Efeito da natação na estrutura da artéria aorta durante o crescimento e desenvolvimento Paulo Alexandre Mendes Gouveia Porto,

Abstract

Swimming is an effective form of physical exercise with an important impact on cardiovascular health. It increases blood circulation, which induces a rise of shear stress, and improves flow-mediated dilation, which is a good indicator for the prevention of cardiovascular disease. Despite the known benefits of swimming, the lack of scientific evidence on the direct impact of artery remodelling on the structure and function of the aortic artery remains unclear. This study aimed to investigate whether swimming throughout growth and development alters the structure and morphology of the descending aortic artery. To match the longitudinal study in humans, an experimental protocol was carried out in male Wistar rats during the period between childhood and adulthood. The protocol lasted eight months and the animals entered the study at the age of three months. They were randomised into three groups of ten animals each: swimming group (SG), active swimming group (ASG) and active group (AG). ASG and AG were housed in free-wheeling cages to allow spontaneous running. SG and ASG were subjected to a swimming protocol (2h/day, 5x/week). After sacrifice and tissue preparation, morphometric evaluations and elastin and collagen percentage counts were carried out. There were no differences in the morphological dimensions of the descending aorta between the groups. However, the percentage of elastin was lower in the SG than in the ASG and AG. The percentage of collagen was lower in AG than in SG and ASG. The conclusion that swimming did not remodel vascular morphology, despite negatively altering the extracellular matrix (ECM), suggests that although regular exercise is widely associated with general health benefits, its effects on vascular health may be more complex than initially thought. This complexity indicates that more research is needed to fully understand the effects of swimming on cardiovascular health. Future studies should investigate whether the changes observed in ECM are temporary or whether they may represent a long-term risk. In addition, it will be important to explore how the intensity and duration of swimming, or the combination with other types of exercise, can influence these effects, potentially mitigating any negative impacts on vascular health.