Physical training improves exercise tolerance, cardiac function and promotes changes in neurotrophins levels in chagasic mice.

AIMS: To investigate the effects of moderate aerobic physical training on cardiac function and morphology as well as on the levels of glial cell-derived neurotrophic factor (GDNF), nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF) of animals infected with the Y strain of Trypanosoma cruzi. MAIN METHODS: Twenty-eight male C57BL/6 mice were distributed into 4 groups: sedentary control (SC), trained control (TC), sedentary infected (CHC) and trained infected (CHT). The infection was performed by intraperitoneal injection of trypomastigote forms and the animals were adapted to treadmill in the week before the beginning of the training protocol, initiated 45 days post infection. Maximal exercise test (TEM) was performed at the baseline as well as at the end of the 4th, 8th and 12th weeks of training. At the end of the 12th week, all animals were evaluated for cardiac morphology and function by echocardiography. KEY FINDINGS: CHC group showed a larger area of right ventricle (RVA), increased end-systolic volume and reduction in ejection fraction (EF), stroke volume (SV), cardiac output (CO) and fractional area change (FAC). The training reduced the RVA and improved the FAC of chagasic animals. GDNF level was higher in TC and CHC groups compared to SC in heart and BDNF levels were higher in CHC compared to SC in heart and serum. SIGNIFICANCE: Physical training ameliorated the cardiac function of infected animals and promoted adjusts in BDNF and GDNF levels. These findings evidenced these neurotrophins as possible biomarkers of cardiac function responsive to exercise stimulus.

COMPARAÇÃO DA MODULAÇÃO AUTONÔMICA CARDÍACA DURANTE ESFORÇO DE FUMANTES E NÃO FUMANTES / COMPARISON OF CARDIAC AUTONOMIC MODULATION DURING EFFORT OF SMOKERS AND NON-SMOKERS / COMPARACIÓN DE LA MODULACIÓN AUTONÓMICA CARDÍACA DURANTE ESFUERZO DE LOS FUMADORES Y LOS NO FUMADORES

Introdução O tabagismo é uma das principais causas de morbimortalidade em todo o mundo. Indivíduos fumantes têm risco aumentado de desenvolver disfunção autonômica, a qual pode ser avaliada tanto pela variabilidade da frequência cardíaca (VFC) como pela frequência cardíaca de recuperação (FCRec). A maioria dos estudos envolvendo esta análise é realizada em adultos de idade avançada e na condição de repouso. Objetivos Comparar a atividade autonômica cardíaca em repouso e esforço, em homens jovens, fumantes e não fumantes. Métodos Trinta e dois jovens voluntários, (idade 22,0 ± 2,8 anos) foram distribuídos em dois grupos: o grupo fumante (GF; n=15) e o não fumante (GNF; n=17). Realizou-se o teste de Cooper, com análise da VFC pelo cardiofrequencímetro Polar(r)s810i, em repouso e durante o esforço e FCRec. Resultados No GF, 73% foram classificados com nível de dependência nicotínica "muito baixa" segundo questionário de Fargeström. A classificação de ativos e muito ativos pelo questionário IPAQ correspondeu a mais de 50% da amostra em ambos os grupos. Não se observou diferenças significativas entre os grupos na VFC, tanto no repouso quanto no esforço. Entretanto, em cada grupo, notou-se diferença na maioria dos índices de VFC do repouso para o esforço. No teste de Cooper não foram observadas diferenças significativas na FCmédia, FCpico e de FCRec entre os grupos, mas notou-se uma melhor capacidade funcional no GNF pela distância caminhada (2050,2 ± 300,0 vs. 1780,3 ± 390,4 m, p=0,036). Conclusão O GF apresentou menor capacidade funcional e ativação parassimpática durante o esforço, além de menores índices de VFC durante repouso, o que pode sugerir um comprometimento precoce na modulação autonômica cardíaca.

Introduction Smoking is one of the major causes of morbidity and mortality worldwide. Smokers have an increased risk of developing autonomic dysfunction, which can be evaluated by both heart rate variability (HRV) and heart rate recovery (HRRec). Most studies involving this analysis is performed on adults of advanced age and in condition of rest. Objectives To compare the cardiac autonomic activity, at rest and during exercise in young men, smokers and non-smokers. Methods Thirty-two young volunteers (aged 22.0 ± 2.8 years) were divided into two groups: the smoking group (SG, n = 15) and non-smokers (NSG, n = 17). We carried out the Cooper test and HRV analysis by heart rate monitor Polar(r)s810i, at rest and during exercise and HRRec. Results In SG, 73% were classified as having a "very low" level of nicotine dependence according to the Fargeström's questionnaire. Classification of active and very active by the IPAQ questionnaire accounted for over 50% of sample in both groups. There were no significant differences between groups in HRV, both at rest and during exercise. However, in each group, difference has been noted in most HRV indexes from rest to exercise. During Cooper test there were no significant differences in mean HR, HRpeak and HRRec between groups, but a better functional capacity was noted in NSG in the distance walked (2050.2 ± 300.0 vs. 1780.3 ± 390.4m, p = 0.036). Conclusion The SG showed lower functional capacity and parasympathetic activation during exercise, besides lower HRV indexes during rest, suggesting an early impairment in cardiac autonomic modulation.

Introducción El consumo de cigarrillos es una de las más importantes causas de morbilidad y mortalidad en todo el mundo. Los individuos fumadores tienen mayor riesgo de desarrollar disfunción autonómica, que puede ser evaluada tanto por la variabilidad del ritmo cardíaco (VRC) como por la frecuencia cardiaca de recuperación (FCrec). La mayoría de los estudios con estos análisis se lleva a cabo en las personas más viejas y en situación de reposo. Objetivos Comparar la actividad autonómica cardiaca, en momento de reposo y durante ejercicios, en hombres jóvenes, fumadores y no fumadores. Métodos Treinta y dos voluntarios jóvenes (edad 22,0 ± 2,8 años) fueron divididos en dos grupos: grupo de fumadores (GF; n = 15) y no fumadores (GNF; n = 17). Se realizó la prueba de Cooper con el análisis de la VRC por pulsómetro Polar(r)s810i, durante reposo y ejercicio y FCrec. Resultados En el GF, el 73% fueron clasificados con niveles de dependencia por la nicotina "muy bajo", según cuestionario Fargeström. La clasificación de activos y muy activos, mediante cuestionario IPAQ, correspondió a más de 50% de la amuestra en ambos los grupos. No hubo diferencia significativa entre los grupos en la VRC, tanto en reposo cuanto en ejercicio. Sin embargo, en cada grupo, observamos una diferencia en la mayoría de los índices de VRC del reposo para el ejercicio. En la prueba de Cooper no se observó diferencias significativas en las FC media, FCpico y FCrec, pero se verificó una mejor capacidad funcional en el GNF por la distancia caminada (2050.2 ± 300.0 vs. 1780,3 ± 390,4 m, p = 0,036). Conclusión El GF mostró una capacidad funcional y una activación parasimpática más baja durante el ejercicio, así como tasas más bajas de VRC en reposo, lo que puede sugerir un deterioro temprano en la modulación autonómica cardíaca.

Assessment of Functional Capacity in Chagas Heart Disease by Incremental Shuttle Walk Test and its Relation to Quality-of-Life.

BACKGROUND: The cardiopulmonary exercise test (CPET) is considered to be the gold standard to evaluate functional capacity (FC) in patients with heart failure. However, field tests such as the 6-min walk test (6MWT) and the incremental shuttle walk test (ISWT) are simple and effective in evaluating the same. Despite the increasing use of ISWT, no studies that used the test in patients with Chagas heart disease (CHD) were found and only few studies have evaluated the health-related quality-of-life (HRQoL) in this population. The objective of this study was to correlate the distance walked in the ISWT with distance walked by 6MWT and peak oxygen uptake (VO2peak) by CPET and HRQoL in patients with CHD. METHODS: A total of 35 patients with CHD were evaluated according to the FC and HRQoL. The FC was assessed by CPET, 6MWT and ISWT. HRQoL was assessed by the generic short-form health survey (SF-36) and Minnesota Living with Heart Failure Questionnaire (MLHFQ). Descriptive data were shown as mean and standard deviation or median and interquartile range. The correlation was carried out with Pearson or Spearman correlation test. A receiver operating characteristic (ROC) curve was constructed to investigate the accuracy of ISWT for predicting low values of VO2peak. RESULTS: The distance walked in ISWT correlated with VO2peak(r = 0.587; P < 0.001), distance walked in 6MWT (r = 0.484; P = 0.003), MLWHFQ scores (r = -0.460; P = 0.006) and physical functioning and role physical domains of the SF-36 scores (r = 0.435, P = 0.009; r = 0.477, P = 0.008, respectively). There was no significant difference between the distances walked in field tests (P = 0.694). The area under the ROC curve was 0.871 for ISWT in predicts a VO2peak value of, at least, 25 mL/kg/min. CONCLUSIONS: The ISWT showed to be effective in evaluating the FC in CHD and in demonstrate the impact of disease on some aspects of the HRQoL of these patients.

Autonomic modulation and functional capacity in diabetes mellitus type 1 and 2 subjects / Modulação autonômica e capacidade funcional em indivíduos portadores de diabetes mellitus do tipo 1 e 2

OBJECTIVES: Evaluation of heart rate variability (HRV) during cardiovascular autonomic tests and functional capacity of patients with type 1 and type 2 DM. METHODS: Fifteen individuals with DM and twelve healthy ones were evaluated during cardiovascular autonomic tests of maneuver enhancement of respiratory sinus arrhythmia (RSA), handgrip and Valsalva. In addition, the Paschoal test was applied to evaluate submaximal functional capacity. During the tests, autonomic heart rate variability (HRV) was collected by recording the RR intervals, considering the rates in the time domain (RMSSD and pNN50) and frequency domain, as low and high frequency (LF and HF) and the relationship between them (LF / HF). Besides the analysis of HRV and capillary glucose, the distance traveled during Paschoal test was also recorded. RESULTS: The values related to blood glucose levels were significantly higher (p <0.05) in DM1 and DM2 groups compared to controls. PNN50 values for DM1 in all tests were lower compared to CDM1. No statistical difference was found when compared DM2 with CDM2. The distance of Paschoal test was similar between groups of individuals with diabetes and their respective controls. CONCLUSION: The variable pNN50 was lower in individuals with DM1, suggesting reduced of the parasympathetic activity in these individuals, but no change in functional capacity, as measured by Paschoal test when compared to the control group.(AU)

OBJETIVOS: avaliar a variabilidade da frequência cardíaca (VFC) durante testes autonômicos cardiovasculares e a capacidade funcional de indivíduos com DM tipos 1 e 2. MÉTODO: foram avaliados 15 indivíduos com DM e 12 indivíduos saudáveis, durante a realização de testes autonômicos cardiovasculares de manobra de acentuação da arritmia sinusal respiratória (ASR), handgrip e valsalva. Além disso, foi aplicado o teste submáximo de Paschoal para avaliação da capacidade funcional. Durante a realização dos testes autonômicos foi coletada a variabilidade da frequência cardíaca (VFC), por meio do registro dos intervalos RR, considerando-se os índices no domínio do tempo (RMSSD e pNN50) e da freqüência, como baixa e alta freqüência (BF e AF) e a relação entre os mesmos (BF/AF). Além da análise da VFC, foi registrado a distância percorrida durante o Teste de Paschoal e a glicemia capilar. RESULTADOS: Os valores referentes à glicemia foram significativamente maiores (p < 0,05) no grupo DM1 e DM2 comparados aos controles. Os valores de pNN50 para o DM1, em todos os testes realizados, foram menores em relação ao CDM1. Nenhuma diferença estatística foi encontrada quando comparados DM2 com o CDM2. A distância percorrida no teste de Paschoal foi similar entre os grupos de indivíduos com DM e seus respectivos controles. CONCLUSÃO: A variável pNN50 foi menor nos indivíduos com DM1, sugerindo redução da atividade parassimpática nesses indivíduos, porém sem alteração da capacidade funcional, avaliada pelo teste de Paschoal quando comparados ao grupo controle.(AU)

Autonomic modulation and functional capacity in diabetes mellitus type 1 and 2 subjects

OBJETIVOS: avaliar a variabilidade da frequência cardíaca (VFC) durante testes autonômicos cardiovasculares e a capacidade funcional de indivíduos com DM tipos 1 e 2. MÉTODO: foram avaliados 15 indivíduos com DM e 12 indivíduos saudáveis, durante a realização de testes autonômicos cardiovasculares de manobra de acentuação da arritmia sinusal respiratória (ASR), handgrip e valsalva. Além disso, foi aplicado o teste submáximo de Paschoal para avaliação da capacidade funcional. Durante a realização dos testes autonômicos foi coletada a variabilidade da frequência cardíaca (VFC), por meio do registro dos intervalos RR, considerando-se os índices no domínio do tempo (RMSSD e pNN50) e da freqüência, como baixa e alta freqüência (BF e AF) e a relação entre os mesmos (BF/AF). Além da análise da VFC, foi registrado a distância percorrida durante o Teste de Paschoal e a glicemia capilar. RESULTADOS: Os valores referentes à glicemia foram significativamente maiores (p < 0,05) no grupo DM1 e DM2 comparados aos controles. Os valores de pNN50 para o DM1, em todos os testes realizados, foram menores em relação ao CDM1. Nenhuma diferença estatística foi encontrada quando comparados DM2 com o CDM2. A distância percorrida no teste de Paschoal foi similar entre os grupos de indivíduos com DM e seus respectivos controles. CONCLUSÃO: A variável pNN50 foi menor nos indivíduos com DM1, sugerindo redução da atividade parassimpática nesses indivíduos, porém sem alteração da capacidade funcional, avaliada pelo teste de Paschoal quando comparados ao grupo controle.(AU)

OBJECTIVES: Evaluation of heart rate variability (HRV) during cardiovascular autonomic tests and functional capacity of patients with type 1 and type 2 DM. METHODS: Fifteen individuals with DM and twelve healthy ones were evaluated during cardiovascular autonomic tests of maneuver enhancement of respiratory sinus arrhythmia (RSA), handgrip and Valsalva. In addition, the Paschoal test was applied to evaluate submaximal functional capacity. During the tests, autonomic heart rate variability (HRV) was collected by recording the RR intervals, considering the rates in the time domain (RMSSD and pNN50) and frequency domain, as low and high frequency (LF and HF) and the relationship between them (LF / HF). Besides the analysis of HRV and capillary glucose, the distance traveled during Paschoal test was also recorded. RESULTS: The values related to blood glucose levels were significantly higher (p <0.05) in DM1 and DM2 groups compared to controls. PNN50 values for DM1 in all tests were lower compared to CDM1. No statistical difference was found when compared DM2 with CDM2. The distance of Paschoal test was similar between groups of individuals with diabetes and their respective controls. CONCLUSION: The variable pNN50 was lower in individuals with DM1, suggesting reduced of the parasympathetic activity in these individuals, but no change in functional capacity, as measured by Paschoal test when compared to the control group.(AU)

Autonomic modulation and functional capacity in diabetes mellitus type 1 and 2 subjects

OBJETIVOS: avaliar a variabilidade da frequência cardíaca (VFC) durante testes autonômicos cardiovasculares e a capacidade funcional de indivíduos com DM tipos 1 e 2. MÉTODO: foram avaliados 15 indivíduos com DM e 12 indivíduos saudáveis, durante a realização de testes autonômicos cardiovasculares de manobra de acentuação da arritmia sinusal respiratória (ASR), handgrip e valsalva. Além disso, foi aplicado o teste submáximo de Paschoal para avaliação da capacidade funcional. Durante a realização dos testes autonômicos foi coletada a variabilidade da frequência cardíaca (VFC), por meio do registro dos intervalos RR, considerando-se os índices no domínio do tempo (RMSSD e pNN50) e da freqüência, como baixa e alta freqüência (BF e AF) e a relação entre os mesmos (BF/AF). Além da análise da VFC, foi registrado a distância percorrida durante o Teste de Paschoal e a glicemia capilar. RESULTADOS: Os valores referentes à glicemia foram significativamente maiores (p < 0,05) no grupo DM1 e DM2 comparados aos controles. Os valores de pNN50 para o DM1, em todos os testes realizados, foram menores em relação ao CDM1. Nenhuma diferença estatística foi encontrada quando comparados DM2 com o CDM2. A distância percorrida no teste de Paschoal foi similar entre os grupos de indivíduos com DM e seus respectivos controles. CONCLUSÃO: A variável pNN50 foi menor nos indivíduos com DM1, sugerindo redução da atividade parassimpática nesses indivíduos, porém sem alteração da capacidade funcional, avaliada pelo teste de Paschoal quando comparados ao grupo controle.

OBJECTIVES: Evaluation of heart rate variability (HRV) during cardiovascular autonomic tests and functional capacity of patients with type 1 and type 2 DM. METHODS: Fifteen individuals with DM and twelve healthy ones were evaluated during cardiovascular autonomic tests of maneuver enhancement of respiratory sinus arrhythmia (RSA), handgrip and Valsalva. In addition, the Paschoal test was applied to evaluate submaximal functional capacity. During the tests, autonomic heart rate variability (HRV) was collected by recording the RR intervals, considering the rates in the time domain (RMSSD and pNN50) and frequency domain, as low and high frequency (LF and HF) and the relationship between them (LF / HF). Besides the analysis of HRV and capillary glucose, the distance traveled during Paschoal test was also recorded. RESULTS: The values related to blood glucose levels were significantly higher (p <0.05) in DM1 and DM2 groups compared to controls. PNN50 values for DM1 in all tests were lower compared to CDM1. No statistical difference was found when compared DM2 with CDM2. The distance of Paschoal test was similar between groups of individuals with diabetes and their respective controls. CONCLUSION: The variable pNN50 was lower in individuals with DM1, suggesting reduced of the parasympathetic activity in these individuals, but no change in functional capacity, as measured by Paschoal test when compared to the control group.