Physical Training Improves Cardiac Structure and Function of Rats After Doxorubicin-Induced Cardiomyopathy

Abstract Background: The use of doxorubicin in chemotherapy has been associated with cardiotoxicity and heart failure. Physical exercise produces favorable morphofunctional adaptations in the cardiovascular system and may reverse cardiac dysfunction in patients undergoing chemotherapy. Objective: To assess the effects of physical training on myocardial structure, cardiac function, and exercise tolerance in Wistar rats initiated after the onset of cardiotoxicity-induced cardiotoxicity. Methods: This study investigated 30 adult male Wistar rats randomly divided into four groups: control (C), exercise (EX), doxorubicin (DX), and doxorubicin and exercise (DXEX). The DX and DXEX groups received six doses of doxorubincin from 1.25 mg/kg body weight up to a cumulative dose of 7.5 mg/kg. Injections were administered intraperitoneally three times a week for two weeks; after this stage, the EX and DXEX groups started physical training (swimming) sessions three times a week with a load of 5% of their body weight. Echocardiography and exercise tolerance tests were performed. Generalized linear models were used in statistical analysis, and a p<0.05 was set as statistically significant. Results: Left ventricular shortening fraction and ejection fraction were reduced in the DX group compared to C, EX, and DXEX. The DXEX group showed greater tolerance to effort when compared to the DX and C groups. Conclusion: Physical training, initiated after the onset of doxorubicin-induced cardiotoxicity, improved cardiac function and exercise tolerance in rats.

Isometric handgrip exercise training reduces resting systolic blood pressure but does not interfere with diastolic blood pressure and heart rate variability in hypertensive subjects: a systematic review and meta-analysis of randomized clinical trials.

To evaluate the effects of isometric handgrip exercise training (IHET) on blood pressure and heart rate variability in hypertensive subjects. Five databases were searched for randomized clinical trials in English, Spanish, or Portuguese evaluating the effect of IHET vs. no exercise on blood pressure (systolic and/or diastolic) and/or heart rate variability (low frequency [LF], high frequency [HF], and/or LF/HF ratio) through December 2020. Random-effects meta-analyses of mean differences (MDs) and/or standardized mean differences (SMDs) with 95% confidence intervals (CIs) were performed. Five trials were selected (n = 324 hypertensive subjects), whose durations ranged from 8 to 10 weeks. Compared to no exercise, IHET reduced systolic blood pressure (MD -8.11 mmHg, 95% CI -11.7 to -4.53, p < 0.001) but did not affect diastolic blood pressure (MD -2.75 mmHg, 95% CI -9.47-3.96, p = 0.42), LF (SMD -0.14, 95% CI -0.65-0.37, p = 0.59), HF (SMD 0.38, 95% CI -0.14-0.89, p = 0.15), or the LF/HF ratio (SMD -0.22, 95% CI -0.95-0.52, p = 0.57). IHET performed for 8-10 weeks had a positive effect on resting systolic blood pressure but did not interfere with diastolic blood pressure or heart rate variability in hypertensive subjects. These data should be interpreted with caution since all volunteers included in the studies were clinically medicated and their blood pressure was controlled.

Fatores de risco cardiovasculares em pacientes com fibromialgia / Cardiovascular risk factors in patients with fibromyalgia

Objetivo: Verificar os fatores de risco cardiovasculares em pacientes com fibromialgia (FM). Métodos: O estudo foi composto por 40 mulheres diagnosticadas com FM e encaminhadas para o setor de Reabilitação Física do Hospital de Clínicas de Uberlândia. Foi aplicado um questionário do American College of Sports Medicine contendo perguntas sobre histórico familiar; tabagismo; hipertensão; dislipidemia; glicose de jejum alterada; obesidade; sedentarismo e etilismo. Resultados: O sedentarismo teve prevalência de 92,5%, hereditariedade 52,5%, obesidade 50%, hipertensão arterial 45%, dislipidemia 37,5%, tabagismo 25%, etilismo 8% e diabetes 7,5%. Além disso, 60% da amostra apresentou três ou mais fatores de risco, 30% apresentou 2 fatores e 10% apresentou apenas um fator de risco. Conclusão: Pacientes com FM apresentam vários fatores de risco cardiovasculares, desse modo, deve-se orientar tais pacientes à mudança do estilo de vida, a fim de reduzir tais fatores e consequentemente eventos cardíacos futuros, e proporciona melhora do quadro de dor

Objective: To assess the cardiovascular risk factors in patients with fibromyalgia. Methods: The study consisted of 40 women diagnosed with FM and forwarded to the Physical Rehabilitation department at the Hospital of Uberlândia. A survey was applied from the American College of Sports Medicine containing questions about family history, smoking, hypertension, dyslipidemia, impaired fasting glucose, obesity, physical inactivity, and alcohol consumption. Results: The prevalence of physical inactivity was 92.5%, heredity 52.5%, obesity 50%, hypertension 45%, dyslipidemia 37.5%, smoking 25%, alcohol consumption 8%, and diabetes 7.5%. Furthermore, 60% of the sample had three or more risk factors, 30% had 2 factors and 10% had only one risk factor. Conclusion: Patients with FM have multiple cardiovascular risk factors, thus, such patients should be advised to change lifestyle in order to reduce such factors and consequent future cardiac events, and provide improvement of the pain.

The thyroid hormone receptor ß-selective agonist GC-1 does not affect tolerance to exercise in hypothyroid rats.

OBJECTIVE: Investigate the effect of GC-1 on tolerance to exercise in rats with experimental hypothyroidism. MATERIALS AND METHODS: Hypothyroidism was induced with methimazole sodium and perchlorate treatment. Six groups with eight animals were studied: control group (C), hypothyroid group without treatment (HYPO); hypothyroidism treated with physiological doses of tetraiodothyronine (T4) or 10 times higher (10×T4); hypothyroidism treated with equal molar doses of GC-1 (GC-1) or 10 times higher (10×GC-1). After eight weeks, each animal underwent an exercise tolerance test by measuring the time (seconds), in which the rats were swimming with a load attached to their tails without being submerging for more than 10 sec. After the test, the animals were killed, and blood samples were collected for biochemical analysis, and the heart and soleus muscle were removed for weighing and morphometric analysis of the cardiomyocyte. RESULTS: Hypothyroidism significantly reduced tolerance to exercise and, treatment with GC-1 1× or T4 in physiological doses recover tolerance test to normal parameters. However, high doses of T4 also decreased tolerance to physical exercise. Conversely, ten times higher doses of GC-1 did not impair tolerance to exercise. Interestingly, hypothyroidism, treated or not with T4 in a physiological range, GC-1 or even high doses of GC-1 (10X) did not change cardiomyocyte diameters and relative weight of the soleus muscle. In contrast, higher doses of T4 significantly increased cardiomyocyte diameter and induced atrophy of the soleus muscle. CONCLUSION: Unlike T4, GC-1 in high doses did not modify tolerance to physical exercise in the rats with hypothyroidism.

The thyroid hormone receptor β-selective agonist GC-1 does not affect tolerance to exercise in hypothyroid rats

Objective Investigate the effect of GC-1 on tolerance to exercise in rats with experimental hypothyroidism. Materials and methods Hypothyroidism was induced with methimazole sodium and perchlorate treatment. Six groups with eight animals were studied: control group (C), hypothyroid group without treatment (HYPO); hypothyroidism treated with physiological doses of tetraiodothyronine (T4) or 10 times higher (10×T4); hypothyroidism treated with equal molar doses of GC-1 (GC-1) or 10 times higher (10×GC-1). After eight weeks, each animal underwent an exercise tolerance test by measuring the time (seconds), in which the rats were swimming with a load attached to their tails without being submerging for more than 10 sec. After the test, the animals were killed, and blood samples were collected for biochemical analysis, and the heart and soleus muscle were removed for weighing and morphometric analysis of the cardiomyocyte. Results Hypothyroidism significantly reduced tolerance to exercise and, treatment with GC-1 1× or T4 in physiological doses recover tolerance test to normal parameters. However, high doses of T4 also decreased tolerance to physical exercise. Conversely, ten times higher doses of GC-1 did not impair tolerance to exercise. Interestingly, hypothyroidism, treated or not with T4 in a physiological range, GC-1 or even high doses of GC-1 (10X) did not change cardiomyocyte diameters and relative weight of the soleus muscle. In contrast, higher doses of T4 significantly increased cardiomyocyte diameter and induced atrophy of the soleus muscle. Conclusion Unlike T4, GC-1 in high doses did not modify tolerance to physical exercise in the rats with hypothyroidism. .

Efeitos de um programa de exercício físico em pacientes com doença arterial obstrutiva periférica / Effects of physical exercise program in patients with obstructive peripheral arterial disease

O objetivo do estudo foi estratificar os fatores de risco cardiovasculares (FR) e avaliar os efeitos de um programa de exercício físico (PEF) por três meses em pacientes diagnosticados com doença arterial obstrutiva periférica (DAOP) através do teste de caminhada de 6 minutos (TC6), utilizando como parâmetro a distância total percorrida (DTP), tempo inicial da dor (TID), tempo final da dor (TFD) e tempo total da dor (TTD). O estudo foi composto por 12 voluntários, encaminhados para o programa de Reabilitação Física. Para estratificar os FR houve aplicação de questionário contendo pergunta objetivas com opção de sim ou não sobre tabagismo, diabetes mellitus, etilismo, hipertensão arterial, sedentarismo, hereditariedade, dislipidemia e obesidade, adotou-se o índice de massa corpórea. O TC6 foi realizado em um corredor de 22 metros e o paciente foi orientado a informar aos avaliadores o momento de início da dor (TID) e somente parar quando a dor tornar-se insuportável para continuar a caminhada. O TFD foi estabelecido quando o paciente retornou ao TC6. Ao final do teste foi calculada a DTP que o paciente atingiu. O teste de ANOVA foi utilizado para comparar as condições pré e pós-reabilitação, tendo nível de significância quando p<0,05. Observou-se que todos os pacientes mostraram-se sedentários, 58,3% são dislipidêmicos, 50% são tabagistas, hipertensos e apresentam hereditariedade. Houve diferença significativa na DTP (327,7±83,3 vs 431,7±90,5), TID (01:52±0:36 vs 02:59±0:41) e TTD (01:55±0:14 vs 00:45±0:36) pré e pós-reabilitação. O PEF para pacientes com DAOP se mostrou eficaz na DTP, TID, TTD.

Análise das respostas cardiovasculares agudas ao exercício resistido em diferentes intervalos de recuperação / Analysis of acute cardiovascular responses on resistance exercise in different recovery interval

INTRODUÇÃO: O sistema cardiovascular sofre sobrecarga durante a prática de exercícios físicos. Entretanto, pouco se sabe sobre a resposta cardíaca em diferentes intervalos de recuperação (IR). OBJETIVO: O presente estudo teve como objetivo analisar a sobrecarga cardíaca, utilizando como parâmetro cardiovascular a frequência cardíaca (FC), pressão arterial sistólica (PAS) e duplo-produto (DP) em IR distintos (IR), sendo delimitados em 45'' (IR45''), 60'' (IR60'') e 90'' (IR90''). MÉTODOS: O estudo analisou 10 voluntários do gênero masculino, com idade 21,5 ± 6,04 anos, peso 77,5 ± 10,62 kg e altura 179 ± 7 cm, que foram submetidos a um protocolo de três séries de 12 repetições à 60% de uma repetição máxima (1RM) no aparelho leg press 45º. O teste de Wilcoxon foi utilizado para comparar as variáveis hemodinâmicas tendo nível de significância quando p ≤ 0,05. RESULTADOS: Houve diferença significativa de todas as variáveis quando compara-se o estado pré-esforço com as séries subsequentes. A PAS apresentou diferença entre a primeira e as demais séries. Foi observada diferença entre a segunda e terceira série com IR45'', além de na terceira série o IR45'' apresentar maiores valores quando comparados ao IR90''. De forma semelhante, a FC apresentou diferença entre a primeira e todas as séries, em todos os IR. Os IR45'' e IR60'' apresentaram diferença entre a segunda e terceira séries. Contudo, o DP demonstrou diferença entre a primeira e todas as séries em todos os IR, além de IR45'' e IR60'' apresentar diferença entre a segunda e terceira série. CONCLUSÃO: De acordo com os resultados encontrados, conclui-se que a PAS e FC é sensível ao número de séries intrasséries, porém, não houve diferença quando se compara os IR entre si. Contudo, há maior tendência do IR45'' causar aumento da sobrecarga cardíaca, principalmente pelo aumento da PAS.

INTRODUCTION: The cardiovascular system is the most submitted to overload during exercise practice. However, there is a lack of knowledge about heart response under different recovery intervals (RI). OBJECTIVE: The purpose of this study was to analyse the heart overload, using as cardiovascular parameter, the heart rate (HR), sistolic blood pressure (SBP) and double product (DP) under different recovery intervals (RI), delimited in 45'' (RI45''), 60'' (RI60'') and 90'' (RI90'') seconds. METHODS: The study analysed 10 volunteers, age 21.5 ± 6.04 years, weight 77.5 ± 10.62 kg and height 179 ± 7 cm, that was submitted a protocol of three sets of 12 repetition of 60% 1RM in Leg Press 45º apparatus. The Wilcoxon test was used to compare hemodynamic variables with significance level when p ≤ 0.05. RESULTS: There were significant differences of all variables when compared to pre-state effort with subsequent sets. The SBP was different between the first and the other sets. Also been observed difference between the second and third sets with RI45'', and in the third set, the RI45'' present greater values when compared to RI90''. Similarly, the HR present difference between the first and all other sets in all RI. The RI45'' and RI60'' showed differences between the second and third sets. However, the DP has demonstrated difference between the first and all others sets in all RI, and, the RI45'' and RI60'' showed difference between the second and third sets. CONCLUSION: According to the results, it is concluded that the SBP and HR is sensitive to the number of sets intra-sets, but there was no difference when comparing the RI with each other. However, there is a greater tendency of RI45'' cause increased cardiac overload, primarily by increased in SBP.

Efeito da leucina na hipertrofia cardíaca e na concentração sérica de creatina quinase em ratos Wistar em hipertireoidismo experimental / Effect of leucine in cardiac hypertrophy and serum creatine kinase in rats in experimental hyperthyroidism

A leucina é um regulador do metabolismo proteico in vivo, e existem poucas informações referentes à sua ação na hipertrofia cardíaca induzida pelo hipertireoidismo experimental e sua relação com a creatina quinase sérica. O estudo teve por objetivo verificar a ação da leucina na hipertrofia cardíaca e na concentração sérica de creatina quinase em ratos Wistar em hipertireoidismo. Foram utilizados 20 animais, divididos em quatro grupos sendo estes o controle, hormônio, leucina e hormônio + leucina. O hipertireoidismo foi induzido administrando-se, diariamente, 20µg/100 gramas de levotiroxina sódica em suspensão aquosa, por gavagem. A leucina foi suplementada adicionando-se 5% do aminoácido à ração convencional. O sangue foi coletado por punção cardíaca e as análises feitas em kits para CK-NAC, CK-MB e TSH. Ao final do período experimental de sete dias o coração foi removido e pesado. Posteriormente, foi separado o ventrículo esquerdo juntamente com o septo interventricular e pesado. Na comparação estatística foi utilizada a análise de variância (ANOVA) de duas vias e pós-teste de Tukey, considerando-se significativos valores de p<0,05. As concentrações séricas de CK-MB sérica foram menores no grupo leucina (p<0,05) e hormônio + leucina (p<0,05) em comparação a controle. O grupo hormônio, apresentou peso relativo do coração maior que o grupo controle (p<0,05) e peso absoluto do coração maior que hormônio + leucina (p<0,05). Em conclusão, a leucina parece reduzir a hipertrofia cardíaca e a concentração sérica da creatina quinase por mecanismos ainda desconhecidos.

Leucine is a regulator of protein metabolism in vivo, and there is little information regarding its action on cardiac hypertrophy induced by experimental hyperthyroidism and its relationship to serum creatine kinase. The study aimed to verify the effect of leucine in cardiac hypertrophy and serum creatine kinase in rats with hyperthyroidism. We used 20 animals were divided into four groups and these control, hormone, hormone + leucine and leucine. Hyperthyroidism was induced by administration of daily 20µg/100 grams of levothyroxine sodium in aqueous suspension by gavage. Leucine was supplemented by adding 5% of the amino conventional diet. Blood was collected by cardiac puncture and analyzes made in kit CK-NAC, CK-MB and TSH. At the end of the trial period of seven days the hearts were removed and weighed. Subsequently, the left ventricle was separated together with the interventricular septum and weighed. In statistical comparison was used analysis of variance (ANOVA) and two-way post-Tukey test, considering p values <0.05. Serum concentrations of serum CK-MB were lower in leucine (p <0.05) and hormone + leucine (p <0.05) compared to control. The hormone group, showed greater relative heart weight than the control group (p <0.05) and absolute heart weight greater than hormone + leucine (p <0.05). In conclusion, leucine appears to reduce cardiac hypertrophy and serum concentration of creatine kinase by unknown mechanisms.

Resposta do duplo produto e pressão arterial Diastólica em exercício de esteira, bicicleta estacionária e circuito na musculação / Double product response and Diatolic Blood pressure in Treadmill, stationary bicycle and muscular circuit exercises

Entre as diversas causas de problemas cardiovasculares que afetam a população mundial, na atualidade,o sedentarismo é apontado como um dos fatores de risco mais relevantes. Vários estudos têm se preocupado em analisar e esclarecer as principais adaptações provocadas pelos diferentes tipos de exercícios sobre o sistema cardiovascular. Seguindo esta linha o presente trabalho teve como objetivo analisar e comparar a resposta aguda do duplo produto (DP) e a pressão arterial diastólica (PAD) em exercício de esteira, bicicleta estacionária ecircuito na musculação. Foram avaliados nove indivíduos sendo seis mulheres e três homens, na esteira, a 60%da freqüência cardíaca de reserva (FCR), na bicicleta estacionária, a 60% FCR e circuito de musculação a 60%de 1 repetição máxima (1RM). Os resultados encontrados apresentaram diferença significativa do DP pré e pós-esforço nos três exercícios. Quando comparado, o DP obtido pós-esforço, nos três exercícios, não houve diferença significativa. A resposta hipotensiva da PAD pós-esforço foi mais acentuada após exercício de circuito em musculação, quando comparada com as outras modalidades exercício analisadas. De acordo com os procedimentos metodológicos adotados e os resultados obtidos, concluiu-se que não há diferença na taxa de exigência de trabalho do miocárdio entre os três exercicios analisados e que o circuito de musculação, a 60% 1RM, provoca uma maior resposta hipotensiva da PAD pós-esforço...

Among the various causes for cardiovascular problems affecting the world population nowadays, the most relevant risk factors is sedentary lifestyle. Many studies have been carried out to analyse and elucidate main adaptations on the cardiovascular system stimulated by different sorts of exercises.In this way, this study had aimed at comparing the acute response of double product (DP) and diastolic blood pressure (DBP) after treadmill(TRM), stationary bicycle (BIC) or muscle circuit training (MCT) exercises. Nine individuals (6 women and 3 men)exercised at 60% of heart rate reserve (HRR) on the TRM and BIC and at 60% of one repetition maximum (1RM)in MCT. The results showed that pre- and post-effort DP were significantly difference in all three exercises. However, DP did not differ among exercise types. The hypotensive DBP pos-effort response was greater in MCT. According to the results, it was concluded that there is no difference on the heart work demand rate estimated by DP among the three exercises and MCT at 60% 1RM provokes a greater hypotensive DBP post-effort response...