Spontaneously hypertensive rats (SHR) show deficit in thermal balance during physical exercise.
To assess the effects of low-intensity physical exercise training on thermal balance of hypertensive ...rats undergoing an acute exercise protocol.
Sixteen-week-old male Wistar rats and SHR were allocated into four groups: control Wistar rats (C-WIS), trained Wistar (T-WIS), control SHR (C-SHR) and trained SHR (T-SHR). Treadmill exercise training was performed for 12 weeks. Blood pressure, resting heart rate and total exercise time was measured before and after the physical exercise program. After the exercise program, a temperature sensor was implanted in the abdominal cavity, and the animals subjected to an acute exercise protocol, during which internal body temperature, tail skin temperature and oxygen consumption until fatigue were continuously recorded. Mechanical efficiency (ME), work, heat dissipation threshold and sensitivity were calculated. Statistical significance was set at 5%.
Physical training and hypertension had no effect on thermal balance during physical exercise. Compared with C-WIS, the T-WIS group showed higher heat production, which was counterbalanced by higher heat dissipation. Hypertensive rats showed lower ME than normotensive rats, which was not reversed by the physical training.
Low-intensity physical training did not affect thermal balance in SHR subjected to acute exercise.
Regulation of intracellular calcium (Ca2+) in cardiomyocytes is altered by hypertension; and aerobic exercise brings benefits to hypertensive individuals.
To verify the effects of aerobic exercise ...training on contractility and intracellular calcium (Ca2+) transients of cardiomyocytes and on the expression of microRNA 214 (miR-214) in the left ventricle of spontaneously hypertensive rats (SHR).
SHR and normotensive Wistar rats of 16 weeks were divided into 4 groups -sedentary hypertensive (SH); trained hypertensive (TH); sedentary normotensive (SN); and trained normotensive (TN). Animals of the TH and TN groups were subjected to treadmill running program, 5 days/week, 1 hour/day at 60-70% of maximum running velocity for 8 weeks. We adopted a p ≤ 0.05 as significance level for all comparisons.
Exercise training reduced systolic arterial pressure in hypertensive rats. In normotensive rats, exercise training reduced the time to 50% cell relaxation and the time to peak contraction and increased the time to 50% decay of the intracellular Ca2+ transients. In SHR, exercise increased the amplitude and reduced the time to 50% decay of Ca2+ transients. Exercise training increased the expression of miR-214 in hypertensive rats only.
The aerobic training applied in this study increased the availability of intracellular Ca2+ and accelerated the sequestration of these ions in left ventricular myocytes of hypertensive rats, despite increased expression of miR-214 and maintenance of cell contractility.
The resistance exercise (RE) is recommended for whole population. However, some variables can promote different physiological responses during the performance, with a direct impact on cardiovascular ...responses. Thus, the objective was to verify the cardiovascular responses to three RE protocols between beginners (BG) and advanced (AD) practitioners. Methodsː thirty male resistance training practitioners divided into two groups: BG and AD. The volunteers were studied during three protocols of bench press exercise: 1:15 repetitions at 65% of 1RM; 2:8 repetitions at 80% of 1RM; 3:4 repetitions at 90% of 1RM. The systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR) and rate pressure product (RPP) were measured before and after the protocols. Resultsː there was a significant increase in HR, SBP, DBP and RPP from rest to post exercise. The AD subjects showed lower values of HR, SBP and RPP in the protocol 1 compared to 2 and 3; and presented higher values of HR and RPP in protocol 3 compared to 2. Discussionː the three protocols increased the cardiovascular overload compared to rest values, and no differences were observed between groups. In AD, the intensity seems to produce more cardiovascular overload than the volume or the total training load.
El ejercicio de resistencia (RE) se recomienda para toda la población. Sin embargo, algunas variables pueden promover diferentes respuestas fisiológicas durante el desempeño, con un impacto directo en las respuestas cardiovasculares. Por lo tanto, el objetivo era verificar las respuestas cardiovasculares a tres protocolos RE entre los principiantes (BG) y los practicantes
avanzados (AD). Métodos: treinta practicantes de entrenamiento de resistencia masculinos divididos en dos grupos: BG y AD.
Los voluntarios fueron estudiados durante tres protocolos de ejercicio de press de banca: 1:15 repeticiones al 65% de una repetición máxima (1RM); 2: 8 repeticiones al 80% de 1RM; 3: 4 repeticiones al 90% de 1RM. La presión arterial sistólica (PAS), la presión arterial diastólica (PAD), la frecuencia cardíaca (FC) y el producto de presión arterial (RPP) se midieron antes y después de los protocolos. Resultadosː hubo un aumento significativo en HR, SBP, DBP y RPP desde el reposo hasta el ejercicio. Los participantes de AD mostraron valores más
bajos de HR, SBP y RPP en el protocolo 1 en comparación con 2 y 3; y presentaron valores más altos de HR y RPP en el protocolo 3 en comparación con 2. Discusiónː los tres protocolos aumentaron la sobrecarga cardiovascular en comparación con los valores de reposo, y no se observaron diferencias entre los grupos. En AD, la intensidad parece producir más sobrecarga cardiovascular
que el volumen o la carga de entrenamiento total.
Back pain is common in adolescents as a result of their typical daily activities. There is a critical need for developing instruments that can assess the adolescents’ knowledge of proper posture, ...because adequate postural habits are essential for preventing back pain and facilitating physical well-being. Unfortunately, there is insufficient understanding about appropriate back health in the general public, even though this knowledge is decisive in the development of physical skills and attainment of health literacy. Furthermore, relevant substantive literature is scarce. Therefore, the proposed systematic review aims to identify instruments that are used for assessing knowledge of back health in adolescents. Relevant search terms and descriptors will be combined, and searches will be carried out in a uniform sequence within the PubMed, Embase, CINAHL, and Cochrane Library databases. Eligible articles must present data on the assessment of the adolescents’ knowledge of back health and describe the applied instrumentation. Articles will be selected by two reviewers independently; all disagreements will be resolved by a third reviewer. Mendeley and the Rayyan software will be used for the systematic review, and the checklist proposed by Brink and Louw will be used to verify the methodological quality of the included studies. Our findings may confirm the relevance of constructing and validating back health instruments for use in Brazil and other countries.
Abstract Background: There are divergences in the literature regarding the experimental model (Wistar-WIS or Wistar Kyoto-WKY) to be used as a Spontaneously Hypertensive Rat (SHR) control. The ...characterization of these models in terms of cardiovascular parameters provides researchers with important tools at the time of selection and application in scientific research. Objective: The aim of this study was to evaluate the use of WIS and WKY as a Spontaneously Hypertensive Rat (SHR) control by assessing the long-term behavior of blood pressure and cardiac structure and function in these strains. Methods: To this end, WIS, WKY, and SHR underwent longitudinal experiments. Blood pressure and body mass were measured every two weeks from the 8th to the 72nd. Echocardiographic analysis was performed in all groups with 16, 48, and 72 weeks of life. After having applied the normality test, the Two-Way ANOVA of repeated measures followed by the Tukey post hoc test was used. A significance level of 5% was established. Results: The WIS group showed higher body mass (p<0.05), while the WKY and SHR presented higher body mass variation over time (p<0.05). SHR exhibited increased values of systolic, diastolic, and mean blood pressure when compared to WKY and WIS, whereas the WKY generally showed higher values than WIS (p<0.05). Regarding the cardiac function, SHR showed reduced values, while the WKY presented an early decrease when compared to WIS with aging (p<0.05). Conclusion: WIS is a more suitable normotensive control for SHR than WKY in experiments to test blood pressure and cardiac structure and function.
Resumo Fundamento A hipertrofia e a dilatação do ventrículo direito observadas na hipertensão arterial pulmonar (HAP) prejudicam a dinâmica do ventrículo esquerdo (VE) achatando o septo ...interventricular. Objetivo Investigar se o treinamento físico resistido (TFR) de intensidade baixa a moderada é benéfico para funções contráteis do VE e de cardiomiócitos em ratos durante o desenvolvimento de HAP induzida por monocrotalina (MCT). Métodos Foram usados ratos Wistar machos (Peso corporal: ~ 200 g). Para avaliar o tempo até o possível surgimento de insuficiência cardíaca (ou seja, ponto de desfecho), os ratos foram divididos em dois grupos, hipertensão com sedentarismo até a insuficiência (HSI, n=6) e hipertensão com treinamento até a insuficiência (HTI, n=6). Para testar os efeitos do TFR, os ratos foram divididos entre grupos de controle sedentários (CS, n=7), hipertensão com sedentarismo (HS, n=7) e hipertensão com treinamento (HT, n=7). A HAP foi induzida por duas injeções de MCT (20 mg/kg, com um intervalo de 7 dias). Os grupos com treinamento foram submetidos a um protocolo de TFR (subir escadas; 55-65% da máxima carga carregada), 5 dias por semana. A significância estatística foi definida em p <0,05. Resultados O TFR prolongou o ponto de desfecho (~25%), melhorou a tolerância ao esforço físico (~55%) e atenuou as disfunções de contratilidade de VE e de cardiomiócitos promovidas pela MCT preservando a fração de ejeção e o encurtamento fracional, a amplitude do encurtamento, e as velocidades de contração e relaxamento nos cardiomiócitos. O TFR também preveniu os aumentos de fibrose e colágeno tipo I no ventrículo esquerdo causados pela MCT, além de manter as dimensões de miócitos e colágeno tipo III reduzidas por MCT. Conclusão O TFR de intensidade baixa a moderada é benéfico para funções contráteis de VE e cardiomiócitos em ratos durante o desenvolvimento de HAP induzida por MCT.
ABSTRACTPulmonary artery hypertension (PAH) imposes right heart and lung detrimental remodeling which impairs cardiac contractility, physical effort tolerance and survival. The effects of an early ...moderate-intensity continuous aerobic exercise training on the right ventricle and lung structure, and on contractility and the calcium (Ca) transient in isolated myocytes from rats with severe PAH induced by monocrotaline were analyzed. Rats were divided into control sedentary (CS); control exercise (CE); monocrotaline sedentary (MS); and monocrotaline exercise (ME) groups. Animals from CE and ME groups underwent a moderate-intensity aerobic exercise on a treadmill (60 min/day; 60% intensity) for 32 days, after a monocrotaline (60 mg/kg body weight i.p.) or saline injection. The pulmonary artery resistance was higher in MS than in CS (1.36-fold) and was reduced by 39.39 % in ME compared with MS. Compared with MS, the ME group presented reduced alveolus (17 %) and blood vessel (46 %) wall, fibrosis (25.37 %) and type I collagen content (55.78 %); and increased alveolus (52.96 %) and blood vessel (146.97 %) lumen. In the right ventricle, ME group exhibited diminished hypertrophy index (25.53 %) and type I collagen content (40.42 %) and improved myocyte contraction i.e. reduced times to peak (29.27 %) and to 50% relax (13.79 %) and intracellular Ca transient i.e. decreased times to peak (16.06 %) and to 50% decay (7.41 %) compared with MS. Thus, early moderate-intensity continuous aerobic exercise prevents detrimental remodeling in the right heart and lung, increases in the pulmonary artery resistance and dysfunction in single myocyte contraction and Ca cycling in this model.
BACKGROUNDThe right ventricular hypertrophy and dilation observed in pulmonary artery hypertension (PAH) damages the left ventricle (LV) dynamics by flattening the interventricular septum. ...OBJECTIVETo investigate whether low- to moderate-intensity resistance exercise training (RT) is beneficial to LV and cardiomyocyte contractile functions in rats during the development of monocrotaline (MCT)-induced PAH. METHODSMale Wistar rats (Body weight: ~ 200 g) were used. To assess the time to potential heart failure onset (i.e., end point), rats were divided into sedentary hypertension until failure (SHF, n=6) and exercise hypertension until failure (EHF, n=6) groups. To test RT effects, rats were divided into sedentary control (SC, n = 7), sedentary hypertension (SH, n=7), and exercise hypertension (EH, n=7) groups. PAH was induced by two MCT injections (20 mg/kg, with 7 days interval). Exercise groups were submitted to an RT protocol (Ladder climbing; 55-65% of carrying maximal load), 5 times/week. Statistical significance was assumed at P < 0.05. RESULTSRT prolonged the end point (~25 %), enhanced the physical effort tolerance (~ 55%), and mitigated the LV and cardiomyocyte contractility dysfunctions promoted by MCT by preserving the ejection fraction and fractional shortening, the amplitude of shortening, and the velocities of contraction and relaxation in cardiomyocytes. RT also prevented increases in left ventricle fibrosis and type I collagen caused by MCT, and maintained the type III collagen and myocyte dimensions reduced by MCT. CONCLUSIONLow- to moderate-intensity RT benefits LV and cardiomyocyte contractile functions in rats during the development of MCT-induced PAH.
A obesidade e o excesso de peso afetam uma parcela considerável da população mundial, assim, vários estudos têm sido realizados com o intuito de verificar qual o melhor tipo de atividade física que ...auxilie no controle da composição corporal. O objetivo deste estudo foi comparar os efeitos do treinamento aeróbico de baixa e alta intensidade na perda de gordura corporal. Para tanto, realizou-se revisão sistemática de artigos publicados entre 2006 e 2016. Os descritores utilizados foram: low-intensity aerobic training, high-intensity aerobic training e body composition, nos idiomas inglês e português, nas bases de dados PubMed e SciELO. Foram encontrados 131 artigos, sendo que 13 foram selecionados para análise. O treinamento aeróbio de alta intensidade melhorou a composição corporal na maioria dos estudos analisados, enquanto o treinamento aeróbio de baixa intensidade alterou a composição corporal em apenas alguns estudos. Concluiu-se pelos estudos analisados que o treinamento aeróbio de alta intensidade é mais eficaz para a perda de gordura corporal quando comparado ao de baixa intensidade. No entanto, deve-se realizar uma avaliação física de qualidade antes da escolha da intensidade do treinamento, respeitando-se com isso os princípios da individualidade biológica e especificidade, visando garantir a segurança e a eficiência da intervenção. ABSTRACT Comparison of the effects of low and high intensity aerobic training on weight loss: a systematic reviewObesity and overweight affect a considerable portion of the world population. Several studies have been carried out to verify the best type of physical activity that assists in the control of body composition control. The objective of this study was to evaluate the effects of low and high intensity aerobic training on body fat loss. For that, a systematic review of articles was carried out between 2006 and 2016. The descriptors applied were: low intensity aerobic training, high intensity aerobic training and body composition, in the English and Portuguese languages, in PubMed and SciELO databases. We found 131 articles, 13 of which were selected for analysis. High-intensity aerobic training improved body composition in most of the studies analyzed, while low-intensity aerobic training changed body composition in a few studies. It was concluded from studies analyzed that high intensity aerobic training is more effective for a loss of body fat when compared to low intensity. However, it must be done a quality physical assessment before choosing the intensity of the training, respect the principles of biological individuality and specificity, in order to guarantee a safety and intervention.
O objetivo do estudo foi fazer uma revisão sistemática acerca dos efeitos do estresse térmico ambiental sobre a termorregulação em jogadores de futebol. Foram avaliados estudos em bases de dados ...pertencentes ao portal Periódicos Capes. Foi empregado o método Prisma para o desenvolvimento da revisão. Jogadores de futebol apresentam grande aumento da temperatura corporal associada à redução de desempenho físico durante o jogo em ambiente quente. Em relação às estratégias para amenizar esse prejuízo (ex. resfriamento, hidratação, aclimatação e aquecimento), o pequeno número de trabalhos encontrado (n = 18) apresenta resultados controversos, portanto são necessários mais estudos.
The objective of the study was to systematically review the effects of the environmental thermal stress on thermoregulation in soccer players. We analyzed studies from databases belonging to the Periódicos Capes portal. The PRISMA method was used to perform the review. Soccer players exhibit high increase in body temperature associated with reduction in physical performance during game in warm environment. Concerning strategies to mitigate such impairment (e.g. cooling, hydration, acclimatization, warm up and heating), the small number of studies analyzed (n = 18) showed controversial results, which warrants more studies.
El objetivo del estudio fue llevar a cabo una revisión sistemática sobre los efectos del estrés térmico ambiental en la termorregulación de jugadores de fútbol. Se evaluaron estudios en bases de datos pertenecientes al portal Periódicos Capes. Se empleó el método PRISMA para el desarrollo de la revisión. Los jugadores de fútbol presentan un gran aumento de la temperatura corporal asociada con la reducción de rendimiento físico durante el juego en un entorno caluroso. En cuanto a las estrategias para disminuir esta alteración (p. ej., enfriamiento, hidratación, aclimatación y calentamiento), el pequeño número de trabajos encontrados (n = 18) presentan resultados controvertidos, por lo que es necesaria la realización de más estudios.
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