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Introduction and Objectives: Consumption of a Western diet during the perinatal period is associated with development of cardiovascular disease. Resistance training (RT) has been used to treat cardiovascular disorders. The aim of this work was to assess the effect of RT on cardiometabolic disorders in rats exposed to a Western diet in the perinatal period., Methods: Female Wistar rats were fed with control or Western diet during pregnancy and lactation. The pups were divided into three groups: Control (C), Western Diet Sedentary (WDS) and Western Diet + RT (WDRT). At 60 days of age, all animals started the RT protocol (five times a week for four weeks). At the end, blood pressure was recorded for analysis of heart rate variability and baroreflex sensitivity (BRS). Blood samples were collected for biochemical analysis., Results: RT reduced blood pressure and vascular sympathetic modulation and increased BRS. There were improvements in biochemical profile, with reductions in fasting blood glucose, total cholesterol and low-density lipoprotein, and an increase in high-density lipoprotein., Conclusion: RT led to beneficial adaptations in the cardiovascular system, mediated by changes in the mechanisms of autonomic control and biochemical profile of animals exposed to a Western diet in the perinatal period., (Copyright © 2019 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.)

Objective: To compare the autonomic behavior between malnourished children and a control group using analysis of heart rate variability (HRV)., Method: Data were analyzed from 70 children who were divided into two groups: malnourished and eutrophic, according to the Z-score nutritional status for height and age. For analysis of HRV indices, heart rate was recorded beat to beat with the child in the supine position for 20min. The analysis of these indices was performed using linear methods, analyzed in the time and frequency domains. Student's t-test for unpaired data and the Mann-Whitney test were used to compare variables between groups, with a significance level of 5%., Results: A reduction in systolic and diastolic blood pressure and an increase in heart rate were found in malnourished children compared to eutrophic children. The HRV indices suggested that malnourished children present reductions in both sympathetic and parasympathetic autonomic nervous system activity. The SDNN, rMSSD, NN50, pNN50, SD1, SD2, TINN, LF (ms 2 ), and HF (ms 2 ) indices were lower in malnourished children., Conclusion: Malnourished children present changes in cardiac autonomic modulation, characterized by reductions in both sympathetic and parasympathetic activity, as well as increased heart rate and decreased blood pressure., (Copyright © 2016 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.)

Introduction: Exercise with flexible poles provides fast eccentric and concentric muscle contractions. Although the literature reports significant muscle chain activity during this exercise, it is not clear if a single bout of exercise induces cardiac changes. In this study we assessed the acute effects of flexible pole exercise on cardiac autonomic regulation., Methods: The study was performed on 22 women between 18 and 26 years old. We assessed heart rate variability (HRV) in the time (SDNN, RMSSD and pNN50) and frequency (HF, LF and LF/HF ratio) domains and geometric indices of HRV (RRTri, TINN, SD1, SD2 and SD1/SD2 ratio). The subjects remained at rest for 10 min and then performed the exercises with the flexible poles. Immediately after the exercise protocol, the volunteers remained seated at rest for 60 min and HRV was analyzed., Results: We observed no significant changes in time domain (SDNN: p=0.72; RMSSD: p=0.94 and pNN50: p=0.92) or frequency domain indices (LF [nu]: p=0.98; LF [ms(2)]: p=0.72; HF [nu]: p=0.98; HF [ms(2)]: p=0.82 and LF/HF ratio: p=0.7) or in geometric indices (RRTri: p=0.54; TINN: p=0.77; SD1: p=0.94; SD2: p=0.67 and SD/SD2: p=0.42) before and after a single bout of flexible pole exercise., Conclusion: A single bout of flexible pole exercise did not induce significant changes in cardiac autonomic regulation in healthy women., (Copyright © 2014 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.)

Introduction: Impaired heart rate (HR) recovery after exercise testing is considered a predictor of cardiovascular mortality as it reflects vagus nerve dysfunction., Objective: To assess the relationship between body mass index (BMI) and HR recovery after exercise., Methods: We analyzed the records of 2443 patients of both sexes, aged between 20 and 59 years, in sinus rhythm, not using negative chronotropic agents and with no myocardial ischemic response to exercise testing carried out at a specialist clinic, between 2005 and 2011. BMI was categorized as normal (18.5-<25 kg/m(2)), overweight (25-≤30 kg/m(2)) or obese (>30 kg/m(2)). The different BMI groups were compared in terms of HR recovery after exercise, which was calculated as the difference between maximum HR during exercise and in the first minute of recovery. Recovery was considered impaired when the difference was ≤12 bpm., Results: Eighty-seven (3.6%) patients presented impaired recovery, which was three times more prevalent in the obese group and twice as prevalent in the overweight group compared with the normal group (p<0.001 and p=0.010, respectively). Obese patients presented higher basal HR and lower maximum HR, as well as reduced chronotropic reserve (p<0.001). In multivariate analysis, impaired HR recovery was associated with overweight (relative risk [RR]=1.8; p=0.035), obesity (RR=2; p=0.016), number of metabolic equivalents (RR=0.82; p<0.001) and resting HR (RR=1.05; p<0.001). The hazard ratio for hypertension was 2 (p=0.083, NS)., Conclusion: Impaired HR recovery was associated with higher BMI, demonstrating that obese individuals present vagus nerve dysfunction., (Copyright © 2014 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.)

Objective: To evaluate the relationship between birth weight and the autonomic nervous system in adulthood through a systematic review. Data source: This is a systematic review of publications without limitation of year and language. We included studies involving the autonomic nervous system and birth weight in adults. Manuscripts were selected based on electronic searches of Medical Literature Analysis and Retrieval System Online (MEDLINE), Cumulative Index to Nursing and Allied Health Literature (CINAHL), Web of Science Cochrane Library and Scopus databases, using “Autonomic Nervous System” OR “Heart Rate” OR “Heart Rate Variability” AND “Birth Weight” as a search strategy. This review is registered on the International Prospective Register of Systematic Reviews — PROSPERO (ID: CRD42020165622). Data synthesis: We found 894 articles; 215 were excluded for duplicity. Of the remaining 679 studies, 11 remained. Two were excluded because they did not specifically treat the autonomic nervous system or birth weight. There were nine publications, two cohort and seven cross-sectional studies. The main findings were that extreme, very low, low or high birth weight may have some impact on the autonomic nervous system in adult life. Conclusions: Birth weight outside the normality rate may have a negative influence on the autonomic nervous system, causing autonomic dysfunction and increasing the risk of cardiovascular diseases in adult life. Thus, the importance of the follow-up of health professionals from pregnancy to gestation and throughout life, with preventive care being emphasized. [ABSTRACT FROM AUTHOR]

Copyright of Revista Portuguesa de Enfermagem de Reabilitação is the property of Associacao Portuguesa dos Enfermeiros de Reabilitacao (APER) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Arquivos de Ciências da Saúde da UNIPAR is the property of Associacao Paranaense de Ensino e Cultura and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Contextualization: Neural mechanisms have been implicated in the pathogenesis of obesity, particularly sympathovagal imbalance, and the relative prevalence of sympathetic activity has been suggested as key role in this complex relationship. The use of only one methodfor analyzing time series from physiological processes limits the complete characterization and does not accurately state whether the series presents chaotic behavior; therefore, are indicated to be used methods that consider the interaction of the mechanisms involved in the regulation and allow the separation of structures of non-linear behavior in the temporal series of heartbeats. Objective: to investigate the relationship between the complexity (simbolic analisys) of autonomic cardiac modulation and pediatric obesity, global and abdominal. Materials and methods: 46 childrens were studied, 23 obeses (BMIpercentile equal or higher than 97) and 23 eutrophic (BMIpercentile equal or lower than 85). The waist circumference and the hip one were measured, also the waist/rip relationship was calculated, to quantify the abdominal obesity. The HR and the instantaneos R-R fiR-R) gaps were registered in rest with spontaneous breathing, in dorsal decubitus, for 15 minutes and the temporal, spectral and symbolic indices were analyzed. Results: In rest condition, the obese children presented lower complexity of HR modulation and this alteration is relationed with both abdominal and global obesity. Conclusion: the obese children present a lower complexity in the autonomic modulation of heart rate and this alteration is associated with global and abdominal obesity. [ABSTRACT FROM AUTHOR]

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To evaluate the effects of different amplitude-modulated frequency (AMF-100Hz and AMF-10Hz) of the interferential current (IC) on autonomic nervous system (ANS) in healthy volunteers. Thirty healthy volunteers (23.7 ±2.7 years old) were randomized into placebo interventions (turned off), IC with AMF-100Hz and IC with AMF-10Hz. Interventions ware applied in the paravertebral ganglionar region for 30 minutes. ANS evaluated by the heart rate variability before and immediately after the interventions. 10Hz intervention reduced the sympathetic activity in 6% and an increase in the parasympathetic in 6%. 100Hz intervention increased 12% to sympathetic activity and decreased 12% to parasympathetic activity. IC changes the autonomic balance in healthy volunteers. 10Hz reduces the sympathetic activity and increases parasympathetic, although the 100Hz has opposite results. The IC at 10Hz improves the autonomic balance and presents potential effects to be tested in hypertensive patients. [ABSTRACT FROM AUTHOR]

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Introduction: One of the benefits of regular exercise at a moderate level is the improvement of the autonomic nervous system modulation over the heart, which supports the idea that heart rate variability (HRV) that is instantly regulated by mechanisms and the measurement of the time elapsed between two consecutive RR intervals resulting from autonomic modulation over the sinoatrial node may be associated with the maximum aerobic capacity level. Objective: To evaluate HRV and its relationship with the risk of developing cardiovascular diseases in individuals in the community after an aerobic exercise program. Methods: A controlled clinical trial composed of 16 female-predominant individuals divided into two groups: exercise group (n = 11) that participated in an aerobic exercise program and control group (n = 5) that maintained their activities. usual. For HRV analysis, the R-R intervals were recorded. After collection the data were analyzed and filtered and released in the Kubios HRV Standard. The paired t test was performed, with a significance level of 5% (p <0.05), for data analysis. Results: Quantitative HRV analysis in the geometric indices showed no significant difference between the groups. As for the visual analysis of the plot, in the exercise group showed greater dispersion of R-R intervals both beat-by-beat and long-term. Conclusion: There was an improvement in HRV and consequently a decrease in the risks of developing cardiovascular disease in individuals after the aerobic exercise program. [ABSTRACT FROM AUTHOR]

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Objective: To analyze the effect of air pollution on heart rate variability in overweight individuals. Methods: A total of 46 adult individuals, both sexes, aged between 18 and 49 years and with body mass index >25kg/m² were analyzed. All volunteers were students from public schools of two cities in the state of São Paulo. The clinical, demographic and anthropometric data of each individual, as well as heart rate variability through time domain, geometric and frequency indices were collected. For the air quality analysis, the following variables were investigated: concentration of carbon dioxide, particulate matter, temperature and relative humidity. The analysis was carried out with descriptive and analytical statistics, adopting a level of significance of 5%. Results: There was a reduction in overall heart rate variability in overweight individuals by the following indices: mean standard deviation of all normal RR intervals, long-term standard deviation of continuous RR intervals, ratio of short-and long-term standard deviation of continuous RR intervals. In addition, the indices responsible for parasympathetic control showed a downward trend in their values, as well as the low frequency index, which represented sympathetic action, although not significant. Conclusion: Overweight individuals exposed to air pollution had lower heart rate variability than the Control Group. [ABSTRACT FROM AUTHOR]

Introduction: All drugs and techniques that induce the anesthetic state act in some way in the Autonomic Nervous System (ANS). The administration of local anesthetics in the subarachnoid space produces motor, sensitive and sympathetic block, with latencies and variable and independent block levels. The motor block is the first to install, followed by the sympathetic and the sensitive. Sympathetic blockage affects 2 to 6 dermatomes above the sensory block. The recovery of spinal anesthesia is assessed through a scale defined in 1979 by Bromage and is based exclusively on the return of motor function and does not take into account the recovery of ANS activity. The persistence of sympathetic block may imply a higher incidence of urinary retention, bradycardia and hypotension. Objective: To assess cardiac autonomic modulation during perioperative hypotension caused by subarachnoid anesthesia Methods: A randomised, double-blind clinical trial will be performed in a large hospital located in the southern region of Ceará, Brazil and at the HUJB in Cajazeiras, Paraíba. Sixty patients from the anaesthesia outpatient clinic were enrolled. Patients were divided into two groups: one group received Bupivacaine with clonidine, and the other group received only bupivacaine at a dose of 15 mg. The sample consisted of 60 ASA patients I to III, submitted to orthopedic surgery of lower limbs and lower abdomen under spinal anesthesia. The Heart Rate Variability will be evaluated in three moments: rest, before anesthesia; 20 min after the blockade was installed, and at the time of motor function recovery according to the Bromage criteria and prognostic indices will be evaluated in the development of perioperative hypotension in two groups. Linear methods will be used in the frequency domain and nonlinear in chaos domain, Poincaré plot, approximate entropy, Detrended Fluctuation Analysis (DFA) and Correlation Dimension. The data will be collected through a Polar V800® heart rate meter and properly submitted for analysis and filtering by Kubios 3.0® software. Discussion: In the literature we find data evaluating the installation of sympathetic block through HRV using linear methods however, there is a lack of studies using methods based on the domain of chaos. Some studies address the value of HRV as a predictor of hypotension following subarachnoid anesthesia, mainly using linear methods in the frequency domain. It is understood to be important to analyze these factors using methods already validated in the domain of chaos, complexity and fractality, more compatible with the complexity of the behavior of biological systems, in the characterization of the autonomic function during the subarachnoid anesthesia. Registry: The clinical trial was registered in the Brazilian Registry of Clinical Trials (ReBEC) under the number RBR-4Q53D6. [ABSTRACT FROM AUTHOR]

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Copyright of ConScientiae Saúde is the property of Nove de Julho University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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This review examines the main applications and limitations of heart rate monitors in sports. The key issues, that researchers and trainers should consider, have been exposed in order to optimize their use in daily training control through monitoring the heart rate variability. These concern the reliability and validity; and methodological considerations for registration and data statistical interpretation. Given its limitations, this work shows the usefulness of the main indicators of parasympathetic activity (i.e. rMSSD) which monitored at rest for sort periods, 3-4 times week, could improve control processes adaptation to training, both physiological and psychological, in individual and team sports. Overall, the analysis shows that resting heart could be a useful to assess the adaptive response and performance in this context. [ABSTRACT FROM AUTHOR]

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Objective: To evaluate heart rate variability among adults with different risk levels for type 2 diabetes mellitus. Methods: The risk for type 2 diabetes mellitus was assessed in 130 participants (89 females) based on the questionnaire Finnish Diabetes Risk Score and was classified as low risk (n=26), slightly elevated risk (n=41), moderate risk (n=27) and high risk (n=32). To measure heart rate variability, a heart-rate monitor Polar S810i® was employed to obtain RR series for each individual, at rest, for 5 minutes, followed by analysis of linear and nonlinear indexes. Results: The groups at higher risk of type 2 diabetes mellitus had significantly lower linear and nonlinear heart rate variability indexes. Conclusion: The individuals at high risk for type 2 diabetes mellitus have lower heart rate variability. [ABSTRACT FROM AUTHOR]

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FUNDAMENTO: O envelhecimento fisiológico leva a uma disfunção autonômica cardíaca que está associada ao surgimento e ao agravamento de doenças cardiovasculares e a um maior risco de morte. Atualmente, o exercício físico é apontado como uma estratégia cardioprotetora, sendo necessários mais estudos do seu benefício na função autonômica cardíaca. OBJETIVO: Avaliar o controle autonômico da frequência cardíaca em voluntários jovens e de meia-idade com diferentes níveis de aptidão aeróbica. MÉTODOS: Participaram do estudo 68 voluntários, estratificados quanto à idade e ao nível de aptidão aeróbica. Com base na aptidão aeróbica avaliada pelo teste de esforço submáximo, os sujeitos foram separados em dois grupos, aptidão boa e aptidão deficiente. A avaliação do controle autonômico cardíaco se deu a partir de medidas da variabilidade da frequência cardíaca em repouso e a recuperação da frequência cardíaca pós-esforço. Para comparação das variáveis investigadas, utilizou-se a análise de variância bifatorial. RESULTADOS: A variabilidade da frequência cardíaca é significativamente menor nos voluntários de meia-idade do que nos jovens, independentemente do nível de aptidão aeróbica (p < 0,01). Melhores níveis de aptidão aeróbica nos voluntários de meia-idade estão associados à reentrada vagal pós-esforço mais precoce - taxa de declínio da FC após 1min30s: 39,6% aptidão aeróbica boa vs. 28,4% deficiente (p < 0,01). CONCLUSÃO: Melhores níveis de aptidão aeróbica atuam beneficamente no controle autonômico da frequência cardíaca pós-esforço, preservando a velocidade de reentrada vagal em voluntários de meia-idade. No entanto, não atenua a redução da variabilidade da frequência cardíaca decorrente do processo natural de envelhecimento.BACKGROUND: Physiological aging leads to cardiac autonomic dysfunction, which is associated with the onset and worsening of cardiovascular disease and an increased risk of death. Currently, physical exercise is considered a cardioprotective strategy and more research is needed on its benefit on cardiac autonomic function. OBJECTIVE: To evaluate the autonomic control of heart rate in healthy young and middle-aged volunteers with different levels of aerobic fitness. METHODS: The study included 68 volunteers, stratified for age and level of aerobic fitness. Based on aerobic fitness assessed by the submaximal exercise test, subjects were separated into two groups, good fitness and poor fitness. Assessment of cardiac autonomic control was performed based on measurements of heart rate variability at rest and heart rate recovery post-exercise. Analysis of variance with two factors was used to compare the variables investigated. RESULTS: The heart rate variability is significantly lower in middle-aged volunteers than in young individuals, regardless of the aerobic fitness level (p

FUNDAMENTO: O envolvimento cardíaco é comum em pacientes com Distrofia Miotônica (DM). A Variabilidade da Frequência Cardíaca (VFC) é uma técnica simples e confiável que pode ser útil para estudar a influência do sistema nervoso autonômico sobre o coração. OBJETIVO: Estudar a variabilidade da frequência cardíaca em pacientes com DM tipo 1. MÉTODOS: Estudamos a VFC durante registros de 5 minutos em pacientes com DM em um grupo controle saudável. Analisamos os domínios da frequência (BF e AF) em unidades normalizadas (un) e balanço simpático-vagal, na posição sentada e em decúbito dorsal. RESULTADOS: Dezessete pacientes (10 homens e 7 mulheres) e dezessete indivíduos pareados saudáveis (10 homens e 7 mulheres) foram estudados. As modulações simpática e parassimpática do coração elevadas em pacientes do sexo masculino com DM da posição em decúbito dorsal para a posição sentada em 19% da AFun e a razão BF/AF aumentaram 42,3%. Na posição sentada, os pacientes do sexo masculino com DM apresentaram balanços simpático-vagal significativamente mais elevados em 50,9% em comparação com indivíduos controles saudáveis. A VFC foi influenciada tanto pelo sexo quanto pela enfermidade apresentada. O sexo influenciou a AFun na posição em decúbito dorsal, enquanto a razão BF/AF e AFun foi afetada em ambas as posições. Análises post hoc mostraram que o sexo afeta significativamente pacientes com DM e indivíduos saudáveis de diferentes maneiras (p < 0,01). O domínio de baixa frequência na posição sentada (AFun) foi significativamente influenciado pela enfermidade. CONCLUSÃO: Os resultados deste estudo sugerem que o estímulo simpático em pacientes de meia-idade do sexo masculino com DM que não está gravemente comprometido e apresenta duração moderada da doença parece ser maior do que em indivíduos saudáveis pareados.BACKGROUND: Cardiac involvement is common in myotonic dystrophy (MD) patients. Heart rate variability (HRV) is a simple and reliable technique that can be useful for studying the influence of the autonomic nervous system on the heart. OBJECTIVE: Study heart rate variability in patients with type 1 MD. METHODS: We studied HRV during 5-minute recordings in MD patients and in a healthy control group. We analyzed frequency domains (LF and HF) in normalized units (nu) and sympathovagal balance, in the sitting and supine position. RESULTS: Seventeen patients (10 men and 7 women) and seventeen matched healthy individuals (10 men and 7 women) were studied. Sympathetic and parasympathetic modulations of the heart increased in male MD patients from supine to sitting position in 19% of LFnu and the LF/HF ratio rose by 42.3%. In the sitting position, male MD patients exhibited significantly higher sympathovagal balances in 50.9% compared to healthy control individuals. HRV was influenced by both gender and disease. Gender influenced LFnu in the supine position while the LF/HF ratio and HFnu were affected in both positions. Post hoc analyses showed that gender significantly impacts MD patients and healthy individuals in different ways (p < 0.01). The low frequency domain in the sitting position (LFnu) was significantly influenced by the disease. CONCLUSION: The results of this study suggest that the sympathetic drive in middle-aged male MD patients who are not severely impaired and present moderate disease duration seems to be greater than in healthy matched individuals.

FUNDAMENTO: Diversos métodos têm sido utilizados para avaliar a modulação vagal cardíaca; entretanto, há lacunas quanto a associação e acurácia desses métodos. OBJETIVO: Investigar a associação entre três métodos válidos, reprodutíveis e comumente utilizados para avaliação da modulação vagal cardíaca, e comparar as suas acurácias. MÉTODOS: Trinta homens saudáveis (23 ± 4 anos) e 15 homens com coronariopatia (61 ± 10 anos) foram avaliados em ordem contrabalanceada pela Variabilidade da Frequência Cardíaca (VFC; variáveis: domínio do tempo = pNN50, DPNN e RMSSD, domínio da frequência = AF ms² e AF u.n.), Arritmia Sinusal Respiratória (ASR) e Teste de Exercício de 4 segundos (T4s). RESULTADOS: Indivíduos saudáveis apresentaram maior modulação vagal nos três métodos (p < 0,05). No grupo saudável houve correlação (p < 0,05) entre os resultados da VFC (pNN50 e DPNN) e da ASR, mas não houve correlação entre o T4s e os outros dois métodos estudados. No grupo com coronariopatia houve correlação entre os resultados da VFC (pNN50, DPNN, RMSSD, AF ms² e AF u.n.) e da ASR. Em adição, houve correlação entre o T4s e a ASR. Por fim, os métodos ASR e T4s apresentaram tamanho do efeito mais preciso e melhor acurácia (p < 0,05) comparados à VFC. CONCLUSÃO: A VFC e a ASR geraram resultados parcialmente redundantes em indivíduos saudáveis e em pacientes com coronariopatia, enquanto o T4s gerou resultados complementares a VFC e ASR em indivíduos saudáveis. Além disso, os métodos ASR e T4s foram mais precisos para discriminar a modulação vagal cardíaca entre indivíduos saudáveis e pacientes com coronariopatia comparados à VFC.BACKGROUND: Several methods have been used to assess cardiac vagal modulation, but there are gaps regarding the association and accuracy of these methods. OBJECTIVE: To investigate the association between three valid, reproducible and commonly methods used to assess cardiac vagal modulation and compare their accuracies. METHODS: Thirty healthy men (23 ± 4 years) and 15 men with coronary artery disease (61 ± 10 years) were evaluated in counterbalanced design by Heart Rate Variability (HRV; variables: the time domain = pNN50, SDNN and RMSSD, the frequency domain HF = ms² and HF n.u.), Respiratory Sinus Arrhythmia (RSA) and 4-second Exercise Test (T4s). Thirty healthy men (23 ± 4 years) and 15 men with coronary artery disease (61 ± 10 years) were evaluated in counterbalanced order by Heart Rate Variability (HRV; variables: the time domain = pNN50, SDNN and RMSSD, the frequency domain HF = ms² and HF n.u.), Respiratory Sinus Arrhythmia (RSA) and 4-second Exercise Test (T4s). RESULTS: Healthy subjects had higher vagal modulation by the three methods (p

FUNDAMENTO: Obesidade promove alterações na modulação autonômica cardíaca. OBJETIVO: Investigar a modulação autonômica de crianças obesas e eutróficas por meio de índices de variabilidade da frequência cardíaca (VFC) obtidos por métodos geométricos. MÉTODOS: Foram analisados dados de 133 crianças, com idade entre 8 e 13 anos, divididas em dois grupos: obeso (n = 61) e eutrófico (n = 72), segundo o índice de massa corporal para sexo e idade. Para a análise da VFC, a frequência cardíaca foi captada batimento-a-batimento. Os intervalos RR obtidos foram convertidos em figuras geométricas e, a partir delas, foram calculados o índice triangular (RRtri), interpolação triangular dos intervalos RR (TINN), os índices SD1, SD2 e relação SD1/SD2, obtidos do plot de Poincaré. Análise visual do plot foi também realizada. Realizaram-se o teste t de Student para dados não pareados e o teste de Mann-Whitney, com nível de significância de 5,0%, para análise dos dados. RESULTADOS: Em crianças obesas, foram observadas reduções dos índices RRtri (0,0730 vs 0,1084 [mediana]), TINN (171,80 ± 55,08 vs 218,26 ± 51,12), SD1 (19,93 ± 9,10 vs 24,10 ± 8,03) e SD2 (51,63 ± 16,53 vs 69,78 ± 17,19). A relação SD1/SD2 não apresentou diferenças significantes (0,3781 ± 0,12 vs 0,3467 ± 0,08). A análise visual do plot, em crianças obesas, mostrou menor dispersão dos intervalos RR tanto batimento-a-batimento, como a longo prazo, indicando menor VFC. CONCLUSÃO: Crianças obesas apresentaram modificações no sistema nervoso autônomo, caracterizadas por reduções na atividade parassimpática e na variabilidade global.FUNDAMENTO: Obesidad promueve alteraciones en la modulación autonómica cardíaca. OBJETIVO: Investigar la modulación autonómica de niños obesos y eutróficos por medio de índices de variabilidad de la frecuencia cardíaca (VFC) obtenidos por métodos geométricos. MÉTODOS: Fueron analizados datos de 133 niños, de edad entre 8 y 13 años, divididos en dos grupos: obeso (n = 61) y eutrófico (n = 72), según el índice de masa corporal para sexo y edad. Para el análisis de la VFC, la frecuencia cardíaca fue captada latido-a-latido. Los intervalos RR obtenidos fueron convertidos en figuras geométricas y, a partir de ellas, fueron calculados el índice triangular (RRtri), interpolación triangular de los intervalos RR (TINN), los índices SD1, SD2 y relación SD1/SD2, obtenidos del plot de Poincaré. Fue también realizado análisis visual del plot . Se realizaron el test t de Student para datos no apareados y el test de Mann-Whitney, con nivel de significancia de 5,0%, para análisis de los datos. RESULTADOS: En niños obesos, fueron observadas reducciones de los índices RRtri (0,0730 vs 0,1084 [media]), TINN (171,80 ± 55,08 vs 218,26 ± 51,12), SD1 (19,93 ± 9,10 vs 24,10 ± 8,03) y SD2 (51,63 ± 16,53 vs 69,78 ± 17,19). La relación SD1/SD2 no presentó diferencias significativas (0,3781 ± 0,12 vs 0,3467 ± 0,08). El análisis visual del plot, en niños obesos, mostró menor dispersión de los intervalos RR tanto latido-a-latido, como a largo plazo, indicando menor VFC. CONCLUSIÓN: Niños obesos presentaron modificaciones en el sistema nervioso autónomo, caracterizadas por reducciones en la actividad parasimpática y en la variabilidad global.BACKGROUND: Obesity causes changes in cardiac autonomic modulation. OBJECTIVE: To investigate the autonomic modulation of eutrophic and obese children by means of indexes of heart rate variability (HRV) obtained through geometric methods. METHODS: We analyzed data from 133 children aged 8 to 13, divided into two groups: obese (n = 61) and eutrophic (n = 72) according to body mass index for age and sex. For the analysis of HRV, heart rate was recorded beat-to-beat. The RR intervals were transformed into geometric figures, and from them, we calculated the triangular index (RRtri), triangular interpolation of RR intervals (TINN), the indexes SD1, SD2 and SD1/SD2 ratio, obtained from the Poincaré plot. Visual analysis of the plot was also performed. Student's t test was performed for unpaired data and Mann-Whitney's test, with significance level of 5.0%, for data analysis. RESULTS: In obese children, RRtri indexes were proven to be reduced (0.0730 vs 0.1084 [median]), TINN (171.80 ± 55.08 vs 218.26 ± 51.12), SD1 (19.93 ± 9.10 vs 24.10 ± 8.03) and SD2 (51.63 ± 16.53 vs 69.78 ± 17.19). The SD1/SD2 ratio showed no significant differences (0.3781 ± 0.12 vs 0.3467 ± 0.08). Visual analysis of the plot, in obese children, revealed a smaller dispersion of RR intervals both beat-to-beat, and in the long term, indicating lower HRV. CONCLUSION: Obese children presented changes in the autonomic nervous system characterized by decreases in parasympathetic activity and overall variability.

FUNDAMENTO: A obesidade pode afetar a modulação autonômica cardíaca, os lípides do sangue e a capacidade física. OBJETIVO: Estudar a interferência da obesidade sobre a variabilidade da frequência cardíaca (VFC), os lípides do sangue e a capacidade física de crianças obesas. MÉTODOS: Foram estudadas 30 crianças com idades entre 9 a 11 anos, divididas em dois grupos: a) 15 crianças obesas (O) com 10,2 ± 0,7 anos de idade e índice de massa corporal (IMC) no percentil entre 95 e 97; b) 15 crianças não-obesas (NO) com 9,8 ± 0,7 anos de idade e IMC no percentil entre 5 e 85. Todas foram submetidas a avaliação antropométrica e clínica, análise da VFC ao repouso e a um protocolo de esforço (PE). Utilizaram-se testes não-paramétricos para comparar as variáveis entre os grupos, e o nível de significância aplicado foi de p < 0,05. RESULTADOS: A circunferência abdominal e os níveis de triglicérides foram maiores em O. A atividade simpática cardíaca, na posição bípede, em unidades normalizadas - BFun, foi maior para os O, com 71,4 %, quando comparada aos 56,3% de NO; e a razão baixa/alta frequência (BF/AF) foi de 3,8 para O e 1,7 para NO. No PE constataram-se diferenças entre os grupos, com maiores valores para as crianças NO, quanto a distância total, tempo de exposição ao PE, consumo de oxigênio pico (VO2 pico) e equivalente metabólico (MET). CONCLUSÃO: A obesidade infantil promoveu modificações no controle autonômico cardíaco na posição bípede e reduziu a capacidade física.FUNDAMENTO: La obesidad puede afectar la modulación autonómica cardiaca, los lípidos de la sangre y la capacidad física. OBJETIVO: Estudiar la interferencia de la obesidad sobre la variabilidad de la frecuencia cardiaca (VFC), los lípidos de la sangre y la capacidad física de niños obesos. MÉTODOS: Se estudiaron a 30 niños con edades entre 9 y 11 años, divididos en dos grupos: a) 15 niños obesos (O) con 10,2 ± 0,7 años de edad e índice de masa corporal (IMC) en el percentil entre 95 y 97; b) 15 niños no obesos (NO) con 9,8 ± 0,7 años de edad e IMC en el percentil entre 5 y 85. Todos se sometieron a evaluación antropométrica y clínica, análisis de la VFC al reposo y a un protocolo de esfuerzo (PE). Se utilizaron pruebas no paramétricas para comparar las variables entre los grupos, y el nivel de significancia aplicado fue de p < 0,05. RESULTADOS: La circunferencia abdominal y los niveles de triglicéridos fueron mayores en O. La actividad simpática cardiaca, en la posición bípeda, en unidades normalizadas -BFun, fue mayor para los O, con el 71,4%, cuando comparada al 56,3% de NO; y la razón baja/alta frecuencia (BF/AF) fue del 3,8 para O y 1,7 para NO. En el PE se constataron diferencias entre los grupos, con mayores valores para los niños NO, en cuanto la distancia total, el tiempo de exposición al PE, consumo de oxígeno pico (VO2 pico) y equivalente metabólico (MET). CONCLUSIÓN: La obesidad infantil provocó modificaciones en el control autonómico cardiaco en la posición bípeda y reduzco la capacidad física.BACKGROUND: Obesity can affect the cardiac autonomic modulation, blood lipid levels and the physical capacity. OBJECTIVE: To study the effect of obesity on the heart rate variability (HRV), blood lipid levels and physical capacity of obese children. METHODS: Thirty children aged 9 to 11 years were studied, divided in two groups: a) 15 obese children (O) aged 10.2 ± 0.7 years and body mass index (BMI) between the 95th and the 97th percentiles; b) 15 non-obese children (NO) aged 9.8 ± 0.7 years and BMI between the 5th and 85th percentiles. All children were submitted to an anthropometric and clinical assessment, analysis of the HRV at rest and a physical exercise protocol (PEP). Non-parametric tests were used to compare the variables between the groups. The level of significance was set at p < 0.05. RESULTS: The waist circumference and levels of triglycerides were higher in O. The cardiac sympathetic activity in the standing position in normalized units (LF n.u.) was higher in O, 71.4%, when compared to NO, 56.3%. The low frequency/high frequency ratio (LF/HF) was 3.8 in O and 1.7 in NO. The PEP showed differences between the groups, with higher values observed in NO children regarding the total distance, time of exposure to PEP, peak oxygen consumption (VO2 peak) and metabolic equivalent (MET). CONCLUSION: Obesity in children resulted in alterations in cardiac autonomic control in the standing position and decreased the physical capacity.

O sistema nervoso autônomo (SNA) desempenha um papel importante na regulação dos processos fisiológicos do organismo humano tanto em condições normais quanto patológicas. Dentre as técnicas utilizadas para sua avaliação, a variabilidade da frequência cardíaca (VFC) tem emergido como uma medida simples e não-invasiva dos impulsos autonômicos, representando um dos mais promissores marcadores quantitativos do balanço autonômico. A VFC descreve as oscilações no intervalo entre batimentos cardíacos consecutivos (intervalos R-R), assim como oscilações entre frequências cardíacas instantâneas consecutivas. Trata-se de uma medida que pode ser utilizada para avaliar a modulação do SNA sob condições fisiológicas, tais como em situações de vigília e sono, diferentes posições do corpo, treinamento físico, e também em condições patológicas. Mudanças nos padrões da VFC fornecem um indicador sensível e antecipado de comprometimentos na saúde. Uma alta variabilidade na frequência cardíaca é sinal de boa adaptação, caracterizando um indivíduo saudável, com mecanismos autonômicos eficientes, enquanto que, baixa variabilidade é frequentemente um indicador de adaptação anormal e insuficiente do SNA, implicando a presença de mau funcionamento fisiológico no indivíduo. Diante da sua importância como um marcador que reflete a atividade do SNA sobre o nódulo sinusal e como uma ferramenta clínica para avaliar e identificar comprometimentos na saúde, este artigo revisa aspectos conceituais da VFC, dispositivos de mensuração, métodos de filtragem, índices utilizados para análise da VFC, limitações de utilização e aplicações clínicas da VFC.Autonomic nervous system (ANS) plays an important role in the regulation of the physiological processes of the human organism during normal and pathological conditions. Among the techniques used in its evaluation, the heart rate variability (HRV) has arising as a simple and non-invasive measure of the autonomic impulses, representing one of the most promising quantitative markers of the autonomic balance. The HRV describes the oscillations in the interval between consecutive heart beats (RR interval), as well as the oscillations between consecutive instantaneous heart rates. It is a measure that can be used to assess the ANS modulation under physiological conditions, such as wakefulness and sleep conditions, different body positions, physical training and also pathological conditions. Changes in the HRV patterns provide a sensible and advanced indicator of health involvements. Higher HRV is a signal of good adaptation and characterizes a health person with efficient autonomic mechanisms, while lower HRV is frequently an indicator of abnormal and insufficient adaptation of the autonomic nervous system, provoking poor patient's physiological function. Because of its importance as a marker that reflects the ANS activity on the sinus node and as a clinical instrument to assess and identify health involvements, this study reviews conceptual aspects of the HRV, measurement devices, filtering methods, indexes used in the HRV analyses, limitations in the use and clinical applications of the HRV.

FUNDAMENTO: Alterações da função autonômica cardíaca são freqüentes no climatério e diferentes métodos têm sido empregados para conhecê-las e minimizá-las. OBJETIVO: Estudar a interferência da atividade física dinâmica aeróbica de baixa intensidade sobre a variabilidade da freqüência cardíaca (VFC) de mulheres climatéricas. MÉTODOS: Estudo transversal que analisou a VFC de 15 mulheres climatéricas com média de idade de 56,8 ± 4,9 anos, que já se encontravam em treinamento físico (caminhada de uma hora diária, três vezes por semana) há pelo menos dois anos (grupo ativo), e de 15 mulheres climatéricas (56,5 ± 3,7 anos) sedentárias (grupo sedentário). Todas as voluntárias não faziam uso de reposição hormonal. Os dados da VFC foram comparados entre os grupos por meio do teste U de Mann-Whitney. RESULTADOS: Houve diferenças significativas tanto no domínio da freqüência como no domínio do tempo das seguintes variáveis da VFC, em medianas, para os grupos ativo e sedentário, respectivamente: potência total (22.626,50 ms² e 4.432,10 ms²), componente baixa freqüência (741,20 ms² e 131,70 ms²), componente alta freqüência (668,90 ms² e 131,70 ms²), desvios padrão dos intervalos RR (51,60 ms e 22,50 ms), raiz quadrada da soma dos quadrados das diferenças entre os intervalos RR (35,30 ms e 15,90 ms) e porcentagem de intervalos RR adjacentes maiores que 50 ms (6,6% e 0,2%). CONCLUSÃO: O estudo sugere que o treinamento aeróbio pode ter propiciado significativa melhoria da função autonômica cardíaca das mulheres climatéricas do grupo ativo, podendo ser uma opção útil para preservar essa condição funcional sem necessidade de terapias de reposição hormonal.BACKGROUND: Changes in autonomic cardiac function are frequent during menopause, and various methods have been used to understand and minimize them. OBJECTIVE: To study the interference of dynamic aerobic physical activity on heart rate variability (HRV) in climacteric women. METHODS: Cross-sectional study that analyzed HRV in 15 menopausal women (mean age 56.8±4.9 years) who had participated in physical training (one-hour walks, 3 times a week) for at least two years (active group), and 15 menopausal women (mean age 56.5 ± 3.7 years) who were sedentary (sedentary group). None of the volunteers received hormonal replacement therapy. HRV data were compared between the groups by means of the Mann Whitney U Test. RESULTS: There were significant differences both in the frequency and time domains of the following variables of HRV (in medians) for the active e sedentary groups, respectively: total power (22,626.50 ms² and 4,432.10 ms²), low frequency component (741.20 ms² and 131.70 ms²), high frequency component (668.90 ms² and 131.70 ms²), standard deviations of RR intervals (51.60 ms and 22.50 ms), square root of the sum of squares of differences between the normal RR intervals (35.30ms and 15.90 ms), and percentage of normal adjacent RR intervals greater than 50ms (6.6% and 0.2%). CONCLUSION: The study suggests that aerobic training may have afforded a significant improvement in the autonomic cardiac function of the menopausal women in the active group, and may be a useful option for preserving this functional condition without the need for hormonal replacement therapy.

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Objective: To analyze the relationship among sports practice, physical education class, habitual physical activity and cardiovascular risk in adolescents. Methods: Cross-sectional study with 120 schoolchildren (mean: 11.7±0.7 years old), with no regular use of medicines. Sports practice and physical education classes were assessed through face-to-face interview, while habitual physical activity was assessed by pedometers. Bodyweight, height and height-cephalic trunk were used to estimate maturation. The following variables were measured: body fatness, blood pressure, resting heart rate, blood flow velocity, intima-media thickness (carotid and femoral) and heart rate variability (mean between consecutive heartbeats and statistical index in the time domain that show the autonomic parasympathetic nervous system activity root-mean by the square of differences between adjacent normal R-R intervals in a time interval). Statistical treatment used Spearman correlation adjusted by sex, ethnicity, age, body fatness and maturation. Results: Independently of potential confounders, sports practice was positively related to autonomic parasympathetic nervous system activity (b=0.039 [0.01; 0.76]). On the other hand, the relationship between sport practice and mean between consecutive heartbeats (b=0,031 [-0.01; 0.07]) was significantly mediated by biological maturation. Conclusions: Sport practice was related to higher heart rate variability at rest. [ABSTRACT FROM AUTHOR]

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