Browsing by Author "Gonzalez-Rojas, Luis"

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    Cardiorespiratory fitness and fat oxidation during exercise as protective factors for insulin resistance in sedentary women with overweight or obesity
    (2018) Cancino-Ramirez, Javiera; Soto-Sanchez, Johana; Zbinden-Foncea, Hermann; Moreno González, Manuel I.; Leyton-Dinamarca, Barbara; Gonzalez-Rojas, Luis
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    Influence of Body Composition on Cardiorespiratory Fitness and Metabolic Markers in Physically Inactive Individuals with Insulin Resistance: An Observational Study
    (2023) Azocar-Gallardo, Jairo; Ojeda-Aravena, Alex; Baez-San Martin, Eduardo; Campos-Uribe, Victor; Gonzalez-Rojas, Luis; Castillo Cerda, Maria A.; Garcia-Garcia, Jose Manuel
    The aim of this study was to determine body composition influence on cardiorespiratory fitness and metabolic markers in physically inactive individuals with insulin resistance (IR). Nineteen overweight and obese (body mass index [BMI] 25.0-29.9 kg center dot m(-2); >= 30.0 kg center dot m(-2), respectively) patients diagnosed with IR (5 men and 14 women; age: 32.74 +/- 10.07 years; BMI: 32.5 +/- 4.60 kg center dot m(-2)). The body composition included BMI, fat mass, and fat-free mass. Cardiorespiratory fitness was measured by maximal oxygen uptake (VO(2)max). Metabolic markers included maximal fat oxidation, fasting glucose, and insulin. IR was determined by homeostatic model assessment (HOMA-IR). The results of the partial correlations (i.e., body mass, age, and sex) reported that fat-free mass, fat mass, and BMI were significantly correlated with VO(2)max. Additionally, the multiple linear regression model indicated that fat-free mass and BMI explained the variance of VO(2)max by 89%. However, no substantial correlations were reported between fat mass or fat-free mass with HOMA-IR, fasting glucose, or insulin. This study concluded that a higher percentage of fat-free mass and lower BMI is positively related to better cardiorespiratory fitness despite the IR status of the participants analyzed.
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    Overweight and Obese Adult Patients Show Larger Benefits from Concurrent Training Compared with Pharmacological Metformin Treatment on Insulin Resistance and Fat Oxidation
    (2022) Azocar-Gallardo, Jairo; Ramirez-Campillo, Rodrigo; Afonso, Jose; Sa, Mario; Granacher, Urs; Gonzalez-Rojas, Luis; Ojeda-Aravena, Alex; Manuel Garcia-Garcia, Jose
    Metformin, a drug widely used to treat insulin resistance, and training that combines aerobic and strength exercise modalities (i.e., concurrent training) may improve insulin sensitivity. However, there is a paucity of clinical trials investigating the effects of concurrent training, particularly on insulin resistance and fat oxidation in overweight and obese patients. Furthermore, only a few studies have compared the effects of concurrent training with metformin treatment. Therefore, the aim of this study was to examine the effects of a 12-week concurrent training program versus pharmaceutical treatment with metformin on maximum fat oxidation, glucose metabolism, and insulin resistance in overweight or obese adult patients. Male and female patients with insulin resistance were allocated by convenience to a concurrent training group (n = 7 (2 males); age = 32.9 +/- 8.3 years; body mass index = 30 +/- 4.0 kg center dot m(-2)) or a metformin group (n = 7 (2 males); age = 34.4 +/- 14.0 years; body mass index = 34.4 +/- 6.0 kg center dot m(-2)). Before and after the interventions, all participants were assessed for total body mass, body mass index, fat mass, fat-free mass, maximum oxygen consumption, maximal fat oxidization during exercise, fasting glucose, and insulin resistance through the homeostatic model assessment (HOMA-IR). Due to non-normal distribution of the variable maximal fat oxidation, the Mann-Whitney U test was applied and revealed better maximal fat oxidization (Delta = 308%) in the exercise compared with the metformin group (Delta = -30.3%; p = 0.035). All other outcome variables were normally distributed, and significant group-by-time interactions were found for HOMA-IR (p < 0.001, Delta = -84.5%), fasting insulin (p < 0.001, Delta = -84.6%), and increased maximum oxygen consumption (p = 0.046, Delta = 12.3%) in favor of the exercise group. Similar changes were found in both groups for the remaining dependent variables. Concurrent training seems to be more effective compared with pharmaceutical metformin treatment to improve insulin resistance and fat oxidation in overweight and obese adult patients with insulin resistance. The rather small sample size calls for more research in this area.
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    Oxygen pulse as a protective factor of insulin resistance in sedentary women with overweight or obesity
    (2018) Gonzalez-Rojas, Luis; Soto-Sanchez, Johana; Cano-Cappellacci, Marcelo; Muñoz Claro, Rodrigo Edgardo; Cancino-Ramirez, Javiera