Study details benefit of aerobic training against chronic hypertension and heart failure

Researchers from the Institute of Biomedical Sciences at the University of São Paulo (ICB-USP) discovered, through experiments with rats, how aerobic exercise improves the control of arterial hypertension in individuals with chronic hypertension or heart failure. According to studies, training helps correct dysfunctions in the blood-brain barrier and restores blood flow in the central nervous system even in case of persistence of the disease.

The blood-brain barrier is a structure whose function is to regulate the transport of substances between the blood and the central nervous system, blocking the entry of toxic substances and excess plasma hormones. These hormones, in amounts above the ideal, are capable of activating neurons involved in the regulation of the cardiovascular system, leading to autonomic dysfunction and imbalance in blood circulation. This facilitates the appearance of lesions in target organs, which may compromise the heart, brain, kidney, among other organs.

“In addition to correcting the autonomic control of circulation, aerobic training contributes to a 10% to 15% reduction in blood pressure levels in hypertensive patients”, says Lisete Compagno Michelini, coordinator of the Laboratory of Cardiovascular Physiology, responsible for the studies, in an interview for the ICB-USP press office.

The investigation received funding from FAPESP through the thematic projects “Blood-brain barrier: a new paradigm in the treatment of hypertension” and “Amelioration of the autonomic imbalances of old age with exercise: exploring the molecular and physiological mechanisms”, in addition to the project “Blood-brain barrier and autonomic regulation in arterial hypertension: effects of angiotensin II and aerobic training”.

Substance filter

Found in the cerebral capillaries through which blood circulates, the blood-brain barrier is composed of endothelial cells closely linked to each other by tight junctions that limit the passage of water-soluble substances. There is no limit to the passage of liposoluble substances, such as oxygen and carbon dioxide, through the endothelial cell. The problem is macromolecules, including toxic substances and plasma hormones.

“In healthy individuals, the passage of macromolecules, which occurs through blood vesicles, is quite limited. However, we observed that in hypertensive and heart failure patients there is a significant increase in the number of these vesicles in autonomic areas, which increases permeability of the blood-brain barrier. On the other hand, we observed that the aerobic training greatly reduced the formation of these vesicles, in addition to normalizing the permeability of the blood-brain barrier”, explains Michelini.

According to the ICB professor, it was already known that in cases of stroke, trauma and neurodegenerative diseases, the integrity of the barrier was compromised by the breakdown of occlusive junctions, which allowed free access to substances. “In our experiments, we observed that in hypertension and heart failure there is no break in areas of cardiovascular control, but an increase in permeability by facilitating the transport of vesicles, which can be promptly corrected by aerobic training”, she points out.

The findings made by the team reinforce the importance of physical training to improve the autonomic control of circulation, since, in addition to being an important ally in the pharmacological treatment of these pathologies, it allows reducing the necessary amount of medication and, consequently, reduces the occurrence of side effects. collateral.

“Physical exercise, like different drugs, favors vascular vasodilation, helps to balance deviations in the renin-angiotensin system, responsible for regulating blood pressure, and improves autonomic control of circulation”, says Michelini.

The group continues to study the functioning of the blood-brain barrier, now with the objective of evaluating whether the increased vesicular transport in hypertension and heart failure, but reduced in both situations by aerobic training, is mediated by the availability of the hormone angiotensin II and/or cytokines pro-inflammatory. The group will also verify whether the results obtained in primary hypertension (without clear cause) are also applicable to secondary hypertension, derived from another condition (such as sleep apnea, renal failure and hypothyroidism, among others).