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The intensity of exercise determines the metabolic pathway and the energetic substrate that is spent. Our study sought to identify the effects of different intensities of swimming on myocardial oxidative status and the blood lipid profile. Eighty Wistar rats (male and female) submitted to different intensities of a swimming regimen (low, LS; moderate, MS; or high, HS) for 16 weeks. Samples of blood and myocardium from the left ventricle were collected to determine lipid profiles and oxidative status. Reactive oxygen species (ROS) and antioxidant capacity against peroxyl radicals (ACAP), lipid profiles and lipid peroxidation was analyzed. ROS levels and ACAP were higher in male rats than in female rats overall (p<0.05). However, ACAP in the myocardium was significantly elevated in LS female rats compared to the MS and HS female rats, which had a significantly lower ACAP compared to all other groups. LS and MS training in both sexes and HS training (in females) led to significant decreases in the heart's lipid peroxidation. Amelioration of the lipid profile and reduction in oxidative damage contributed to a physiological state that benefits cardiovascular function in exercised animals. The results show that low and moderate intensity exercise promotes beneficial adaptations.

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Estuaries present an environmental gradient that ranges from almost fresh water conditions to almost marine conditions. Salinity and flooding are the main abiotic drivers for plants. Therefore, plant zonation in estuaries is closely related to the tidal cycles. It is expected that the competitive abilities of plants would be inversely related to the tolerance toward environmental stress (tradeoff). Thus, in estuaries, plant zonation tends to be controlled by the environment near the sandbar and by competition away from it. This zonation pattern has been proposed for regular non-tropical estuaries. For tropical estuaries, the relative importance of rain is higher, and it is not clear to what extent this model can be extrapolated. We measured the tidal influence along the environmental gradient of a tropical irregular estuary and quantified the relative importance of the environment and the co-occurrence degree. Contrary to the narrow occurrence zone that would be expected for regular estuaries, plants presented large occurrence zones. However, the relative importance of the environment and competition followed the same patterns proposed for regular estuaries. The environmental conditions allow plants to occur in larger zones, but these zones arise from smaller and infrequent patches distributed across a larger area, and most species populations are concentrated in relatively narrow zones. Thus, we concluded that the zonation pattern in the Massaguaçu River estuary agrees with the tradeoff model.

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Estuaries present an environmental gradient that ranges from almost fresh water conditions to almost marine conditions. Salinity and flooding are the main abiotic drivers for plants. Therefore, plant zonation in estuaries is closely related to the tidal cycles. It is expected that the competitive abilities of plants would be inversely related to the tolerance toward environmental stress (tradeoff). Thus, in estuaries, plant zonation tends to be controlled by the environment near the sandbar and by competition away from it. This zonation pattern has been proposed for regular non-tropical estuaries. For tropical estuaries, the relative importance of rain is higher, and it is not clear to what extent this model can be extrapolated. We measured the tidal influence along the environmental gradient of a tropical irregular estuary and quantified the relative importance of the environment and the co-occurrence degree. Contrary to the narrow occurrence zone that would be expected for regular estuaries, plants presented large occurrence zones. However, the relative importance of the environment and competition followed the same patterns proposed for regular estuaries. The environmental conditions allow plants to occur in larger zones, but these zones arise from smaller and infrequent patches distributed across a larger area, and most species populations are concentrated in relatively narrow zones. Thus, we concluded that the zonation pattern in the Massaguaçu River estuary agrees with the tradeoff model.(AU)

Estuários apresentam um gradiente ambiental que varia de condições próximas a de água doce a condições quase marinhas. A salinidade e o alagamento são os principais fatores abióticos para as plantas. Por isso, a zonação vegetal em estuários está proximamente relacionada aos ciclos da maré. É esperado que as habilidades competitivas das plantas sejam inversamente relacionadas à tolerância ao estresse ambiental (tradeoff). Assim, em estuários, a zonação vegetal tende a ser controlada pelo ambiente, próximo à barra, e pela competição, longe da mesma. Esse padrão de zonação tem sido proposto para estuários regulares não tropicais. Para estuários tropicais, a importância relativa da chuva é maior, e não é claro até que ponto esse modelo pode ser extrapolado. Nós medimos a influência da maré ao longo do gradiente ambiental de um estuário tropical irregular e quantificamos a importância relativa do ambiente e o grau de correlação. Contrariamente à ocorrência estreita que seria esperada para estuários regulares, as plantas apresentaram amplas zonas de ocorrência. No entanto, a importância relativa do ambiente e da competição seguiram os mesmos padrões propostos para estuários regulares. As condições ambientais permitem às plantas ocorrerem em zonas mais amplas, mas estas zonas resultam de pontos ocasionais, e as populações da maioria das espécies estão concentradas em zonas relativamente estreitas. Desse modo, concluímos que o padrão de zonação no estuário do Rio Massaguaçu está de acordo com o modelo tradeoff.(AU)

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The acute administration of L-arginine (L-arg), a nitric oxide (NO) precursor, reduces lactate (LAC) concentration after exercise in healthy individuals. Lower concentration of L-arg may enhance the action of some inflammatory cytokines in HIV-1 infected patients. We tested the hypothesis that acute L-arg administration may reduce post-exercise blood LAC and inflammatory cytokines levels in HIV-infected patients. 10 HIV-infected men performed 2 maximal incremental cardiopulmonary exercise tests, separated by one week. 30 min before each test, patients received oral placebo or 20 g of L-arg, in random order. Blood LAC, tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), and interleukin-10 (IL-10) were measured before and up to 60 min after exercise. L-arg administration had no significant effect on exercise performance. Compared to placebo, L-arg administration reduced maximal post-exercise blood LAC from 8.7±0.6 to 6.9±0.4 mmol.L-1 (p<0.05). L-arg administration had no significant effect on TNF-alpha or IL-10 concentrations, but increased post-exercise IL-6 (placebo=19±3pg.mL-1; L-arg=63±8 pg.mL-1; p<0.05). In HIV-1 infected men, acute administration of L-arg reduces post-exercise blood LAC and increases IL-6 levels, suggesting the activation of the L-arg-NO pathway, with possible anti-inflammatory consequences.

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AIMS/HYPOTHESIS: Supervised exercise programmes improve glycaemic control in type 2 diabetes, but training characteristics associated with reduction in HbA(1c) remain unclear. We conducted a systematic review with meta-regression analysis of randomised clinical trials (RCTs) assessing the association between intensity and volume of exercise training (aerobic, resistance or combined) and HbA(1c) changes in patients with type 2 diabetes. METHODS: Five electronic databases were searched (1980-2012) to retrieve RCTs of at least 12 weeks' duration, consisting of supervised exercise training vs no intervention, that reported HbA(1c) changes and exercise characteristics. Two independent reviewers conducted study selection and data extraction. RESULTS: Twenty-six RCTs (2,253 patients) met the inclusion criteria. In multivariate analysis, baseline HbA(1c) and exercise frequency explained nearly 58% of between-study variance. Baseline HbA(1c) was inversely correlated with HbA(1c) reductions after the three types of exercise training. In aerobic training, exercise volume (represented by frequency of sessions) was associated with changes in HbA(1c) (weighted r = -0.64), while no variables were correlated with glycaemic control induced by resistance training. In combined training, weekly volume of resistance exercise explained heterogeneity in multivariate analysis and was associated with changes in HbA(1c) levels (weighted r = -0.70). CONCLUSIONS/INTERPRETATION: Reduction in HbA(1c) is associated with exercise frequency in supervised aerobic training, and with weekly volume of resistance exercise in supervised combined training. Therefore, exercise volume is a major determinant of glycaemic control in patients with type 2 diabetes.

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BACKGROUND: non-steroidal anti-inflammatory drugs (NSAIDs) are frequently used in sports medicine to reduce time of incapacity. OBJECTIVE: to describe the frequency of NSAIDs use by athletes in the XV Pan-American Games. METHODS: all athletes who were tested by the anti-doping control filled a form. The voluntarily declared medications were recorded and categorised according to sport modality, sex, region and control situation according to the World Anti-Doping Agency. RESULTS: among the 1261 athletes tested (231 out-competition (OC) and 1030 in-competition (IC); 733 men and 528 women), 63% reported use of drugs, NSAIDs being the most frequently (64% of users) used medications. The use of medications was not significantly different between sexes or among different regions of the world. The number of users of only one type of NSAID was higher than those who used more than one type of NSAIDs or a combination with analgesics (335 vs 168 cases). IC reports presented higher use of NSAIDs than OC. CONCLUSION: athletes tested by the anti-doping control of the XV Pan-American Games reported a high frequency of NSAIDs use. The frequent utilisation in competition suggests that these medications might be used as ergogenic aid.

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This study investigated the effects of pedal frequency on the slow component of pulmonary oxygen uptake ( V O(2)) kinetics during heavy exercise at the same relative intensity. We hypothesized that higher pedal frequency (expected to enhance fast-twitch muscle fiber recruitment) would be associated with greater slow component amplitude (A' (s)), surface electromyography (normalized root mean square; RMS) and blood lactate concentration ([lactate]). Eight subjects performed square-wave transitions to heavy exercise at 35 and 115 rpm. Furthermore, alternated cadences square-wave transitions (35-115 rpm) were performed to examine the potential effects of additional fast-twitch muscle fiber recruitment on the slow component. Significance was accepted when P<0.05. The A' (s) was greater at higher cadences (0.58+/-0.08 and 0.70+/-0.09 L.min (-1) at 115 and 35-115 rpm, respectively) than at 35 rpm (0.35+/-0.04 L.min (-1)). Greater EMG increase over time (DeltaRMS ((10-3 min))) and [lactate] were observed at 115 and 35-115 rpm compared with 35 rpm. There was a significant correlation between A' (s) and overall DeltaRMS ((10-3 min)) for all pedal frequencies combined (r=0.63; P=0.001). Pedal frequency had no effect on time constants or time delays. These findings are consistent with the concept that progressive recruitment of muscle fibers is associated with the V O(2) slow component.

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