Cardiac Structural Repercussions Induced by Exhaustive Physical Training in the Animal Model

The levels of physical activity (PA), as well as their intensity, are major impactors to achieve the full benefits of such practice. Exhaustive physical training (EPT) may be associated with the projection of structural damage to the heart muscle. Thus, the objective of the experimental study in the animal model, was to analyse how demanding training is related to structural changes in cardiomyocyte tissue. Sample of 15 male WISTAR rats at 04 weeks of age were randomly assigned to 02 groups: Sedentary (SED n = 5) and trained (TR n = 10) who were subdivided into a 1-week training (TR1 n = 5) and week (TR3 n = 5). The TR animals practiced running on a treadmill (-25º; 30m / minute; 60 min whose intensity increased 1.25 meters/ minute in each training session 6x / week for 03 weeks. The animals of the TR subgroup were sacrificed at the end of the first week (TR1 n = 5) and at the end of the third week (TR3 n = 5). For the inferential analysis, ANOVA was used and the data with non-normal distribution were then analysed with Kruskal-Wallis with a significance level of 5 % for macrophage M2, there was a significance between SED and TR1 with p = 0.0096, supposed to be a harmful process to the cardiac tissue due to excessive exposure. In the case of the M1 macrophage, significant differences were found in every period of training, meaning a picture of inflammation and interaction with adaptive immunity. The eccentric exercise practiced during the first three weeks induced cellular responses to stress stimuli in the cardiac tissue, maintaining the interaction of adaptive immunity. Potential benefits from the metabolic point of view, public health efforts should also focus on maintaining levels of physical activity since our study showed that intense physical activity had harmful effects at the cardiac level.

Keyword: Physical training, damage, cardiomyocytes, rats.