Effect of experimental pulmonary arterial hypertension on renal and bone parameters of rats submitted to resistance exercise training.

Pulmonary arterial hypertension (PAH) is characterized by right ventricular failure and diminished cardiac output, potentially leading to renal and bone impairments. In contrast, resistance exercise training (RT) offers cardiovascular and bone health benefits. This study aimed to assess the impacts of stable PAH induced by monocrotaline (MCT) and RT on renal morphometry, as well as bone morphometry and biomechanical properties in male Wistar rats. Four experimental groups, untrained control (UC, n=7), trained control (TC, n=7), untrained hypertensive (UH, n=7), trained hypertensive (TH, n=7), were defined. After the first MCT or saline injection (20 mg/kg), trained rats were submitted to a RT program (i.e., Ladder climbing), 5 times/week. Seven days later the rats received the second MCT or saline dose. After euthanasia, renal and femoral histomorphometry and femoral biomechanical properties were assessed. PAH reduced renal glomerular area and volume, which was prevented by the RT. While PAH did not harm the femoral morphometry, structural and mechanical properties, RT improved the femoral parameters (e.g., length, percentage of trabeculae and bone marrow, ultimte and yield loads). Experimental stable PAH promotes renal but not bone damages, whereas RT prevents renal deteriorations and improves the femoral morphological and biomechanical properties.

Effects of voluntary running on the skeletal muscle of rats with pulmonary artery hypertension.

The effects of voluntary running on the skeletal muscle of rats with pulmonary arterial hypertension (PAH) were tested in the present study. PAH was induced in rats by a single injection of monocrotaline (MCT, 60 mg/kg). Rats in the sedentary hypertension (HS) group had their tolerance to physical exertion reduced throughout the experiment, while those in the sedentary control (SC), exercise control (EC), exercise hypertension (EH) and median exercise (EM) groups maintained or increased. Despite that, the muscular citrate synthase activity was not different between groups. The survival time was higher in the EH (32 days) than in the SH (28 days) (p = 0.0032). SH and EH groups showed a lower percentage of muscle fiber and a higher percentage of extracellular matrix compared to control groups (p < 0.0001). However, the EM and EH groups presented higher percentage of muscle fiber and lower percentage of extracellular matrix than SH group (p < 0.0001). Regarding muscular gene expression, the SH and EM groups showed a lower expression of PGC1-α (p = 0.0024) and a higher expression of VEGF (p = 0.0033) compared to SC, while PGC1-α was elevated in the EH. No difference between groups was found for the carbonylated protein levels (p > 0.05), while the TNF-α/IL-10 ratio was augmented in the EH (p = 0.0277). In conclusion, voluntary running augments the proportion of fiber and affects the gene expression of inflammatory and mitochondrial biogenesis' markers in the skeletal muscle of rats with MCT-induced PAH, which benefits their survival and tolerance to physical effort.

Resistance Training Improves Sleep and Anti-Inflammatory Parameters in Sarcopenic Older Adults: A Randomized Controlled Trial.

Sleep and exercise have an important role in the development of several inflammation-related diseases, including sarcopenia. Objective: To investigate the effects of 12 weeks of resistance exercise training on sleep and inflammatory status in sarcopenic patients. Methods: A randomized controlled trial comparing resistance exercise training (RET) with a control (CTL) was conducted. Outcomes were obtained by physical tests, polysomnography, questionnaires, isokinetic/isometric dynamometry tests, and biochemical analysis. Results: Time to sleep onset (sleep latency) was reduced in the RET group compared to the CTL group (16.09 ± 15.21 vs. 29.98 ± 16.09 min; p = 0.04) after the intervention. The percentage of slow-wave sleep (N3 sleep) was increased in the RET group (0.70%, CI: 7.27−16.16 vs. −4.90%, CI: 7.06−16.70; p = 0.04) in an intention to treat analysis. Apnea/hour was reduced in the RET group (16.82 ± 14.11 vs. 7.37 ± 7.55; p = 0.001) and subjective sleep quality was improved compared to the CTL (−1.50; CI: 2.76−6.14 vs. 0.00; CI: 1.67−3.84 p = 0.02) in an intention-to-treat analysis. Levels of interleukin-10 (IL-10) (2.13 ± 0.80 vs. 2.51 ± 0.99; p < 0.03) and interleukin-1 receptor antagonist (IL-1ra) (0.99 ± 0.10 vs. 0.99 ± 0.10 ng/mL; p < 0.04; delta variation) were increased in the RET group. Conclusions: RET improves sleep parameters linked to muscle performance, possibly due to an increase in anti-inflammatory markers in older sarcopenic patients.

O Treinamento Físico Resistido Atenua as Disfunções Ventriculares Esquerdas em Modelo de Hipertensão Arterial Pulmonar / Resistance Exercise Training Mitigates Left Ventricular Dysfunctions in Pulmonary Artery Hypertension Model

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.

Abstract Background The right ventricular hypertrophy and dilation observed in pulmonary artery hypertension (PAH) damages the left ventricle (LV) dynamics by flattening the interventricular septum. Objective To 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. Methods Male 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. Results RT 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. Conclusion Low- to moderate-intensity RT benefits LV and cardiomyocyte contractile functions in rats during the development of MCT-induced PAH.

Resistance Exercise Training Mitigates Left Ventricular Dysfunctions in Pulmonary Artery Hypertension Model. / O Treinamento Físico Resistido Atenua as Disfunções Ventriculares Esquerdas em Modelo de Hipertensão Arterial Pulmonar.

BACKGROUND: The right ventricular hypertrophy and dilation observed in pulmonary artery hypertension (PAH) damages the left ventricle (LV) dynamics by flattening the interventricular septum. OBJECTIVE: To 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. METHODS: Male 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. RESULTS: RT 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. CONCLUSION: Low- to moderate-intensity RT benefits LV and cardiomyocyte contractile functions in rats during the development of MCT-induced PAH.

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.

Effects of moderate-continuous and high-intensity interval aerobic training on cardiac function of spontaneously hypertensive rats.

The aim of this study was to verify the effects of moderate-intensity continuous (MICT) and high-intensity interval (HIIT) aerobic training on cardiac morphology and function and the mechanical properties of single cardiomyocytes in spontaneously hypertensive rats (SHR) in the compensated phase of hypertension. Sixteen-week-old male SHR and normotensive Wistar (WIS) rats were allocated to six groups of six animals each: SHR CONT or WIS CONT (control); SHR MICT or WIS MICT (underwent MICT, 30 min/day, five days per week for eight weeks); and SHR HIIT or WIS HIIT (underwent HIIT, 30 min/day, five days per week for eight weeks). Total exercise time until fatigue and maximum running speed were determined using a maximal running test before and after the experimental period. Systolic (SAP), diastolic (DAP), and mean (MAP) blood pressures were measured using tail plethysmography before and after the experimental period. Echocardiographic evaluations were performed at the end of the experimental period. The rats were euthanized after in vivo assessments, and left ventricular myocytes were isolated to evaluate global intracellular Ca2+ transient ([Ca2+]i) and contractile function. Cellular measurements were performed at basal temperature (~37°C) at 3, 5, and 7 Hz. The results showed that both training programs increased total exercise time until fatigue and, consequently, maximum running speed. In hypertensive rats, MICT decreased SAP, DAP, MAP, interventricular septal thickness during systole and diastole, and the contraction amplitude at 5 Hz. HIIT increased heart weight and left ventricular wall thickness during systole and diastole and reduced SAP, MAP, and the time to peak [Ca2+]i at all pacing frequencies. In conclusion, both aerobic training protocols promoted beneficial adaptations to cardiac morphology, function, and mechanical properties of single cardiomyocytes in SHR.

Multicomponent exercise training is effective in improving health and behavior indicators in Brazilian elderly women: A non-randomized trial.

OBJECTIVE: The aim was to evaluate the effects of a supervised 12-week Multicomponent exercise training on elderly women health and behavior indicators. METHODS: Anthropometric characteristics and body composition, functional capacity, sedentary behavior, physical activity level and biochemical profile were evaluated in the control group (67.2 ± 5.2 years, n = 14) and in the experimental group (67.4 ± 6.1 years, n = 41). The experimental group were composed by 41 elderly women who performed 12 weeks of Multicomponent exercise training involving strength, aerobic, flexibility and balance exercises. The inclusion criteria for the study were women aged 60 years or more and presentation of a medical certificate authorizing the practice of physical exercise. RESULTS: Maintenance of anthropometric characteristics and body composition was observed in both groups (p > 0.05). There was an improvement in aerobic capacity, lower and upper limb strength in the experimental group (p < 0.01), while the control group showed a reduction in aerobic capacity, lower limb strength, agility and dynamic balance (p < 0.01), as shown in Fi.gure 3. There was a reduction in sedentary behavior and an increase in physical activity level in experimental group (p < 0.05), but not in control group. Experimental group showed an improvement in glucose levels and lipid profile (p < 0.01). CONCLUSION: Multicomponent exercise training was efficient to improve health and behavior indicators of the elderly women.

Is the Wistar Rat a more Suitable Normotensive Control for SHR to Test Blood Pressure and Cardiac Structure and Function?

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.

Swimming Training Does Not Affect the Recovery of Femoral Midshaft Structural and Mechanical Properties in Growing Diabetic Rats Treated with Insulin.

BACKGROUND: The effects of swimming training associated with insulin treatment on the cortical bone health in young rats with severe type 1 diabetes remain unclear, although there is evidence of such effects on the cancellous bone. This study examined the effects of swimming training combined with insulin therapy on the femoral midshaft structural and mechanical properties in growing rats with type 1 diabetes. METHODS: Male Wistar rats were divided into six groups (n = 10): control sedentary, control exercise, diabetic sedentary, diabetic exercise, diabetic sedentary plus insulin and diabetic exercise plus insulin. Diabetic rats received an injection (60 mg/kg body weight) of streptozotocin (STZ). Exercised animals underwent a swimming program for eight weeks. RESULTS: Diabetes induced by STZ decreased the bone mineral content (BMC) and density (BMD), and cortical thickness and maximum load and tenacity in the femoral midshaft. Insulin treatment partially counteracted the damages induced by diabetes on BMC, BMD and cortical thickness and tenacity. Swimming training did not affect the femoral structural and mechanical properties in diabetic rats. The combination of treatments did not potentiate the insulin effects. In conclusion, swimming training does not affect the benefits of insulin treatment on the femoral midshaft structural and mechanical properties in growing rats with severe type 1 diabetes.

Effects of β-hydroxy-β-methylbutyrate (hmb) and resistance training on body fat and lipid metabolism signaling pathways

ABSTRACT Excess body fat is a serious problem for increasing the risk of cardiovascular diseases such as obesity, compromising the health and quality of life of the population. In this sense, resistance training (RT) is type of physical exercise which improves body composition by increasing lean mass and reducing fat mass. RT in combination with nutrition (i.e. protein supplementation) is a key intervention to improve body fat metabolism and reducing obesity. Concerning protein supplementation, the β-hydroxy-β-methylbutyrate (HMB) is a metabolite of the branched-chain amino acid leucine that has demonstrated positive effects on body fat reduction. However, the effects of combining HMB supplementation with RT related to adipose tissue metabolic activity are controversial and warrant further investigation. This study analyzed the effects of HMB supplementation associated with RT on body fat concentration and lipid metabolism signaling pathways.

RESUMEN El exceso de grasa corporal es un problema grave que aumenta tu riesgo de enfermedades y problemas de salud, tales como enfermedad cardíaca, diabetes, presión arterial alta y ciertos tipos de cáncer. En este sentido, y dentro del ejercicio físico, el entrenamiento de resistencia (ER) es un tipo de entrenamiento con pesos que mejora la composición corporal aumentando la masa magra y perdiendo masa grasa. El ER asociado con la nutrición (ej. suplementación proteica) es una excelente intervención para mejorar el metabolismo de los lípidos al reducir la grasa corporal. En relación con la suplementación proteica el β-hidroxi-β-metilbutirato (HMB) es un metabolito del aminoácido de cadena ramificada esencial leucina que ha demostrado efectos positivos en la reducción de grasa corporal. Sin embargo, los efectos de la suplementación con HMB asociados con TR relacionados con la actividad metabólica del tejido adiposo son controvertidos y necesita la realización de investigaciones adicionales. Este estudio analizó los efectos de la suplementación con HMB asociados con TR en la concentración de grasa corporal y en las vías de señalización que participan en la regulación del metabolismo de los lípidos.

Effects of conventional and sugar-free energy drinks intake in runners: a double-blind, randomized, placebo-controlled crossover clinical trial.

BACKGROUND: This study evaluated the effects of two types of energy drinks (ED) intake in trained runners. METHODS: A double-blind randomized placebo-controlled clinical trial was conducted over 6 weeks. Participants and beverages were allocated by randomization. Twelve men 23±2.6 years, 177±3.4 cm, 74.4±5.5 kg, VO2max=59.8±5.5 mL·(kg.min)-1] ingested either a conventional energy drink containing carbohydrates and 3 mg·kg-1 of caffeine, (ED1), a sugar-free energy drink 3 mg·kg-1 of caffeine (ED2), or a carbohydrate-containing, decaffeinated placebo (PL) 40-minutes before an exercise protocol. Sprint time, rate of perceived exertion (RPE), respiratory exchange ratio (RER), blood pressure (BP), heart rate and plasmatic glucose were evaluated during the experimental protocol. RESULTS: Performance improved after consuming both ED (P<0.004 ED1 and P=0.001 ED2) with lower RPE (P<0.05 for ED1 and P<0.05 for ED2) compared to PL. Consumption of ED2 decreased RER values at 0-5 minutes and 40-45 minutes (P<0.001), and ED1 increased systolic BP (P<0.05) during exercise compared to PL. There were no differences in the evaluated parameters between EDs (P>0.05). CONCLUSIONS: Consumption of conventional or sugar free ED represents a valid ergogenic strategy to improve acute performance with reduction of RPE. However, intake of a conventional ED warrants caution, mainly because the effects on systolic BP.

Aerobic Exercise Increases the Damage to the Femoral Properties of Growing Rats with Protein-Based Malnutrition

Abstract The present study investigated the effects of aerobic physical training on the femoral morphological, densitometric and biomechanical properties in growing male rats subjected to protein-based malnutrition. Four-week-old male Wistar rats were randomized into groups of 10 animals: Control Sedentary (CS), Control Trained (CT), Malnourished Sedentary (MS) and Malnourished Trained (MT). Control and malnourished animals received diets with 12% protein and 6% protein, respectively. The trained groups were submitted to a treadmill running program for 8 weeks. Total proteins and albumin were analyzed in the animals' blood plasma. Histological, densitometric and biomechanical analyzes were performed on the animals' femur. Body mass gain, physical performance, biochemical markers and the femoral morphological, densitometric and biomechanical properties were determined. Exercise tolerance increased in trained groups. Malnourished animals exhibited lower serum protein and albumin levels than controls. Porosity and trabecular bone density were not different between groups. The femoral maximum load, maximum load until fracture, resilience, stiffness, tenacity and densitometric properties were reduced by malnutrition. Physical training associated with malnutrition exacerbated the impairment in the femoral maximum load, maximum load until fracture, bone mineral content and density. Aerobic physical training worsens the damages induced by protein-based malnutrition in the femoral biomechanical and densitometric properties of growing male rats.

Effects of exercise training and stem cell therapy on the left ventricle of infarcted rats.

INTRODUCTION AND OBJECTIVES: Stem cell therapy and aerobic exercise are non-pharmacological therapies following myocardial infarction. The aim of this study was to test whether aerobic exercise training enhances the benefits of mesenchymal stem cell (MSC) therapy on remodeling of the extracellular matrix and fetal gene expression in the left ventricle of infarcted rats. METHODS: Myocardial infarction was surgically induced in six-week old male Wistar rats. Animals were divided into four groups: sedentary control (SC) and sedentary and stem cell treated (SCMSC); exercised (EX) and exercised and stem cell treated (EXMSC). Bone marrow-derived MSCs were immediately transplanted via the tail vein (concentration: 1×106 cells). Exercise training (five days/week, 60 min/day; 60% of maximal running speed) started 24 hours after myocardial infarction and lasted for 12 weeks. RESULTS: Exercise capacity was higher in exercised than in sedentary groups. Animals in the SCMSC, EX and EXMSC groups exhibited better cardiac function than those in SC. Collagen content was lower in the SCMSC, EX and EXMSC groups than in SC and skeletal α-actin expression was lower in EX and EXMSC than in SC. The α/ß-MHC ratio was higher in EX and EXMSC than in SC. The combination of therapies further reduced collagen content in the remote region of the infarct (∼24%) and skeletal α-actin expression (∼30%). CONCLUSION: Aerobic exercise training appears to enhance the beneficial effects of stem cell therapy on remodeling of the extracellular matrix and fetal gene expression in the left ventricle of rats with moderate infarction.

Voluntary running counteracts right ventricular adverse remodeling and myocyte contraction impairment in pulmonary arterial hypertension model.

AIM: Analyze the effects of voluntary running during the development of pulmonary arterial hypertension (PAH) induced by monocrotaline (MCT) on the right ventricle (RV) structure, RV myocyte contractility and intracellular Ca2+ transient in rats with MCT-induced PAH. MAIN METHODS: Male Wistar rats were housed sedentary or with free access to a running wheel after MCT or saline injection for until HF or median end-point day of HF in sedentary animals (24 days). Echocardiographic examination and exercise tolerance test were carried out at specific time points of the experimental period. After euthanasia, the heart was dissected, weighed and processed for either histological or single myocyte contractility and intracellular Ca2+ transient analyzes. KEY FINDINGS: Voluntary running delayed the onset of HF (29 days) and the increase in pulmonary artery resistance, and improved exercise tolerance. In the median end-point day of HF, exercise retarded RV adverse remodeling (i.e. increase in extracellular matrix and collagen content). At this stage, exercise also delayed impairments in cell contractile function (i.e. amplitude and times to peak and to half relaxation) and intracellular calcium cycling (i.e. amplitude and times to peak and to half decay) in RV single myocytes. SIGNIFICANCE: Along with HF onset delay and physical effort tolerance enhancement, voluntary running during the development of PAH postpones pulmonary artery resistance increases, RV adverse remodeling and myocyte contractility and intracellular calcium cycling deterioration in rats. Therefore, self-paced intermittent exercise of high intensity may contribute positively to the health and survival of individuals with PAH.

Swimming training potentiates the recovery of femoral neck strength in young diabetic rats under insulin therapy.

OBJECTIVE: To test whether swimming training benefits femoral neck strength in young diabetic rats under insulin therapy. METHODS: A total of 60 male Wistar rats (age: 40 days) were divided equally into the following six groups: control sedentary, control exercise, diabetic sedentary, diabetic exercise, diabetic sedentary plus insulin and diabetic exercise plus insulin. Diabetes was induced with a unique intraperitoneal injection (60 mg/kg body weight) of streptozotocin. Seven days after the injection and after 12 hours of fasting, the animals with blood glucose levels ≥300 mg/dL were considered diabetic. Seven days after the induction of diabetes, the animals in the exercise groups were subjected to progressive swimming training (final week: 90 min/day; 5 days/week; 5% load) for eight weeks. The animals in the insulin groups received a daily dose of insulin (2-4 U/day) for the same period. RESULTS: Severe streptozotocin-induced diabetes reduced the structural properties of the femoral neck (trabecular bone volume, trabecular thickness and collagen fiber content). The femoral neck mechanical properties (maximum load and tenacity) were also impaired in the diabetic rats. Insulin therapy partially reversed the damage induced by diabetes on the structural properties of the bone and mitigated the reductions in the mechanical properties of the bone. The combination of therapies further increased the femoral neck trabecular bone volume (∼30%), trabecular thickness (∼24%), collagen type I (∼19%) and type III (∼13%) fiber contents, maximum load (∼25%) and tenacity (∼14%). CONCLUSIONS: Eight weeks of swimming training potentiates the recovery of femoral neck strength in young rats with severe streptozotocin-induced diabetes under insulin therapy.

Thermoregulation in Hypertensive Rats during Exercise: Effects of Physical Training / Termorregulação durante o Exercício em Ratos Hipertensos: Efeitos do Treinamento Físico

Abstract Background: Spontaneously hypertensive rats (SHR) show deficit in thermal balance during physical exercise. Objective: To assess the effects of low-intensity physical exercise training on thermal balance of hypertensive rats undergoing an acute exercise protocol. Methods: 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%. Results: 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. Conclusion: Low-intensity physical training did not affect thermal balance in SHR subjected to acute exercise.

Resumo Fundamento: Ratos espontaneamente hipertensos (SHR) apresentam déficits no balanço térmico durante o exercício físico. Objetivo: Avaliar os efeitos do treinamento físico de baixa intensidade sobre o balanço térmico de ratos hipertensos submetidos a um protocolo de exercício físico agudo. Métodos: Ratos machos Wistar e SHR, com 16 semanas de idade, foram divididos em quatro grupos experimentais: Wistar controle (WIS-C), Wistar treinado (WIS-T), SHR controle (SHR-C) e SHR treinado (SHR-T). O treinamento físico em esteira rolante foi realizado durante 12 semanas. A pressão arterial, a frequência cardíaca de repouso e o tempo de exercício foram medidos previamente e após o programa de treinamento físico. Após o programa de treinamento físico, um sensor de temperatura foi implantado na região intraperitoneal e os ratos foram submetidos a um protocolo de exercício físico agudo com registros contínuos da temperatura corporal interna, temperatura da pele da cauda e do consumo de oxigênio até a fadiga. A eficiência mecânica (EM), o trabalho, o limiar e a sensibilidade para dissipação de calor foram calculados. Para as análises estatísticas o nível de significância adotado foi de 5%. Resultados: O treinamento físico e a hipertensão arterial não alteraram o balanço térmico durante o exercício físico. O grupo WIS-T quando comparado ao WIS-C, apresentou maior produção de calor, que foi contrabalanceado por uma maior dissipação de calor. Os animais hipertensos apresentaram menor EM em comparação aos animais normotensos, e o treinamento físico não foi capaz de reverter esta alteração. Conclusão: O treinamento físico de baixa intensidade não provocou alterações no balanço térmico de ratos hipertensos submetidos a um protocolo de exercício físico agudo.

Thermoregulation in Hypertensive Rats during Exercise: Effects of Physical Training.

BACKGROUND: Spontaneously hypertensive rats (SHR) show deficit in thermal balance during physical exercise. OBJECTIVE: To assess the effects of low-intensity physical exercise training on thermal balance of hypertensive rats undergoing an acute exercise protocol. METHODS: 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%. RESULTS: 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. CONCLUSION: Low-intensity physical training did not affect thermal balance in SHR subjected to acute exercise.

Estresse térmico ambiental e termorregulação em jogadores de futebol: uma revisão sistemática / Environmental thermal stress and thermoregulation in soccer players: a systematic review / Estrés térmico ambiental y termorregulación en jugadores de fútbol: una revisión sistemática

Resumo 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.

Abstract 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.

Resumen 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.

Swimming training potentiates the recovery of femoral neck strength in young diabetic rats under insulin therapy

OBJECTIVE: To test whether swimming training benefits femoral neck strength in young diabetic rats under insulin therapy. METHODS: A total of 60 male Wistar rats (age: 40 days) were divided equally into the following six groups: control sedentary, control exercise, diabetic sedentary, diabetic exercise, diabetic sedentary plus insulin and diabetic exercise plus insulin. Diabetes was induced with a unique intraperitoneal injection (60 mg/kg body weight) of streptozotocin. Seven days after the injection and after 12 hours of fasting, the animals with blood glucose levels ≥300 mg/dL were considered diabetic. Seven days after the induction of diabetes, the animals in the exercise groups were subjected to progressive swimming training (final week: 90 min/day; 5 days/week; 5% load) for eight weeks. The animals in the insulin groups received a daily dose of insulin (2-4 U/day) for the same period. RESULTS: Severe streptozotocin-induced diabetes reduced the structural properties of the femoral neck (trabecular bone volume, trabecular thickness and collagen fiber content). The femoral neck mechanical properties (maximum load and tenacity) were also impaired in the diabetic rats. Insulin therapy partially reversed the damage induced by diabetes on the structural properties of the bone and mitigated the reductions in the mechanical properties of the bone. The combination of therapies further increased the femoral neck trabecular bone volume (∼30%), trabecular thickness (∼24%), collagen type I (∼19%) and type III (∼13%) fiber contents, maximum load (∼25%) and tenacity (∼14%). CONCLUSIONS: Eight weeks of swimming training potentiates the recovery of femoral neck strength in young rats with severe streptozotocin-induced diabetes under insulin therapy.

Efeitos agudos da ingestão de bebidas energéticas sobre os paramêtros hidro-eletrolíticos durante exercício em esteira / Acute effects of energy drink intake on hydro-electrolytic parameters during the exercise on a treadmill

RESUMO O objetivo do estudo foi verificar se bebidas enegéticas com diferentes composições nutricionais afetam o balanço hidro-eletrolítico de corredores de resistência. Doze homens participaram desse estudo duplo cego e crossover randomizado, ingerindo 3mg.kg-1 de cafeína de bebida energética convencional e sugar free, e um placebo carboidratado e não cafeinado, 40 minutos antes de sessão de exercício em ambiente termoneutro. Em cada situação experimental, os avaliados realizaram exercício de corrida em esteira com duração de 60 minutos e intensidade constante entre 65 e 75% do VO2max, seguidos por um sprint correspondendo a 100% do VO2max até a exaustão. Foram avaliados o peso corporal (PC), desidratação absoluta e relativa, densidade da urina, taxa de sudorese e níveis de Na+, K+ e hematócrito. Durante o exercício os avaliados receberam somente água a cada 15 minutos. Foi verificada alteração nos níveis de densidade da urina antes e depois do exercício para todos os tratamentos (p<0,05). Não houve diferença significativa entre as bebidas nos níveis de Na+, K+ e hematócrito (p>0,05) mantendo-se dentro dos níveis de normalidade. Conclui-se que diferentes tipos de bebidas energéticas não afetam o balanço hidro-eletrolítico de corredores de resistência ao longo do exercício.

ABSTRACT This work compares the effects promoted by energy drinks with diferente nutricional compositions on the hydro-electrolytic balance of resistance runners. Twelve men participated in this double blinded, randomized crossover study, ingesting 3mg*Kg-1 of a conventional energy drink with caffeine or sugar-free, and a placebo 40-minutes before tests on thermoneutral environment. The duration of the session was 60 minutes with constant intensity between 65 and 75% of VO2max, followed by a sprint corresponding to 100% of VO2max until exhaustion. There were evaluated body weight (BW), absolute and relative dehydration, urine density, sweating rate and Na+, K+ and hematocrit levels. During the exercise, the participants drunk only water every 15 minutes. Changes in urine density levels were observed before and after exercise for all procedures (p <0.05). There was no significant difference on the levels of Na+, K+ and hematocrit between the drinks (p> 0.05), remaining within normal levels. It is concluded that different types of energy drinks do not affect the hydro-electrolytic balance of resistance runners during the exercise.