Abstract
Background: A session of resistance training (RT) will lead to metabolic and inflammatory changes. The aim of this study is to investigate metabolic and inflammatory changes in trained and untrained men.
Methods: Twenty-eight young healthy men (14 trained and 14 untrained people) participated in this present study. To assess metabolic and inflammatory responses and muscle damage, blood samples were gathered before, immediately and 1 hour after training.
Results: The percentage of muscle mass and baseline CK activity were significantly greater within the trained than the untrained group. After conducting a RT session, there was a significant reduction in insulin concentration and resistance within the two groups and in blood glucose only within the untrained group. In addition, RT was also associated with an increase in muscle damage biomarkers, CK, and LDH after training. Unlike CK, the activity of LDH was reduced during 1 hour of training (P < 0.05). Among the different inflammatory markers, only IL-6 concentration significantly increased within the two groups, which remained after 1 hour of training at the untrained group (P < 0.05).
Conclusions: The results of this study have shown that a RT session causes metabolic and inflammatory changes. The inflammatory response is significantly greater among subjects within the untrained group. Moreover, blood pressure response was also greater within the untrained group, which is directly related to the training intensity. However, there were no significant differences in metabolic responses and muscle damages between the trained and untrained subjects.
Keywords: Inflammation, Cytokine, Exercise, Resistance Training, Single Bout
1. Background
Elevated inflammatory biomarkers are important risk factors for age related morbidity and chronic diseases (1). Pro-inflammatory cytokines play a central role in immune responses. Furthermore, pro-inflammatory cytokines may be related to atherosclerosis, insulin resistance, and hypertension (2). According to previous studies, physical activity induces anti-inflammatory effects and reduces the risks of inflammatory related disease (3). Moreover, participants that tend to be active are at less risk of being diagnosed with chronic diseases than those that are not active or less active (4).
Resistance training (RT) is defined as the static or dynamic contractions of muscle against external resistances with different intensities. Long-term health benefits of RT have been presented previously (5). Systematic RT leads to the increase in muscle strength, endurance, and mass. Moreover, in addition, RT is related to the reduction in low grade inflammation related diseases, such as type 2 diabetes and cardiovascular diseases (6).
Unlike chronic exercise, a heavy training session may cause transient increases in inflammation (7). However, this finding is inconsistent, and the increases range from mild to intense (7, 8). This controversy may be related to different factors including differences in the characteristics of the participants, exercise type and intensity, intervention period, sampling time, genetic differences, and the method used to estimate circulatory cytokine concentrations. Furthermore, training experience may also have an effect on metabolic and inflammatory responses. Few studies are available regarding the comparison of metabolic and inflammatory responses in trained and untrained people. The present study tests two hypotheses....