Moderate and regular physical activity helps reduce the risk of cardiovascular diseases. However, recent studies suggest that the practice of high-intensity exercise favors the appearance of coronary pathologies, that is, alterations in the arteries that supply blood, oxygen and nutrients to the heart.
Edward Guaschcardiologist at Clinical Hospital of Barcelona and head of the IDIBAPS Arrhythmias and physical activity group explains in a statement that: “We do not have many data, a fact that makes it difficult to establish a cause-effect relationship, due to the risk of bias and the possibility of confounding factors. However, it seems that the prevalence of these diseases increases in those who run marathons or participate in extreme or high-intensity sports for many years. However, we do not know why this happens.», explains Eduard Guasch, cardiologist at the Hospital Clínic de Barcelona and head of the IDIBAPS Arrhythmias and physical activity group.
Now, Guasch and his team are leading a study, published by the Journal of the American College of Cardiology – Basic to Translational Science, that evaluates the effect of intense exercise in an animal model. Researchers from the University of Barcelona, the Institute of Bioengineering of Catalonia and the Hospital Sant Joan de Déu have also participated in the work.
How the study was done
The study carried out in an animal model to be able to precisely control the intensity of the exercise for long periods of time. The male rats used in the experiments were divided into three groups. The first followed a moderate exercise regimenwhich reproduced an active lifestyle, while the second underwent a very high intensity routine, similar to that of extreme athletes. Finally, the third group of animals, the sedentary, remained in the cages. «The training, with a treadmill for rodents, lasted sixteen weeks, equivalent, very roughly, to regarding 10-12 years of exercise in humans. After this time, we analyzed the stiffness and structure of the aortic artery, as well as its endothelial function. This last parameter is an early marker of atherosclerosis, or hardening of the arteries, the main cause of myocardial infarctions”, Guasch points out.
According to the results, compared to a sedentary lifestyle, high-intensity physical exercise dilates and increases the stiffness of the aortic and carotid arteries. Likewise, it also increases the rigidity of the cells and favors the rupture of the elastic sheets of the walls of the blood vessels. “These effects, however, are not observed in the case of moderate exercise,” the researcher points out. “In contrast, both intense and moderate exercise improve endothelial function, although intense activity seems to alter the balance between the processes of dilation and contraction of blood vessels.”
High-intensity physical exercise dilates and increases stiffness of the aortic and carotid arteries, according to the study
The research team also identified some of the mechanisms involved in this vascular remodeling, which persisted for up to four weeks following stopping physical activity. ‘Despite the limitations of using an animal model, our data suggest that intense exercise does not directly cause atherosclerosis, but rather a different process, similar to vascular aging. In addition, this type of activity might also reduce the benefits of moderate exercise, “concludes Guasch.
The project has received direct funding from the Carlos III Health Institute (ISCIII) and the National Plan (Ministry of Economy), as well as indirect funding from the Generalitat, since the group is one of the Research Groups Recognized by this institution, from the CIBERCV and the ERDF.
