Reference values for short-term resting-state heart rate variability in healthy adults: Results from the Brazilian Longitudinal Study of Adult Health-ELSA-Brasil study.

Heart rate variability (HRV) is a psychophysiological phenomenon with broad implications, providing an accessible index of vagal function, underpinning psychological constructs, including the capacity for social engagement and emotion regulation, and may predict future morbidity and mortality. However, the lack of reference values for short-term HRV indices for participants of both sexes across the age spectrum is a limiting factor. This was the objective of the present study. Resting electrocardiographic records were obtained from 13,214 participants (both sexes, 35-74 years), and HRV indices in time and frequency domains (mean ± SD) were determined from 5-min records. Results were based on a subsample of 2,874 nonmedicated, healthy participants stratified by sex across 10-year age groupings. Men showed lower heart rate (HR, 64 ± 8 bpm vs. 68 ± 8 bpm, p < .05) and normalized high frequency (HF; 39.4 ± 18.0 normalized units [n.u.] vs. 50.4 ± 18.5 n.u., p < .05) than women, and higher N-N variance (2,214 ± 1,890 ms2 vs. 1,883 ± 1,635 ms2 , p < .05), standard deviation of all N-N intervals (SDNN; 43.7 ± 17.3 ms vs. 40.3 ± 15.8 ms, p < .05) and LF/HF (2.30 ± 2.68 vs. 1.33 ± 1.82, p < .05). HR and HF (n.u.) were also higher in younger than older women. LF/HF was lower in women than men. Percentile curves showed almost all HRV indices decreasing with aging. The availability of short-term, resting-state HRV reference values in a large sample of healthy and nonmedicated participants from 35-74 years will provide a valuable tool for researchers, clinicians, and those in the quantified-self community.

Nonverbal behaviors are associated with increased vagal activity in major depressive disorder: Implications for the polyvagal theory.

BACKGROUND: Major depressive disorder (MDD) is associated with impairments in nonverbal behaviors (NVBs) and vagal activity. The polyvagal theory proposes that vagal activity regulates heart rate and NVBs by modulating a common anatomically and neurophysiologically discrete social engagement system. However, the association between these putative endophenotypes has not yet been explored. We hypothesize that in MDD, NVBs indicating positive affects and social interest and those indicating negative feelings and social disinterest could be associated with different patterns of vagal activity. METHODS: For this cross-sectional study we recruited 50 antidepressant-free participants with moderate-to-severe MDD. Vagal activity was indexed by heart rate variability (HRV) measures, and positive and negative nonverbal behaviors (NVBs) by a validated ethogram. Associations between NVBs and HRV were explored by bivariate analyses and multivariable models were adjusted by age, gender, depression severity, and self-reported positive and negative affects. RESULTS: HRV measures indicative of higher vagal activity were positively correlated with positive NVBs exhibited during the clinical interview. Conversely, NVBs related to negative affects, low energy and social disinterest were not associated with HRV. LIMITATIONS: Absence of a control group. CONCLUSIONS: The findings highlight that the examined depression endophenotypes (nonverbal behaviors and vagal activity) are related, shedding light on MDD pathophysiology in the context of the polyvagal theory.

Comparison between symbolic and spectral analyses of short-term heart rate variability in a subsample of the ELSA-Brasil study.

Linear and nonlinear analyses of heart rate variability (HRV) have been largely used to evaluate the autonomic balance directed to the cardiovascular system. However, comparative studies evaluating the agreement between methods are scarce. Therefore, our aim was to examine the relationship between spectral (SPA; linear) and symbolic analyses (SYA; nonlinear) indexes. A subsample of 683 participants of the Brazilian Longitudinal Study of Adult Health was investigated. Linear and nonlinear analyses were obtained from 10 min ECG recording at rest. Reliability and agreement between methods were evaluated by kappa-statistic and proportion of agreement. According to SYA, the most frequent pattern was P1V (sympathovagal balance, without sympathetic or vagal predominance) comprising 62.7% of the sample, followed by P2V (vagal predominance) with 33.2%, and finally P0V pattern (sympathetic predominance) with 4.1%. Overall proportion of agreement between SYA and SPA was 39.68% (95% CI 0.360-0.433), with expected agreement by chance of 30.8%. Kappa value was 0.128 indicating a slight agreement between methods. Proportion of agreement was 7.93% (95% CI 0.032-0.126) for predominant sympathetic modulation, 10.39% (95% CI 0.075-0.132) for sympathovagal modulation, and 40.29% (95% CI 0.361-0.444) for parasympathetic modulation. Our data provide evidence for important differences between SPA and SYA on HRV analysis. More studies are needed to clarify the causes of disagreement between two methods designed to evaluate the autonomic modulation of heart beats.

Heart rate at 4 s after the onset of exercise in endurance-trained men.

It has been suggested that the increase in heart rate (HR) at the onset of exercise is caused by vagal withdrawal. In fact, endurance runners show a lower HR in maximum aerobic tests. However, it is still unknown whether endurance runners have a lower HR at 4 s after the onset of exercise (4th-sec-HR). We sought to measure the HR at the onset of the 4 s exercise test (4-sET), clarifying its relationship to heart rate variability (HRV), spectral indices, and cardiac vagal index (CVI) in endurance runners (ER) and healthy untrained controls (CON). HR at 4th-sec-HR, CVI, and percent HR increase during exercise were analyzed in the 4-sET. High frequency spectrum (HF-nu), low frequency spectrum (LF-nu), and low frequency/high frequency band ratio (LF/HF) were analyzed from the HRV. ER showed a significantly higher HF, and both a lower LF and LF/HF ratio compared with the CON. ER presented a significantly lower 4th-sec-HR, although neither CVI nor HR increases during exercise were statistically different from the CON. In conclusion, ER presented a lower 4th-sec-HR secondary to increased vagal influence over the sinus node. CVI seems to be too weak to use for discriminating individuals with respect to the magnitude of HR vagal control.

Strengthening exercises improve symptoms and quality of life but do not change autonomic modulation in fibromyalgia: a randomized clinical trial.

OBJECTIVE: Autonomic dysfunction is an important mechanism that could explain many symptoms observed in fibromyalgia (FM). Exercise is an effective treatment, with benefits potentially mediated through changes in autonomic modulation. Strengthening is one of the less studied exercises in FM, and the acute and chronic effects of strengthening on the autonomic system remain unknown. The objective of this study was to assess the chronic effects of strengthening exercises (STRE) on autonomic modulation, pain perception and the quality of life (QOL) of FM patients. METHODS: Eighty sedentary women with FM (ACR 1990) were randomly selected to participate in STRE or flexibility (FLEX) exercises in a blinded controlled trial. The intensity of STRE was set at 45% of the estimated load of 1 Repetition Maximum (RM) in 12 different exercises. Outcomes were Visual Analog Scale (VAS) for pain, Heart Rate Variability (HRV) analysis, treadmill test, the sit and reach test (Wells and Dillon's Bench), maximal repetitions test and handgrip dynamometry; and quality of life by the Fibromyalgia Impact Questionnaire (FIQ), the Beck and Idate Trait-State Inventory (IDATE), a short-form health survey (SF-36). RESULTS: The STRE group was more effective to strength gain for all muscles and pain control after 4 and 16 weeks (p<0.05). The FLEX group showed higher improvements in anxiety (p<0.05). Both groups showed improvements in the QOL, and there was no significant difference observed between the groups. There was no change in the HRV of the STRE and FLEX groups. CONCLUSIONS: Strengthening exercises show greater and more rapid improvements in pain and strength than flexibility exercises. Despite the benefits in fitness, pain, depression, anxiety and quality of life, no effect was observed on the autonomic modulation in both groups. This observation suggests that changes in autonomic modulation are not a target tobe clinically achieved in fibromyalgia. TRIAL REGISTRATION: ClinicalTrials.gov NCT02004405.

[Medical assessments and measurements in ELSA-Brasil]. / Aferições e exames clínicos realizados nos participantes do ELSA-Brasil.

The article describes assessments and measurements performed in the Brazilian Longitudinal Study for Adult Health (ELSA-Brasil). Some assessments including anthropometric assessment, casual blood pressure measurement, and ankle-brachial index have an established clinical application while others including pulse wave velocity, heart rate variability, and carotid intima-media thickness have no established application and do not have reference values for healthy Brazilian population but may be important predictors of cardiovascular outcomes. Blood pressure measurement following postural change maneuver was included in the ELSA-Brasil because it has not been much tested in epidemiological studies. Innovative approaches were developed for assessing the ankle-brachial index using an automatic device instead of the mercury column to measure blood pressure and for assessing the anterior-posterior diameter of the right lobe of the liver by ultrasound for quantitative assessment of nonalcoholic fatty liver disease. All ELSA-Brasil subjects were younger (35 years or more) than those included in other cohorts studying subclinical atherosclerosis. The inclusion of younger individuals and a variety of assessments make the ELSA-Brasil a relevant epidemiology study nationwide and worldwide.

Comparação da resposta autonômica cardiovascular de praticantes de musculação, corredores de longa distância e não praticantes de exercício / Comparison of cardiovascular autonomic response among body builders, long distance runners and non-trained

Objetivou-se comparar a resposta autonômica cardiovascular (RAC) de praticantes de musculação, corredores de longa distância e não praticantes de exercício. Homens, 21 a 55 anos, foram agrupados em: Praticantes Musculação (PM, n = 31); Praticantes Corrida (PC, n = 28); Controle (C, n = 35). Foram selecionadas quatro técnicas para avaliação da RAC: Frequência cardíaca de repouso (FCR), Teste pressórico do frio (TPF), Variabilidade da FC (VFC) e recuperação da FC pós-teste máximo em esteira. A FCR foi menor no grupo PC (PC = 54 ± 2; PM= 62 ± 2; C = 65 ± 2 bpm; média ± EPM). A recuperação da FC aos 60 s pós-teste de esforço foi maior no grupo PC (PC = 34 ± 3; PM = 23 ± 1; C = 24 ± 2; bpm). Quanto aos parâmetros espectrais de alta (HF) e baixa (LF) frequência da VFC, o grupo PC apresentou maior HF (55,1 ± 4,0 n.u) e menor LF (43,1 ± 4,0 n.u) comparado ao grupo C (HF = 40,7 ± 3,3; LF = 56,7 ± 3,5 n.u). O grupo PM não apresentou qualquer diferença de RAC em comparação ao grupo C. Conclui-se que prática contínua em musculação por longo prazo, diferentemente da prática de corrida de longa distância, não é capaz de alterar significativamente a RAC.

The aim of the study was to compare the cardiovascular autonomic response (CAR) of recreational weight trainers, long distance runners and non-exercised subjects. Men, 21 to 55 years old, were grouped in: recreational weight trainers (W, n = 31), long distance runners (R, n = 28) and non-exercised (C, n = 35). Four strategies of evaluation of the CAR were selected: Resting heart rate (RHR), cold pressor test (CPT), heart rate variability (HRV) and heart rate recovery (HHR) following maximal exercise test. The RHR was lower (R = 54 ± 2; W = 62 ± 2; C= 65 ± 2 bpm; mean ± SE) and the HHR 60s post exercise was larger in the R group (R = 34 ± 3; W = 23 ± 1; C = 24 ± 2 bpm). The R group presented larger high-frequency (HF; 55.1 ± 4.0 n.u) and smaller low-frequency (LF; 43.1 ± 4.0 n.u) components of HRV than C group (HF = 40.7 ± 3.3; LF = 56.7 ± 3.5 n.u.). The W group did not show any differences compared to C group. The study's conclusion was that long-term weight-training program, unlike of long-term running training, it is not able to alter significantly the regulatory pattern of CAR.

Carvedilol recovers normal blood pressure variability in rats with myocardial infarction.

BACKGROUND: The aim of this study was to investigate the effects of chronic treatment with carvedilol in blood pressure (BPV) and heart rate (HRV) variability of rats with myocardial infarction (MI). METHODS: MI was produced in male rats by ligature of anterior interventricular branch of left coronary artery. Control rats were submitted to a sham surgery (SO). MI and SO rats were randomized to receive for 30 days placebo (Plac 0.5% metilcelulose) or carvedilol (Carv, 2mg/Kg body weight/day, drinking water): SO-Plac (N = 10), SO-Carv (N = 10), MI-Plac (N = 12), MI-Carv (N = 13). Blood pressure (BP) was directly recorded in the awake animals and BPV was determined, in time (variance, mmhg(2)) and frequency domains by the autoregressive method. Statistical significance was set in P<0.05. Data are median and interquartile range. RESULTS: No significant changes in HRV was observed in MI rats, while BPV showed significant decreasing of blood pressure variance (SO-Plac = 42.08 (39.21) mmHg(2) vs. MI-Plac = 21.67 (12.58) mmHg(2), P<0.05), reversed by the Carv treatment (MI-Plac = 21.67 (12.58) vs. MI-Carv = 38.64 (29.25), P<0.05). In the frequency domain analyses, MI reduced absolute and normalized LF component (LF (mmHg(2)): SO-Plac = 8.98 (14.84) vs. MI-Plac = 2.08 (4.84), P<0.05; LF(nu): SO-Plac = 79.48 (45.03) nu vs. MI-Plac = 24.25 (40.67) nu, P<0.05) and increased the normalized HF component of the BPV (SO-Plac = 20.51 (39.18) vs. MI-Plac = 60.51 (39.73). Carv treatment significantly attenuated the LF component fall. CONCLUSION: Chronic treatment with carvedilol restored the variance of BPV altered by the MI.

Afericoes e exames clinicos realizados nos participantes do ELSA-Brasil / Medical assessments and measurements in ELSA-Brasil

Este artigo descreve os exames clínicos realizados no Estudo Longitudinal de Saúde do Adulto (ELSA-Brasil). Alguns deles (antropometria, pressão arterial e índice tornozelo-braquial) já têm uso clínico consolidado. Outros, como a velocidade de onda de pulso, variabilidade da frequência cardíaca e medida da espessura médio-intimal de carótidas, carecem de valor de referência na população brasileira não doente e podem constituir preditores importantes de desfechos cardiovasculares. A medida da pressão arterial após manobra postural foi incluída no ELSA-Brasil porque foi pouco testada em estudos epidemiológicos. O ELSA-Brasil inovou na realização do índice tornozelo-braquial, ao usar um aparelho automático em substituição à coluna de mercúrio na medida da pressão arterial, e também na medida do diâmetro ântero-posterior do lobo direito do fígado pela ultrassonografia, proposta para avaliação quantitativa da doença hepática gordurosa não-alcoólica. Os participantes são indivíduos mais jovens (a partir dos 35 anos) do que em outras coortes focadas no estudo da aterosclerose subclínica. A inclusão de indivíduos mais jovens e a diversidade dos exames realizados tornam o ELSA-Brasil um estudo relevante no contexto da epidemiologia brasileira e internacional.

The article describes assessments and measurements performed in the Brazilian Longitudinal Study for Adult Health (ELSA-Brasil). Some assessments including anthropometric assessment, casual blood pressure measurement, and ankle-brachial index have an established clinical application while others including pulse wave velocity, heart rate variability, and carotid intima-media thickness have no established application and do not have reference values for healthy Brazilian population but may be important predictors of cardiovascular outcomes. Blood pressure measurement following postural change maneuver was included in the ELSA-Brasil because it has not been much tested in epidemiological studies. Innovative approaches were developed for assessing the ankle-brachial index using an automatic device instead of the mercury column to measure blood pressure and for assessing the anterior-posterior diameter of the right lobe of the liver by ultrasound for quantitative assessment of nonalcoholic fatty liver disease. All ELSA-Brasil subjects were younger (35 years or more) than those included in other cohorts studying subclinical atherosclerosis. The inclusion of younger individuals and a variety of assessments make the ELSA-Brasil a relevant epidemiology study nationwide and worldwide.

Detection of left ventricular hypertrophy by the R-wave voltage in lead aVL: population-based study.

BACKGROUND: According to hypertension guidelines, the recommended electrocardiographic (ECG) diagnostic criteria for left ventricular hypertrophy (LVH) are the Sokolow-Lyon and Cornel voltage criteria, both with general acceptance by primary care physicians. However, it was recently reported that the R-wave voltage in lead aVL (RaVL) was as good as other more complicated and time-consuming ECG criteria to detect LVH in hypertensive patients. Therefore, our aim was to investigate if the ability of the RaVL to identify echocardiographic left ventricular hypertrophy (ECHO-LVH) could be translated to the general population, a more realistic assessment of its utility in a nonreferral setting. METHODS: 682 participants (43.5 % males), aged between 27 and 72 years from the urban population of Vitoria, ES, Brazil, were enrolled. We investigated the association of ECHO-LVH (LV mass >51 g/Ht(2.7)) with several ECG voltage measurements: Sokolow-Lyon and Cornel criteria, S-wave voltage in lead V3 (SV3) and RaVL. RESULTS: The RaVL showed the best positive correlation with LV mass indexed to Ht(2.7), superior to both Cornell and Sokolow-Lyon criteria and was not influenced by gender. Analysis of the ROC curves showed that the RaVL depicted a significant superior performance in relation to all the other measurements in the ability to detect ECHO-LVH. SV3 was not correlated with LV mass. Thus, it seems that most of Cornell's performance depends on its simplified version, that is, RaVL. CONCLUSION: We have shown that the simple and single assessment of RaVL presented a greater diagnostic ability in detecting ECHO-LVH in the general population, signaling its value mainly as a screening tool.

Polarity- and valence-dependent effects of prefrontal transcranial direct current stimulation on heart rate variability and salivary cortisol.

Recent evidence has supported the notion that the hypothalamic-pituitary-adrenal (HPA) and the sympatho-adreno-medullary (SAM) systems are modulated by cortical structures such as the prefrontal cortex. This top-down modulation may play a major role in the neuroendocrine changes associated with stressful events. We aimed to investigate further this hypothesis by modulating directly prefrontal cortex excitability using transcranial direct current stimulation (tDCS) - a non-invasive, neuromodulatory tool that induces polarity-dependent changes in cortical excitability - and measuring effects on salivary cortisol and heart rate variability as proxies of the HPA and SAM systems. Twenty healthy participants with no clinical and neuropsychiatric conditions were randomized to receive bifrontal tDCS (left anodal/right cathodal or left cathodal/right anodal) or sham stimulation, in a within-subject design. During each stimulation session, after a resting period, subjects were shown images with neutral or negative valence. Our findings showed that excitability enhancing left anodal tDCS induced a decrease in cortisol levels. This effect is more pronounced during emotional negative stimuli. Moreover, vagal activity was higher during left anodal tDCS and emotional negative stimuli, as compared to sham stimulation and neutral images. We also observed an association between higher mood scores, higher vagal activation and lower cortisol levels for anodal stimulation. Subjective mood and anxiety evaluation revealed no specific changes after stimulation. Our findings suggest that tDCS induced transient, polarity specific modulatory top-down effects with anodal tDCS leading to a down-regulation of HPA and SAM systems. Further research using tDCS and neuroendocrine markers should explore the mechanisms of stress regulation in healthy and clinical samples.

Distribuição por gênero de ácido úrico sérico e fatores de risco cardiovascular: estudo populacional / Gender distribution of serum uric acid and cardiovascular risk factors: population based study / Distribución por género del ácido úrico sérico y factores de riesgo cardiovascular: estudio poblacional

FUNDAMENTO: Não há dados relativos à epidemiologia da hiperuricemia em estudos brasileiros de base populacional. OBJETIVO: Investigar a distribuição de ácido úrico sérico e sua relação com variáveis demográficas e cardiovasculares. MÉTODOS: Estudamos 1.346 indivíduos. A hiperuricemia foi definida como > 6,8 e > 5,4 mg/dL para homens e mulheres, respectivamente. A síndrome metabólica (SM) foi definida utilizando-se os critérios NCEP ATP III. RESULTADOS: A prevalência de hiperuricemia foi de 13,2 por cento. A associação de ácido úrico sérico (AUS) com fatores de risco cardiovasculares foi específica para o gênero: em mulheres, maiores níveis de AUS estiveram associados com IMC elevado, mesmo após ajustes da pressão arterial sistólica para idade (PAS). Em homens, a relação do AUS com o colesterol HDL esteve mediada pelo IMC, enquanto em mulheres, o AUS mostrou-se semelhante e dependente do IMC, independentemente dos níveis glicose e presença de hipertensão. Nos homens, os triglicerídeos, a circunferência abdominal (CA) e a PAS explicaram 11 por cento, 4 por cento e 1 por cento da variabilidade do AUS, respectivamente. Nas mulheres, a circunferência abdominal e os triglicerídeos explicaram 9 por cento e 1 por cento da variabilidade de AUS, respectivamente. Em comparação com o primeiro quartil, homens e mulheres no quarto quartil apresentavam 3,29 e 4,18 vezes mais de aumento de risco de SM, respectivamente. As mulheres apresentaram uma prevalência quase três vezes maior de diabetes melito. Homens normotensos com MS apresentaram maiores níveis de AUS, independente do IMC. CONCLUSÃO: Nossos resultados parecem justificar a necessidade de uma avaliação baseada no gênero em relação à associação do AUS com fatores de risco cardiovasculares, que se mostraram mais acentuados em mulheres. A SM esteve positivamente associada com AUS elevado, independentemente do gênero. A obesidade abdominal e a hipertrigliceridemia foram os principais fatores associados com a hiperuricemia mesmo em indivíduos normotensos, o que pode adicionar maior risco para a hipertensão.

BACKGROUND: There is no data concerning the epidemiology of hyperuricemia in Brazilian population-based studies. OBJECTIVE: To investigate the distribution of serum uric acid and its relationship with demographics and cardiovascular variables. MEHTODS: We studied 1,346 individuals. Hyperuricemia was defined as > 6.8 and > 5.4 mg/dL for men and women, respectively. Metabolic syndrome (MS) was defined with NCEP ATP III criteria. RESULTS: The prevalence of hyperuricemia was 13.2 percent. The association of serum uric acid (SUA) with cardiovascular risk factors was gender-specific: in women, higher SUA was associated with increasing BMI, even after adjustments for age-systolic blood pressure (SBP). In men, the relationship of SUA with HDLc was mediated by BMI, whereas in women, SUA was similar and dependent on BMI, regardless of glucose levels and presence of hypertension. In men, triglycerides, waist circumference (WC) and SBP explained 11 percent, 4 percent and 1 percent of SUA variability, respectively. In women, WC and triglycerides explained 9 percent and 1 percent of SUA variability, respectively. Compared to the first quartile, men and women in the fourth quartile had a 3.29 fold and 4.18 fold increase of MS risk, respectively. Women had almost three fold higher prevalence of diabetes mellitus. Normotensive men with MS presented higher SUA, regardless of BMI. CONCLUSION: Our results seem to justify the need for gender-based evaluation regarding the association of SUA with cardiovascular risk factors, which was more pronounced in women. MS was positively associated with increasing SUA, regardless of gender. Abdominal obesity and hypertriglyceridemia were the main factors associated with hyperuricemia even in normotensive individuals, which may add a higher risk for hypertension.

RFUNDAMENTO: No existen datos relativos a la epidemiología de la hiperuricemia en los estudios brasileros de base poblacional. OBJETIVO: Investigar la distribución del ácido úrico sérico y su relación con las variables demográficas y cardiovasculares. MÉTODOS: Estudiamos 1.346 individuos. La hiperuricemia se definió como > 6,8 y > 5,4 mg/dL para hombres y mujeres, respectivamente. El síndrome metabólico (SM) fue definido utilizando los criterios NCEP ATP III. RESULTADOS: La prevalencia de hiperuricemia fue de un 13,2 por ciento. La asociación del ácido úrico sérico (AUS), con los factores de riesgo cardiovasculares fue específica para el género: en las mujeres, mayores niveles de AUS estuvieron asociados con un IMC elevado, incluso después de los ajustes para la presión arterial sistólica (PAS) y edad . En los hombres, la relación del AUS con el colesterol HDL fue mediada por el IMC, mientras que en las mujeres, el AUS demostró ser parecido y dependiente del IMC, independientemente de los niveles de glucosa y de la presencia de hipertensión. En los hombres, los triglicéridos, la circunferencia abdominal (CA) y la PAS, explicaron el 11 por ciento, 4 por ciento y el 1 por ciento de la variabilidad del AUS, respectivamente. En las mujeres, la circunferencia abdominal y los triglicéridos explicaron el 9 por ciento y el 1 por ciento de la variabilidad de AUS, respectivamente. En comparación con el primer cuartil, los hombres y las mujeres, en el cuarto cuartil, tenían 3,29 y 4,18 veces más aumento de riesgo de SM, respectivamente. Las mujeres tenían una prevalencia casi tres veces mayor de diabetes mellitus. Los hombres normotensos con MS tenían mayores niveles de AUS, independiente del IMC. CONCLUSIONES: Nuestros resultados parecen justificar la necesidad de una evaluación con base en el género, respecto de la asociación del AUS con los factores de riesgo cardiovasculares, que demostraron ser más acentuados en las mujeres. La SM estuvo positivamente asociada con el AUS elevado, independientemente del género. La obesidad abdominal y la hipertrigliceridemia fueron los principales factores asociados con la hiperuricemia incluso en los individuos normotensos, lo que puede añadirle un riesgo mayor a la hipertensión.

Spectral analysis of heart rate variability with the autoregressive method: what model order to choose?

This work assessed the influence of the autoregressive model order (ARMO) on the spectral analysis of the heart rate variability (HRV). A sample of 68 R-R series obtained from digital ECG records of young healthy adults in the supine position was used. Normalized spectral indexes for each ARMO were compared by Friedman test followed by the Dunn's procedure and statistical significance was set at P<0.05. The results showed that the AR method using orders from 9 to 25 produces normalized spectral parameters statistically similar and, hence, the algorithms commonly employed to estimate optimum order are not mandatory in this case.

Gender distribution of serum uric acid and cardiovascular risk factors: population based study.

BACKGROUND: There is no data concerning the epidemiology of hyperuricemia in Brazilian population-based studies. OBJECTIVE: To investigate the distribution of serum uric acid and its relationship with demographics and cardiovascular variables. METHODS: We studied 1,346 individuals. Hyperuricemia was defined as ≥ 6.8 and ≥ 5.4 mg/dL for men and women, respectively. Metabolic syndrome (MS) was defined with NCEP ATP III criteria. RESULTS: The prevalence of hyperuricemia was 13.2%. The association of serum uric acid (SUA) with cardiovascular risk factors was gender-specific: in women, higher SUA was associated with increasing BMI, even after adjustments for age-systolic blood pressure (SBP). In men, the relationship of SUA with HDLc was mediated by BMI, whereas in women, SUA was similar and dependent on BMI, regardless of glucose levels and presence of hypertension. In men, triglycerides, waist circumference (WC) and SBP explained 11%, 4% and 1% of SUA variability, respectively. In women, WC and triglycerides explained 9% and 1% of SUA variability, respectively. Compared to the first quartile, men and women in the fourth quartile had a 3.29 fold and 4.18 fold increase of MS risk, respectively. Women had almost three fold higher prevalence of diabetes mellitus. Normotensive men with MS presented higher SUA, regardless of BMI. CONCLUSION: Our results seem to justify the need for gender-based evaluation regarding the association of SUA with cardiovascular risk factors, which was more pronounced in women. MS was positively associated with increasing SUA, regardless of gender. Abdominal obesity and hypertriglyceridemia were the main factors associated with hyperuricemia even in normotensive individuals, which may add a higher risk for hypertension.

Impacto da atividade física sobre o risco cardiovascular na população adulta de Vitória-ES / Impact of physical activity on cardiovascular risk in adults from Vitória-ES

A atividade física (AF) regular é considerada hábito de vida saudável por reduzir o risco de doenças cardiovasculares. Entretanto, há poucos estudos neste sentido realizados em amostras populacionais. Avaliar o impacto da AF de lazer (AFL), ocupacional (AFO) e mista (AFLO) sobre o risco cardiovascular mensurado pelo escore de Framingham (EF) na população adulta (25-64 anos) de Vitória-ES. Estudo transversal em amostra probabilística (N=1.663; ambos os sexos). Os dados foram coletados por meio de questionário, avaliação clínica e laboratorial (coleta de sangue). A estimativa de gasto calórico semanal em AFL, AFO e AFLO foi feita por meio de entrevista e, dessa forma, 4 grupos foram constituídos: Sedentário (S), AFL, AFO e AFLO. Análises de variância e covariância, bem como testes qui-quadrado e Mantel-Haenszel, foram usados para análise estatística. O grupo AFO apresentou valores inferiores para % gordura (%G), colesterol total (CT) e LDL se comparado ao grupo S. A prevalência de tabagismo foi menor nos grupos AFL (11,5%) e AFLO (10,2%), e maior nos grupos S (26,4%) e AFO(30,2%). O EF e o risco (%) de desenvolvimento de doença arterial coronariana em 10 anos (risco DAC), não ajustados, apresentaram-se menores no grupo AFO (EF= 3; 2,65±6,20; risco DAC= 4; 6,79±6,68%;mediana; média±DP ) se comparado ao grupo S (EF= 5; 3,85±7,07; risco DAC= 6; 8,41±7,74%). Entretanto, após ajuste para idade e CT, o EF e o risco DAC foram menores no grupo AFL (EF:2,54±4,18; risco DAC: 6,55±5,29%; média±DP) se comparado aos grupos S (EF: 3,50±4,17; risco DAC:8,05±5,33%) e AFO (EF: 4,09±4,19; risco DAC: 8,08±5,35%), evidenciando, assim, que as variáveis CT e idade foram as principais determinantes das diferenças iniciais em favor do grupo AFO. O estudo denota impacto positivo da AF de lazer ou laboral na redução do risco cardiovascular populacional.

Regular physical activity (PA) has been considered a healthy habit to reduce thecardiovascular risk. However, there are few studies to determine this association in population-based studies. To evaluate the contribution of leisure-time (LPA), occupational (OPA) and combined physical activity (LOPA) on the cardiovascular risk computed by Framingham score (FS) on the adult population (25-64 y) of Vitória, Brazil. Cross-sectional study in a probabilistic sample (N=1,661; both sexes). Datawere collected by questionnaires and clinical and laboratorial (blood collection) exams. Estimation of week caloric expenditure in LPA, OPA and LOPA were obtained by interview and 4 groups were designed accordingly: Sedentary, LPA, OPA and LOPA. Analysis of variance and covariance, qui-squareand Mantel-Haenszel tests were used for statistical analysis. Before and after adjustment to age, the OPA group showed lower values of body fat, total cholesterol (TC) and LDL-cholesterol compared to the sedentary group. The smoking prevalence was smaller in LPA (11.5%) and LOPA (10.2%) than insedentary (26.4%) and OPA (30.2%) groups. The unadjusted FS and the 10-year risk for coronary heart disease (CHD-risk) were smaller in the OPA (FRS= 3; 2.65±6.20; CHD-risk= 4; 6.79±6.68%; median; mean±SD) compared to the sedentary group (FRS= 5; 3.85±7.07; CHD-risk= 6; 8.41±7.74%). However, after adjustment for age and TC, the FRS and CHD-risk were smaller in the LPA (FR: 2.54±4.18; CHDrisk: 6.55±5.29%; mean±SD) than in the sedentary (FR: 3.50±4.17; CHD-risk: 8.05±5.33%) and OPA (FR: 4.09±4.19; CHD-risk: 8.08±5.35%) groups, showing that age and TC were the main responsible tosupport the initial differences to the OPA group. The study shows positive impact of leisure-time and occupational physical activity to reduce the global cardiovascular risk in the studied population.

Salt excretion in normotensive individuals with metabolic syndrome: a population-based study.

The objective of this study was to investigate the association between sodium intake and metabolic syndrome (MS) in individuals free from the confounding effects of increased blood pressure (BP). In all, a total of 1655 individuals (45.8% men) who participated in the MONICA-WHO/Vitoria Project, mean age 45+/-11 years were investigated. According to NCEP-ATP lll criteria, MS prevalence was 32.9 and 85% of these individuals had BP >130/85 mm Hg. Thus, high BP represents the main MS risk factor. Twelve-hour nocturnal urine (1900 to 0700 hours) was used to measure urinary sodium and potassium excretion. Sodium excretion was associated with BP. From the optimal BP level up to stage lll hypertension, the mean (median) sodium excretion increased from 99 (89) to 128 (134) mEq and from 81 (69) to 112 (103) mEq in men and women, respectively (P<0.001 for trend; median). However, when 781 individuals with BP <130/85 mm Hg (including 80 drug-free normotensive individuals with MS) were stratified according to the gender and number of MS components, no significant differences were observed either in the urinary volume or in the sodium or potassium excretion. For each of the four MS components, sodium excretion was 96+/-48, 97+/-53, 108+/-65 and 97+/-49 mEq for men, and 83+/-51, 83+/-58, 80+/-49 and 93+/-45 mEq for women, respectively. No differences were found in urinary sodium excretion in normotensive individuals, regardless of the presence of MS. Therefore, it seems that high sodium intake is not an MS predictor per se as suggested earlier.