Multiple metabolic syndrome is associated with lower heart rate variability. The Atherosclerosis Risk in Communities Study

Guideline for the application of heart rate and heart rate variability in occupational medicine and occupational health science

This updated guideline replaces the "Guideline for the application of heart rate and heart rate variability in occupational medicine and occupational health science" first published in 2014. Based on the older version of the guideline, the authors have reviewed and evaluated the findings on the use of heart rate (HR) and heart rate variability (HRV) that have been published in the meantime and incorporated them into a new version of this guideline.This guideline was developed for application in clinical practice and research purposes in the fields of occupational medicine and occupational science to complement evaluation procedures with respect to exposure and risk assessment at the workplace by the use of objective physiological workload indicators. In addition, HRV is also suitable for assessing the state of health and for monitoring the progress of illnesses and preventive medical measures. It gives an overview of factors influencing the regulation of the HR and HRV at rest and during work. It further illustrates methods for measuring and analyzing these parameters under standardized laboratory and real workload conditions, areas of application as well as the quality control procedures to be followed during the recording and evaluation of HR and HRV.

Interplay of heart rate variability and resting heart rate on mortality in type 2 diabetes

AIMS

Heart rate variability (HRV) and resting heart rate (RHR) are usually analyzed and interpreted separately. We aimed to assess the interplay of HRV and RHR on mortality in type 2 diabetes.

METHODS

The study included 7,529 participants from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial. HRV metrics included standard deviation of all normal-to-normal intervals (SDNN) and root mean square of successive differences between normal-to-normal intervals (rMSSD). Abnormal values were defined based on <25th percentile for HRV and >75th percentile for RHR. Interactions of HRV status and RHR status were tested on multiplicative and additive scales. Results were validated in a subset of patients with type 2 diabetes (n = 745) from the Multi-Ethnic Study of Atherosclerosis.

RESULTS

Low SDNN was associated with increased all-cause mortality in the high RHR group (HR 1.60; 95% CI 1.29-1.97), but not in the normal RHR group. Compared with those who had neither low SDNN nor high RHR, the presence of either low SDNN or high RHR was not significantly associated with an increased risk of all-cause mortality. In contrast, the combination of low SDNN and high RHR was associated with a significantly increased risk of all-cause mortality (HR 1.68; 95% CI 1.43-1.97). Significant multiplicative and additive interactions were found between HRV status and RHR status on risk of all-cause mortality (all Pinteraction < 0.05). Similar findings were observed for cardiovascular mortality, in analyses using rMSSD, and in the Multi-Ethnic Study of Atherosclerosis.

CONCLUSIONS

The association between HRV and mortality risk is modified by RHR levels. Furthermore, low HRV and high RHR have interdependent and synergistic associations with mortality risk.

Short-Term Heart Rate Variability in Metabolic Syndrome: A Systematic Review and Meta-Analysis

BACKGROUND

Our aim was to determine the differences in short-term heart rate variability (HRV) between patients with metabolic syndrome (MS) and healthy controls.

METHODS

We searched electronic databases for primary works with short-term HRV recordings (≤30 min) that made comparisons between individuals with MS versus healthy controls. This systematic review and meta-analysis (MA) was performed according to PRISMA guidelines and registered at PROSPERO (CRD42022358975).

RESULTS

Twenty-eight articles were included in the qualitative synthesis and nineteen met the criteria for the MA. Patients with MS showed decreased SDNN (-0.36 [-0.44, -0.28], p < 0.001), rMSSD (-7.59 [-9.98, -5.19], p < 0.001), HF (-0.36 [-0.51, -0.20], p < 0.00001) and LF (-0.24 [-0.38, -0.1], p = 0.001). In subsequent subanalyses, we found a decrease in SDNN (-0.99 (-1.45, -0.52], p < 0.001), rMSSD (-10.18 [-16.85, -3.52], p < 0.01) and HF (-1.04 [-1.97, -0.1] p < 0.05) in women. In men, only LF showed a significant lower value (-0.26 [-0.5, -0.02], p < 0.05). We could not perform MA for non-linear variables.

CONCLUSIONS

Patients with MS showed changes in time-domain analyses, with lower values in SDNN and rMSSD. Regarding frequency-domain analyses, MS patients showed a decrease in HF and LF When sex was used as a grouping variable, the MA was only possible in one of both sexes (men or women) in rMSSD and LF/HF. Lastly, when data for both men and women were available, subanalyses showed a different behavior compared to mixed analyses for SDNN, HF and LF, which might point towards a different impact of MS in men and women.

FABP3, FABP4, and heart rate variability among patients with chronic schizophrenia

Introduction

The prevalence of cardiovascular disease (CVD) and CVD-related deaths in patients with schizophrenia is high. An elevated risk of CVD has been associated with low heart rate variability (HRV). There is increasing evidence that fatty acid-binding protein (FABP)3 and FABP4 play roles in the development and progression of CVD. This study aimed to explore the association of circulating FABP3/FABP4 levels with HRV in patients with chronic schizophrenia.

Methods

We included 265 consecutive patients with chronic schizophrenia who attended a disease management program. We used an enzyme-linked immunosorbent assay for the measurement of plasma concentrations of FABP3 and FABP4. Standard HRV was recorded at baseline following a standard protocol. Mean high- and low-frequency (HF/LF) HRV values were analyzed by tertile of FABP3 and FABP4 using one-way analysis of variance, and linear regression analysis was performed to assess trends.

Results

A positive association between FABP3 and creatinine was found in multiple regression analysis. In addition, negative associations between levels of hematocrit, hemoglobin, HF HRV, and estimated glomerular filtration rate (eGFR) with FABP3 were also found. Moreover, positive associations between FABP4 with body mass index, diabetes mellitus, hypertension, systolic blood pressure, low-density lipoprotein-cholesterol, triglycerides, creatinine, and FABP3 were found. Furthermore, negative associations between levels of high-density lipoprotein-cholesterol, eGFR, and HF HRV with FABP4 were found. We also found a significant inverse association between FABP3 and HF HRV (p for trend = 0.008), and significant inverse associations between FABP4 with HF and LF HRV (p for trend = 0.007 and 0.017, respectively).

Discussion

Together, this suggests that elevated levels of FABP3 and FABP4 may be linked to health problems related to CVD in patients with chronic schizophrenia.

The role of sleep and heart rate variability in metabolic syndrome: evidence from the Midlife in the United States study

STUDY OBJECTIVES

Poor sleep and autonomic dysregulation can both disrupt metabolic processes. This study examined the individual and combined effects of poor sleep and reduced heart rate variability (HRV) on metabolic syndrome among 966 participants in the Midlife in the United States II (MIDUS II) study.

METHODS

Self-reported sleep was assessed using the Pittsburgh Sleep Quality Index (PSQI). HRV was acquired from 11-minute resting heart rate recordings. Spearman correlations, general linear regression, and logistic regression models were used to examine the study hypotheses.

RESULTS

Poor sleep quality was associated with metabolic syndrome when global PSQI scores were evaluated as a continuous (odds ratio [OR]: 1.07, 95% confidence interval [CI]: 1.03 to 1.11) or categorical measure (cutoff > 5, OR: 1.58, 95% CI: 1.19 to 2.10), after adjustment for confounding. There also was an association between reduced HRV and metabolic syndrome (ln [HF-HRV] OR: 0.89, 95% CI: 0.80 to 0.99; ln [LF-HRV] OR: 0.82, 95% CI: 0.72 to 0.92; ln [SDRR] OR: 0.59, 95% CI: 0.43 to 0.79; ln [RMSSD] OR: 0.75, 95% CI: 0.60 to 0.94). When the combined effects of poor sleep and low HRV were examined, the association with metabolic syndrome was further strengthened relative to those with normal sleep and HRV.

CONCLUSIONS

To the best of the author's knowledge, this is the first study to suggest a combined effect of poor sleep and low HRV on the odds of metabolic syndrome.

Correlation among Poincare plot and traditional heart rate variability indices in adults with different risk levels of metabolic syndrome: a cross-sectional approach from Southern India

OBJECTIVES

Heart rate variability (HRV) is an important marker of cardiac autonomic modulation. Metabolic syndrome (MetS) can alter cardiac autonomic modulation, raising the risk of cardiovascular disease (CVD). Poincaré plot analysis (PPA) is a robust scatter plot-based depiction of HRV and carries similar information to the traditional HRV measures. However, no prior studies have examined the relationship between PPA and traditional HRV measures among different risk levels of MetS. We evaluated the association between the Poincare plot and traditional heart rate variability indices among adults with different risk levels of MetS.

METHODS

We measured anthropometric data and collected fasting blood samples to diagnose MetS. The MetS risk was assessed in 223 participants based on the number of MetS components and was classified as control (n=64), pre-MetS (n=49), MetS (n=56), and severe MetS (n=54). We calculated the Poincaré plot (PP) and traditional HRV measures from a 5 min HRV recording.

RESULTS

Besides the traditional HRV measures, we found that various HRV indices of PPA showed significant differences among the groups. The severe MetS group had significantly lower S (total HRV), SD1 (short-term HRV), SD2 (long-term HRV), and higher SD2/SD1. The values of S, SD1, SD2, and SD2/SD1 were significantly correlated with most traditional HRV measures.

CONCLUSIONS

We found gradual changes in HRV patterns as lower parasympathetic and higher sympathetic activity alongside the rising number of MetS components. The HRV indices of PPA integrating the benefits of traditional HRV indices distinguish successfully between different risk levels of MetS and control subjects.

Association between metabolic syndrome components and cardiac autonomic modulation in southern Indian adults with pre-metabolic syndrome: hyperglycemia is the major contributing factor

Metabolic syndrome (MetS) involves multi-factorial conditions linked to an elevated risk of type 2 diabetes mellitus and cardiovascular disease. Pre-metabolic syndrome (pre-MetS) possesses two MetS components but does not meet the MetS diagnostic criteria. Although cardiac autonomic derangements are evident in MetS, there is little information on their status in pre-MetS subjects. In this study, we sought to examine cardiac autonomic functions in pre-MetS and to determine which MetS component is more responsible for impaired cardiac autonomic functions. A total of 182 subjects were recruited and divided into healthy controls (n=89) and pre-MetS subjects (n=93) based on inclusion and exclusion criteria. We performed biochemical profiles on fasting blood samples to detect pre-MetS. Using standardized protocols, we evaluated anthropometric data, body composition, baroreflex sensitivity (BRS), heart rate variability (HRV), and autonomic function tests (AFTs). We further examined these parameters in pre-MetS subjects for each MetS component. Compared to healthy controls, we observed a significant cardiac autonomic dysfunction (CAD) through reduced BRS, lower overall HRV, and altered AFT parameters in pre-MetS subjects, accompanied by markedly varied anthropometric, clinical and biochemical parameters. Furthermore, all examined BRS, HRV, and AFT parameters exhibited an abnormal trend and significant correlation toward hyperglycemia. This study demonstrates CAD in pre-MetS subjects with reduced BRS, lower overall HRV, and altered AFT parameters. Hyperglycemia was considered an independent determinant of alterations in all the examined BRS, HRV, and AFT parameters. Thus, hyperglycemia may contribute to CAD in pre-MetS subjects before progressing to MetS.

Reduced heart rate variability is related to the number of metabolic syndrome components and manifest diabetes in the sixth Tromsø study 2007-2008

Both diabetes mellitus (DM) and the metabolic syndrome (MetS) are associated with autonomic neuropathy, which predisposes to cardiac events and death. Measures of heart rate variability (HRV) can be used to monitor the activity of the autonomic nervous system (ANS), and there are strong indications that HRV can be used to study the progression of ANS-related diabetes complications. This study aims to investigate differences in HRV in healthy, MetS and diabetic populations. Based on 7880 participants from the sixth health survey in Tromsø (Tromsø 6, 2007–2008), we found a significant negative association between the number of MetS components and HRV as estimated from short-term pulse wave signals (PRV). This decrease in PRV did not appear to be linear, instead it leveled off after the third component, with no significant difference in PRV between the MetS and DM populations. There was a significant negative association between HbA1c and PRV, showing a decrease in PRV occurring already within the normal HbA1c range. The MetS and DM populations are different from healthy controls with respect to PRV, indicating impaired ANS in both conditions. In the future, a study with assessment of PRV measurements in relation to prospective cardiovascular events seems justified.

Sympathetic Nervous System Predominance in Intimate Partner Violence Perpetrators After Coping With Acute Stress

It has been suggested that intimate partner violence (IPV) against women perpetrators present emotional dysregulations when dealing with acute stress, which in turn could help to explain their proneness to violence. Emotional regulation can be objectively measured by means of psychophysiological parameters/variables/indicators of autonomic nervous system (ANS) activity, such as cardiorespiratory (heart rate [HR], pre-ejection period [PEP] and respiratory sinus arrythmia [RSA]) and electrodermal (skin conductance levels [SCL]) signals. Therefore, this study aims to assess whether IPV perpetrators (n = 107) present differential psychophysiological and psychological state changes when coping with an acute cognitive laboratory stressor (a set of cognitive tests performed in front of an expert committee) in comparison with nonviolent men (n = 87). Moreover, the study assesses whether psychological state variables foster the psychophysiological response to acute stress. Our results demonstrate that, compared to nonviolent controls, IPV perpetrators showed higher HR and SCL values, shorter PEP, and lower RSA values during recovery from stress. They also presented higher negative affect (i.e., more anger and worse mood) after stress. Thus, high baseline anger explained the increases in emotional arousal when measured as SCL increases. The present study contributes evidence showing that IPV perpetrators and nonviolent men cope differently with stress. These findings might help forensic science to identify characteristics of violent individuals to establish their therapeutic needs. Furthermore, it would be appropriate to combine psychophysiological measurements with self-reports, thus increasing the reliability of the assessment of violent individuals.

Reliability of the Heart Rate Variability Threshold During Treadmill Exercise

The heart rate variability threshold (HRVT) is a clinical parameter used to gain insight into autonomic balance. Prior validation of the HRVT has been with cycle ergometry, with no studies examining the viability of treadmill exercise. The purpose of this study was to examine the reliability of the HRVT during treadmill exercise, and to compare the HRVT to the ventilatory threshold (VT). Ten healthy, college‐aged males completed two maximal graded exercise tests on a treadmill. A Polar RS800CX watch was used for heart rate and HRVT data. The HRVT was determined from three HRV variables including the root mean square of successive differences of continuous R−R intervals (RMSSD), the standard deviation of normal R−R intervals (SDNN) and the standard deviation of instantaneous beat intervals (SD1). A metabolic cart was utilized to determine the VT. Results showed no difference between the HRVT (2.4 ± 0.6 and 2.2 ± 0.3 for RMSSD, 2.8 ± 0.5 and 2.7 ± 0.5 for SDNN and 2.4 ± 0.6 and 2.3 ± 0.6 for SD1) or the VT (3.0 ± 0.3 and 3.1 ± 0.3) between trials. When compared to the VT, averaged HRVT values for RMSSD (2.3 ± 0.3) and SD1 (2.3 ± 0.5) were lower than averaged VT (2.8 ± 0.4, p < 0.05). The averaged HRVT from SDNN (2.8 ± 0.5) did not differ from the VT. These results suggest that treadmill is a viable mode for HRVT determination, and that HRVT determined by SDNN may be a better comparison to the VT.

Measuring psychosocial stress with heart rate variability-based methods in different health and age groups

Autonomic nervous system function and thereby bodily stress and recovery reactions may be assessed by wearable devices measuring heart rate (HR) and its variability (HRV). So far, the validity of HRV-based stress assessments has been mainly studied in healthy populations. In this study, we determined how psychosocial stress affects physiological and psychological stress responses in both young (18-30 yrs) and middle-aged (45-64 yrs) healthy individuals as well as in patients with arterial hypertension and/or either prior evidence of prediabetes or type 2 diabetes. We also studied how an HRV-based stress index (Relax-Stress Intensity, RSI) relates to perceived stress (PS) and cortisol (CRT) responses during psychosocial stress.

APPROACH

A total of 197 participants were divided into three groups: 1) healthy young (HY, N=63), 2) healthy middle-aged (HM, N=61) and 3) patients with cardiometabolic risk factors (Pts, N=73, 32-65 yrs). The participants underwent a group version of Trier Social Stress Test (TSST-G). HR, HRV (quantified as root mean square of successive differences of R-R intervals, RMSSD), RSI, PS, and salivary CRT were measured regularly during TSST-G and a subsequent recovery period.

MAIN RESULTS

All groups showed significant stress reactions during TSST-G as indicated by significant responses of HR, RMSSD, RSI, PS, and salivary CRT. Between-group differences were also observed in all measures. Correlation and regression analyses implied RSI being the strongest predictor of CRT response, while HR was more closely associated with PS.

SIGNIFICANCE

The HRV-based stress index mirrors responses of CRT, which is an independent marker for physiological stress, around TSST-G. Thus, the HRV-based stress index may be used to quantify physiological responses to psychosocial stress across various health and age groups.

Factors Associated with Reduced Heart Rate Variability in the General Japanese Population: The Iwaki Cross-Sectional Research Study

Although many studies have reported factors associated with reduced heart rate variability (HRV) in Western populations, evidence is limited among Asian populations. Therefore, we investigated the factors associated with reduced HRV values in a general Japanese population by measuring HRV among the participants of the Iwaki Health Promotion Project who underwent medical examination in 2019. We performed 90-s HRV measurements in 1065 participants. Of these, we evaluated the coefficient of variation in R–R intervals (CVRR) and standard deviation in R–R intervals (SDNN). Blood was collected under a fasting condition, and investigations of glucose metabolism, lipid metabolism, renal function, liver function, advanced glycation end products, and blood pressure were performed. A multivariate regression analysis of the association between CVRR or SDNN and blood test parameters and blood pressure in 987 participants with adequately completed HRV assessments showed that reduced CVRR or SDNN was associated with higher levels of glycated hemoglobin (HbA1c), glycoalbumin, blood glucose, triglycerides, creatinine, plasma pentosidine, and diastolic blood pressure. In the general Japanese population, higher levels of HbA1c, glycoalbumin, blood glucose, triglycerides, creatinine, plasma pentosidine, and diastolic blood pressure are associated with reduced CVRR or SDNN, which are typical HRV parameters.

Impaired baroreflex sensitivity and cardiac autonomic functions are associated with cardiovascular disease risk factors among patients with metabolic syndrome in a tertiary care teaching hospital of South-India

BACKGROUND & AIM

Baroreflex sensitivity (BRS) and heart rate variability (HRV) have been proposed to assess early autonomic dysfunction in metabolic syndrome (MetS) patients. Autonomic dysfunction in MetS patients may increase the risk of developing cardiovascular disease (CVD). However, the association of BRS and HRV with CVD risk factors remains elusive in MetS. The primary aim of this study was to assess the BRS and HRV in MetS patients among South-Indian adults and check whether BRS and HRV are associated with CVD risk factors.

METHODS

We performed anthropometric indices, body composition, physiological parameters such as BRS, HRV, and other autonomic function tests in 176 subjects divided into MetS patients (n = 88) and healthy controls (n = 88). Fasting blood samples were collected for biochemical profiles and calculated insulin resistance indices, atherogenic index (AI), and rate pressure product (RPP).

RESULTS

When compared to controls, we found significantly reduced BRS and an increased ratio of low-frequency (LF) to high-frequency (HF) power of HRV (LF/HF) in the MetS group. We observed significant differences in body composition and biochemical profiles among the MetS group. BRS and LF/HF ratio of HRV have shown a significant association with CVD risk factors in the MetS group.

CONCLUSIONS

We observed autonomic dysfunction as low BRS and high LF/HF ratio of HRV in MetS patients. Additionally, the present results emphasize that the association of BRS and LF/HF ratio with anthropometric, glucose, lipid parameters, and other CVD risk factors may increase the susceptibility of MetS patients to higher CVD risk.

Heart Rate Variability in Patients with Hypertension: the Effect of Metabolic Syndrome and Antihypertensive Treatment

Metabolic syndrome (MetS) is a combination of factors which, collectively, increase cardiovascular risk to a greater extent than each of them separately. Previous studies showed high cardiovascular risk to be associated with autonomic nervous system dysfunction. The purpose of this study was to assess the effects of antihypertensive treatment on heart rate variability (HRV) in patients with hypertension (HTN), depending on cooccurrence of MetS. 118 patients with uncontrolled HTN were enrolled to the study. HRV was compared among patients with and without MetS (MetS [+], n = 70) at baseline and following 12 months antihypertensive treatment. The HRV indices measured from RR intervals recorded form using 24-hour ambulatory electrocardiography. The measured HRV domains were the standard deviation of the average of NN intervals [SDNN], square root of the mean of the sum of the squares of differences between adjacent NN intervals [rMSSD], percentage of NN50 [pNN50], low frequency [LF], high frequency [HF], total power of variance of all NN intervals [TP], and LF/HF ratio. Baseline parameters: SDNN, rMSSD, pNN50, and HF were significantly lower in the MetS[+] compared to the MetS[-] subgroup (p < 0.05). After a 12-month antihypertensive treatment, MetS[+] patients achieved a significant improvement in parameters: SDNN, rMSSD, pNN50, and TP (p < 0.05), while the changes in HRV observed in the MetS[-] subgroup were not statistically significant. The cooccurrence of HTN and other components of MetS is associated with disturbances of the autonomic balance. HTN control has a beneficial effect on HRV, with the effect being more evident in patients with MetS.

Parasympathetic activity as a potential biomarker of negative symptoms in patients with schizophrenia

INTRODUCTION

Autonomic dysfunction in patients with schizophrenia has raised concern considering the higher cardiovascular mortality and morbidity rate. This phenomenon has been demonstrated using various measurements and is inferred to be associated with demographics, medical treatment, and psychopathology. However, few have targeted the role of negative symptoms within schizophrenia.

METHODS

Schizophrenia patients with stationary psychopathology were recruited from a chronic ward, a daycare center, and a nonintensive case management program. Demographic data, medication history, the Positive and Negative Syndrome Scale (PANSS) score, the Personal and Social Performance Scale (PSP) score, and the five-minute resting-state heart rate variability (HRV) were collected at trial initiation (Time 1) and a year later (Time 2). The relationships between variables and HRV indices were evaluated using correlation and regression analyses.

RESULTS

A total of 63 participants were recruited at Time 1, with 29 participants remaining at Time 2. Correlation analyses showed a negative correlation between the PANSS negative score (PANSS-N) and total power (TP), low-frequency power (LF), and high-frequency power (HF) at Time 1. The results were further examined with multiple linear regression analysis and remained significant between the PANSS-N score and HF (β = -0.306, P = .012). A generalized estimating equation model revealed the above negative association to be significant considering both timepoints.

DISCUSSION

The negative association between negative symptom severity and parasympathetic activity was significant, which may inspire further research into the corresponding treatment, the mechanisms, and the use of HRV as an applicable biomarker for treatment response.

Vitamin D deficiency and metabolic syndrome in elderly Chinese individuals: evidence from CLHLS

Objectives

Both low vitamin D status and metabolic syndrome (MetS) are worldwide concerns, and low 25-hydroxyvitamin D [25(OH)D] levels are associated with MetS; however, related epidemiological evidence based on elderly Chinese individuals, especially those over 80 years of age, is limited. In the present study, we aimed to evaluate the association between serum 25(OH)D and MetS in elderly Chinese individuals.

Method

Serum 25(OH)D was measured in a cross-sectional sample of 2493 elderly people aged 65–112 years from eight areas of China in which the density of centenarians is exceptionally high. MetS was diagnosed according to blood pressure, lipid, and blood sugar levels; waist circumference; and body mass index (BMI). Adjusted multivariable logistic regression was used to analyze the associations between vitamin D and MetS based on different diagnostic criterias.

Results

A total of 890 (35.7%) of the recruited elderly individuals had insufficient levels of vitamin D, and 1029 participants (41.3%) were vitamin D deficient. High serum vitamin D concentrations were associated with a low prevalence of MetS according to the modified Adult Treatment Panel III (ATP III) criteria for adequate versus deficient vitamin D levels (OR: 0.63, 95% CI: 0.45, 0.88) and inadequate versus deficient vitamin D levels (OR: 0.70, 95% CI: 0.52, 0.92). Each 10 ng/ml increase in serum vitamin D was significantly associated with a decreased prevalence of MetS according to the modified ATP III criteria for people with normal waist circumference (WC) (OR: 0.55, 95% CI: 0.43,0.71). However, no significant statistical correlation was found among elderly people with a high WC. Additionally, in the analysis of the individual components, the ORs of adequate versus deficient vitamin D levels were 0.46 (95% CI: 0.30, 0.71) for elevated triglycerides and 0.64 (95% CI: 0.42, 0.97) for reduced high-density lipoprotein cholesterol (HDL-C) after adjustment for other components.

Conclusions

Vitamin D deficiency is very common among elderly Chinese individuals. Vitamin D deficiency may be a risk factor for MetS; however, the association was only statistically significant among elderly people with noncentral obesity. Further studies are needed to examine the causal direction of the association.

Parasympathetic Response Patterns are Associated with Metabolic Syndrome Among Older Women but Not Men

Background

Little is known about the role of physiological stress responses in metabolic syndrome (MetS).

Purpose

To examine whether patterns of autonomic response to psychological stress are associated with MetS and whether this association is moderated by sex

Methods

1121 men and women (M_age = 65.3 ± 6.77 years) with and without coronary artery disease (CAD) underwent an anger recall stressor task. Heart rate and heart-rate variability (HRV; HF, LF/HF) were assessed. Clusters of participants showing similar patterns of response across baseline, stress, and recovery periods were created using ACECLUS and FASTCLUS in SAS. Logistic regressions included clusters and interaction between clusters and sex as independent variables, controlling for relevant covariates. ANCOVAs were conducted in secondary analyses utilizing a continuous composite representation of MetS.

Results

Men and women showing greater tonic and phasic HR elevations were more likely to meet MetS criteria (OR = 1.45, [95% CI = 1.02–2.07], p = .037). HF-HRV cluster interacted significantly with sex (p < .001) to predict MetS. In women, those with significant parasympathetic withdrawal to stress and poor recovery were more likely to have MetS than women with a more moderate response (OR = 2.56, [95% CI = 1.23–5.41], p = .013). Women who displayed stress-related parasympathetic activation were also at greater risk of MetS (OR = 2.30, [95% CI = 1.30–4.07], p = .004). Results using a continuous measure of MetS were generally consistent with these findings.

Conclusion

Among older participants with CAD or other noncardiovascular disease, hyperreactivity to stress was associated with greater prevalence of MetS, particularly in women. Consistent with emerging literature, women who showed blunting or activation of parasympathetic responses to stress were similarly at greater risk.

Exploring a 1-Minute Paced Deep-Breathing Measurement of Heart Rate Variability as Part of a Workers' Health Assessment

Low heart rate variability (HRV) is related to health problems that are known reasons for sick-leave or early retirement. A 1-minute-protocol could allow large scale HRV measurement for screening of health problems and, potentially, sustained employability. Our objectives were to explore the association of HRV with measures of health. Cross-sectional design with 877 Dutch employees assessed during a Workers' Health Assessment. Personal and job characteristics, workability, psychological and mental problems, and lifestyle were measured with questionnaires. Biometry was measured (BMI, waist circumference, blood pressure, glucose, cholesterol). HRV was assessed with a 1-minute paced deep-breathing protocol and expressed as mean heart rate range (MHRR). A low MHRR indicates a higher health risk. Groups were classified age adjusted for HRV and compared. Spearman correlations between raw MHRR and the other measures were calculated. Significant univariable correlations (p < 0.05) were entered in a linear regression model to explore the multivariable association with MHRR. Age, years of employment, BMI and waist circumference differed significantly between HRV groups. Significant correlations were found between MHRR and age, workability, BMI, waist circumference, cholesterol, systolic and diastolic blood-pressure and reported physical activity and alcohol consumption. In the multivariable analyses 21.1% of variance was explained: a low HRV correlates with aging, higher BMI and higher levels of reported physically activity. HRV was significantly associated with age, measures of obesity (BMI, waist circumference), and with reported physical activity, which provides a first glance of the utility of a 1-minute paced deep-breathing HRV protocol as part of a comprehensive preventive Workers' Health Assessment.

Circadian-timed quick-release bromocriptine lowers elevated resting heart rate in patients with type 2 diabetes mellitus

OBJECTIVE

Sympathetic nervous system (SNS) overactivity is a risk factor for insulin resistance and cardiovascular disease (CVD). We evaluated the impact of bromocriptine-QR, a dopamine-agonist antidiabetes medication, on elevated resting heart rate (RHR) (a marker of SNS overactivity in metabolic syndrome), blood pressure (BP) and the relationship between bromocriptine-QR's effects on RHR and HbA1c in type 2 diabetes subjects.

DESIGN AND SUBJECTS

RHR and BP changes were evaluated in this post hoc analysis of data from a randomized controlled trial in 1014 type 2 diabetes subjects randomized to bromocriptine-QR vs placebo added to standard therapy (diet ± ≤2 oral antidiabetes medications) for 24 weeks without concomitant antihypertensive or antidiabetes medication changes, stratified by baseline RHR (bRHR).

RESULTS

In subjects with bRHR ≥70 beats/min, bromocriptine-QR vs placebo reduced RHR by -3.4 beats/min and reduced BP (baseline 130/79; systolic, diastolic, mean arterial BP reductions [mm Hg]: -3.6 [P = .02], -1.9 [P = .05], -2.5 [P = .02]). RHR reductions increased with higher baseline HbA1c (bHbA1c) (-2.7 [P = .03], -5 [P = .002], -6.1 [P = .002] with bHbA1c ≤7, >7, ≥7.5%, respectively] in the bRHR ≥70 group and more so with bRHR ≥80 (-4.5 [P = .07], -7.8 [P = .015], -9.9 [P = .005]). Subjects with bRHR <70 had no significant change in RHR or BP. With bHbA1c ≥7.5%, %HbA1c reductions with bromocriptine-QR vs placebo were -0.50 (P = .04), -0.73 (P = .005) and -1.22 (P = .008) with bRHR <70, ≥70 and ≥80, respectively. With bRHR ≥70, the magnitude of bromocriptine-QR-induced RHR reduction was an independent predictor of bromocriptine-QR's HbA1c lowering effect.

CONCLUSION

Bromocriptine-QR lowers elevated RHR with concurrent decrease in BP and hyperglycaemia. These findings suggest a potential sympatholytic mechanism contributing to bromocriptine-QR's antidiabetes effect and potentially its previously demonstrated effect to reduce CVD events.

The Relationship between Heart Rate Variability and Aortic Knob Width

BACKGROUND

The aortic knob width (AKW) and the heart rate variability (HRV) were suggested to be related to development of cardiovascular diseases. However, the relationship between them has not been investigated; thus, this study aimed to determine this relationship.

METHODS

This study included 587 Koreans aged 18-79 years. Their physical measurements, medical and social histories, blood test findings, and chest radiographs were obtained. The HRV parameters included the standard deviation of the N-N interval (SDNN), root mean square of successive differences (RMSSD), approximate entropy (ApEn), total power (TP), very low frequency (VLF), low frequency (LF), high frequency (HF), and LF/HF ratio, which were measured for 5 minutes. The AKW was measured on chest radiographs by a single reviewer.

RESULTS

The AKW was significantly correlated with the HRV parameters, except for the LF/HF ratio. However, RMSSD and ApEn were not significantly related to the AKW in women. After dividing the participants into quartile groups, the AKW was significantly related to the SDNN, RMSSD, TP, VLF, LF, and HF. The HRV parameter values decreased in the higher AKW quartile groups, the HRV parameter values decreased. After adjusting for sex, drinking status, exercise habits, smoking status, waist circumference, and triglyceride, low-density lipoprotein cholesterol, fasting blood sugar, and glycated hemoglobin levels, the AKW showed significant negative associations with the HRV parameters, except for the LF/HF ratio.

CONCLUSION

The AKW is significantly associated with the HRV parameters of SDNN, RMSSD, ApEn, TP, VLF, LF, and HF.

Visceral Fat Accumulation Is Associated with Asthma in Patients with Type 2 Diabetes

OBJECTIVE

The number of patients with type 2 diabetes has increased in Japan, and type 2 diabetes has attracted attention as a risk factor for asthma. However, the risk factors for the development of asthma in patients with type 2 diabetes have not been determined. This study was performed to clarify whether visceral fat accumulation (VFA) and insulin resistance are risk factors for the development of asthma in patients with type 2 diabetes.

MATERIALS AND METHODS

A cross-sectional study was conducted. The study group comprised 15 patients with type 2 diabetes with asthma, and the control group comprised 145 patients with type 2 diabetes without asthma. Their fat distribution was evaluated by measuring the VFA by abdominal computed tomography at the umbilical level. Their glucose status was assessed by measuring the fasting plasma glucose (FPG) concentration, fasting immunoreactive insulin concentration, homeostasis model assessment (HOMA) index, and hemoglobin A1c concentration.

RESULTS

Among patients with type 2 diabetes, VFA was significantly greater in patients with asthma than those without asthma (P < 0.0001). The FPG concentration, fasting immunoreactive insulin concentration, and HOMA index were higher in patients with asthma than those without asthma (P < 0.05, P < 0.0001, and P < 0.0001, respectively). Multiple logistic regression analysis showed that VFA and the HOMA index were significantly associated with asthma in patients with type 2 diabetes (odds ratio, 1.78; 95% confidence interval, 1.31-3.89; P = 0.0115 and odds ratio, 3.65; 95% confidence interval, 1.37-7.85; P = 0.0078, respectively).

CONCLUSIONS

Our data suggest that VFA and insulin resistance are associated with the development of asthma in patients with type 2 diabetes.

Co-Existence of hypertension worsens post-exercise cardiac autonomic recovery in type 2 diabetes

BACKGROUND

Cardiac autonomic neuropathy (CAN) is a commonly overlooked complication of Type 2 Diabetes Mellitus (T2DM) characterized by imbalance between sympathetic and parasympathetic supply to the heart. The susceptibility of heart to dysrhythmias and fatal events increases during and after exercise due to a shift in autonomic regulation. Diabetes and hypertension (HTN) frequently occur concurrently and both conditions lead to impaired cardiac autonomic control. However, their impact together on post-exercise autonomic recovery remains to be explored.

OBJECTIVE

The objective of the study was to investigate the effect of co-existence of HTN on cardiac autonomic recovery (assessed by heart rate recovery and heart rate variability) in patients with T2DM.

METHODS

Forty eight type 2 diabetic patients (24 normotensive, 24 hypertensive), 24 non-diabetic patients with essential HTN, and 27 healthy controls, were recruited into the study and assessed for heart rate recovery (HRR) following a graded maximal test. Also, heart rate variability (HRV) was recorded before and following the bout of maximal exercise.

RESULTS

Heart rate recovery at 1 (HRR1min) and 2 (HRR2min) minute(s) showed significant effects for DM (p < 0.001) and HTN (p < 0.001), while DM × HTN interaction was found to be non-significant. Resting HRV showed a significant decline in time-domain variables for the DM group (p < 0.01). Recovery of HRV showed a significant effect of time (p < 0.05) for all indices, the group effect was found significant only for time-domain measures (p < 0.05).

CONCLUSION

Both HRR and HRV recovery were impaired in DM and HTN. Moreover, the co-existence of HTN had a synergistic effect, causing further worsening of autonomic recovery in T2DM.

Acute Physical Effort Increases Sympathovagal Balance Responses to Autonomic Stimulation in Metabolic Syndrome

BACKGROUND

There is little evidence of how metabolic syndrome (MS) affects sympathovagal balance responses to acute physical effort (APE) and autonomic stimulation (AS). This study aimed to evaluate the heart rate variability (HRV) responses to the combined APE and AS challenges.

METHODS

Fourteen subjects (8 men; 49.15 ± 8.67 years) divided into two groups: 7 healthy volunteers [control group (CG)] and 7 patients with MS. Sympathovagal balance [low frequency (LF)/high frequency (HF) ratio] was accessed by HRV through the beat-to-beat heart rate (HR) electrocardiogram. Other variables analyzed were as follows: HR, RR-interval variance (VAR/ms²), LF and HF normalized units (un). The APE consisted of a 30-min walk at 65%-75% of the age-predicted maximal HR. The AS was achieved by changing from the supine to standing position (activity orthostatic position).

RESULTS

At rest, all HRV variables differ with on MS, but after APE and AS LF (nu) and HF (nu) become similar to the CG. However, the LF/HF ratio responses to the AS were significantly different after APE, but only in the MS (CG rest: 367% ± 59% vs. recovery 495% ± 116%, P > 0.05; MS rest: 316% ± 88% vs. recovery: 665% ± 165%; P = 0.045). Comparing the difference between AS in rest and recovery (ΔAS = rest - recovery), the LF/HF ratio was notably higher in the MS group (CG: 94% ± 29% vs. MS: 415% ± 76%; P < 0.0001).

CONCLUSIONS

The APE and AS induced by body posture changes activated a clear distinction in sympathovagal balance response in MS.

Associations of immunometabolic risk factors with symptoms of depression and anxiety: The role of cardiac vagal activity

OBJECTIVES

This study examined 1) the cross-sectional relationships between symptoms of depression/anxiety and immunometabolic risk factors, and 2) whether these relationships might be explained in part by cardiac vagal activity.

METHODS

Data were drawn from the Adult Health and Behavior registries (n = 1785), comprised of community dwelling adults (52.8% women, aged 30-54). Depressive symptoms were measured with the Center for Epidemiological Studies Depression Scale (CES-D) and the Beck Depression Inventory-II (BDI-II), and anxious symptoms with the Trait Anxiety scale of the State-Trait Anxiety Inventory (STAI-T). Immunometabolic risk factors included fasting levels of triglycerides, high-density lipoproteins, glucose, and insulin, as well as blood pressure, waist circumference, body mass index, C-reactive protein, and interleukin-6. Measures of cardiac autonomic activity were high- and low-frequency indicators of heart rate variability (HRV), standard deviation of normal-to-normal R-R intervals, and the mean of absolute and successive differences in R-R intervals.

RESULTS

Higher BDI-II scores, in contrast to CES-D and STAI-T scores, were associated with increased immunometabolic risk and decreased HRV, especially HRV likely reflecting cardiac vagal activity. Decreased HRV was also associated with increased immunometabolic risk. Structural equation models indicated that BDI-II scores may relate to immunometabolic risk via cardiac vagal activity (indirect effect: β = .012, p = .046) or to vagal activity via immunometabolic risk (indirect effect: β = -.015, p = .021).

CONCLUSIONS

Depressive symptoms, as measured by the BDI-II, but not anxious symptoms, were related to elevated levels of immunometabolic risk factors and low cardiac vagal activity. The latter may exhibit bidirectional influences on one another in a meditational framework. Future longitudinal, intervention, an nonhuman animal work is needed to elucidate the precise and mechanistic pathways linking depressive symptoms to immune, metabolic, and autonomic parameters of physiology that predispose to cardiovascular disease risk.

Heart rate variability in type 2 diabetes mellitus: A systematic review and meta-analysis

BACKGROUND

Cardiac autonomic neuropathy in type 2 dibetes mellitus (T2DM) patients is frequent and associated with high cardiovascular mortality. Heart rate variability (HRV) is the gold standard to measure cardiac autonomic neuropathy. We aimed to conduct a systematic review and meta-analysis to evaluate the impact of T2DM on HRV parameters.

METHODS

The PubMed, Cochrane Library, Embase and Science Direct databases were searched on 1st October 2017 using the keywords "diabetes" AND ("heart rate variability" OR "HRV"). Included articles had to report HRV parameters in T2DM patients and healthy controls measured during 24 hours with a Holter-electrocardiogram. Measurements of HRV retieved were: RR-intervals (or Normal to Normal intervals-NN), standard deviation of RR intervals (SDNN), percetange of adjacent NN intervals differing by more than 50 milliseconds (pNN50), square root of the mean squared difference of successive RR intervals (RMSSD), total power, Low Frequency (LF), High Frequency (HF) and LF/HF ratio, as per Task Force recommendations.

RESULTS

We included twenty-five case-control studies with 2,932 patients: 1,356 with T2DM and 1,576 healthy controls. T2DM patients had significantly (P<0.01) lower RR-intervals (effect size = -0.61; 95%CI -1.21 to -0.01), lower SDNN (-0.65; -0.83 to -0.47), lower RMSSD (-0.92; -1.37 to -0.47), lower pNN50 (-0.46; -0.84 to -0.09), lower total power (-1.52; -2.13 to -0.91), lower LF (-1.08; -1.46 to -0.69]), and lower HF (-0.79; -1.09 to -0.50). LF/HF did not differ between groups. Levels of blood glucose and HbA1c were associated with several HRV parameters, as well as Time from diagnosis of T2DM.

CONCLUSIONS

T2DM was associated with an overall decrease in the HRV of T2DM patients. Both sympathetic and parasympathetic activity were decreased, which can be explained by the deleterious effects of altered glucose metabolism on HRV, leading to cardiac autonomic neuropathy.

Autonomic Nervous System and Stress to Predict Secondary Ischemic Events after Transient Ischemic Attack or Minor Stroke: Possible Implications of Heart Rate Variability

Transient ischemic attack (TIA) and minor stroke have high risks of recurrence and deterioration into severe ischemic strokes. Risk stratification of TIA and minor stroke is essential for early effective treatment. Traditional tools have only moderate predictive value, likely due to their inclusion of the limited number of stroke risk factors. Our review follows Hans Selye’s fundamental work on stress theory and the progressive shift of the autonomic nervous system (ANS) from adaptation to disease when stress becomes chronic. We will first show that traditional risk factors and acute triggers of ischemic stroke are chronic and acute stress factors or “stressors,” respectively. Our first review shows solid evidence of the relationship between chronic stress and stroke occurrence. The stress response is tightly regulated by the ANS whose function can be assessed with heart rate variability (HRV). Our second review demonstrates that stress-related risk factors of ischemic stroke are correlated with ANS dysfunction and impaired HRV. Our conclusions support the idea that HRV parameters may represent the combined effects of all body stressors that are risk factors for ischemic stroke and, thus, may be of important predictive value for the risk of subsequent ischemic events after TIA or minor stroke.

Association between resting heart rate, metabolic syndrome and cardiorespiratory fitness in Korean male adults

BACKGROUND/OBJECTIVE

The present study aimed to investigate the association between metabolic syndrome and cardiorespiratory fitness according to resting heart rate of Korean male adults.

METHODS

A total of 11,876 male adults aged 20-65 years who underwent health examinations from 2010 to 2015 at a National Fitness Centre in South Korea were included. Subjects' resting heart rate, cardiorespiratory fitness (VO2max), and metabolic syndrome parameters were collected. The subjects were divided into 5 categories (<60 bpm, 60-69 bpm, 70-79 bpm, 80-89 bpm, and ≥90 bpm) of resting heart rate for further analysis.

RESULTS

We found that elevated resting heart rate was positively associated with body mass index, systolic blood pressure, diastolic blood pressure, triglycerides, and fasting blood glucose levels (p < 0.001, respectively); in contrast, elevated resting heart rate was inversely associated with VO2max (p < 0.001). When resting heart rate of subjects was categorized into quintiles and analysed, the results showed that the relative risk of metabolic syndrome was 1.53-fold higher (95% CI, 1.34 to 1.82) in the range of 60-69 beats per minute (bpm), 2.08-fold higher (95% CI, 1.77 to 2.45) in the range of 70-79 bpm, 2.28-fold higher (95% CI, 1.73 to 3.00) in the range of 80-89 bpm, and 2.61-fold higher (95% CI, 1.62 to 4.20) in the range of ≥90 bpm, compared to those <60 bpm; this indicated that as resting heart rate increased, the relative risk of metabolic syndrome also increased.

CONCLUSION

Resting heart rate of male adults was found to be associated with cardiorespiratory fitness; the risk factors for metabolic syndrome and relative risk of metabolic syndrome increased as resting heart rate increased.

Does the ability to express different emotions predict different indices of physical health? A skill-based study of physical symptoms and heart rate variability

OBJECTIVES

The outward expression of emotion has been frequently associated with better health outcomes, whereas suppressing emotion is thought to contribute to worse physical health. However, work has typically focused on trait expressive tendencies and the possibility that individual differences in the ability to express specific emotions may also be associated with health has not been widely tested.

DESIGN

A cross-sectional study of community dwelling adults.

METHODS

One hundred and twenty-eight participants aged 18-88 years completed questionnaires assessing demographics and health status, before attending a testing session in which resting heart rate variability (HRV) was assessed. Participants then completed a performance-based test of expressive regulatory skill in which they were instructed to enhance and suppress their emotional expressions while they watched film clips validated to elicit amusement, sadness, and anger. Participants rated subjective emotional experience before and after each clip, and their degree of expressivity was scored using FACS-based Noldus FaceReader.

RESULTS

Missing data resulted in a final sample size of 117. Linear regressions controlling for age, sex, diagnoses, and trait emotion revealed that greater ability to enhance sad expressions was associated with higher HRV while the ability to enhance expressions of joy was associated with lower symptom interference. In parallel models, the ability to flexibly regulate (both enhance and suppress) expressions of joy and sadness was also associated with lower symptom interference.

CONCLUSIONS

Findings suggest that the ability to regulate expressions of both sadness and joy is associated with health indices even when controlling for trait affect and potential confounds. The present findings offer early evidence that individual differences in the ability to regulate the outward expression of emotion may be relevant to health and suggest that expressive regulatory skills offer a novel avenue for research and intervention. Statement of contribution What is already known on this subject The tendency to outwardly express felt emotion generally predicts better health, whereas expressive suppression typically predicts worse health outcomes. Most work has been based on trait assessments; however, the ability to regulate the expression of felt emotion can be objectively assessed using performance-based tests. Prior work in mental health suggests that the ability to flexibly up- and downregulate the expression of emotion predicts better outcomes. What does this study add The first evidence that the ability to flexibly regulate expressions predicts indices of health. Skill in both expressing and suppressing facial expressions predicts better reported health. Skills with different emotions differentially predict symptom interference and cardiac vagal tone.

Basal autonomic activity, stress reactivity, and increases in metabolic syndrome components over time

CONTEXT

Basal autonomic nervous system (ANS) functioning has been linked to the metabolic syndrome (MetS), but the role of ANS reactivity in response to stress remains unclear.

OBJECTIVE

To examine cross-sectionally and longitudinally to what extent ANS basal level and stress reactivity are related to MetS.

DESIGN

2-year and 6-year data from a prospective cohort: the Netherlands Study of Depression and Anxiety.

SETTING

Participants were recruited from the general community, primary care, and mental health care organizations.

PARTICIPANTS

1922 respondents (mean age=43.7years).

MAIN OUTCOME MEASURES

Indicators of ANS functioning were heart rate (HR), respiratory sinus arrhythmia (RSA) and pre-ejection period (PEP). ANS stress reactivity was measured during a cognitively challenging stressor and a personal-emotional stressor. MetS components included triglycerides, high-density lipoprotein cholesterol, blood pressure, glucose and waist circumference.

RESULTS

Cross-sectional analyses indicated that higher basal HR, lower basal values of RSA and PEP, and higher RSA reactivity during cognitive challenge were related to less favorable values of almost all individual MetS components. Longitudinal analyses showed that higher basal HR and shorter basal PEP predicted 4-year increase in many MetS abnormalities. Higher RSA stress reactivity during cognitive challenge predicted 4-year increase in number of MetS components.

CONCLUSION

Higher basal sympathetic, lower basal parasympathetic activity, and increased parasympathetic withdrawal during stress are associated with multiple MetS components, and higher basal sympathetic activity predicts an increase in metabolic abnormalities over time. These findings support a role for ANS dysregulation in the risk for MetS and, consequently, the development of cardiovascular disease.

Associations between heart rate variability, metabolic syndrome risk factors, and insulin resistance

The purpose of this study was to examine differences in heart rate variability (HRV) in metabolic syndrome (MetS) and to determine associations between HRV parameters, MetS risk factors, and insulin resistance (homeostasis model assessment for insulin resistance (HOMA-IR)). Participants (n = 220; aged 23-70 years) were assessed for MetS risk factors (waist circumference, blood pressure, fasting plasma glucose, triglycerides, and high-density lipoprotein cholesterol) and 5-min supine HRV (time and frequency domain and nonlinear). HRV was compared between those with 3 or more (MetS+) and those with 2 or fewer MetS risk factors (MetS-). Multiple linear regression models were built for each HRV parameter to investigate associations with MetS risk factors and HOMA-IR. Data with normal distribution are presented as means ± SD and those without as median [interquartile range]. In women, standard deviation of R-R intervals 38.0 [27.0] ms, 44.5 [29.3] ms; p = 0.020), low-frequency power (5.73 ± 1.06 ln ms(2), 6.13 ± 1.05 ln ms(2); p = 0.022), and the standard deviation of the length of the Poincaré plot (46.8 [31.6] ms, 58.4 [29.9] ms; p = 0.014) were lower and heart rate was higher (68 [13] beats/min, 64 [12] beats/min; p = 0. 018) in MetS+ compared with MetS-, with no differences in men. Waist circumference was most commonly associated with HRV, especially frequency domain parameters. HOMA-IR was associated with heart rate. In conclusion, MetS+ women had a less favourable HRV profile than MetS- women, but there were no differences in men. HOMA-IR was associated with heart rate, not HRV.

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.

Which is responsible for cardiac autonomic dysfunction in non-diabetic patients with metabolic syndrome: Prediabetes or the syndrome itself?

AIMS

Cardiac autonomic dysfunction (CAD) is associated with both prediabetes and metabolic syndrome (MS). Heart rate variability (HRV) and heart rate turbulence (HRT) are reliable 24-h Holter-ECG findings of cardiac autonomic function. This study aimed to investigate the relation between MS and its components and CAD using HRV and HRT.

MATERIALS AND METHODS

The study included 80 non-diabetic patients with MS and 70 control subjects. All study population and the patients with MS were further analyzed for each diagnostic component of MS to investigate which criteria impaired HRV and HRT.

RESULTS

HRV and HRT parameters were disturbed in patients in the MS group. While impairment in HRV and HRT was significantly related to the presence of the fasting plasma glucose (FPG) criterion, there were no differences between groups in terms of the other 4 MS criteria. Moreover, FPG level was significantly correlated with SDNN (r=-0.352, p<0.001), SDNN index (r=-0.423, p<0.001), SDANN (r=-0.301, p<0.001), RMSSD (r=-0.237, p<0.001), pNN50 (r=-0.237, p<0.001), turbulence onset (TO) (r=0.365, p<0.001) and turbulence slope (TS) (r=-0.365, p<0.001). Among the MS diagnostic criteria, only FPG level was an independent determinant of all HRV and HRT parameters.

CONCLUSIONS

This study confirms the relation between MS and CAD. Increased FPG alone appears to be responsible for the mentioned findings among the 5 diagnostic criteria. Accordingly, CAD may be the result of prediabetes, not MS in patients with MS.

Alteration of Heart Rate Variability in People With Bowel Preparation Before Colonoscopy

In current health examination setting, people frequently undergo heart rate variability (HRV) analysis and colonoscopy on the same day. However, it remains unclear whether the bowel preparation before colonoscopy affects HRV. This study aimed to evaluate the association between HRV and bowel preparation.We conducted a cross-sectional observational study of 1755 people from January 2012 to December 2013 in Taipei, Taiwan. The participants, aged 45 to 65 years, received health examinations that included a physical examination, blood tests, and an HRV analysis. Among these people, 1099 additionally received a colonoscopy on the same day and underwent bowel preparation 1 day before the colonoscopy. The association between HRV and bowel preparation was derived by a multivariable linear regression with adjusted confounding factors.Bowel preparation was associated with a lower standard deviation of the normal-to-normal intervals (SDNN), the root mean square of the successive differences (RMSSD), low-frequency power (LF), and high-frequency power (HF) (all P < 0.0001). After adjusting confounding factors, bowel preparation remained correlated with lower SDNN, RMSSD, LF, and HF (all P < 0.0001). Higher serum phosphorus and lower serum potassium levels were noted in the bowel preparation group (P < 0.0001), and an association between lower HRV and higher serum phosphorus and lower serum potassium levels was only noted in the bowel preparation group.Bowel preparation was significantly associated with lower HRV. The underlying mechanism may be related to an electrolyte imbalance. Cautions may be needed when interpreting HRV reports for people receiving bowel preparations before colonoscopy.

Dynamics of heart rate variability in patients with type 2 diabetes mellitus during spinal anaesthesia: prospective observational study

Background

Little is known about the changes in autonomic function during spinal anaesthesia in type 2 diabetic patients. The purpose of the study was to assess the influence of spinal anaesthesia on the heart rate variability in type 2 diabetic patients according to the glycated hemoglobin (HbA_1c) level.

Methods

Sixty-six patients who were scheduled for elective orthostatic lower limb surgery were assigned to three groups (n = 22, each) according to HbA_1c; controlled diabetes mellitus (HbA_1c < 7 %), uncontrolled diabetes mellitus (HbA_1c > 7 %) and the control group. The heart rate variability was measured 10 min before (T0), and at10 min (T1), 20 min (T2) and 30 min (T3) after spinal anaesthesia.

Results

Before spinal anaesthesia, total, low-and high-frequency power were significantly lower in the uncontrolled diabetec group than in other group (p < 0.05). During spinal anaesthesia, total, low- and high-frequency powers were did not change in the uncontrolled diabetec group while the low-frequency power in the controlled diabetec group was significantly depressed (p < 0.05). The ratio of low-to high-frequency was comparable among the groups, while it was reduced at T1-2 than at T0 in all the groups. The blood pressures were higher in the uncontrolled diabetec group than in the other groups.

Conclusions

Spinal anaesthesia had an influence on the cardiac autonomic modulation in controlled diabetec patients, but not in uncontrolled diabetec patients. There were no differences in all haemodynamic variables during an adequate level of spinal anaesthesia in controlled and uncontrolled type 2 DM.

Trial registration

ClinicalTrials.gov NCT02137057

Electronic supplementary material

The online version of this article (doi:10.1186/s12871-015-0125-6) contains supplementary material, which is available to authorized users.

[Relationship between blood pressure, heart rate and cardiac autonomic dysfunction in non-diabetic obese patients]

RATIONALE

Some studies suggest that a high heart rate (HR) would be predictive of the incidence of an elevated blood pressure (BP). Cardiac autonomic dysfunction (CAD) affects a high proportion of obese patients. CAD could be involved in BP increase. Our aim was to examine the relationship between CAD, HR and BP in obese patients without known diabetes.

PATIENTS AND METHODS

We included 428 overweight or obese patients. CAD was assessed by analyzing HR variations during three standard tests (Valsalva, deep breathing, lying-to-standing), which are mostly dependent on vagal control. An oral load in glucose was performed and the Matsuda index was calculated.

RESULTS

The population was separated in 4 groups according to the grade of CAD (no or only one abnormal test, 2 or 3 abnormal tests) and HR (< or ≥ 75 bpm). Age was similar in the four groups. Systolic (P=0.05), diastolic (P<0.005) and mean BP (P<0.001) differed significantly between the 4 groups, and was the highest in the group of patients who had 2 or 3 abnormal tests and HR ≥ 75 bpm. Matsuda index differed across the groups (P=0.018) and was the lowest in this group.

CONCLUSION

These data indicate that among overweight or obese patients with a defect in cardiac vagal activity BP is elevated only in those with a high heart rate, which is indicative of a more marked insulin resistance and probably an excess in sympathetic activity.

Metabolic syndrome burden in apparently healthy adolescents is adversely associated with cardiac autonomic modulation--Penn State Children Cohort

BACKGROUND

Reduced cardiac autonomic modulation (CAM) has been associated with metabolic syndrome (MetS) in adults. However, the association between MetS component cluster and CAM has not been examined in adolescents.

METHODS

We conducted a cross-sectional analysis using data from the Penn State Child Cohort follow-up examination. CAM was assessed by heart rate variability (HRV) analysis of 39-h RR intervals, including frequency (high frequency, HF; low frequency, LF; and LF/HF ratio) and time (SDNN, standard deviation of all RR intervals; RMSSD, square root of the mean of the sum of the squares of differences between adjacent RR intervals; and HR, heart rate) domain variables. To assess the MetS burden, we used continuous MetS score (cMetS)--sum of the age and sex-adjusted standardized residual (Z-score) of five established MetS components. Linear mixed-effect models were used to analyze the association between cMetS and CAM in the entire population and stratified by gender.

RESULTS

After adjusting for age, sex, and race, cMetS was significantly associated with reduced HRV and higher HR. With 1 standard deviation increase in cMetS, there was a significant decrease in HF (-0.10 (SE = 0.02)), LF (-0.07 (SE = 0.01)), SDNN (-1.97 (SE = 0.50)), and RMSSD (-1.70 (SE = 0.72)), and increase in LF/HF (0.08 (SE = 0.02)) and HR (1.40 (SE = 0.26)). All cMetS components, with the exception of high-density lipoprotein (HDL), were associated with significantly decreased HRV and increased HR. High blood pressure (MAP) and triglyceride (TG) levels were also associated with an increase in LF/HF and decrease in RMSSD. An increase in high-density lipoprotein was only associated with higher LF and SDNN. Moreover, cMetS and HRV associations were more pronounced in males than in females. The associations between HRV and. MAP, TG, and HDL were more pronounced in females.

CONCLUSIONS

cMetS score is associated with lower HRV, suggesting an adverse impact on CAM, even in apparently healthy adolescents.

Autonomic dysfunction independently predicts poor cardiovascular outcomes in asymptomatic individuals with type 2 diabetes in the DIAD study

Objective:

The primary aim of this secondary analysis was to determine whether cardiac autonomic neuropathy independently predicted adverse cardiac outcomes in asymptomatic individuals with type 2 diabetes. Additional aims include the determination of the correlation of standard autonomic testing measures and power spectral analysis of heart rate variability, and the association of diabetes-related and cardiac risk factors with cardiac autonomic neuropathy measures.

Methods:

Cardiac autonomic neuropathy was assessed at the study entry into the Detection of Ischemia in Asymptomatic Diabetics study, using autonomic heart rate and blood pressure testing, and power spectral analysis of heart rate variability. All participants were prospectively followed for the composite clinical outcome of cardiac death, acute coronary syndromes, heart failure, or coronary revascularization.

Results:

Over 5 years of follow-up, 94 of 1119 (8.4%) subjects developed symptomatic cardiac disease. In unadjusted bivariate analyses, abnormalities in several cardiac autonomic neuropathy tests, including lower Valsalva and Standing Heart Rate Ratios, higher resting Heart Rate, greater systolic blood pressure decrease on standing, and lower low-frequency power, were predictive of symptomatic disease. Independent predictors of poor cardiac outcome were a lower Valsalva Heart Rate Ratio, non-Black ethnicity, longer diabetes duration, higher glycated hemoglobin (HbA1c), insulin use, reported numbness in the extremities, higher pulse pressure, family history of coronary artery disease, and higher waist-to-hip ratio. Clinical factors independently associated with a lower Valsalva Heart Rate Ratio were insulin use, clinical proteinuria, higher pulse pressure, use of angiotensin-converting enzyme inhibitor and non-Black ethnicity.

Conclusion:

Cardiac autonomic neuropathy predicted adverse cardiac outcomes in asymptomatic type 2 diabetes without known cardiac disease. Clinical variables may help to identify patients who might have cardiac autonomic neuropathy and warrant consideration for autonomic testing.

Modeling of performance and ANS activity for predicting future responses to training

PURPOSE

Our aim was to assess whether we can predict satisfactorily performance in swimming and high frequency power (HF power) of heart rate variability from the responses to previous training. We have tested predictions using the model of Banister and the variable dose-response model.

METHODS

Data came from ten swimmers followed during 30 weeks of training with performance and HF power measured each week. The first 15-week training period was used to estimate the parameters of each model for both performance and HF power. Both were then predicted in response to the training done during the second 15-week training period. The bias and precision were estimated from the mean and SD of the difference between prediction and actual value expressed as a percentage of performance or HF power at the first week.

RESULTS

With the variable-dose response model, the bias for performance prediction was -0.24 ± 0.06 and the precision 0.69 ± 0.24% (mean ± between-subject SD). For HF power, the bias was 0 ± 21 and the precision 22 ± 8%. When HF power was transformed into performance using a quadratic relation in each swimmer established from the first 15-week period, the bias was 0.18 ± 0.74 and the precision 0.80 ± 0.30%. No clear trend in the error was observed during the second period.

CONCLUSIONS

This study showed that the modeling of training effects on performance allowed accurate performance prediction supporting its relevance to control and predict week after week the responses to future training.

The circadian pattern of cardiac autonomic modulation and obesity in adolescents

PURPOSE

To assess the impact of obesity and population attributes on the circadian pattern of cardiac autonomic modulation (CAM) in a population-based sample of adolescents.

METHODS

We used data from 421 adolescents who completed the follow-up exam in the Penn State Children Cohort study. CAM was assessed by heart rate variability (HRV) analysis of beat-to-beat, normal R-R intervals from a 24-hour ECG, on a 30-minute basis. The HRV indices included frequency-domain (HF, LF, and LF/HF ratio) and time-domain (SDNN, RMSSD, and HR) variables. Nonlinear mixed-effect models were used to calculate a cosine periodic curve, each having three parameters quantifying its circadian period: M (mean levels of the HRV variables), Â (amplitude of the oscillation), and θ (the time of the highest oscillation).

RESULTS

The mean (SD) age was 16.9 (2.2) years, with 54 % male and 77 % white. The mean BMI percentile was 66, with 16 % obese (BMI percentile ≥ 95). Overall, HF (a marker of parasympathetic modulation) gradually increased from the late afternoon, reached peak amplitude around 3 a.m., and then decreased throughout the daytime until late afternoon. In contrast, obesity had adverse effects on all circadian parameters. The age, sex and race showed varying differences on the CAM circadian parameters. The adjusted means (95 %Cls) of M, Â, and θ for HF were 5.99 (5.79-6.19), 0.77 (0.66-0.89), 3:15 (2:15-4:15) a.m., and 6.21 (6.13-6.29), 0.66 (0.61-0.70), 2:45 (2:30-3:15) a.m. for obese and non-obese subjects, respectively.

CONCLUSION

The circadian pattern of CAM can be quantified by the three cosine parameters. Obesity is associated with lower HRV even in young individuals like children/adolescents.

Cardiovascular autonomic function analysis using approximate entropy from 24-h heart rate variability and its frequency components in patients with type 2 diabetes

Aims/Introduction

The principal aim of the present study was to investigate the cardiovascular autonomic system status of diabetes patients using approximate entropy (ApEn) extracted from 24-h heart rate variability (HRV) and its frequency components.

Materials and Methods

A total of 29 healthy controls and 63 type 2 diabetes patients were included. Participants’ 24-h HRV signals were recorded, and decomposed and reconstructed into four frequency components: high, low, very low and ultra low. The total 24-h HRV and its four components were divided into 24 1-h segments. ApEn values were extracted and statistically analyzed. Four traditional HRV indices, namely standard deviation of the RR intervals, root mean square of successive differences, coefficient of variance of RR intervals and ratio of low to high power of HRV, were also calculated.

Results

The low-frequency component contained the most abundant non-linear information, so was potentially most suitable for studying the cardiovascular system status with non-linear methods. ApEn values extracted from low- and high-frequency components of healthy controls were higher than those of diabetes patients. Except for root mean square of successive differences, standard deviation of the RR intervals, low to high power of HRV and coefficient of variance of RR intervals of healthy controls were all higher than those of diabetes patients.

Conclusions

The results showed that ApEn contained information on disorders of autonomic system function of diabetes patients as traditional HRV indices in time and frequency domains. ApEn and three traditional indices showed accordance to some degree. Non-linear information in subcomponents of HRV was shown, which is potentially more effective for distinguishing healthy individuals and diabetes patients than that extracted from the total HRV. Compared with diabetes patients, the cardiovascular system of healthy controls showed information of higher complexity, and better regulation function in response to changes of environment.

Deterioration of heart rate recovery index in patients with non-alcoholic fatty liver disease (NAFLD)

Background

Non-alcoholic fatty liver disease (NAFLD) has been considered as a benign disease often associated with central obesity and insulin resistance and, in general, with factors of the metabolic syndrome. Heart rate recovery after exercise is a function of vagal reactivation, and its impairment is an independent prognostic indicator for cardiovascular and all-cause mortality. The aim of our study was to evaluate the heart rate recovery index in patients with NAFLD.

Material/Methods

The study population included 59 patients with NAFLD (mean age=42.3±9.3 years) and 22 healthy subjects as controls (mean age=40.7±6.5 years). Basal electrocardiography, echocardiography, and treadmill exercise testing were performed on all patients and controls. The heart rate recovery index was defined as the reduction in the heart rate from the rate at peak exercise to the rate at the 1^st minute (HRR1), 2^nd minute (HRR2), 3^rd minute (HRR3), and 5^th minute (HRR5) after stopping exercise stress testing.

Results

There were significant differences in HRR1 and HRR2 indices between patients with ED and the control group (19.9±8.2 vs. 34.1±9.6; p<0.001 and 24.3±5.4 vs. 40.5±9.1; p=0.006, respectively). Similarly, HRR indices after the 3^rd and 5^th minutes of the recovery period were significantly lower in patients with NAFLD compared with those indices in the control group (32.3±8.5 vs. 58.4±6.5; p=0.001 and 58±18.2 vs. 75.1±15.8; p<0.001). Effort capacity was markedly lower (11±1.9 vs. 12.5±1.5 METs; p=0.001) among the patients with NAFLD.

Conclusions

The heart rate recovery index is deteriorated in patients with NAFLD. When the prognostic significance of the heart rate recovery index is considered, these results may help explain the increased occurrence of cardiac death. It points to the importance of the heart rate recovery index in the identification of high-risk patients.

Sex-specific impact of maternal-fetal risk factors on depression and cardiovascular risk 40 years later

Major depressive disorder (MDD) and cardiovascular disease (CVD) represent leading causes of morbidity and mortality worldwide. We tested the hypothesis that growth restriction and preeclampsia (referred to as fetal risk) are significant predictors of these conditions, with women at higher risk in adulthood. Adult offspring exposed to fetal risk factors and their discordant siblings were from two prenatal cohorts, whose mothers were followed through pregnancy and whom we recruited as adults 40 years later (n = 538; 250 males and 288 females). Subjects were psychiatrically diagnosed and underwent a stress challenge during which parasympathetic regulation was assessed by electrocardiogram, operationalized as high-frequency R-R interval variability (HF-RRV). Linear mixed models and generalized estimating equations were used to examine the relationship of fetal risk on HF-RRV, MDD and comorbidity of low HF-RRV (lowest 25th percentile) and MDD, including interactions with sex and socioeconomic status (SES). Fetal risk was significantly associated with low HF-RRV response (F = 3.64, P = 0.05), particularly among low SES (interaction: F = 4.31, P < 0.04). When stratified by MDD, the fetal risk impact was three times greater among MDD compared with non-MDD subjects (effect size: 0.21 v. 0.06). Females had a significantly higher risk for the comorbidity of MDD and low HF-RRV than males (relative risk (RR) = 1.36, 95% CI: 1.07-1.73), an association only seen among those exposed to fetal risk (RR = 1.38, 95% CI: 1.04-1.83). Findings suggest that these are shared fetal antecedents to the comorbidity of MDD and CVD risk 40 years later, an association stronger in females than in males.

Childhood obesity and autonomic dysfunction: risk for cardiac morbidity and mortality

OPINION STATEMENT

The epidemic of childhood obesity is becoming a major predictor for risk of cardiovascular diseases (CVD) and mortality during adulthood. Alterations in the morphology of the heart due to obesity could be a predictor for the dysfunction of cardiac autonomic modulation (CAM). A number of epidemiologic studies have evaluated the effect of obesity and CAM in children, finding that obesity impaired the balance of CAM toward a sympathetic overflow and reduced parasympathetic modulation, a significant predictor of CVD morbidity and mortality in adults. Lifestyle modifications, for example long-term exercise programs, have been shown to improve CAM in the obese. This review discusses the recent evidence on childhood and adolescent obesity and its impact on CAM, as well as how early lifestyle changes could help improve CAM, which may in turn reduce the burden of CVD in adults.

Heart rate variability is severely impaired among type 2 diabetic patients with hypertension

INTRODUCTION

The aim of our study was to evaluate the relative effect of diabetes and hypertension on heart rate variability.

RESEARCH DESIGN AND METHODS

Four age-matched groups including type 2 diabetic patients with and without hypertension, non-diabetic patients with essential hypertension and healthy control subjects were studied. Autonomic function was evaluated by the standard cardiovascular reflex tests and 24-hour heart rate variability measurement. Heart rate variability was characterized by the triangular index value and by the spectral components of the frequency domain analysis.

RESULTS

According to the two-way analysis of variance on ranks, all parameters were influenced negatively by diabetes (heart rate variability triangular index: p < 0.001; low-frequency component: p < 0.0001; high-frequency component: p < 0.001; and total power: p < 0.0001), whereas hypertension had a negative effect only on the low-frequency component (p < 0.05). The interaction between hypertension and diabetes was not significant, indicating that their effects on the heart rate variability parameters are additive. Beat-to-beat variation upon deep breathing, the most sensitive cardiovascular reflex test was also negatively influenced by both diabetes (p < 0.001) and hypertension, (p < 0.05), and their effects were additive.

CONCLUSIONS

Diabetes appears to have a greater effect on autonomic dysfunction compared with hypertension. Patients suffering from both diabetes and hypertension are at the highest risk of reduced heart rate variability. Early assessment of the autonomic nerve function is suggested in diabetic patients with hypertension.

Plasma norepinephrine is an independent predictor of adverse cerebral and cardiovascular events in type 2 diabetic patients without structural heart disease

BACKGROUND

Resting plasma norepinephrine (NE) level was reportedly related to high mortality in patients with heart failure. The current study investigated whether resting NE could predict long-term major adverse cerebral and cardiovascular events (MACCEs) in Japanese type 2 diabetic patients without heart disease.

METHODS AND SUBJECTS

We evaluated resting NE in 95 patients with type 2 diabetes who did not have severe complications. Based on the ROC curves, high NE was defined as ≥333pg/ml. Accurate follow-up information during a mean of 3.6±1.9 years was obtained in 27 high NE patients (13 female, mean age 64±12 years) and 68 low NE patients (29 female, 60±12 years).

ESSENTIAL RESULTS

The Kaplan-Meier curves revealed that MACCE-free ratio was significantly lower in the high NE patients than in the low NE patients (log-rank 10.3, p=0.0013). Cox proportional hazards regression analysis revealed that female gender (hazard ratio 7.75), low baroreflex sensitivity (hazard ratio 6.66), and high NE (hazard ratio 5.40) were independently associated with the incidence of MACCE.

PRINCIPAL CONCLUSIONS

Our results suggest that resting NE is comparably useful to identify the high-risk patients for MACCE to baroreflex sensitivity in type 2 diabetic patients. The results also suggest that pathogenic sympathetic activation leading to MACCE may be identified by the assessment of resting NE, more easily and less expensively compared to cardiac iodine 123 metaiodobenzylguanidine scintigraphy in this population.