Interval or continuous aerobic exercise performed 3 days a week increases endothelium-dependent relaxation in female rats fed with fructose

Abstract Aim: We investigated the effects of continuous or interval aerobic exercise training on vascular reactivity of female rats fed with fructose. Methods: Female Wistar rats (8-wk old) were divided into: sedentary (SD), continuous training (CTR), and interval training (ITR). Moderate intensity training protocols consisted of running 3 days/week for 7 weeks. CTR ran 40 min at 30%-40% of the maximal speed (MS) and TRI consisted of 7 sets of 1 min at 70% of MS followed by 3 min at 35% of MS. Animals were fed with standard chow and fructose (10%) in drinking water. Concentration-response curves to acetylcholine and phenylephrine, and oxidative stress biomarkers, were determined in the aorta. Body weight gain, visceral fat, and plasma triglycerides and glucose were also evaluated. Results: Endothelium-dependent relaxation was significantly increased by both exercise regimens (CTR: Emax = 85 ± 6% and ITR: Emax = 84 ± 1%) compared to sedentary rats (SD: Emax = 62 ± 5%). The contractile maximal response was not different but phenylephrine potency was increased in CTR (pEC50: 8.41 ± 0.19) and reduced in ITR (pEC50: 7.06 ± 0.11) compared to SD (pEC50: 7.77 ± 0.08). In addition, the generation of superoxide was lower in trained groups as compared with sedentary (about −28% in CTR and −22% in ITR). TBARS and nitrate/nitrite levels were not modified. Compared to the SD group, ITR gained 39% less body weight and CTR has 29% less visceral fat. Glucose and triglycerides were not modified. Conclusion: CTR and ITR, carried out 3 days/week, were efficient to improve endothelium-dependent relaxation and reduce superoxide generation in the aorta from female rats fed with fructose.

Moderate-intensity exercise training improves long-term memory in fructose-fed rats

Abstract Aim: Animal disease model studies are widely used to show the effectiveness of physical exercise to improve cognitive function. Thus far, few studies are investigating the effects of exercise training on memory performance in fructose feed animals. Method: The present study investigated the effects of physical exercise protocol carried out with three weekly sessions, on the short and long-term memory performance of animals fed with fructose. Male Wistar rats were divided into sedentary (SD); sedentary+fructose (SDF); trained (TR); trained+fructose (TRF). Treadmill running sessions consisted of a five-minute warm-up at 20% maximum speed (MS) followed by 40 minutes at 40% MS and a 5-minute cool-down at 20% MS. Sessions were carried out three days a week (Monday, Wednesday, and Friday) for six weeks. Object Recognition Test was used to evaluate short and long-term memory. Results: The access to fructose altered food intake and drinking volume, as fructose-fed animals had lower food intake (SDF: -27% and TRF: -24%) and higher drinking volume (SDF: +49% and TRF: +45%) than an animal which drank water. Trained groups had lower epididymal fat pad compared to their sedentary counterparts (TR: -30% and TRF: -11%). In addition, TR and TRF had an improvement in glucose tolerance. Regarding memory performance, neither fructose intake nor exercise training influenced short-term memory. On the other hand, long-term memory was enhanced by exercise training. An improvement of about 39% was observed for TR and the largest effect was seen for TRF, which improved long-term memory in 76%. Conclusion: In conclusion, moderate-intensity exercise training, carried out three days a week, for six weeks was effective to improve long-term memory in fructose-fed rats. This result was related neither to the visceral fat amount nor to the glucose metabolism. Further studies should considerer the investigation regarding cerebral areas, associated with memory that might be adapted facing physical exercise.

Twice-weekly exercise training reduces oxidative stress and proinflammatory cytokine levels in elder women

Aim: Reactive oxygen species and high concentrations of proinflammatory cytokines are related to diseases that are often triggered during the aging process. This study aimed to investigate the effect of moderate-intensity physical exercise, twice a week, on oxidative stress and inflammation biomarkers. Methods: Participants were older women aged 60-70 years, engaged in a moderate-intensity exercise program carried out in 60 minutes sessions, twice a week, for 24 weeks. Exercise sessions consisted of step, resistance and stretch exercises. Thiobarbituric acid reactive substances (TBARS), serum iron and cytokines IL-6, IL-1β and IL-1ra were determined using specific kits. Physical fitness was assessed using tests provided by AAPHERD. A paired t test was performed. Results: Moderate-intensity exercise program provided a reduction in lipid peroxidation (27%) and in the serum release of prooxidant iron ions (40%). Cytokine levels were reduced by 37% for IL-6, 16% for IL-1β and 32% for IL-1ra. Improvements in cardiorespiratory fitness (13%), muscular endurance (11%) and flexibility (12%) were also observed. Conclusion: Diminished redox state and inflammation were obtained using a twice-weekly exercise program. These results have important implications for older adults who are unable or unwilling to attend exercise programs more than twice a week. Moreover, these results could re-establish the minimum exercise activity necessary for obtaining health benefits in the elderly population.(AU)

Percepção do ambiente para a prática de atividade física de pessoas com Diabetes Mellitus / Perception of the environment for physical activity of people with Diabetes Mellitus

Este estudo analisou a percepção do ambiente para a prática de atividade física de pessoas com diabetes mellitus tipo 2 de uma cidade do interior paulista. Foram entrevistadas 86 pessoas, quanto aos dados sociodemográficos, Questionário Internacional de Atividade Física, e a Escala de Percepção do Ambiente adaptada. A maioria das pessoas estão acima dos 60 anos de idade, são mulheres, aposentados, baixa renda e não atingiram 150 minutos de prática de atividade física por semana. As pessoas que percebem acesso a conveniências mais próximas à sua residência são mais ativas no tempo de lazer do que as que não percebem. Assim como, as que recebem convite de vizinhos e/ou amigos têm mais chance de praticarem atividade física do que as pessoas que não recebem. As pessoas que percebem acesso a conveniências longe de sua residência e ruas planas próximas à sua residência têm mais chance de praticar caminhada como forma de deslocamento do que as pessoas que não percebem. Há necessidade de adequação dos espaços públicos que favoreça a motivação, o ambiente físico e social para a prática de atividade física de pessoas com diabetes mellitus.

This study analyzed the perception of the environment for the practice of physical activity of people with type 2 diabetes mellitus of a city in the interior of São Paulo. A total of 86 people were interviewed regarding sociodemographic data, the International Physical Activity Questionnaire, and the adapted Environmental Perception Scale. Most people are over 60 years of age, are women, retirees, low income and have not reached 150 minutes of physical activity per week. People who perceive access to conveniences closer to their home are more active at leisure than those they do not realize. As well, those who receive invitations from neighbors and / or friends are more likely to engage in physical activity than people who do not. People who experience access to conveniences far from their home and flat streets near their home are more likely to practice walking as a form of travel than people they do not notice. There is a need for adaptation of the public spaces that favors the motivation, the physical and social environment for the practice of physical activity of people with diabetes mellitus.

Liver metabolic changes induced by conjugated linoleic acid in calorie-restricted rats

ABSTRACT Objective Complexes like conjugated linoleic acid (CLA) reduce the percentage of body fat by increasing energy expenditure, fat oxidation, or both. The aim of this study was to verify if CLA is able to mimic caloric restriction (CR), and determine the effects of CLA on liver metabolic profile of young adult male Wistar rats. Materials and methods We divided 36 animals into the following groups: 1) Control; 2) CLA (1% of daily food intake, 21 days, orogastric intubation); 3) Restr (fed 60% of the diet offered to controls); and 4) CLA Restr. Liver tissues were processed for biochemical and molecular or mitochondrial isolation (differential centrifugation) and blood samples were collected for biochemical analyses. Results Treatment of the animals for 21 days with 1% CLA alone or combined with CR increased liver weight and respiration rates of liver mitochondria suggesting significant mitochondrial uncoupling. We observed a decrease in adipose tissue leading to insulin resistance, hyperinsulinemia, and hepatic steatosis due to increased liver cholesterol and triacylglycerol levels, but no significant effects on body mass. The expression of hepatic cellular connexins (43 and 26) was significantly higher in the CLA group compared with the Control or Restr groups. Conclusion CLA does not seem to be a safe compound to induce mass loss because it upregulates the mRNA expression of connexins and induces hepatic mitochondrial changes and lipids disorders.

7-week aerobic exercise training reduces adipocyte area and improves insulin sensitivity in wistar rats fed a highly palatable diet

The aim of this study was to evaluate the effect aerobic exercise training on fat pad mass, adipocyte size, leptin release and insulin sensitivity in rats fed with high fat-palatable diet. Twenty-four male Wistar rats (250-260g) were divided into four groups: sedentary control (CTR/SD), trained control (CTR/TR), obese sedentary (OB/SD) and obese trained (OB/TR). Obese groups were fed with high fat-palatable diet (27% of fat) and control groups fed with AIN-93. Our results showed that aerobic exercise training was effective to reduce body weight and epididymal fat mass in CTR/TR and OB/TR. Insulin and glucose levels were increased in OB/TR compared with OB/SD. Aerobic exercise training reduced the average area of adipocytes in CTR/TR and OB/TR and it was associated with reduced plasma insulin and leptin. In conclusion, 7-week aerobic exercise training reduces adipocyte area and improves insulin sensitivity and leptin levels in high fat-palatable diet-fed Wistar rats.

Formação de jogadores profissionais de voleibol: relações entre atletas de elite e a especialização precoce / Development of professional volleyball players: relations between elite athletes and early specialization

Embora a literatura aponte malefícios da especialização esportiva precoce, sua aplicação permanece recorrente, embasada na crença que quanto mais cedo os treinos e a participação em competições se iniciarem, maiores serão as chances de sucesso no alto rendimento. O objetivo deste estudo foi investigar como ocorreu o processo de formação esportiva de 52 jogadores profissionais de voleibol masculino, atuantes no Campeonato Paulista e Superliga Nacional. O foco foi analisar a possível ocorrência de especialização precoce e de vivências esportivas diversificadas. Os dados foram coletados através de questionário por escrito e apresentados com estatística descritiva. Os resultados apontam que a maioria dos atletas não foi especializada precocemente e vivenciou práticas diversificadas durante sua formação, em diferentes modalidades esportivas. Os dados sinalizam para a tese que quando os treinamentos com foco nos resultados competitivos se iniciam após ou durante a puberdade há maiores chances de sucesso esportivo em comparação à especialização esportiva precoce.

Although the literature indicates harms of early sport specialization, this procedure remains applicant, based on the belief that sooner training and participation in competition increase the chance of success in highest level. The purpose of this study was to investigate how was the process of sports initiation of 52 male professional volleyball players, in the Paulista Championship and National Superligue. The focus was to analyze the possible occurrence of early specialization and diverse sporting experiences. Data was collected using a questionnaire and analyzed by descriptive statistics. Results show that the majority of the athletes were not early specialized and experienced different practices during training in childhood in different sports. The data support the belief that when sport training focusing on competitive results begins after or during the puberty there are greater chances of success in sports compared to early sport specialization.

Obesidade induzida por consumo de dieta: modelo em roedores para o estudo dos distúrbios relacionados com a obesidade / Diet-induced obesity: rodent model for the study of obesity-related disorders

A obesidade vem aumentando significativamente em todo o mundo, e os fatores ambientais, como o consumo excessivo de alimentos e o sedentarismo, são os principais fatores relacionados com a gênese dessa doença. Em animais de laboratório, a gênese da obesidade está relacionada, em sua maioria, com mutações genéticas, porém esse modelo é muito distante do encontrado nos humanos. A adoção de dietas hipercalóricas ou hiperlipídicas vem sendo utilizada como modelo de indução da obesidade em animais, devido à sua semelhança com a gênese e às respostas metabólicas decorrentes da obesidade em humanos. Assim, o objetivo dessa revisão de literatura é apresentar os diferentes tipos de dietas utilizadas para a indução da obesidade em roedores, as modificações metabólicas induzidas e identificar alguns cuidados que devem ser tomados para que esse modelo seja eficaz para o estudo das complicações relacionadas com a obesidade. Realizou-se busca na base de dados PubMed utilizando as expressões: 1-"hipercaloric diet" AND "rodent", 2- "hiperlipidic diet" AND "rodent", sendo selecionadas aquelas consideradas mais relevantes a partir dos critérios: data de publicação (1995-2011), a utilização de animais wild type, a descrição detalhada sobre a dieta utilizada e a análise de parâmetros bioquímicos e vasculares de interesse. Foram inseridas referências para introduzir assuntos como o aumento da prevalência da obesidade e questões relacionadas com a gênese da obesidade em humanos. Podemos considerar eficiente o modelo de obesidade induzida por dieta em roedores quando o objetivo é o estudo da fisiopatologia das complicações metabólicas e vasculares associadas à obesidade.

Obesity has been significantly increasing worldwide, and environmental factors such as excessive food intake and sedentary lifestyle are the main factors related to the genesis of this disease. In laboratory animals, the genesis of obesity is related mostly to genetic mutations, but this model is far from that found in humans. The use of hypercaloric or hyperlipidemic diets has been used as a model of obesity induction in animals, because of its similarity to the genesis and metabolic responses caused by obesity in humans. The objective of this review is to show the different types of diets used to induce obesity in rodents, the induced metabolic alterations, and to identify some points that should be taken into account so that the model can be effective for the study of obesity-related complications. A search was performed in the PubMed database using the following keywords: 1- "hypercaloric diet" AND "rodent", 2- "hyperlipidic diet" AND "rodent", selecting those considered the most relevant according to the following criteria: date of publication (1995-2011); the use of wild-type animals; detailed description of the diet used and analysis of biochemical and vascular parameters of interest. References were included to introduce subjects such as the increased prevalence of obesity and questions related to the genesis of obesity in humans. The model of diet-induced obesity in rodents can be considered effective when the objective is the study of the physiopathology of metabolic and vascular complications associated with obesity.

Estresse oxidativo e envelhecimento: papel do exercício físico / Oxidative stress and aging: role of physical exercise

Dentre as várias teorias que procuram explicar o processo de envelhecimento, a teoria das espécies reativas de oxigênio (EROs) tem apontado evidências experimentais significativas, sugerindo que o envelhecimento é o resultado do acúmulo de ações tóxicas causadas pelas EROs que podem ocasionar danos ao DNA celular, aos lipídios e as proteínas. Existem evidências de que a produção das EROs durante o exercício físico não pode ser modificada pelo treinamento regular, mas é possível que o metabolismo celular endógeno aumente suas defesas antioxidantes. Assim, o objetivo dessa revisão de literatura é apresentar os principais mecanismos de produção das EROs e os mecanismos de defesa antioxidante, assim como as adaptações induzidas pelo exercício físico que atuam como uma proteção contra os danos provocados pelo estresse oxidativo.

Different theories have been developed to explain the aging process and the Free-radical Theory of Aging had shown significant evidence that aging is the result of ROS toxicity action that lead to cellular DNA injury, lipid and protein oxidation. While during exercise session a major oxygen consumption increases ROS production, an adaptation occurs at cellular level and antioxidant enzymes concentration or activity are increase. Therefore, this review aims to show the mainly mechanisms of ROS generation and antioxidant defense mechanisms, as well the adaptations induced by physical exercise that act as a protection against oxidative stress related-injuries.

Influência da ingestão de espirulina sobre o metabolismo de ratos exercitados / Influence of spirulina intake on metabolism of exercised rats

No presente estudo foram comparadas as respostas metabólicas agudas ao exercício em ratos alimentados com dieta padrão e à base de espirulina. Ratos Wistar jovens foram divididos em dois grupos de acordo com a dieta: controle (C) (dieta padrão) e espirulina (S) (dieta à base de espirulina). Ao final do período experimental (cinco semanas) os animais foram submetidos a uma sessão aguda de exercício de natação (20 minutos, suportando sobrecarga equivalente a 5 por cento do peso corporal) para avaliação do lactato sanguíneo, glicose, insulina, proteínas, albumina e ácidos graxos livres (AGL) séricos. Amostras do músculo gastrocnêmio e fígado foram utilizadas para determinação dos teores de glicogênio e lipídeos. Ambos os grupos C e S apresentaram aumento da glicemia e dos AGL, queda da insulinemia e redução dos teores de glicogênio muscular e hepático pós-exercício. A lactacidemia durante o exercício foi superior no grupo S em relação ao C. Conclui-se que o padrão de respostas ao exercício agudo dos grupos C e S foi semelhante. Contudo, a proteína da dieta pareceu influenciar aspectos do metabolismo glicídico.