Different exercise protocols improve metabolic syndrome markers, tissue triglycerides content and antioxidant status in rats

Background: An increase in the prevalence of obesity entails great expenditure for governments. Physical exercise is a powerful tool in the combat against obesity and obesity-associated diseases. This study sought to determine the effect of three different exercise protocols on metabolic syndrome and lipid peroxidation markers and the activity of antioxidant enzymes in adult Wistar rats (120 days old).Methods: Animals were randomly divided into four groups: the control (C) group was kept sedentary throughout the study; the aerobic group (A) swam1 h per day, 5 days per week, at 80% lactate threshold intensity; the strength group (S) performed strength training with four series of 10 jumps, 5 days per week; and the Concurrent group (AS) was trained using the aerobic protocol three days per week and the strength protocol two days per week.Results: Groups A and S exhibited a reduction in body weight compared to group C. All exercised animals showed a reduction in triglyceride concentrations in fatty tissues and the liver. Exercised animals also exhibited a reduction in lipid peroxidation markers (TBARS) and an increase in serum superoxide dismutase activity. Animals in group A had increased levels of liver catalase and superoxide dismutase activities.Conclusions: We concluded that all physical activity protocols improved the antioxidant systems of the animals and decreased the storage of triglycerides in the investigated tissues.

Atenolol blunts blood pressure increase during dynamic resistance exercise in hypertensives

center dot Dynamic resistance exercise promotes a sizeable increase in blood pressure during its execution in non medicated hypertensives. WHAT THIS STUDY ADDS center dot Atenolol not only decreases blood pressure level but also mitigates the increase of blood pressure during dynamic resistance exercise in hypertensive patients. An increase in blood pressure during resistance exercise might be at least in part attributed to an increase in cardiac output. AIMS This study was conducted to determine whether atenolol was able to decrease BP level and mitigate BP increase during dynamic resistance exercise performed at three different intensities in hypertensives. METHODS Ten essential hypertensives (systolic/diastolic BP between 140/90 and 160/105 mmHg) were blindly studied after 6 weeks of placebo and atenolol. In each phase, volunteers executed, in a random order, three protocols of knee-extension exercises to fatigue: (i) one set at 100% of 1 RM; (ii) three sets at 80% of 1 RM; and (iii) three sets at 40% of 1 RM. Intra-arterial radial blood pressure was measured throughout the protocols. RESULTS Atenolol decreased systolic BP maximum values achieved during the three exercise protocols (100% = 186 +/- 4 vs. 215 +/- 7, 80% = 224 +/- 7 vs. 247 +/- 9 and 40% = 223 +/- 7 vs. 252 +/- 16 mmHg, P < 0.05). Atenolol also mitigated an increase in systolic BP in the first set of exercises (100% = +38 +/- 5 vs. +54 +/- 9; 80% = +68 +/- 11 vs. +84 +/- 13 and 40% = +69 +/- 7 vs. +84 +/- 14, mmHg, P < 0.05). Atenolol decreased diastolic BP values and mitigated its increase during exercise performed at 100% of 1 RM (126 +/- 6 vs. 145 +/- 6 and +41 +/- 6 vs. +52 +/- 6, mmHg, P < 0.05), but not at the other exercise intensities. CONCLUSIONS Atenolol was effective in both reducing systolic BP maximum values and mitigating BP increase during resistance exercise performed at different intensities in hypertensive subjects.

Exercise Intensity, Inflammatory Signaling, and Insulin Resistance in Obese Rats

DA SILVA, A. S. R., J. R. PAULI, E. R. ROPELLE, A. G. OLIVEIRA, D. E. CINTRA, C. T. DE SOUZA, L. A. VELLOSO, J. B. C. CARVALHEIRA, and M. J. A. SAAD. Exercise Intensity, Inflammatory Signaling, and Insulin Resistance in Obese Rats. Med. Sci. Sports Exerc., Vol. 42, No. 12, pp. 2180-2188, 2010. Purpose: To evaluate the effects of intensity of exercise on insulin resistance and the expression of inflammatory proteins in the skeletal muscle of diet-induced obese (DIO) rats after a single bout of exercise. Methods: In the first exercise protocol, the rats swam for two 3-h bouts, separated by a 45-min rest period (with 6 h in duration-DIO + EXE), and in the second protocol, the rats were exercised with 45 min of swimming at 70% of the maximal lactate steady state-MLSS (DIO + MLSS). Results: Our data demonstrated that both protocols of exercise increased insulin sensitivity and increased insulin-stimulated tyrosine phosphorylation of insulin receptor and insulin receptor substrate 1 and serine phosphorylation of protein kinase B in the muscle of DIO rats by the same magnitude. In parallel, both exercise protocols also reduced protein tyrosine phosphatase 1B activity and insulin receptor substrate 1 serine phosphorylation, with concomitant reduction in c-jun N-terminal kinase and I kappa B kinase activities in the muscle of DIO rats in a similar fashion. Conclusions: Thus, our data demonstrate that either exercise protocols with low intensity and high volume or exercise with moderate intensity and low volume represents different strategies to restore insulin sensitivity with the same efficacy.

Exercise reduces inflammation and cell proliferation in rat colon carcinogenesis

Purposes: There is evidence that the risk of colon cancer is reduced by appropriate levels of physical exercise. Nevertheless, the mechanisms involved in this protective effect of exercise remain largely unknown. Inflammation is emerging as a unifying link between a range of environment exposures and neoplastic risk. The carcinogen dimethyl-hydrazine (DMH) induces an increase in epithelial cell proliferation and in the expression of the inflammation-related enzyme cyclooxigenase-2 (COX-2) in the colon of rats. Our aim was to verify whether these events could be attenuated by exercise. Methods: Four groups of eight Wistar rats were used in the experiment. The groups G1 and G3 were sedentary (controls), and the groups G2 and G4 were submitted to 8 wk of swimming training, 5 d wk(-1). The groups G3 and G4 were given subcutaneous injections of DMH immediately after the exercise protocols. Fifteen days after the neoplasic induction, the rats were sacrificed and the colon was processed for histological examination and immunohistochemistry staining of proliferating cell nuclear antigen (PCNA) and COX-2. Results: We found a significant increase in the PCNA-labeling index in both DMH-treated groups of rats. However, this increase was significantly attenuated in the training group G4 (P < 0.01). Similar results were observed in relation to the COX-2 expression. Conclusions: From our findings, we conclude that exercise training exerts remarkable antiproliferative and antiinflammatory effects in the rat colonic mucosa, suggesting that this may be an important mechanism to explain how exercise protects against colonic cancer.

Exercise-induced alterations in neutrophil degranulation and respiratory burst activity: possible mechanisms of action

Neutrophils constitute 50-60% of all circulating leukocytes; they present the first line of microbicidal defense and are involved in inflammatory responses. To examine immunocompetence in athletes, numerous studies have investigated the effects of exercise on the number of circulating neutrophils and their response to stimulation by chemotactic stimuli and activating factors. Exercise causes a biphasic increase in the number of neutrophils in the blood, arising from increases in catecholamine and cortisol concentrations. Moderate intensity exercise may enhance neutrophil respiratory burst activity, possibly through increases in the concentrations of growth hormone and the inflammatory cytokine IL-6. In contrast, intense or long duration exercise may suppress neutrophil degranulation and the production of reactive oxidants via elevated circulating concentrations of epinephrine (adrenaline) and cortisol. There is evidence of neutrophil degranulation and activation of the respiratory burst following exercise-induced muscle damage. In principle, improved responsiveness of neutrophils to stimulation following exercise of moderate intensity could mean that individuals participating in moderate exercise may have improved resistance to infection. Conversely, competitive athletes undertaking regular intense exercise may be at greater risk of contracting illness. However there are limited data to support this concept. To elucidate the cellular mechanisms involved in the neutrophil responses to exercise, researchers have examined changes in the expression of cell membrane receptors, the production and release of reactive oxidants and more recently, calcium signaling. The investigation of possible modifications of other signal transduction events following exercise has not been possible because of current methodological limitations. At present, variation in exercise-induced alterations in neutrophil function appears to be due to differences in exercise protocols, training status, sampling points and laboratory assay techniques.

Participation of endogenous opioids in the antinociception induced by resistance exercise in rats

Exercise is a low-cost intervention that promotes health and contributes to the maintenance of the quality of life. The present study was designed to investigate the influence of different resistance exercise protocols on the nociceptive threshold of rats. Female Wistar rats were used to perform exercises in a weight-lifting exercise model. The following groups were examined (N = 6 per group): untrained rats (control group); an acute protocol group consisting of rats submitted to 15 sets of 15 repetitions of resistance exercise (acute group); rats exercised with 3 sets of 10 repetitions, three times per week for 12 weeks (trained group), and a group consisting of trained rats that were further submitted to the acute protocol (trained-acute group). The nociceptive threshold was measured by the paw-withdrawal test, in which the withdrawal threshold (escape reaction) was measured by an apparatus applying force to the plantar surface of the animal paw. The opioid antagonist naloxone (2 mg/kg) was administered subcutaneously 10 min before the exercise protocols. The trained group demonstrated antinociception only up to day 45 of the 12-week training period. A significant increase (37%, P < 0.05) in the nociceptive threshold was produced immediately after exercise, decreasing to 15% after 15 min, when the acute exercise protocol was used. Naloxone reversed this effect. These data show that the acute resistance exercise protocol was effective in producing antinociception for 15 min. This antinociceptive effect is mediated by the activation of opioid receptors.

Acute endocrine responses to plyometrics versus resistance exercise in children

The purpose of this study was to examine the acute hormonal responses to a bout of resistance versus plyometric exercise in young male athletes. Specifically, changes in salivary cortisol, testosterone and testosterone-to-cortisol ratio from pre- to post-exercise between the two different exercise protocols were examined. Twenty-six peri-pubertal active boys participated in this cross-over study, completing two exercise sessions. During each session, participants first completed a 30 min control period, which did not include any exercise, and then was randomly assigned to perform a 45 min of either a resistance exercise or a plyometric exercise protocol. All participants crossed over to perform the other exercise protocol during their second exercise session, a week later. Four saliva samples during each protocol were taken at: baseline, pre-exercise, 5 min post-exercise and 30 min post-exercise. Significant increases in testosterone values were reported 5 min post-exercise following the resistance protocol, but not the plyometric protocol. Both exercise protocols resulted in significant cortisol decreases overtime, as well as significant testosterone-to-cortisol ratio increases. The post-exercise increases in salivary testosterone and testosterone-to-cortisol ratio followed the typical exercise induced anabolic response seen in adults. However, the post-exercise decrease in salivary cortisol was different than the typical adult response indicating an insufficient stimulus for this age group maybe due to their stage of the biological development. Thus, in the adolescent boys, exercise appears to change the anabolic to catabolic balance in favor of anabolism.

The hypotensive effect of exercise on IOP : an interaction of physical fitness and parasympathetic efficacy

RÉSUMÉ Suite à une centaine de publications sur la réduction de la PIO post-exercice, il est connu que parmi un grand nombre de programme d'exercices de différentes durées et intensités, les effets hypotenseurs de l'exercice sur la PIO sont atténués chez les sujets en bonne condition physique. Le mécanisme proposé est l'augmentation potentielle de l'efficacité du système parasympathique avec l'activité physique. Le principal objectif de cette thèse est d'identifier les facteurs contribuants à la réduction de la PIO post-exercice et d'élucider les différents mécanismes possibles. L'étude 1, une méta-analyse, a été menée afin de quantifier les contributions relatives de l'intensité et de la durée de l'effet de l'exercice sur la PIO et la mesure dans laquelle ces variables affectent les sujets sédentaires et normalement actifs. La tendance ressortant des résultats est que la diminution de la PIO suite à de l'exercice aérobie est plus élevée chez les sujets sédentaires que les sujets en bonne condition physique. (ES = -4.198 mm Hg et -2.340 mm Hg, respectivement). L'absence d'un contrôle des liquides ingérés avant l'activité physique est à souligné dans cette étude. L'hyperosmolarité (un effet secondaire de la déshydratation) est l'un des mécanismes proposés influant l'effet hypotenseur de l'exercice. L'étude 2 comparait la réduction de la PIO dans deux conditions, soit hypohydraté et hyperhydraté, avant, pendant et après un effort de 90 minutes sur un ergocycle. Après une diminution initiale pour les deux conditions, la PIO revient aux valeurs de départ pour la condition hypohydratée malgré une perte de poids significative et elle augmente pour la condition hyperhydratée (résultat du protocole d'hydratation). Étant donné le niveau élevé de participants en bonne condition physique dans l'étude 2, la troisième étude a été conçue afin de etude la relation entre la PIO et la condition physique. À l'aide d'analyses corrélationnelles il a été possible d'observer la relation entre le test de vo2max et la moyenne des mesures de PIO prises sur un intervalle de huit semaines. Une relation significative n'existait que pour les participants se situant dans la portion supérieure du continuum de la condition physique. Conclusion: Les résultats de la présente étude suggèrent que l'effet hypotenseur de l'exercice sur la PIO est probablement une réponse homéostatique à la dérégulation de l'humeur aqueuse causée par l'initiation de l'exercice et le protocole d'ingestion de fluides pré-exercice.

Effects of 2 or 5 consecutive exercise days on adipocyte area and lipid parameters in Wistar rats

Background: Exercise has been prescribed in the treatment and control of dyslipidemias and cholesterolemia, however, lipid responses to different training frequencies in hypercholesterolemic men have been inconsistent. We sought to verify if different frequencies of continuous moderate exercise (2 or 5 days/week, swimming) can, after 8 weeks, promote adaptations in adipocyte area and lipid parameters, as well as body weight and relative weight of tissues in normo and hypercholesterolemic adult male rats.Methods: Normal cholesterol chow diet or cholesterol-rich diet (1% cholesterol plus 0.25% cholic acid) were freely given during 8 weeks to the rats divided in 6 experimentals groups: sedentary normal cholesterol chow diet (C); sedentary cholesterol-rich diet (H); 5x per week continuous training normal cholesterol chow diet (TC5) and cholesterol-rich diet (TH5); 2x per week continuos traning normal cholesterol chow diet (TC2) and cholesterol-rich diet (TH2).Results: No changes were observed in lipid profile in normal cholesterol chow diet, but both 2 a 5 days/week exercise improved this profile in cholesterol-rich diet. Body weight gain was lower in exercised rats. Decrease in retroperitoneal and epididymal relative weights as well as reductions in adipocyte areas under all diets types were observed only in 5 days/week, while 2 days/week showed improvements mainly in cholesterol-rich diet rats.Conclusion: Our results confirm the importance of exercise protocols to control dyslipidemias and obesity in rats. The effects of 5 days/week exercise were more pronounced compared with those of 2 consecutive days/week training.

Effects of different intensities of physical exercise on insulin sensitivity and protein kinase B/Akt activity in skeletal muscle of obese mice

Objetivo: Investigar os efeitos do exercício físico agudo com diferentes intensidades sobre a sensibilidade à insulina e a atividade da proteína quinase B/Akt no músculo esquelético de camundongos obesos. Método: Foram utilizados camundongos Swiss, divididos aleatoriamente em quatro grupos, que receberam dieta padrão (grupo controle) ou dieta hiperlipídica (grupos obeso sedentário e grupos obesos exercitados 1 e 2), por período de 12 semanas. Dois diferentes protocolos de exercício foram utilizados: natação durante 1 hora com ou sem sobrecarga de 5% da massa corporal. O teste de tolerância à insulina foi realizado para estimar a sensibilidade à insulina. E os níveis protéicos da proteína quinase B/Akt e de sua fosforilação foram determinados no músculo esquelético dos camundongos, através da técnica de Western blot. Resultado: Uma sessão de exercício físico foi capaz de inibir a resistência à insulina em decorrência de uma dieta hiperlipídica. Foi possível demonstrar um aumento na fosforilação da proteína quinase B/Akt, melhora da sinalização da insulina e redução da glicemia de jejum nos camundongos que realizaram 1 hora de natação sem sobrecarga adicional e nos camundongos que realizaram 1 hora de natação com sobrecarga adicional de 5% de sua massa corporal. Entretanto, não houve diferença significativa entre os grupos que realizaram o exercício em diferentes intensidades. Conclusão: Independente da intensidade, o exercício físico aeróbio conseguiu aumentar a sensibilidade à insulina e a fosforilação da proteína quinase B/Akt, revelando ser uma boa forma de tratamento e prevenção do diabetes tipo 2.

Physical exercise and vascular endothelial growth factor (VEGF) in elderly: A systematic review

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The effect of prior exercise intensity on oxygen uptake kinetics during high-intensity running exercise in trained subjects

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

AEROBIC OR RESISTANCE EXERCISE IMPROVES PERFORMANCE IN ACTIVITIES OF DAILY LIVING IN ELDERLY WOMEN

The purpose of this randomized non-controlled study was to determine the effect of an aerobic or resistance exercise protocol on performance of activities of daily living in elderly women. The sample was constituted of 41 apparently healthy elderly women aged 60 to 85 years (x: 65.1 +/- 7.9 years) randomly assigned in resistance exercise (n: 22) or aerobic groups (n: 19). The resistance exercise protocol consisted of three sets of eight to 12 repetitions at 60% of one repetition maximum test for the leg press 45 degrees. The aerobic exercise protocol consisted in cycling in a cycle ergometer during 40 minutes at 60% of reserve heart rate. Both protocols were performed three times per week during five weeks. Activities of daily living were estimated by velocity to stand from sitting to standing position (VSitting), velocity to move from supine to standing position (VSupine), velocity to climb stairs (VCS) and velocity to wear sneakers (VWS). Volunteers of aerobic exercise protocol improved significantly the time to perform VWS (19.1%), while the volunteers of resistance exercise protocol improved the capacity to perform VCS (4.3%) and VSupine (8.9%). These results let us conclude that aerobic as well as resistance exercise protocols induced positive effect on activities of daily living, suggesting that both protocols must be associated for an adequate exercise program to improve the functional capacity of elderly people.

Eccentric Exercise in Treatment of Patellar Tendinopathy in High Level Basketball Players. A Randomized Clinical Trial.

Chronic patellar tendinopathy is a common pathology in sporting population. To date, there is no agreed upon protocol as election treatment. Eccentric exercises have been used with satisfactory outcomes (3). The purpose of this trial was to compare the effects of two eccentric exercise protocols.