports, and case series. Results: 11 articles were involved and predominantly included procedures observed during approximately 12 weeks with a distribution of three sessions per week, each session being 30–60 min of aerobic exercise; additionally, the exercise grades were typically completed at a percentage of subjects’ maximum heart rates. The meta-analyses displayed a significant effect on the domains of time (R-R interval, SDNN, rMSSD), frequency (HF ms², HF (n.u.), LF/HF), and the non-linear index (SD1). Conclusions: Chronic exposure to exercise influences heart rate variability in children and adolescents affected by obesity by elevating the variability and parasympathetic activity and improving the sympathetic-vagal balance. Exercises should be recommended for the improvement of cardiac autonomic modulation to prevent the likelihood of further chronic diseases.

Association between Metabolic Syndrome Components and Cardiac Autonomic Modulation among Children and Adolescents: A Systematic Review and Meta-Analysis

Simple Summary

The clustering of metabolic syndrome (MetS) risk factors is becoming more prevalent in young people (up to the age of 19 years) leading to the development of type 2 diabetes (T2D) and cardiovascular diseases in early adulthood. The impact of MetS risk factors on cardiac autonomic modulation (CAM) or vice versa have been noted to track from childhood to pre-adolescence and adolescence. Understating associations in this age group may help improve the clinical outcomes of the MetS, even when MetS symptoms are not visible. Potential damage from each individual MetS component and the ability to predict early cardiac damage or upcoming cardiovascular events is very important. Therefore, the present systematic review and meta-analysis investigated the associations between CAM and MetS risk factors individually to verify which MetS risk components were significantly correlated with which heart rate variability (HRV) indices before or at the onset of the MetS among young people. The purpose of this review was to outline the importance of potentially screening HRV indices in young people even with only one MetS risk factor, as a pre-indicator for early cardiovascular risk stratification. Cross-sectional studies that examined the relationship of MetS risk factors with HRV indices were searched using four databases including PubMed, the Cochrane clinical trials library, Medline and the Web of Science. Correlation coefficients with 95% confidence intervals (95% CI), and random effects meta-analyses of the association between MetS risk factors with HRV indices were performed. Our results propose that lipid profiles including high density lipoprotein (HDL) and triglycerides (TGs), waist circumference (WC) and blood pressure (BP) are associated with CAM in young people up to the age of 19 years. The use of HRV indices to predict future MetS risk, and relationships with individual risk factors including HDL, BP, WC and TGs, were established. Furthermore, arterial pressure, respiration, stress and physical activity must be taken into consideration for future studies along with CAM related to young people (up to the age of 19 years), and it is recommended to explore further the associations reported here, as CAM is not the only determinant of neurovisceral regulation.

Abstract

Background: the clustering of metabolic syndrome (MetS) risk factors is becoming more prevalent in children, leading to the development of type 2 diabetes (T2D) and cardiovascular diseases in early adulthood. The impact of MetS risk factors on cardiac autonomic modulation (CAM) or vice versa has been noted to track from childhood to pre-adolescence and adolescence. Understating associations in this age group may help to improve the clinical outcomes of the MetS, even when MetS symptoms are not visible. Potential damage from each individual MetS component and the ability to predict early cardiac damage or upcoming cardiovascular events is very important. Therefore, the present systematic review and meta-analysis investigated the associations between CAM and MetS risk factors individually to verify which of the MetS risk components were significantly correlated with heart rate variability (HRV) indices before or at the onset of the MetS among young people. The purpose of this review was to outline the importance of potentially screening HRV indices in young people even with only one MetS risk factor, as a pre-indicator for early cardiovascular risk stratification. Methods: cross-sectional studies that examined the relationship of MetS risk factors with HRV indices were searched using four databases including PubMed, the Cochrane clinical trials library, Medline and the Web of Science. Correlation coefficients with 95% confidence intervals (95% CI), and random effects meta-analyses of the association between MetS risk factors with HRV indices were performed. Results: out of 14 cross-sectional studies and one case-control study, 8 studies (10 data sets) provided association data for the meta-analysis. Our results indicated significant positive correlations for systolic blood pressure (SBP) (correlation coefficient 0.13 (95%CI: 0.06; 0.19), I² = 47.26%) and diastolic blood pressure (DBP) (correlation coefficient 0.09 (95%CI: −0.01; 0.18), I² = 0%) with a Low Frequency/High Frequency ratio (LF/HF). Significant negative correlations for waist circumference (WC) (correlation coefficient −0.12 (95%CI: −0.19; −0.04), I² = 51.50%), Triglycerides (TGs) (correlation coefficient −0.09 (95%CI: −0.15; −0.02), I² = 0%) and ≥2 MetS risk factors (correlation coefficient −0.10 (95%CI: −0.16; −0.03), I² = 0%); with high frequency (HF) were revealed. Significant positive correlations for high density lipoprotein (HDL) (correlation coefficient 0.08 (95%CI: 0.05; 0.11), I² = 0%) and significant negative correlations of ≥2 MetS risk (correlation coefficient −0.04 (95%CI: −0.12; 0.03), I² = 0.0%) with low frequency (LF) were revealed. Significant negative correlations for TGs (correlation coefficient −0.09 (95%CI: −0.23; 0.05), I² = 2.01%) with a mean square root of the sum of differences between mean time between two successive intervals (rMSSD) and significant positive correlation of HDL (correlation coefficient 0.09 (95%CI: −0.01; 0.19), I² = 0.33%) with standard deviation of the time between two successive intervals (SDNN) were also revealed. An Egger’s test indicated that there was no obvious publication bias for any of the above relationships except for TGs and rMSSD. The significance level stipulated for the meta-analysis was p < 0.05. Conclusions: lipid profiles (HDL and TGs), WC and BP were associated with CAM in young people up to the age of 19 years. The use of HRV indices to predict future MetS risk, and relationships with individual risk factors including HDL, BP, WC and TGs, were established. Future studies related to young people (up to the age of 19 years) are recommended to explore the associations reported here further.

Differences in heart rate variability and body composition in breast cancer survivors and women without cancer

The aim of this study was to explore cardiac autonomic changes assessed by linear and nonlinear indexes of heart rate variability (HRV) and body composition modifications in breast cancer survivors and cancer-free control women. Women who were breast cancer survivors (BCS, n = 27) and without cancer with similar characteristics (Control, n = 31) were recruited for this study. We calculated some relevant linear and nonlinear parameters of 5 min of RR interval time series such as mean RR interval (RRave), the corrected Poincaré index (cSD1/SD2), the sample entropy (SampEn), the long-term fractal scaling exponent (α2) and 2UV from symbolic dynamics. Additionally, we indirectly assessed body composition measures such as body weight, fat mass, visceral fat rating (VFR), normalized VRF (nVFR), muscle mass, metabolic age, and total body water. We found that diverse HRV indexes and only one body composition measure showed statistical differences (p < 0.05) between the BCS and Control groups. RRave: 729 (648-802) vs. 795 (713-852) ms; cSD2/SD1: 3.4 (2.7-5.0) vs. 2.9 (2.3-3.5); SampEn: 1.5 (1.3-1.8) vs. 1.7 (1.5-1.8); α2: 0.6 (0.3-0.6) vs. 0.5 (0.4-0.5); 2UV: 7.1 (4.3-11.5) vs. 10.8 (6.4-15.7) and nVFR 0.12 (0.11-0.13) vs. 0.10 (0.08-0.12) points/kg, respectively. The nVFR was strongly significantly correlated with several indexes of HRV only in the BCS group.Our findings suggest that BCS exhibit lower parasympathetic cardiac activity and changes in HRV patterns compared to Controls. A concomitant increase of visceral fat, among other factors, may contribute to cardiac autonomic disturbances and changes in HRV patterns in BCS.

Holter-Derived Autonomic Function, Arrhythmias and Carbohydrate Metabolism in Patients with Class III Obesity Treated with Laparoscopic Sleeve Gastrectomy

The effects of weight loss following bariatric surgery on autonomic balance, arrhythmias and insulin resistance are still of interest. We prospectively investigated 50 patients with BMI > 40 kg/m², aged 36.5 (18–56) years who underwent laparoscopic sleeve gastrectomy. Among other examinations, all subjects had 24-h Holter monitoring with heart rate variability (HRV) and heart rate turbulence (HRT) evaluation. After a median of 15 months, BMI decreased from 43.9 to 29.7 kg/m², the incidence of hypertension decreased from 54 to 32% (p = 0.04) and any carbohydrate disorders decreased from 24 to 6% (p = 0.02). Fasting insulin concentration and insulin resistance index improved significantly (p < 0.001). Improvements in HRV parameters related to the sympathetic autonomic division were also observed (p < 0.001), while HRT evaluation was not conclusive. The enhancement of autonomic tone indices was correlated with reduction of BMI (SDNN-I r = 0.281 p = 0.04; SDNN r = 0.267 p = 0.05), but not with reduction of waist circumference, and it was also associated with decrease of mean heart rate (OR 0.02, 95%CI 0.0–0.1, p < 0.001). The incidence of arrhythmias was low and similar before and after follow-up. In conclusion, improvement of homeostasis of carbohydrate metabolism and autonomic function is observed in relatively young patients after weight loss due to laparoscopic sleeve gastrectomy.

Cardiac autonomic dysfunction is associated with hypothalamic damage in patients with childhood-onset craniopharyngioma

BACKGROUND

Autonomic nervous system dysfunction is implicated in the development of hypothalamic obesity. We investigated the relationship between hypothalamic involvement (HI), central obesity, and cardiac autonomic dysfunction by assessing heart rate variability (HRV) indices in patients with childhood-onset craniopharyngioma.

METHODS

A cross-sectional study of 48 patients (28 males, 10-30 years old) with hypothalamic damage after childhood-onset craniopharyngioma was performed. Postoperative HI was graded as mild (n = 19) or extensive (n = 29) on magnetic resonance imaging. Anthropometry, body composition and HRV indices including the standard deviation of all normal R-R intervals (SDNN) and total power (TP) as overall variability markers, root-mean square differences of successive R-R intervals (RMSSD) and high frequency (HF) as parasympathetic modulation markers, and low frequency (LF) as a sympathetic/sympathovagal modulation marker were measured.

RESULTS

Patients with extensive HI had increased means of body mass index, waist circumference, and fat mass than those with mild HI (P < 0.05, for all). Centrally obese patients had a lower mean HF, a parasympathetic modulation marker, than centrally non-obese patients (P < 0.05). The extensive HI group had lower means of overall variability (SDNN and TP), parasympathetic modulation (HF), and sympathetic/sympathovagal modulation (LF) than the mild HI group (P < 0.05, for all). The interaction effect of HI and central obesity on HRV indices was not significant. In models adjusted for age, sex, and family history of cardiometabolic disease, the means of the overall variability indices (P < 0.05 for both SDNN and TP) and a sympathetic/sympathovagal modulation index (P < 0.05 for LF) were lower with extensive HI, without differences according to central obesity.

CONCLUSIONS

The reduced HRV indices with extensive HI suggests that hypothalamic damage may contribute to cardiac autonomic dysfunction, underscoring the importance of minimizing hypothalamic damage in patients with childhood-onset craniopharyngioma.

Assessment of arrhythmias and cardiac autonomic tone at a relatively young age patients with obesity class III

There is no sufficient data on arrhythmias occurrence in obesity class III. The influence of hyperinsulinemia and insulin resistance on arrhythmias and cardiac autonomic tone is also of ongoing interest in these subjects. We prospectively studied 81 selected patients with body mass index >40 kg/m² , aged 34 (18-65) years. Among other examinations all subjects underwent electrocardiography and Holter monitoring with heart rate variability (HRV) and turbulence (HRT) evaluation. Controls consisted of 45 healthy, sex- and aged-matched lean volunteers. In patients median BMI was 44.5 kg/m² (40.1-58.1), benign arterial hypertension was present in 43.2% and dysglycemia in 27.2% of cases. In the group with obesity longer PR interval (P < .001) and corrected QT interval (P < .001) were observed, while in Holter monitoring no significant differences in supraventricular or ventricular arrhythmias and also bradyarrhythmias prevalence were observed in comparison to controls. In individuals with obesity HRV indices associated with sympathetic tone were significantly impaired and also abnormal HRT values (21.9 vs 0%, P = .04) were more frequently observed. There were no significant correlations between anthropometric obesity parameters and fasting insulin concentration, insulin resistance index and also HRV/HRT parameters in studied individuals. Univariate regression analysis revealed that only age influenced abnormal HRT occurrence (OR 1.69, 95%CI 1.08-2.98, P = .04). In conclusions, patients with obesity class III at a relatively young age who reported they felt healthy, do not present increased prevalence of arrhythmias, including life-threatening ones. Cardiac autonomic dysfunction is observed in these patients, however it has not been shown to be associated with anthropometric measurements.

Comparison of effect of aquatic interventions on cardiac modulation of obese young males in motion. A crossover trial

Study aim: The study aimed to compare the effects of passive Watsu therapy and immersion on cardiac locomotor synchronization of obese young males.

Material and methods: Twenty-six volunteer obese males participated in this study (age 18.3 ± 0.32, BMI 36.9 ± 6.52). Heart rate variability parameters were recorded in different positions by the Polar H7 heart rate sensor and HRV+ software. Participants were assigned to two groups, randomly, in a single-blinded crossover design. Kubios HRV 2.2 and MATLAB were used to analyze the bio-signals. Statistical analysis was performed via t-test and ANOVA (analysis of variance) using SPSS. For the significance in results and group comparison, the paired t-test and the independent t-test were used respectively.

Results: Combined results indicated that Watsu therapy increased 3 HRV vertical position parameters and immersion increased 3 HRV non-locomotor parameters, significantly (p < 0.05).

Conclusion: The findings show that Watsu and immersion improved the specific autonomic cardiac modulation. However, non-contact immersion seemed to provide better synchronization of cardiac control and locomotion. The close contact Watsu approach provided improvements in autonomic cardiac regulation. Collectively, these improvements suggest the combination of both therapies in maximizing the cardiac benefits sought by aquatic therapy programs.

Heart rate variation and human body burdens of environmental mixtures in the Cree First Nation communities of Eeyou Istchee, Canada

INTRODUCTION

Heart rate variability (HRV) is a measure of cardiac autonomic regulation that examines the variation in beat-to-beat fluctuations in heart rate. While many exposure-based studies have examined the effects of single or similar groups of contaminants on HRV parameters, none have examined the association between complex environmental mixtures, including organic and elemental contaminants, and HRV.

METHODS

Using data collected from the Multi-Community Environment-and-Health Study in Eeyou Istchee (Quebec, Canada), we assessed HRV in two time domain measures: root mean square of successive differences (RMSSD) and standard deviation of the N-N (RR) intervals (SDNN); and in three frequency domains: high frequency (HF), low-frequency (LF), and very-low frequency (VLF) in 443 participants. We first examined mixture effects of nineteen organic and metal contaminants in blood using principal component analysis (PCA) and a multivariable general linear regression on HRV responses, adjusting for age, sex, body mass index, smoking status, and kidney disease covariates. We subsequently assessed HRV outcome response variables using Bayesian kernel machine regression (BKMR) to further examine individual contaminant contribution and overall mixture effects.

RESULTS

In the PCA, a significant positive association was observed between RMSSD and principal component (PC) axis 2, which was highly positively-loaded for nickel and moderately negatively-loaded for mercury. A negative association between SDNN and PC-1, which was highly positively-loaded for all PCBs (polychlorinated biphenyls) and organochlorines and moderately positively-loaded for mercury, was observed. Additionally, a significant and positive association was observed between PC-2 and SDNN and a significant and negative association between PC-3 (negatively loaded for cadmium) and LF. Associations with contaminants were not observed for HF or VLF. BKMR results suggest that trans-nonachlor and cis-nonachlor are primarily responsible for reductions in HRV; however, their contributions to HRV deficits was non-significant when examined as a complete mixture.

CONCLUSIONS

While PCA results suggested that organochlorines, mercury, nickel, and cadmium may all play a role in altering various HRV, subsequent BKMR analysis illustrated the individual components driving these effects may be trans- and cis-nonachlor and nickel and likely not mercury or cadmium. However, other contaminants appear to temper this effect when the entire mixture of chemicals is assessed as a whole. This study expands our knowledge of the effects of environmental contaminant mixtures on HRV, which is especially important in exposed populations such as those in the Eeyou Istchee territory, whilst utilizing novel statistical methods such as PCA and BKMR to examine co-exposures concurrently.

Heart rate variability in frontal lobe epilepsy: Association with SUDEP risk

OBJECTIVES

Frontal lobe epilepsy (FLE) may impair autonomic heart rate modulation. Decreased heart rate variability (HRV) may enhance risk of sudden death. Our objective was to describe whole day and wakefulness/sleep HRV parameters from FLE patients in comparison with those of healthy controls and correlate HRV parameters to SUDEP-7 scores.

METHODS

Ten patients with FLE and 15 healthy controls underwent a 24-hour electrocardiogram holter. The SUDEP-7 score was calculated for patients. Subgroups were identified according to active epilepsy, number of generalized seizures, cognitive deficit, medication load, and time-length of epilepsy. Time-domain SDNN, SDNNi, SDANN, rMSDD, and pNN50 and frequency-domain LF, HF, and LF/HF parameters were analyzed. Wilcoxon and Spearman correlation tests were used. A P < .05 was considered significant.

RESULTS

Patients SDNN, SDNNi, rMSSD, and pNN50 were decreased in 24-hour recordings. Although a tendency for a protective effect of sleep was seen for both patients and controls, intragroup comparisons of sleeping/waking states revealed a significant increase in sleep rMSSD (P = .046) and pNN50 (P = .041) only for controls. All 24-hour time-domain parameters and LF were inversely and significantly correlated to SUDEP-7, particularly SDANN (ρ = -0.896, P = .00019), known to deteriorate with diminished physical activity and decreased in patients with more generalized seizures. Wakefulness parameters did not correlate to SUDEP-7, whereas correlations to sleep parameters were very strong, particularly with rMSSD (ρ = -0.945, P = .00012). Cognitive deficit was associated with decreased pNN50, sleep pNN50, and LH.

CONCLUSION

HRV is impaired in patients with FLE. Low HRV scores are associated with increased risk for SUDEP as measured by the SUDEP-7 score.

Race and sex differences in cardiovascular autonomic regulation

Racial and ethnic differences in cardiovascular morbidity and mortality persist despite advances in risk factor identification and implementation of evidence-based treatment strategies. African American men and women are disproportionately affected by cardiovascular risk factors, particularly hypertension. In this context, previous studies have identified sex and racial differences in autonomic cardiovascular regulation which may contribute to the development of hypertension and its high morbidity burden among African Americans. In this review, we provide a comprehensive evaluation of the potential pathophysiological mechanisms of blood pressure control and their differences based on sex and race. These mechanisms include obesity-induced sympathetic activation, sympatho-vascular transduction, baroreflex sensitivity and adrenoreceptor vascular sensitivity, which have been the subjects of prior investigation in this field. Understanding the racial differences in the pathophysiology of hypertension and its co-morbid conditions would allow us to implement better treatment strategies tailored to African Americans, with the ultimate goal of reducing cardiovascular mortality in this population.

Influence of ageing on circadian rhythm of heart rate variability in healthy subjects

BACKGROUND

The analysis of the circadian rhythm of heart rate variability (HRV) represents a relevant physiological tool to assess the vagal system. However, the influence of age (mostly >75 years) on HRV is not widely known.

AIMS

The aim of this study was to evaluate the influence of age on HRV, particularly in the elderly and to identify a model of this relationship. The study was carried out by examining linear and nonlinear parameters extracted from HRV, including individuals over 75 years for which there is no research available.

METHODS

Data from 140 healthy subjects were sex matched and divided into young (young group: 15-39 years old), adult (adult group: 40-64 years old) and senior (senior group: 65-90 years old) groups. 24-h Holter monitoring was used and several HRV parameters were extracted from time, and spectral and nonlinear analyses were examined.

RESULTS

Time-domain parameters, mainly standard deviation of the NN interval (SDNN) and number of successive differences of intervals which differ by more than 50 ms, presented significant differences between the young group and the other two groups during the 24-h period, while normalized spectral parameters (LFn, HFn and low frequency/high frequency), as well as nonlinear parameters, mainly β exponent and fractal dimension, showed significant difference between the senior group and the other two groups. All these parameters showed a similar circadian rhythm with significant differences between the mean day and night values, especially in young and adult group cohorts. Moreover, a parabolic relationship between these parameters and age was highlighted with an opposite trend over about 60 years compared with younger people.

CONCLUSION

A progressive physiological autonomic imbalance is present in ageing. The inverse trend in the relation between HRV parameters and age found in the senior group could be mainly due to a faster fluctuation of RR. This should be considered when studying changes in the cardiac autonomic nervous control.

Changes in Continuous, Long-Term Heart Rate Variability and Individualized Physiological Responses to Wellness and Vacation Interventions Using a Wearable Sensor

There are many approaches to maintaining wellness, including taking a simple vacation to attending highly structured wellness retreats, which typically regulate the attendee's personal time and activities. In a healthy English-speaking cohort of 112 women and men (aged 30–80 years), this study examined the effects of participating in either a 6-days intensive wellness retreat based on Ayurvedic medicine principles or unstructured 6-days vacation at the same wellness center setting. Heart rate variability (HRV) was monitored continuously using a wearable ECG sensor patch for up to 7 days prior to, during, and 1-month following participation in the interventions. Additionally, salivary cortisol levels were assessed for all participants at multiple times during the day. Continual HRV monitoring data in the real-world setting was seen to be associated with demographic [HRV_ALF: β_Age = 0.98 (95% CI = 0.96–0.98), false discovery rate (FDR) < 0.001] and physiological characteristics [HRV_PLF: β = 0.98 (95% CI = 0.98–1), FDR =0.005] of participants. HRV features were also able to quantify known diurnal variations [HRV_LF/HF: β_{ACT:night vs. early−morning} = 2.69 (SE = 1.26), FDR < 0.001] along with notable inter- and intraperson heterogeneity in response to intervention. A statistically significant increase in HRV_ALF [β = 1.48 (SE = 1.1), FDR < 0.001] was observed for all participants during the resort visit. Personalized HRV analysis at an individual level showed a distinct individualized response to intervention, further supporting the utility of using continuous real-world tracking of HRV at an individual level to objectively measure responses to potentially stressful or relaxing settings.

Do the Same Central Anthropometric Variables that Best Predict Blood Pressure in European Americans also Best Predict Blood Pressure in African Americans?

Objective

The purpose of this study was to determine if central anthropometric variables that best estimate blood pressure risks in European Americans also best estimate blood pressure risks in African Americans.

Design

The participants were 357 normotensive African and European American volunteers with a mean age of 32.6 ± 12.4 years. Participants were evaluated for central adiposity with dual energy X-ray absorptiometry, abdomen and thigh skinfolds, waist and hip circumferences, waist/hip ratio, waist/height ratio, body mass index, and systolic and diastolic blood pressures. Descriptive statistics, partial correlations, ANOVA and stepwise regressions were used to analyze the data.

Results

Central adiposity anthropometric indices made different contributions to blood pressure in African and European American men and women. When weight was held constant, waist circumference shared stronger partial relationships with blood pressure in African Americans (r = .30 to .47) than in European Americans (r = .11 to .32). Waist circumference in combination with other indices was a predictor of systolic and diastolic blood pressures in European American men (P<.05) but only a predictor for diastolic blood pressure in African American men and women (P<.01). Hip circumference was the only predictor for systolic blood pressure (P<.01) in African American men and women.

Conclusions

Further research on the relative contributions of central anthropometric indices to blood pressure in African and European Americans is warranted. A better understanding of this relationship may help reduce hypertensive morbidity and mortality disparities between African and European Americans.

Novel Invasive and Noninvasive Cardiac-Specific Biomarkers in Obesity and Cardiovascular Diseases

Cardiovascular disease (CVD) is the leading cause of fatality and disability worldwide regardless of gender. Obesity has reached epidemic proportions in population across different regions. According to epidemiological studies, CVD risk markers in childhood obesity are one of the significant risk factors for adulthood CVD, but have received disproportionally little attention. This review has examined the evidence for the presence of traditional cardiac biomarkers (nonspecific; lactate dehydrogenase, alanine aminotransferase, aspartate aminotransferase, creatine kinase, myoglobulin, glycogen phosphorylase isoenzyme BB, myosin light chains, ST2, and ischemia-modified albumin) and novel emerging cardiac-specific biomarkers (cardiac troponins, natriuretic peptides, heart-type fatty acid-binding protein, and miRNAs). Besides, noninvasive anatomical and electrophysiological markers (carotid intima-media thickness, coronary artery calcification, and heart rate variability) in CVDs and obesity are also discussed. Modifiable and nonmodifiable risk factors associated with metabolic syndrome in the progression of CVD, such as obesity, diabetes, hypertension, dyslipidemia, oxidative stress, inflammation, and adipocytokines are also outlined. These underlying prognostic risk factors predict the onset of future microvascular and macrovascular complications. The understanding of invasive and noninvasive cardiac-specific biomarkers and the risk factors may yield valuable insights into the pathophysiology and prevention of CVD in a high-risk obese population at an early stage.

Is the Brain a Key Player in Glucose Regulation and Development of Type 2 Diabetes?

Ever since Claude Bernards discovery in the mid 19th-century that a lesion in the floor of the third ventricle in dogs led to altered systemic glucose levels, a role of the CNS in whole-body glucose regulation has been acknowledged. However, this finding was later overshadowed by the isolation of pancreatic hormones in the 20th century. Since then, the understanding of glucose homeostasis and pathology has primarily evolved around peripheral mechanism. Due to scientific advances over these last few decades, however, increasing attention has been given to the possibility of the brain as a key player in glucose regulation and the pathogenesis of metabolic disorders such as type 2 diabetes. Studies of animals have enabled detailed neuroanatomical mapping of CNS structures involved in glucose regulation and key neuronal circuits and intracellular pathways have been identified. Furthermore, the development of neuroimaging techniques has provided methods to measure changes of activity in specific CNS regions upon diverse metabolic challenges in humans. In this narrative review, we discuss the available evidence on the topic. We conclude that there is much evidence in favor of active CNS involvement in glucose homeostasis but the relative importance of central vs. peripheral mechanisms remains to be elucidated. An increased understanding of this field may lead to new CNS-focusing pharmacologic strategies in the treatment of type 2 diabetes.

Emotional overactivity in patients with irritable bowel syndrome

BACKGROUND

Negativity is often observed in patients with irritable bowel syndrome (IBS). No study has examined their emotional expressiveness as a marker of emotional reactivity. We investigated IBS patients' vulnerability to an emotional load by associating their expressiveness with psychological and neurophysiological assessments. We hypothesized that IBS would be characterized by a lack of expressiveness coupled with high scores in psychological and neurophysiological parameters.

METHODS

We assessed the emotional facial expressions (EMFACS), psychological (anxiety, depression, alexithymia), and neurophysiological (cortisol, heart rate variability (HRV)) parameters of 25 IBS patients and 26 healthy controls (HC) while they watched fear-eliciting movie extracts.

KEY RESULTS

Overall, the task elicited an increase in state anxiety and consistent HRV responses. However, IBS patients differed from HC as they displayed more sadness and tended to display more rage. Contrary to HC, IBS patients showed an increase in heart rate and a decrease in parasympathetic regulation, reflecting an enhanced responsiveness corroborated by higher scores in depression and state anxiety. Consistent with their higher difficulty in identifying feelings, a component of alexithymia positively correlated with their expressions of rage, they were not aware of their increase in anxiety during the task, whereas HC were. No linear relationship between patients' expressions and their neurophysiological responses was found.

CONCLUSIONS & INFERENCES

Irritable bowel syndrome patients displayed greater emotional expressiveness with negative prevalence. This reflects an emotional vulnerability potentially related to low regulation skills and underscores the importance of considering the central dysregulation hypothesis in IBS as a promising avenue of research.

Does resistance training modulate cardiac autonomic control? A systematic review and meta-analysis

PURPOSE

To systematically evaluate the literature on the effects of resistance training (RT) on cardiac autonomic control in healthy and diseased individuals.

METHODS

Electronic databases Pubmed, PEDro, and Scopus were systematically searched from their inception up to June 2018. Randomized controlled trials, quasi-experimental trials, and cross-over controlled trials investigating the effect of RT (of at least 4 weeks duration) on cardiac autonomic control assessed either by linear or non-linear measures of heart rate variability (HRV), baroreflex sensitivity, or post-exercise heart rate recovery were included. Of the studies retrieved, 28 were included in the systematic review. Meta-analysis was performed on 21 studies of the total 28 studies.

RESULTS

Quality and characteristic assessment revealed fair quality evidence. The majority of literature on healthy humans suggested no change in cardiac autonomic control following RT. Standardized mean differences (SMD) showed a significant effect of RT on root mean square of successive differences between adjacent inter-beat (R-R) intervals (RMSSD) [SMD 0.96, 95% confidence interval (CI) 0.20-1.73; p = 0.01], ratio of low- to high-frequency power of HRV (LF/HF ratio; SMD -0.72, 95% CI -1.03 to -0.42; p < 0.00001), standard deviation of the instantaneous beat-to-beat variability (SD1; SMD 1.78, 95% CI 1.07-2.49, p < 0.00001), and sample entropy (SMD 1.17, 95% CI 0.36-1.97, p = 0.005) in diseased individuals.

CONCLUSION

This rigorous systematic analysis revealed that RT has no or minimal effects on cardiac autonomic control of healthy individuals, but RT leads to improvement in cardiac autonomic control of diseased individuals.

Higher body mass index predicts cardiac autonomic dysfunction: A longitudinal study in adolescent type 1 diabetes

BACKGROUND

Obesity is associated with an increased risk of cardiovascular morbidity in adults with diabetes.

OBJECTIVE

To examine the predictive role of body mass index (BMI) and adiposity on cardiac autonomic function in childhood onset type 1 diabetes.

SUBJECTS

Two hundred and fifty-three participants with type 1 diabetes (aged 8-30 years) were assessed for diabetes complications at a tertiary hospital, and followed over 7 years (total 922 visits).

METHODS

Heart rate variability (HRV) measures assessed by 10-minute electrocardiography recording using LabChart Pro were standard deviation of RR intervals, time between consecutive QRS complexes, [SDNN], root mean squared difference of successive RR intervals (RMSSD), triangular index (TI), and low to high frequency ratio [LF:HF]. Multivariable generalized estimating equations were used to model the longitudinal associations between HRV measures and clinical variables (BMI standard deviation scores [SDS], waist:height ratio, total daily insulin dose/kg (TDD) and hemoglobin A1c [HbA1c]).

RESULTS

At baseline, mean age was 14.4 ± 2.7 years, diabetes duration 7.1 ± 3.7 years, HbA1c 8.3% ± 1.5% (67 ± 16 mmol/mol), and 33% were overweight/obese (BMI ≥85th percentile). At final visit, mean age was 18.5 ± 2.7 years, duration 11.3 ± 3.9 years, HbA1c 9.0% ± 1.8% (75 ± 20 mmol/mol), and 40% were overweight/obese. Adiposity (higher BMI SDS or waist: height ratio) was a significant predictor of worse HRV (lower SDNN, RMSSD; P < .05), while higher HbA1c and TDD predicted all adverse HRV measures (lower SDNN, RMSSD, TI; P < .05) and abnormal sympathovagal balance (higher LF:HF ratio; P < .05).

CONCLUSIONS

Higher BMI and central adiposity are associated with cardiac autonomic dysfunction in childhood onset type 1 diabetes, after adjusting for HbA1c. Interventions targeting overweight/obesity during adolescence may optimize long-term vascular health in type 1 diabetes.

Lower Heart Rate Variability Is Associated with Lower Pulse Pressure Amplification: Role of Obesity

Background

Heart rate variability (HRV), pulse pressure amplification, and obesity represent risk factors for cardiovascular events. The aims of the present study are (1) to explore the impact of HRV on pulse pressure amplification and (2) to investigate whether the association between HRV and pulse pressure amplification differs in obese and lean subjects.

Methods

A total of 342 patients (age 61 ± 11 years) were enrolled. HRV was analyzed concerning both the frequency and time domain as well as concerning the HRV triangular index. Pulse pressure amplification was estimated as the ratio between brachial and carotid pulse pressure, the latter measured with SphygmoCor.

Results

Time domain HRV indices were directly correlated with pulse pressure amplification (the lower the HRV indices, the lower the pulse pressure amplification). This association was stronger in obese than in lean subjects after controlling for age and sex.

Conclusion

Larger controlled studies are needed to provide a more detailed insight into the relation between HRV and pulse pressure amplification and to determine which pathways are differentially activated in lean and obese subjects.

Resting high-frequency heart rate variability moderates the association between early-life adversity and body adiposity

This study investigates resting high-frequency heart rate variability as a moderator of the association between early-life adversity and two measures of body adiposity. Data were collected from 149 young adults attending a large university in the Midwestern United States (M_age = 18.8 years; 45% black; 55% white; 56% female). Self-reported early-life adversity was associated with greater waist-to-height ratio and body mass index. The strength of these associations was moderated by high-frequency heart rate variability, such that the link was stronger for individuals with lower heart rate variability. Resting high-frequency heart rate variability thus has potential health significance as a biomarker of stress vulnerability.

Cardiac Concomitants of Feedback and Prediction Error Processing in Reinforcement Learning

Successful learning hinges on the evaluation of positive and negative feedback. We assessed differential learning from reward and punishment in a monetary reinforcement learning paradigm, together with cardiac concomitants of positive and negative feedback processing. On the behavioral level, learning from reward resulted in more advantageous behavior than learning from punishment, suggesting a differential impact of reward and punishment on successful feedback-based learning. On the autonomic level, learning and feedback processing were closely mirrored by phasic cardiac responses on a trial-by-trial basis: (1) Negative feedback was accompanied by faster and prolonged heart rate deceleration compared to positive feedback. (2) Cardiac responses shifted from feedback presentation at the beginning of learning to stimulus presentation later on. (3) Most importantly, the strength of phasic cardiac responses to the presentation of feedback correlated with the strength of prediction error signals that alert the learner to the necessity for behavioral adaptation. Considering participants' weight status and gender revealed obesity-related deficits in learning to avoid negative consequences and less consistent behavioral adaptation in women compared to men. In sum, our results provide strong new evidence for the notion that during learning phasic cardiac responses reflect an internal value and feedback monitoring system that is sensitive to the violation of performance-based expectations. Moreover, inter-individual differences in weight status and gender may affect both behavioral and autonomic responses in reinforcement-based learning.

Diagnosis of major depressive disorder by combining multimodal information from heart rate dynamics and serum proteomics using machine-learning algorithm

OBJECTIVE

Major depressive disorder (MDD) is a systemic and multifactorial disorder that involves abnormalities in multiple biochemical pathways and the autonomic nervous system. This study applied a machine-learning method to classify MDD and control groups by incorporating data from serum proteomic analysis and heart rate variability (HRV) analysis for the identification of novel peripheral biomarkers.

METHODS

The study subjects consisted of 25 drug-free female MDD patients and 25 age- and sex-matched healthy controls. First, quantitative serum proteome profiles were analyzed by liquid chromatography-tandem mass spectrometry using pooled serum samples from 10 patients and 10 controls. Next, candidate proteins were quantified with multiple reaction monitoring (MRM) in 50 subjects. We also analyzed 22 linear and nonlinear HRV parameters in 50 subjects. Finally, we identified a combined biomarker panel consisting of proteins and HRV indexes using a support vector machine with recursive feature elimination.

RESULTS

A separation between MDD and control groups was achieved using five parameters (apolipoprotein B, group-specific component, ceruloplasmin, RMSSD, and SampEn) at 80.1% classification accuracy. A combination of HRV and proteomic data achieved better classification accuracy.

CONCLUSIONS

A high classification accuracy can be achieved by combining multimodal information from heart rate dynamics and serum proteomics in MDD. Our approach can be helpful for accurate clinical diagnosis of MDD. Further studies using larger, independent cohorts are needed to verify the role of these candidate biomarkers for MDD diagnosis.

Comparison of anthropometric measurements associated with the risk of endoscopic erosive esophagitis: A cross-sectional study

BACKGROUND

In this cross-sectional study, we assessed five anthropometric measurements to determine the most reliable indicator of the erosive esophagitis (EE) risk: body mass index (BMI), waist circumference (WC), waist to height ratio (WHtR), a body shape index (ABSI), and body roundness index (BRI).

METHODS

This study included 182,407 participants who underwent an esophagogastroduodenoscopy as part of a routine health check-up. We used the area under the receiver-operating characteristic curve (AUC) to assess the discriminatory power of each anthropometric measure as an indicator of EE risk.

RESULTS

The prevalence of EE increased per quartile for all five anthropometric measurements in patients of both sexes (1st quartile vs. 4th quartile, all P<0.05). ABSI had the lowest AUCs for EE in both sexes (AUC: 0.524, 95% CI: 0.519-0.529 for male patients; AUC: 0.524, 95% CI: 0.513-0.535 for female patients). In contrast, BRI was the best predictor of EE in male patients (OR: 2.095, 95% CI: 1.982-2.215, P<0.0001), and WC was the best predictor of EE in female patients (OR: 2.028, 95% CI: 1.785-2.307, P<0.0001). WC showed the highest AUC values for EE in both male patients (AUC: 0.571, 95% CI: 0.566-0.576) and female patients (AUC: 0.596, 95% CI: 0.585-0.608).

CONCLUSIONS

BRI and WC were the most relevant indicators of EE risk in male and female patients, respectively. ABSI was the least reliable indicator of EE risk in patients of both sexes.

Cardio-metabolic profile of subjects with early stages of glucose intolerance and cardiovascular autonomic dysfunction

AIMS

The present study evaluates the cardio-metabolic profile of subjects with early stages of glucose intolerance and presence of cardiovascular autonomic dysfunction (CAD).

MATERIALS AND METHODS

478 subjects, of mean age 49.3±13.7years and mean BMI 31.0±6.2kg/m², divided according to glucose tolerance: 130 with normal glucose tolerance, 227 with prediabetes, and 121 with newly-diagnosed type 2 diabetes, were enrolled. Glucose tolerance was studied during OGTT applying 2006 WHO criteria. Anthropometric indices, blood pressure, HbA1c, serum lipids, hsCRP, and albumin-to-creatinine ratio (ACR) were measured. Body fat distribution was estimated by a bioimpedance method (InBody720, BioSpace). Tissue AGEs accumulation was assessed by skin autofluorescence (AGE-Reader-DiagnOptics™). CAD was assessed by ANX-3.0 method.

RESULTS

CAD was found in 24.1% of subjects with any disorder of glucose tolerance in comparison to 12.3% in NGT, OR 2.0 (95% CI: 1.2-3.2), p=0.005. Sympathetic and parasympathetic tone declined with the progression of glucose intolerance. Age, waist circumference, visceral fat area, fasting and 120-min plasma glucose, HbA1c, AGEs, ACR and QTc interval were higher in subjects with CAD, p<0.05. In a logistic regression analysis the panel of age >53years (76% sensitivity, 61% specificity), HbA1c >6.0% (66% sensitivity, 60% specificity), QTc interval >423ms (65% sensitivity, 61% specificity) and presence of arterial hypertension (83% sensitivity, 55% specificity) was related to the presence of CAD - AUC 0.778 (95% CI: 0.73-0.83), p<0.001.

CONCLUSION

Our results demonstrate a high prevalence of CAD in early stages of glucose dysmetabolism. Age, HbA1c, QTc interval and presence of arterial hypertension are related to the presence of CAD in this population.

Heart rate variability in normal-weight patients with polycystic ovary syndrome

Objective:

Polycystic ovary syndrome (PCOS) is an endocrine disease closely related to several risk factors of cardiovascular disease. Obese women with PCOS show altered autonomic modulation. The results of studies investigating cardiac autonomic functions of normal-weight women with PCOS are conflicting. The aim of the study was to assess the reactivity of cardiac sympathovagal balance in normal-weight women with PCOS by heart rate variability analysis.

Methods:

We examined the heart rate variability in 60 normal-weight women with PCOS and compared them with that in 60 age-matched healthy women having a similar metabolic profile. Time and frequency domain parameters of heart rate variability were analyzed based on 5-min-long continuous electrocardiography recordings for the following 3 periods: (1) during rest in supine position, (2) during controlled breathing, and (3) during isometric handgrip exercise.

Results:

Time and frequency domain parameters of heart rate variability for the 3 periods assessed were similar in the two groups. Although modified Ferriman–Gallwey score and serum testosterone and luteinizing hormone levels were significantly higher in women with PCOS, homeostatic model assessment-insulin resistance (HOMA-IR) was not different the between the PCOS and control groups. There were no significant correlations between serum testosterone levels and heart rate variability parameters among the study population.

Conclusion:

The findings of this study suggest that the reactivity of cardiac sympathovagal balance is not altered in normal-weight women with PCOS having a normal HOMA-IR.

The effects of body weight status on orthostatic intolerance and predisposition to noncardiac syncope

Orthostatic intolerance (OI) is frequently the mechanism underlying the occurrence of noncardiac syncope (NCS) and is associated with substantial risk for injury. Body weight status appears to be a modifier of orthostatic responses and possibly influences the propensity to NCS. The majority of cross-sectional studies have found that the lower the body mass index (BMI) the greater the predisposition to OI is, accompanied with both down-regulation of sympathetic nervous system activity and up-regulation of parasympathetic nervous system activity. These changes appear to occur across the whole spectrum of BMI values from underweight to obesity, while they may be associated more strongly with central body fat than total body fat. Weight loss following bariatric surgery has been consistently found to increase OI, attributed first to the effects of weight loss per se, second to the specific type of surgical procedure and third to the potential postoperative autonomic neuropathy due to vitamin deficiency. The increased OI following bariatric surgery renders this intervention not easily tolerable for the affected individuals, mandating increased fluid and salt intake, pharmacological measures or surgical adjustments to attenuate OI. All future studies investigating orthostatic responses and NCS should implement a matching of the population arms for BMI and ideally for body fat.

Risk factors for autonomic and somatic nerve dysfunction in different stages of glucose tolerance

AIM

The present study evaluates autonomic and somatic nerve function in different stages of glucose tolerance and its correlation with different cardio-metabolic parameters.

MATERIAL AND METHODS

Four hundred seventy-eight subjects, mean age 49.3±13.7years and mean BMI 31.0±6.2kg/m2, divided according to glucose tolerance: 130 with normal glucose tolerance (NGT), 227 with prediabetes (125 with impaired fasting glucose (IFG) and 102 with isolated impaired glucose tolerance (iIGT)), and 121 with newly-diagnosed T2D (NDT2D), were enrolled. Glucose tolerance was studied during OGTT. Antropometric indices, blood pressure, HbA1c, serum lipids, hsCRP and albumin-to-creatinine ratio were assessed. Body composition was estimated by a bioimpedance method (InBody 720, BioSpace). Tissue AGEs accumulation was assessed by skin autofluorescence (AGE-Reader-DiagnOpticsTM). Electroneurography was performed by electromyograph Dantec Keypoint. Cardiovascular autonomic neuropathy (CAN) was assessed by ANX-3.0 method applying standard clinical tests.

RESULTS

CAN was found in 12.3% of NGT, 19.8% of prediabetes (13.2% of IFG and 20.6% of iIGT), and 32.2% of NDT2D. The prevalence of diabetic sensory polyneuropathy (DSPN) was 5.7% in prediabetes and 28.6% in NDT2D. The panel of age, QTc interval, waist circumference, diastolic blood pressure, and 120-min plasma glucose was related to sympathetic activity (F [5451]=78.50, p<0.001). The panel of age, waist circumference, and QTc interval was related to parasympathetic power (F [3453]=132.26, p<0.001). HbA1c and age were related to sural SNAP (F [2454]=15.12, p<0.001). HbA1c and AGEs were related to sural SNCV (F [2454]=12.18, p<0.001).

CONCLUSIONS

Our results demonstrate a high prevalence of autonomic and sensory nerve dysfunction in early stages of glucose intolerance. Age, postprandial glycemia, central obesity, diastolic blood pressure and QTc interval outline as predictive markers of CAN; hyperglycemia, glycation and age of DSPN.

The adverse impact of obesity on heart rate variability is modified by a NFE2L2 gene variant: The SAPALDIA cohort

BACKGROUND

Overweight has been associated with an increase in inflammatory markers and with an imbalance in the autonomic nervous system, such as a decrease in heart rate variability (HRV). In this study we aimed to investigate the modifying effect of a genetic variation in a major anti-inflammatory marker gene, NFE2L2, on the relationship between overweight and HRV.

METHODS

We analyzed participants of the SAPALDIA cohort aged 50years and older, twice in 2002/2003 (N=1472) and 2010/2011 (N=1235). We included persons with valid genotype data, who underwent ambulatory 24-h electrocardiogram monitoring, and reported on medical history and lifestyle. The association between HRV and BMI, measured as standard deviation of normal-to-normal intervals (SDNN) by BMI and the modifying effect of the cardiovascular health-related NFE2L2 gene variant rs2364723 were tested, applying multivariable mixed linear regression models.

RESULTS

We found study participants with overweight (BMI>25) over two follow-up surveys 10years apart to have a negative association between SDNN, calculated as geometric means, with BMI. The examined NFE2L2 variant sustainably modified (p_interaction=0.014) the found inverse association between a BMI increment and SDNN, causing a stronger decrement in SDNN for participants with the CC genotype (-20.7%; 95%-confidence interval: -12.33 to -28.28) compared with participants carrying the GC (-7.43; 95%CI: -3.56 to -11.15) or GG (-11.26%; 95%CI: -7.68 to -14.7) genotype, estimated for the difference from the 90^th to the 10^th percentile of BMI by the NFE2L2 variant.

CONCLUSIONS

Our results are consistent with the hypothesis that overweight decreases heart rate variability through inflammatory processes.

Autonomic Reactivity Differs in Young Adults Classified using Revised Indian and WHO Guidelines for Obesity

INTRODUCTION

Many studies have reported alteration in autonomic activity in obesity. However, there is paucity of literature comparing autonomic reactivity using different guidelines of obesity. As Indian guidelines were revised recently and WHO states that countries should use all categories of BMI for reporting purposes, it is prudent to compare physiological state in different categories of BMI.

AIM

The aim of the present study was to compare the autonomic alteration in young adults using revised Indian and WHO guidelines for obesity.

MATERIALS AND METHODS

A battery of autonomic tests (Valsalva Manoeuvre (VM), Deep Breathing Test (DBT), Lying to Standing Test (LST) and Hand Grip isometric exercise Test (HGT) was conducted on 34 overweight and obese and 30 normal weight volunteers categorised using revised Indian guidelines of body mass index. Same participants were regrouped and analysed using WHO guidelines of BMI and waist hip ratio (WHR).

RESULTS

For analysis, participants were grouped into 3 categories of normal, overweight and obese using revised Indian guidelines for obesity. Same participants were regrouped according to WHO guidelines. E:I ratio during DBT, 30:15 ratio during LST, Valsalva ratio during VM and increase in DBP during HGT were compared in different subgroups. There was no difference in sympathetic and parasympathetic activities in participants classified according to revised Indian guidelines. In participants classified using WHO criteria, sympathetic reactivity in overweight subjects was significantly less as compared to normal subjects (p<0.05).

CONCLUSION

Autonomic alterations might be more related to body fat percent rather than BMI. Indian guidelines are based on the observation that Asian population has more adipose tissue in WHO range of BMI. As the guidelines of BMI are applicable to all age groups and do not consider physical activity profile, they might still not be a good predictor of body fat.

Predicting depressed patients with suicidal ideation from ECG recordings

Globally suicidal behavior is the third most common cause of death among patients with major depressive disorder (MDD). This study presents multi-lag tone-entropy (T-E) analysis of heart rate variability (HRV) as a screening tool for identifying MDD patients with suicidal ideation. Sixty-one ECG recordings (10 min) were acquired and analyzed from control subjects (29 CONT), 16 MDD subjects with (MDDSI+) and 16 without suicidal ideation (MDDSI-). After ECG preprocessing, tone and entropy values were calculated for multiple lags (m: 1-10). The MDDSI+ group was found to have a higher mean tone value compared to that of the MDDSI- group for lags 1-8, whereas the mean entropy value was lower in MDDSI+ than that in CONT group at all lags (1-10). Leave-one-out cross-validation tests, using a classification and regression tree (CART), obtained 94.83 % accuracy in predicting MDDSI+ subjects by using a combination of tone and entropy values at all lags and including demographic factors (age, BMI and waist circumference) compared to results with time and frequency domain HRV analysis. The results of this pilot study demonstrate the usefulness of multi-lag T-E analysis in identifying MDD patients with suicidal ideation and highlight the change in autonomic nervous system modulation of the heart rate associated with depression and suicidal ideation.

Rosiglitazone influences adipose tissue distribution without deleterious impact on heart rate variability in coronary heart disease patients with type 2 diabetes

INTRODUCTION

Obesity is associated with decreased heart rate variability (HRV). Rosiglitazone, a PPARγ agonist, is generally associated with increases in body mass.

PURPOSE

To assess whether the gain in body mass and adiposity expected from rosiglitazone treatment has an influence on HRV in patients with type 2 diabetes and coronary artery disease.

METHODS

One hundred and twenty-five patients with type 2 diabetes and coronary artery disease aged between 40 and 75 years were studied. Anthropometric measurements: (1) body mass index (BMI), (2) waist circumference (WC), (3) abdominal computed tomography (CT) scan, and HRV (using a 24 h Holter) were measured at baseline and after 12 months of treatment. Patients were randomized to rosiglitazone or placebo regimen.

RESULTS

In the rosiglitazone vs. placebo group, there were significant increases in body mass [3.5 (2.6;4.4); mean (95 % CI) vs. 0.2 (-0.4;0.8)] kg), BMI [1.3 (1.0;1.6) vs. 0.1 (-0.1;0.3) kg/m²], WC [2.1 (0.9;3.3) vs. 0.4 (-0.4;1.2) cm, all p ≤ 0.001] and subcutaneous adipose tissue [253 (187;319) vs. 6 (-24;36) cm³, p ≤ 0.001] without statistically significant changes in visceral adipose tissue [-22 (-91;47) vs. 57 (43;71) cm³, p = 0.546], respectively. There was no change in HRV in either group after 12 months. There were no correlations between changes in HRV variables and fat distribution.

CONCLUSION

Our results suggest that changes in adiposity indices observed after 12 months of rosiglitazone therapy have no deleterious influence on HRV in patients with type 2 diabetes and coronary artery disease.

The Association between Central Adiposity and Autonomic Dysfunction in Obesity

OBJECTIVE

To determine the relationship between central adiposity parameters and autonomic nervous system (ANS) dysfunction.

SUBJECTS AND METHODS

The study included 114 obese individuals without any cardiovascular risk factors. Weight (in kg), height (in m), and waist circumference (WC; in cm) were measured and body mass index was calculated. Echocardiographic examination was performed to measure left ventricular mass and epicardial fat thickness (EFT). All the participants underwent an exercise test and electrophysiological evaluation using electromyography. Heart rate recovery (HRR) at 1-5 min, R-R interval variation at rest and during hyperventilation, and sympathetic skin response were measured. Pearson's correlation analysis was used. Multiple linear regression analysis was used to identify the factors associated with autonomic dysfunction.

RESULTS

The HRR at 1-5 min was negatively correlated with WC and age (WC-HRR1: r = -0.32; WC-HRR2: r = -0.31; WC-HRR3: r = -0.26; WC-HRR4: r = -0.23; WC-HRR5: r = -0.21; age-HRR2: r = -0.32; age-HRR3: r = -0.28; age-HRR4: r = -0.41; age-HRR5: r = -0.42). Age was the only independent predictor of reduced HRR at 1-5 min. In addition, WC predicted a reduced HRR at 3 min. There were no significant associations between central obesity and electrophysiological parameters. EFT was not associated with ANS dysfunction.

CONCLUSION

In this study, central adiposity and aging were associated with ANS dysfunction in obese individuals. The WC could be a marker of ANS dysfunction in obese individuals without any cardiovascular risk factors. The HRR assessment at a later decay phase could be more valuable for evaluating ANS function than during early recovery.

When rumination counts: Perceived social support and heart rate variability in daily life

Rumination and social support could modulate cardiac activity. Although both variables are somehow interrelated, they are often studied independently, and their interplay is seldom considered. We aimed to analyze the interaction of rumination and perceived social support on vagally mediated heart rate variability (HRV) in daily life. The sample consisted of 117 healthy participants (57% female, mean age = 27.9, SD = 5.5 years). Ambulatory HRV (root mean squared successive differences), respiration, body position, and body movements were recorded continuously on three consecutive weekdays. Momentary social, situational, and cognitive-affective variables (affect, ruminative thoughts, perceived social support) were assessed using a computerized diary. There was a significant interaction between momentary rumination and perceived social support on ambulatory HRV: When participants were involved in social interactions with low social support, concurrent rumination was associated with attenuated HRV. However, when rumination was accompanied by a strong sense of support, HRV significantly increased. The quality of social interactions and rumination seem to interact in daily life to predict cardiac autonomic control. The results stress the necessity to consider the interplay of psychological and social factors in order to evaluate beneficial or adverse effects on cardiac health.

The Contribution of Autonomic Imbalance to the Development of Metabolic Syndrome

OBJECTIVES

Obesity, diabetes, and heart disease-the most costly epidemics of our time-share a common but rarely treated mechanism: autonomic imbalance. We examined the contribution of autonomic imbalance, relative to selected demographic and biobehavioral risk factors, to the development of metabolic syndrome in a community sample for 12 years.

METHODS

We identified offspring cohort participants from the Framingham Heart Study who did not have metabolic syndrome at Examination 3 (1983-1987, baseline for this analysis) and whose metabolic syndrome status was assessed at the 4-, 8-, and 12-year follow-ups. We created logistic regression models, using baseline resting heart rate (RHR) and heart rate variability (HRV), to predict the odds of developing metabolic syndrome within 12 years, adjusting for age, sex, depressive symptoms, and smoking. HRV indices (standard deviation of the beat-to-beat interval [SDNN] and root mean square of the standard deviation) were calculated from 2-hour Holter monitor data.

RESULTS

Our sample consisted of 1143 participants (mean [SD] age = 46.6 (9.9) years, 57% female). One standard deviation of a decrease in SDNN increased the odds of developing metabolic syndrome within 12 years by 43% (95% confidence interval = 1.302-1.572, p < .001). Without HRV in the model, each increase in RHR of 10 beats/min increased the odds of developing metabolic syndrome by 24% (95% confidence interval = 1.094-1.426, p < .001).

CONCLUSIONS

In this community sample, low HRV by both measures (SDNN and root mean square of the standard deviation), high RHR, increased age, cigarette smoking, and being male significantly increased the odds of developing metabolic syndrome within 12 years of baseline.

Association between anthropometric measures of regional fat mass and heart rate variability in obese women

AIM

Impaired autonomic function could be the mechanism for the development of cardiometabolic diseases in obesity. Hence, simple anthropometric measures of overall and central obesity could be screening markers for autonomic imbalance. We analysed the relationship between heart rate variability (HRV) parameters and obesity indicators.

METHODS

Sixty-three obese women underwent blood pressure, lipids and anthropometric measurements, body composition assessment, HOMA (homeostasis model assessment) index calculation and short-term HRV analysis.

RESULTS

The correlation between obesity indicators and HRV parameters was influenced by age. In the multiple regression model, sagittal abdominal diameter (SAD) was a significant negative predictor of lnLF/HF (logarithmically transformed ratio of low to high frequencies) and lnLFnorm, and positive predictor of HFnorm (normalized high frequencies); the significant relationship remained even after adjustment for age, HOMA, blood pressure, lipid profile, menopause, body mass index (BMI) and body fat percentage (FAT). Anterior forearm skinfold showed inverse association with HRV. Correlation between waist circumference and waist-to-height ratio (WHtR) with lnLF/HF, as well as between anterior thigh skinfold with lnLF/HF, LFnorm (normalised low frequencies) and HFnorm was lost after further adjustments.

CONCLUSION

Among all anthropometric measures, SAD and anterior forearm skinfold thickness showed the highest predictive ability for HRV. Markers of lower sympathetic and higher cardiac parasympathetic activity corresponded with indicator of central obesity, while indicators of peripheral obesity showed completely opposite relationship with markers of cardiac autonomic activity.

Sex differences in healthy human heart rate variability: A meta-analysis

The present meta-analysis aimed to quantify current evidence on sex differences in the autonomic control of the heart, indexed by measures of heart rate variability (HRV) in healthy human subjects. An extensive search of the literature yielded 2020 titles and abstracts, of which 172 provided sufficient reporting of sex difference in HRV. Data from 63,612 participants (31,970 females) were available for analysis. Meta-analysis yielded a total of 1154 effect size estimates (k) across 50 different measures of HRV in a cumulated total of 296,247 participants. Females showed a significantly lower mean RR interval and standard deviation of RR intervals (SDNN). The power spectral density of HRV in females is characterized by significantly less total power that contains significantly greater high- (HF) and less low-frequency (LF) power. This is further reflected by a lower LF/HF ratio. Meta-regression revealed significant effects of age, respiration control and the length of recording available for analysis. Although women showed greater mean heart rate, they showed greater vagal activity indexed by HF power of HRV. Underlying mechanisms of these findings are discussed.

Correlation between heart rate variability and pulmonary function adjusted by confounding factors in healthy adults

The autonomic nervous system maintains homeostasis, which is the state of balance in the body. That balance can be determined simply and noninvasively by evaluating heart rate variability (HRV). However, independently of autonomic control of the heart, HRV can be influenced by other factors, such as respiratory parameters. Little is known about the relationship between HRV and spirometric indices. In this study, our objective was to determine whether HRV correlates with spirometric indices in adults without cardiopulmonary disease, considering the main confounders (e.g., smoking and physical inactivity). In a sample of 119 asymptomatic adults (age 20-80 years), we evaluated forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1). We evaluated resting HRV indices within a 5-min window in the middle of a 10-min recording period, thereafter analyzing time and frequency domains. To evaluate daily physical activity, we instructed participants to use a triaxial accelerometer for 7 days. Physical inactivity was defined as <150 min/week of moderate to intense physical activity. We found that FVC and FEV1, respectively, correlated significantly with the following aspects of the RR interval: standard deviation of the RR intervals (r =0.31 and 0.35), low-frequency component (r =0.38 and 0.40), and Poincaré plot SD2 (r =0.34 and 0.36). Multivariate regression analysis, adjusted for age, sex, smoking, physical inactivity, and cardiovascular risk, identified the SD2 and dyslipidemia as independent predictors of FVC and FEV1 (R2=0.125 and 0.180, respectively, for both). We conclude that pulmonary function is influenced by autonomic control of cardiovascular function, independently of the main confounders.