Fructose consumption has been growing exponentially and, concomitant with this, the increase in the incidence of obesity and associated complications has followed the same behavior. Studies indicate that fructose may be a carbohydrate with greater obesogenic potential than other sugars. In this context, the liver seems to be a key organ for understanding the deleterious health effects promoted by fructose consumption. Fructose promotes complications in glucose metabolism, accumulation of triacylglycerol in the hepatocytes, and alterations in the lipid profile, which, associated with an inflammatory response and alterations in the redox state, will imply a systemic picture of insulin resistance. However, physical exercise has been indicated for the treatment of several chronic diseases. In this review, we show how each exercise protocol (aerobic, strength, or a combination of both) promote improvements in the obesogenic state created by fructose consumption as an improvement in the serum and liver lipid profile (high-density lipoprotein (HDL) increase and decrease triglyceride (TG) and low-density lipoprotein (LDL) levels) and a reduction of markers of inflammation caused by an excess of fructose. Therefore, it is concluded that the practice of aerobic physical exercise, strength training, or a combination of both is essential for attenuating the complications developed by the consumption of fructose.

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The aim of this study was to compare the effects of aerobic, strength, and combined training on metabolic disorders induced by a fructose-rich diet. Wistar rats (120 days old) were randomized into five groups (n = 8–14): C (control diet and sedentary), F (fed the fructose-rich diet and sedentary), FA (fed the fructose-rich diet and subject to aerobic exercise), FS (fed the fructose-rich diet and subject to strength exercise), and FAS (fed the fructose-rich diet and subject to combined aerobic and strength exercises). After the 8-week experiment, glucose homeostasis, blood biochemistry, tissue triglycerides, and inflammation were evaluated and analyzed. The strength protocol exerted greater effects on glucose homeostasis, insulin sensitivity, and liver lipid contents than other protocols (all P < 0.05). All three exercise protocols induced a remarkable reduction in inflammation, tissue triglyceride content, and inflammatory pathways, which was achieved through c-Jun NH2-terminal kinase (JNK) phosphorylation and factor nuclear kappa B (NFkB) activation in both the liver and the muscle. Our data suggest that strength training reduced the severity of most of the metabolic disorders induced by a fructose-rich diet and could be the most effective strategy to prevent or treat fructose-induced metabolic diseases.

BackgroundThis study aimed to analyze the effects of exercise at the aerobic/anaerobic transition on the markers of non-alcoholic fatty liver disease (NAFLD), insulin sensitivity and the blood chemistry of rats kept on a fructose-rich diet.MethodsWe separated 48 Wistar rats into two groups according to diet: a control group (balanced diet AIN-93 G) and a fructose-rich diet group (60% fructose). The animals were tested for maximal lactate-steady state (MLSS) in order to identify the aerobic/anaerobic metabolic transition during swimming exercises at 28 and 90 days of age. One third of the animals of each group were submitted to swimming training at an intensity equivalent to the individual MLSS for 1 hours/day, 5 days/week from 28 to 120 days (early protocol). Another third were submitted to the training from 90 to 120 days (late protocol), and the others remained sedentary. The main assays performed included an insulin tolerance test (ITT) and tests of serum alanine aminotransferase [ALT] and aspartate aminotransferase [AST] activities, serum triglyceride concentrations [TG] and liver total lipid concentrations.ResultsThe fructose-fed rats showed decreased insulin sensitivity, and the late-exercise training protocol counteracted this alteration. There was no difference between the groups in levels of serum ALT, whereas AST and liver lipids increased in the fructose-fed sedentary group when compared with the other groups. Serum triglycerides concentrations were higher in the fructose-fed trained groups when compared with the corresponding control group.ConclusionsThe late-training protocol was effective in restoring insulin sensitivity to acceptable standards. Considering the markers here evaluated, both training protocols were successful in preventing the emergence of non-alcoholic fatty liver status disease.

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ObjectiveFindings on weight training and waist circumference (WC) change are controversial. This study examined prospectively whether weight training, moderate-to-vigorous aerobic activity (MVAA), and replacement of one activity for another were associated with favorable changes in WC and body weight (BW).MethodsPhysical activity, WC, and BW were reported in 1996 and 2008 in a cohort of 10,500 healthy U.S. men in the Health Professionals Follow-up Study. We used multiple linear regression models (partition/substitution) to assess these associations.ResultsAfter adjusting for potential confounders, we observed a significant inverse dose-response relationship between weight training and WC change (P-trend<0.001). Less age-associated WC increase was seen with a 20 min/day activity increase; this benefit was significantly stronger for weight training (-0.67cm, 95%CI -0.93, -0.41) than for MVAA (-0.33cm, 95%CI -0.40, -0.27), other activities (-0.16cm, 95%CI -0.28, -0.03), or TV watching (0.08cm, 95%CI 0.05, 0.12). Substituting 20 min/day of weight training for any other discretionary activity had the strongest inverse association with WC change. MVAA had the strongest inverse association with BW change (-0.23kg, 95%CI -0.29, -0.17).ConclusionsAmong various activities, weight training had the strongest association with less WC increase. Studies on frequency /volume of weight training and WC change are warranted.

Sestrins and autophagy deficiencies are associated with several aging-related organic dysfunctions and metabolic disorders. Here we evaluate the effects of acute exercise on Sestrin 2 (Sesn2) protein content and autophagy markers in the skeletal muscle of experimental models of aging. Twenty-four months-old C57BL/6J male mice were submitted to a single bout of swimming exercise and the gastrocnemius muscle was evaluated by Western blot. Transcriptomic and phenotypic analysis were also performed by using strains of genetically-diverse BXD mice. The bioinformatics analysis showed a negative correlation between Sesn2 mRNA levels in the skeletal muscle and body weight gain, plasma triglycerides and fasting glucose and positive correlation with several autophagic markers in the muscle of BXD mice. Consistent with these findings, low levels of Sesn2 protein content were observed in the gastrocnemius muscle of C57BL/6J old mice when compared to young group. Interestingly, the acute aerobic exercise induced Sesn2 accumulation and modulated several markers of autophagy in the gastrocnemius muscle old mice, including unc-51-like kinase-1 (Ulk1) phosphorylation and the protein levels of Atg5, Atg7, p62 and LC3-II. Finally, exercise increased insulin sensitivity in old animals, as demonstrated by kITT. Taken together, these findings demonstrated the acutely, aerobic physical exercise recovers Sestrin 2 protein content and induces autophagy in the skeletal muscle of old mice, contributing with the improvement of insulin sensitivity an aging animal model.

The endoplasmic reticulum (ER) stress and inflammation relationship occurs at different levels and is essential for the adequate homeostatic function of cellular systems, becoming harmful when chronically engaged. Intense physical exercise enhances serum levels of interleukin 6 (IL-6). In response to a chronic exhaustive physical exercise protocol, our research group verified an increase of the IL-6 concentration and ER stress proteins in extensor digitorium longus (EDL) and soleus. Based on these results, we hypothesized that IL-6-knockout mice would demonstrate a lower modulation in the ER stress proteins compared to the wild-type mice. To clarify the relationship between exercise-induced IL-6 increased and ER stress, we studied the effects of an acute exhaustive physical exercise protocol on the levels of ER stress proteins in the skeletal muscles of IL-6-knockout (KO) mice. The WT group displayed a higher exhaustion time compared to the IL-6 KO group. After 1 h of the acute exercise protocol, the serum levels of IL-6 and IL-10 were enhanced in the WT group. Independent of the experimental group, the CHOP and cleaved caspase 12/total caspase 12 ratio in EDL as well as ATF6 and CHOP in soleus were sensitive to the acute exercise protocol. Compared to the WT group, the oscillation patterns over time of BiP in EDL and soleus as well as of peIF2-alpha/eIF2-alpha ratio in soleus were attenuated for the IL-6 KO group. In conclusion, IL-6 seems to be related with the ER stress homeostasis, once knockout mice presented attenuation of BiP in EDL and soleus as well as of pEiF2-alpha/EiF2-alpha ratio in soleus after the acute exhaustive physical exercise protocol.