Visceral lipid accumulation, organ hypertrophy and a reduction in skeletal muscle strength are all signs associated with the severity of obesity-related disease. Intermittent fasting (IF) and high-intensity intermittent exercise (HIIE) are natural strategies that, individually, can prevent and help treat obesity along with metabolic syndrome and its associated diseases. However, the combinatorial effect of IF and HIIE on energetic metabolism is currently not well understood. We hypothesized that their combination could have a potential for more than strictly additive benefits. Here, we show that two months of every-other-day intermittent fasting regimen combined with a high-intensity intermittent exercise protocol (IF/HIIE) produced a synergistic effect, enhancing physical endurance (vs. control, HIIE and IF) and optimizing metabolic pathways of energy production in male Wistar rats. The IF/HIIE group presented enhanced glucose tolerance (vs. control, HIIE and IF), lower levels of plasma insulin (vs. control and HIIE), and a global activation of low Km hexokinases in liver (vs. control, HIIE and IF), heart (vs. control and HIIE) and skeletal muscle (vs. control, HIIE and IF). The IF/HIIE synergism, rather than a simply additive effect, is evidenced by increase in muscle mass and cross-section area, activation of the FoF1 ATP synthase, and the gain of characteristics suggestive of augmented mitochondrial mass and efficiency observed in this group. Finally, important reductions in plasma oxidative stress markers were present preferentially in IF/HIIE group. These findings provide new insights for the implementation of non-pharmaceutical strategies to prevent/treat metabolic syndrome and associated diseases.

Background: Cirrhosis represents an advanced stage of hepatic fibrosis, and the metabolic changes resulting from liver dysfunction can cause impairment in physical capacity and quality of life. This study aimed to evaluate the effect of 12 weeks of resistance exercise on inflammatory markers, oxidative stress, physical conditioning, and quality of life in patients with liver cirrhosis. Methods: A total of 38 patients paired in the exercise (EG) and control (CG) groups participated in this study. The EG submitted to two weekly sessions of a program composed of resistance exercises. We evaluated the inflammatory markers (IL-6, IL-10, and TNF-α), oxidative stress (carbonylated protein, total thiols, enzyme superoxide dismutase, and catalase activity), body composition, handgrip strength (HGS), total volume of training, cardiorespiratory capacity (VO₂, VCO₂, and VE_peak), exercise capacity, and quality of life. Results: Regarding the EG, when comparing the follow-up period to the baseline, significant differences (p < 0.05) were found in BMI, HGS, total training volume, cardiorespiratory capacity variables, the 6 min walk test, and quality of life. Improvements were observed, without significant differences, in the inflammatory profile, oxidative stress, and one of the markers of liver function. The CG showed a significant decrease (p < 0.05) in HGS and cardiorespiratory capacity after the intervention. Conclusions: In patients with liver cirrhosis, a resistance exercise program improved physical fitness and quality of life, without adverse events. In addition, it seems that this type of training can bring some benefit to the inflammatory profile and oxidative stress of this population.

Visceral lipid accumulation, organ hypertrophy and a reduction in skeletal muscle strength are all signs associated with the severity of obesity related disease. Intermittent fasting (IF) and high-intensity intermittent exercise (HIIE) are natural strategies that, individually, can prevent and ameliorate obesity along with metabolic syndrome and its associated diseases. However, the combinatorial effect of IF and HIIF on energetic metabolism is currently not well understood. We hypothesized that their combination could have a potential for more than strictly additive benefits. Here, we show that two months of every-other-day intermittent fasting regimen combined with a high-intensity intermittent exercise protocol (IF/HIIE) produce a synergetic effect, preventing fat accumulation, enhancing physical performance and optimizing energy production. The IF/HIIE group presented increased glucose uptake, lower levels of serum insulin and a global activation of hexokinases in skeletal muscle, heart and liver comparing to control, IF and HIIE groups. IF/HIIE synergism led to activation of the FoF1 ATP synthase and promoted a more oxidative profile of mitochondria in observed skeletal muscle. Additionally, high-resolution respirometry of muscle fibers showed that animals in the IF/HIIE group presented characteristics suggestive of augmented mitochondrial mass and efficiency. Finally, an important reduction in serum oxidative stress markers were observed in IF/HIIE group. These findings provide new insights for the implementation of non-pharmaceutical strategies to prevent/treat metabolic syndrome and associated diseases.

High accuracy in estimating energy expenditure is essential for enhancing sports performance. The resting metabolic rate (RMR), as a primary component of total energy expenditure (TEE), is commonly estimated using predictive equations. However, these references may not be applicable to adolescent athletes. The purpose of this cross-sectional study was to analyse the differences between predicted RMR in relation to energy expenditure measured by indirect calorimetry (IC) among 45 Brazilian male adolescent football athletes. Indirect calorimetry (IC) and anthropometric (bioimpedance) measurements were recorded at a single visit to the laboratory after fasting overnight. The mean age was 15.6 ± 1.14 years, body mass was 63.05 ± 7.8 kg, and height was 172 ± 7.5 cm. The RMR values predicted by equations proposed by the Food and Agriculture Organization (FAO) (United Nations), Henry and Rees (HR), Harris Benedict (HB), and Cunningham (CUN) were compared with IC RMR values, by correlation analysis. The FAO and HR predictive equations yielded different values from IC (IC: 1716.26 ± 202.58, HR: 1864.87 ± 147.78, FAO: 1854.28 ± 130.19, p = 0.001). A moderate correlation of 0.504 was found between the results of HB and IC. In the survival-agreement model, the CUN equation showed low disagreement with the IC RMR, with error values between 200 and 300 kcal/day. The results showed that HB and CUN yielded similar values as IC, with the CUN equation showing low disagreement with IC; hence, adolescent athletes should undergo evaluation with precise laboratory methods to ensure that accurate information about RMR is recorded.

This cross-sectional study analysed the effect of the gas exchange data selection methods on the resting metabolic rate (RMR) estimation and proposed a protocol shortening providing a suitable RMR estimation for young athletes. Sixty-six healthy young Brazilian athletes performed a 30-minute RMR assessment. Different methods of gas exchange data selection were applied: short and long-time intervals, steady-state (SSt), and filtering. A mixed one-way ANOVA was used to analyse the mean differences in gas exchange, RMR, respiratory exchange ratio (RER), and coefficients of variation across all methods. Additionally, paired Student’s t-test were used to compare the first and best SSt RMR values for each SSt method (3, 4, and 5-min). The 5-min SSt method provided the lowest RMR estimate (1454 kcal.day^-1). There was a statistical difference between methods (F = 2.607, p = 0.04), but they presented a clinically irrelevant absolute difference (~36 kcal.day^-1). There were no differences in RER among methods. In addition, using the SSt method, 12 minutes of assessment were enough to obtain a valid estimation of RMR. The 5-min SSt method should be employed for assessing the RMR among young athletes, considering the possibility of obtaining a shortened assessment (~12 min) with an acceptable and low coefficient of variation.

This study investigated oxidative stress, anthropometric measurements, and performance after an eight-week training program with soccer players. Sixteen U-17 male players participated in an eight-week training program, which included daily soccer training sessions lasting approximately two hours. Data collection was conducted at three distinct time points: one week prior to the start of the competitive season (Baseline), one week before the onset of the training program (Pre-training), and immediately following the eight-week intervention (Post-training). During the pre- and post-training phase, participants completed a standardized battery of physical performance tests, followed by blood sample collection. The battery of physical tests was performed in the following order: a) 30-m sprint, b) countermovement jump (CMJ), c) dribbling with/without the ball, and e) the field-based Yo-Yo Intermittent Recovery Test Level 2 (Yo-Yo IR2). Acceleration (10 m) and sprint time (30 m) were lower in the pre-training than in the post-training (p = .02 and p = .048, respectively). Creatine kinase levels were higher in the pre-training than at baseline and the post-training (p ≤ .001). Protein carbonyl levels were elevated in both the pre- and post-training compared to baseline (p ≤ .001). Catalase activity was higher in the post-training than at baseline (p = .001). The total distance covered in the Yo-Yo IR2 test and VO₂max increased in the post-training. This study demonstrated that an eight-week structured training program increases catalase activity and stabilizes creatine kinase and protein carbonyl levels following repeated exposure to soccer-specific physical testing.