Resumo Objetivo Investigar a relação entre diferentes domínios de atividade física e frequência cardíaca de repouso (FCRep) em meninos e meninas. Método A amostra incluiu 1.011 adolescentes, entre 10 e 17 anos. A FCRep foi medida por um monitor de frequência cardíaca e a atividade física foi avaliada no total e em três diferentes domínios (escolar, ocupacional e prática esportiva) através de um questionário. A antropometria foi obtida diretamente para o índice de massa corporal e gordura central. Etnia, comportamento sedentário e tabagismo foram autorrelatados e usados para ajustar a análise, através da regressão linear hierárquica. Resultados A atividade física total foi associada à baixa FCRep nos meninos (β = −0,52; IC95% −0,92; −0,12) e meninas (β = −0,67; IC95% −1,07; −0,28). Embora as atividades físicas esportivas estivessem associadas à baixa FCRep em ambos, meninos (β = −0,58; IC95% −1,05, −0,11) e meninas (β = −0,87; IC95% −1,34, −0,39), a atividade física ocupacional estava relacionada à baixa FCRep apenas em meninos (β = −1,56; IC95% −2,99; −0,14). Conclusão A prática de atividade física no domínio da prática esportiva e a atividade física total foram relacionadas à baixa FCRep em ambos os sexos, enquanto as atividades físicas ocupacionais foram associadas à FCRep apenas em meninos.

Abstract Objective: Investigate the relationship between different domains of physical activity and resting heart rate (RHR) in boys and girls. Method: The sample included 1011 adolescents, aged between 10 and 17 years. RHR was measured by a heart rate monitor and physical activity was assessed in total and in three different domains (school, occupational, and sports practice) by a questionnaire. Anthropometry was directly obtained for body mass index and central fat. Ethnicity, sedentary behavior, and smoking habits were self-reported and used to adjust the analysis, through hierarchical linear regression. Results: Total physical activity was associated with low RHR in boys (β = −0.52; 95% CI: −0.92, −0.12) and girls (β = −0.67; 95% CI: −1.07, −0.28). Although sporting physical activities were associated with low RHR in both boys (β = −0.58; 95% CI: −1.05, −0.11) and girls (β = −0.87; 95% CI: −1.34, −0.39), occupational physical activity was related to low RHR only in boys (β = −1.56; 95% CI: −2.99, −0.14). Conclusion: The practice of physical activity in the sport practice domain and total physical activity were related to low RHR in both sexes, while occupational physical activities were associated with RHR only in boys.

INTRODUÇÃO: A pressão arterial de repouso demonstrou estar associada à mortalidade cardiovascular. O controle autonômico da frequência cardíaca durante a recuperação pós-exercício é estimado para detetar mudanças no sistema cardiovascular, porque tais mudanças podem levar a doenças cardiovasculares. Avaliamos o envolvimento da pressão arterial diastólica de repouso (PAD) na dinâmica da frequência cardíaca após o exercício em homens normalmente ativos fisicamente normotensos. MÉTODO: Avaliamos homens saudáveis e fisicamente ativos com idades compreendidas entre os 18 e os 22 anos divididos em dois grupos desiguais: PAD de relaxamento G1 entre 80 e 90 mmHg (n=11) e PAD <80mmHg (n=24). Os voluntários realizaram exercícios físicos em uma esteira com intensidade equivalente a 60% da Vmax. A recuperação da frequência cardíaca no primeiro (HRR1) e terceiro (HRR3) minuto após o exercício foi medida e a variação da frequência cardíaca (VFC) foi examinada no domínio do tempo e da frequência. Além disso, realizamos a análise quantitativa da trama de Poincaré. A VFC foi registrada nas seguintes fases: os períodos de 10 minutos antes do exercício, durante o exercício e os períodos de 60 minutos após o exercício. RESULTADOS: Não encontramos diferença significativa entre G1 e G2 em relação às alterações da VFC durante o exercício. O G2 apresentou uma recuperação tardia dos índices SDNN, RMSSD, RRTri, LF, HF, LF/HF, SD1 e SD2 durante a recuperação do exercício. HRR1 e HRR3 foi maior no G2. CONCLUSÃO: Homens normais e fisicamente ativos com PAD entre 80 e 90 mmHg apresentaram RHE mais rápida e recuperação mais acelerada do controle autonômico da freqüência cardíaca após o exercício aeróbio.

OBJECTIVE: Rest arterial pressure has been shown to be associated with cardiovascular mortality. Autonomic heart rate control during recovery from exercise is estimated to detect changes in cardiovascular system, which may lead to cardiovascular diseases. We assessed the involvement of rest diastolic arterial pressure (DAP) on heart rate dynamics after exercise in normotensive physically active men. METHOD: We evaluated healthy physically active men aged 18 to 22 years old divided into two unequal groups: G1- rest DAP between 80 and 90 mmHg (N=11) and G2- rest DAP < 80mmHg (N=24). Volunteers performed physical exercise on a treadmill with intensity equivalent to 60% of Vmax. Heart rate recovery in the first (HRR1) and third (HRR3) minute after exercise were measured and heart rate variability (HRV) was examined in the time and frequency domain. Additionally, we performed the quantitative analysis of the Poincaré plot. HRV was recorded in the following phases: the 10-minute period before exercise, during exercise and the 60 minute period after exercise. RESULTS: We found no significant difference between G1 and G2 concerning HRV changes during exercise. The G2 group exhibited a delayed recovery of SDNN, RMSSD, RRTri, LF, HF, LF/HF, SD1 and SD2 indices during recovery from exercise. HRR1 and HRR3 was greater in the G2 group. CONCLUSION: Normotensive physically active men with DAP between 80 and 90 mmHg presented faster heart rate recovery and an accelerated recovery of heart rate autonomic control after aerobic exercise.

OBJETIVO: Métodos não-lineares para avaliar a variabilidade da freqüência cardíaca (VFC) têm recebido muita atenção recente. Nosso objetivo é analisar as respostas não-lineares da VFC durante a recuperação do exercício através do novo algoritmo da análise fractal da dimensão de Higuchi. MÉTODO: Foram examinados 35 voluntários saudáveis, com idade entre 18 e 35 anos. Para o treinamento de intensidade de exercício utilizamos 60% de Vmax determinado através de um teste progressivo utilizando o limiar de Conconi. A VFC foi analisada 10 minutos antes e 10 minutos após o exercício. Analisamos os índices geométricos de VFC (SD1, uma medida de VFC em curto prazo e SD2, uma medida de VFC em longo prazo) e aplicamos a Dimensão Fractal de Higuchi aos intervalos RR. RESULTADOS: Durante a recuperação do exercício, os índices de plot de Poincaré SD1 e SD1/SD2 diminuíram, enquanto que SD2 e SD2/SD1 aumentaram (p <0,0001) em relação ao repouso. Todos os parâmetros da análise da Dimensão Fractal de Higuchi foram reduzidos após o exercício em comparação com o controle em repouso (p <0,0001). CONCLUSÃO: O exercício físico diminuiu agudamente o comportamento complexo da VFC, conforme medido pela análise da Dimensão Fractal de Higuchi. Fisiologicamente, isso indica que detectamos alterações na complexidade da VFC imediatamente após o exercício.

OBJECTIVE: Nonlinear techniques to assess heart rate variability (HRV) have received much recent attention. We aimed to evaluate nonlinear HRV responses during recovery from exercise through the novel algorithm Higuchi Fractal Dimension. METHOD: We examined 35 healthy male volunteers aged between 18 and 35 years old. For the training of exercise intensity we used 60% of Vmax determined through a progressive test using the Conconi threshold. HRV was analyzed 10 minutes before and 10 minutes after exercise. We analyzed the geometric indices of HRV (SD1, a measure of short-term HRV and SD2, a measure of long-term HRV) and applied the Higuchi Fractal Dimension to RR intervals. RESULTS: During recovery from exercise the Poincaré plot indices SD1 and SD1/SD2 decreased while SD2 and SD2/SD1 increased (p<0.0001) compared to control at rest. All parameters of Higuchi Fractal Dimension analysis were lowered after exercise compared to control at rest (p<0.0001). CONCLUSION: Physical exercise acutely decreased the chaotic behavior of HRV as measured through the Higuchi Fractal Dimension analysis. Physiologically, this indicates that we detected complex changes in HRV immediately after exercise.

Abstract This study examined the relationship between resting heart rate (RHRr) and anthropometric, metabolic and hemodynamic parameters in subjects aged 80 years and over. One hundred thirteen individuals were divided into two groups (RHR:<66 beats/min and ≥66 beats/min). Anthropometric parameters (weight, height, body mass index and waist circumference (WC) were measured. Hemodynamic parameters (systolic (SBP) and diastolic (DBP) pressure) were measured and pulse pressures (PP) were obtained. Metabolic parameters were fasting blood glucose, triglycerides and total cholesterol. In elderly aged 80 and over, RHR influenced the changes observed in DBP, PP and triglycerides. Additionally, subjects with RHR≥66 beats/min had higher DBP, glucose, total cholesterol and lower PP as compared with elderly with RHR<66 beats/min. Men demonstrated greater weight, height, and WC than women while women had higher percentage of body fat, trunk fat, and higher total cholesterol. Thus, subjects with 80 years old and over who present RHR≥66 have higher DBP and lower PP and heart rate variability compared with the elderly with RHR<66.

RESUMO OBJETIVOS: Os efeitos do teste ortostático sobre o sistema cardiovascular já foram investigados, mas não há dados sobre o comportamento dos índices geométricos de variabilidade da frequência cardíaca. Aqui, foram avaliados os efeitos do teste ortostático ativo nos índices geométricos de variabilidade da frequência cardíaca em mulheres. MÉTODO: O estudo foi realizado em 12 mulheres saudáveis com idades entre 18 e 30 anos. Para a análise da variabilidade da frequência cardíaca, este parâmetro foi registrado batimento a batimento. Os intervalos RR foram transformados em figuras geométricas e, a partir destas, foi calculado o índice triangular, a interpolação triangular dos intervalos RR, o SD1, SD2 e a relacão SD1/SD2, que foram obtidos a partir da plotagem de Poincaré. A análise visual do gráfico foi também realizada. Para o teste, os participantes levantaram-se rapidamente de uma posicão sentada (em 3 segundos ou menos) e permaneceram imóveis, de pé, por 15 minutos. Amostras de variacão de frequência cardíaca foram coletadas em quatro momentos: repouso, 0-5 minutos, 5-10 minutos e 10-15 minutos a pé. RESULTADOS: O índice triangular, a interpolacão triangular dos intervalos RR, o SD1 e SD2 índices apresentaram-se reduzidos (p < 0,05) no intervalo 10-15 minutos depois de os voluntários se levantarem. A relacão SD1/SD2 apresentou-se reduzida durante o intervalo 0-15 minutos depois dos participantes passarem à posicão ortostática. CONCLUSÃO: Os índices geométricos de variabilidade da freqüência cardíaca diminuiram em resposta ao teste ortostático ativo em mulheres saudáveis.

OBJECTIVES: The effects of the orthostatic test on the cardiovascular system have been investigated, but there are no data on the behavior of the geometric indices of heart rate variability. We evaluated the effects of the active orthostatic test on the geometric indices of heart rate variability in women. METHOD: The study was performed on 12 healthy women between ages 18 and 30. For the analysis of heart rate variability, heart rate was recorded beat-to-beat. The RR intervals were transformed into geometric figures, and from these we calculated the triangular index, the triangular interpolation of RR intervals, the SD1, SD2 indexes and the SD1/SD2 ratio, which were obtained from the Poincare´ plot. Visual analysis of the plot was also performed. For the test, participants quickly stood up from a seated position in 3 seconds or less, and remained standing still for 15 minutes. Heart rate variability samples were collected at four moments: rest, 0-5 minutes, 5- 10 minutes and 10-15 minutes at standing position. RESULTS: The triangular index, the triangular interpolation of RR intervals, the SD1 and SD2 indices were reduced (p < 0.05) at 10-15 minutes after the volunteers stood up from seated position. The SD1/SD2 ratio was decreased at 0-15 minutes after the subjects changed from seated to orthostatic position. CONCLUSION: The geometric indices of heart rate variability decreased in response to the active orthostatic test in healthy women.

OBJETIVO: Reunir informações atuais acerca dos efeitos do diabetes melito tipo 1 sobre o comportamento autonômico cardíaco de crianças.FONTES DE DADOS:A busca dos artigos foi realizada nas bases de dados PubMed, Ibecs, Medline, Cochrane, Lilacs, SciELO e PEDro por meio dos seguintes descritores da área da saúde (DeCS): "sistema nervoso autônomo", "diabetes mellitus", "criança", "diabetes mellitus tipo 1", "sistema nervoso simpático" e "sistema nervoso parassimpático" e suas respectivas versões em língua inglesa (MeSH). Os artigos foram publicados de janeiro de 2003 a fevereiro de 2013, envolvendo crianças de nove a 12 anos portadoras de diabetes melito tipo 1.SÍNTESE DOS DADOS: A busca resultou em quatro artigos que abordam a variabilidade da frequência cardíaca em crianças com diabetes melito tipo 1, demonstrando que, em geral, essas crianças apresentam redução da variabilidade da frequência cardíaca global e da atividade vagal. A prática de atividade física promove benefícios no organismo de crianças com diabetes melito tipo 1.CONCLUSÕES: Crianças diabéticas tipo 1 apresentam modificações na modulação autonômica, o que demonstra a necessidade de atenção precoce a essa população para evitar complicações futuras.

OBJECTIVE:To gather current information about the effects of type 1 diabetes mellitus on children's cardiac autonomic behavior.DATA SOURCES: The search of articles was conducted on PubMed, Ibecs, Medline, Cochrane, Lilacs, SciELO and PEDro databases using the MeSH terms: "autonomic nervous system", "diabetes mellitus", "child", "type 1 diabetes mellitus", "sympathetic nervous system" and "parasympathetic nervous system", and their respective versions in Portuguese (DeCS). Articles published from January 2003 to February 2013 that enrolled children with 9-12 years old with type 1 diabetes mellitus were included in the review.DATA SYNTHESIS: The electronic search resulted in four articles that approached the heart rate variability in children with type 1 diabetes mellitus, showing that, in general, these children present decreased global heart rate variability and vagal activity. The practice of physical activity promoted benefits for these individuals.CONCLUSIONS: Children with type 1 diabetes mellitus present changes on autonomic modulation, indicating the need for early attention to avoid future complications in this group.

OBJETIVO: Reunir informaciones actuales sobre los efectos de la diabetes mellitus tipo 1 sobre el comportamiento cardiaco de niños.FUENTES DE DATOS: La búsqueda de artículos se realizó en las bases de datos PubMed, Ibecs, Medline, Cochrane, Lilacs y PEDro por medio de los descriptores del área de salud (DeCS) a continuación: "sistema nervioso autónomo", "diabetes mellitus", "niño", "diabetes mellitus tipo 1", "sistema nervioso simpático" y "sistema nervioso parasimpático" sus respectivas versiones en lengua inglesa (MeSH).Los artículos fueron publicados de enero de 2003 a febrero de 2013, implicando a niños de nueve a 12 años portadores de diabetes mellitus tipo 1.SÍNTESIS DE LOS DATOS: La búsqueda resultó en cuatro artículos que trataban la variabilidad de la frecuencia cardiaca en niños con diabetes mellitus tipo 1, demostrando que, por lo general, esos niños presentan reducción de la variabilidad de la frecuencia cardiaca global y de la actividad vagal. La práctica de actividad física promueve beneficios al organismo de niños con diabetes mellitus tipo 1.CONCLUSIONES: Niños diabéticos tipo 1 presentan modificaciones en la modulación autonómica, lo que demuestra la necesidad de atención temprana a esa población para evitar complicaciones futuras.

OBJECTIVES: There are no data in the literature with regard to the acute effects of different styles of music on the geometric indices of heart rate variability. In this study, we evaluated the acute effects of relaxant baroque and excitatory heavy metal music on the geometric indices of heart rate variability in women. METHODS: We conducted this study in 21 healthy women ranging in age from 18 to 35 years. We excluded persons with previous experience with musical instruments and persons who had an affinity for the song styles. We evaluated two groups: Group 1 (n = 21), who were exposed to relaxant classical baroque musical and excitatory heavy metal auditory stimulation; and Group 2 (n = 19), who were exposed to both styles of music and white noise auditory stimulation. Using earphones, the volunteers were exposed to baroque or heavy metal music for five minutes. After the first music exposure to baroque or heavy metal music, they remained at rest for five minutes; subsequently, they were re-exposed to the opposite music (70-80 dB). A different group of women were exposed to the same music styles plus white noise auditory stimulation (90 dB). The sequence of the songs was randomized for each individual. We analyzed the following indices: triangular index, triangular interpolation of RR intervals and Poincaré plot (standard deviation of instantaneous beat-by-beat variability, standard deviation of the long-term RR interval, standard deviation of instantaneous beat-by-beat variability and standard deviation of the long-term RR interval ratio), low frequency, high frequency, low frequency/high frequency ratio, standard deviation of all the normal RR intervals, root-mean square of differences between the adjacent normal RR intervals and the percentage of adjacent RR intervals with a difference of duration greater than 50 ms. Heart rate variability was recorded at rest for 10 minutes. RESULTS: The triangular index and the standard deviation of the long-term RR interval indices were reduced during exposure to both music styles in the first group and tended to decrease in the second group whereas the white noise exposure decreased the high frequency index. We observed no changes regarding the triangular interpolation of RR intervals, standard deviation of instantaneous beat-by-beat variability and standard deviation of instantaneous beat-by-beat variability/standard deviation in the long-term RR interval ratio. CONCLUSION: We suggest that relaxant baroque and excitatory heavy metal music slightly decrease global heart rate variability because of the equivalent sound level.

OBJECTIVE: Previous studies have demonstrated a relationship between brain oxidative stress and cardiovascular regulation. We evaluated the effects of central catalase inhibition on cardiovascular responses in spontaneously hypertensive rats exposed to sidestream cigarette smoke. METHODS: Male Wistar Kyoto (WKY) rats and spontaneously hypertensive rats (SH) (16 weeks old) were implanted with a stainless steel guide cannula leading into the fourth cerebral ventricle (4th V). The femoral artery and vein were cannulated for arterial pressure and heart rate measurement and drug infusion, respectively. The rats were exposed to sidestream cigarette smoke for 180 minutes/day, 5 days/week for 3 weeks (CO: 100-300 ppm). The baroreflex was tested using a pressor dose of phenylephrine (8 μg/kg, bolus) and a depressor dose of sodium nitroprusside (50 μg/kg, bolus). Cardiovascular responses were evaluated before and 5, 15, 30 and 60 minutes after injection of a catalase inhibitor (3-amino-1,2,4-triazole, 0.001 g/100 μL) into the 4th V. RESULTS: Vehicle administration into the 4th V did not affect the cardiovascular response, whereas administration of the central catalase inhibitor increased the basal HR and attenuated the bradycardic peak (p<0.05) to a greater extent in WKY rats exposed to sidestream cigarette smoke than in WKY rats exposed to fresh air. However, in spontaneously hypertensive rats, the effect of the catalase inhibitor treatment was stronger in the fresh air condition (p<0.05). CONCLUSION: Administration of a catalase inhibitor into the 4th V combined with exposure to sidestream cigarette smoke has a stronger effect in WKY rats than in SH rats.

Previous studies have already demonstrated that auditory stimulation with music influences the cardiovascular system. In this study, we described the relationship between musical auditory stimulation and heart rate variability. Searches were performed with the Medline, SciELO, Lilacs and Cochrane databases using the following keywords: "auditory stimulation", "autonomic nervous system", "music" and "heart rate variability". The selected studies indicated that there is a strong correlation between noise intensity and vagal-sympathetic balance. Additionally, it was reported that music therapy improved heart rate variability in anthracycline-treated breast cancer patients. It was hypothesized that dopamine release in the striatal system induced by pleasurable songs is involved in cardiac autonomic regulation. Musical auditory stimulation influences heart rate variability through a neural mechanism that is not well understood. Further studies are necessary to develop new therapies to treat cardiovascular disorders.