Respostas lactacidêmicas de ratos ao treinamento intermitente de alta intensidade

High-intensity interval resistance training (HIIRT) improves liver gluconeogenesis from lactate in Swiss mice

High-intensity physical exercise favors anaerobic glycolysis and increases lactatemia. Lactate is converted back to glucose in the liver, so that the lactate threshold, an indicator of physical performance, must be related to the gluconeogenic capacity of the liver. This research assessed the effect of a high-intensity interval resistance training (HIIRT) on liver gluconeogenesis from lactate. Swiss mice were trained (groups T) on vertical ladder with overload of 90% of their maximal load. Control animals remained untrained (groups C0 and C8). In situ liver perfusion with lactate and adrenaline was performed in rested mice after 6 hours of food deprivation. There were larger outputs of glucose (T6, 71.90%; T8, 54.53%) and pyruvate (T8, 129.28%) (representative values for 4 mM lactate) in the groups trained for 6 or 8 weeks (T6 and T8), and of glucose in the presence of adrenaline in group T8 (280%). The content of PEPCK, an important regulatory enzyme of the gluconeogenic pathway, was 69.13% higher in group T8 than in the age-matched untrained animals (C8). HIIRT augmented liver gluconeogenesis from lactate and this might improve the lactate threshold. Novelty: The liver metabolizes lactate from muscle into glucose. Physical training may enhance the gluconeogenic capacity of the liver. As lactate clearance by the liver improves, lactate threshold is displaced to higher exercise intensities.

Strength Training Modulates Prostate of Wistar Rats Submitted to High-Fat Diet

Our aim is to evaluate the effects of high-fat diet and strength training on ventral prostate health through investigations of rat prostate histology, endocrine modulation, and the expression of proliferative and apoptotic marker, including androgen receptors (AR), glucocorticoid receptors (GR), B-cell lymphoma 2 (Bcl-2), Bcl-2 associated X protein (BAX), Fas cell surface death receptor (Fas/CD95/Apo-1), and Nuclear Factor Kappa-B (NF-κB). Eighty Wistar rats were into one of four subgroups: control (CT), strength training (ST), high-fat diet consumption (HF), and high-fat diet consumption with strength training (HFT). Animals then underwent strength training and/or high-fat diet consumption for 8 or 12 weeks, after which animals were euthanized and markers of prostatic health were evaluated histologically and through immunolabeling. Our results indicate that physical strength training reduced the expression of the prostate cell proliferation marker Bcl-2 while increasing expression of the pro-apoptotic marker BAX, as well as increasing expression of AR and GR relevant in the Bcl-2 pathway. We conclude that a high-fat diet can alter hormone receptor levels and cell-cycle protein expression, thereby modifying prostatic homeostasis, and that strength training was able to reduce prostate damage induced by high-fat diet consumption.

Intermittent resistance exercise and obesity, considered separately or combined, impair spermatic parameters in adult male Wistar rats

Obesity and absence of physical exercise are global problems that affect concentration and sperm quality in the male reproductive system. The purpose of this study was to examine the effect of obesity and resistance training, considered separately or in association, on testicular function and reproductive capacity. Twenty pubertal male Wistar rats were distributed into four groups: control (C) and exercise (E) groups that received standard rat chow; and obese (O) and obese with exercise (OE) groups that received a high-fat diet. All the groups received filtered water during the experimental conditions. Groups E and OE were submitted to 8 weeks of high-intensity intermittent training. Afterwards, testes were collected for sperm count, spermatogenic kinetics, histopathology, morphometry and immunodetection of androgen receptors (AR). The vas deferens was collected for sperm morphology. The results showed that obesity increased body weight, naso-anal length, liver and epididymal fat weight, abnormal spermatozoa and immunodetectable AR. Intermittent exercise decreased daily sperm production (DSP), sperm count and normal spermatozoa, whereas the number of tubules with immunodetectable AR increased. The combination of obesity and intermittent training led to reduced sperm count and DSP, although abnormal spermatozoa and the number of tubules with immunodetectable AR increased. Thus, in conclusion, both obesity and resistance training impaired testicular function during puberty in rats; and this type of exercise has also been shown to be detrimental to testicular physiology.

Light-intensity and high-intensity interval training improve cardiometabolic health in rats

Physical activity has the potential to reduce cardiometabolic risk factors but evaluation of different intensities of physical activity and the mechanisms behind their health effects still need to be fully established. This study examined the effects of sedentary behaviour, light-intensity training, and high-intensity interval training on biometric indices, glucose and lipid metabolism, inflammatory and oxidative stress markers, and vascular and cardiac function in adult rats. Rats (12 weeks old) were randomly assigned to 1 of 4 groups: control (CTL; no exercise), sedentary (SED; no exercise and housed in small cages to reduce activity), light-intensity trained (LIT; four 30-min exercise bouts/day at 8 m/min separated by 2-h rest period, 5 days/week), and high-intensity interval trained (HIIT, four 2.5-min work bouts/day at 50 m/min separated by 3-min rest periods, 5 days/week). After 12 weeks of intervention, SED had greater visceral fat accumulation (p < 0.01) and slower cardiac conduction (p = 0.04) compared with the CTL group. LIT and HIIT demonstrated beneficial changes in body weight, visceral and epididymal fat weight, glucose regulation, low-density lipoprotein cholesterol, total cholesterol, and mesenteric vessel contractile response compared with the CTL group (p < 0.05). LIT had significant improvements in insulin sensitivity and cardiac conduction compared with the CTL and SED groups whilst HIIT had significant improvements in systolic blood pressure and endothelium-independent vasodilation to aorta and mesenteric artery compared with the CTL group (p < 0.05). LIT and HIIT induce health benefits by improving traditional cardiometabolic risk factors. LIT improves cardiac health while HIIT promotes improvements in vascular health.