Associating the practice of aerobic physical activity with the use of the drug losartan increases the benefits for hypertensive patients, especially with regard to cardiac autonomic regulation, contributing to the proper functioning of the cardiovascular system.
That was the conclusion of a survey carried out with male volunteers in the FMRP-USP (University of São Paulo at Ribeirão Preto School of Medicine).
Scientists have shown that walking for 45 minutes, three times a week, improves heart rate variability, a scientifically validated marker that measures the functioning of the autonomic nervous system, responsible for regulating physiological processes in the body, such as blood pressure and respiratory rate.
The drug is considered the first line of treatment for high blood pressure (reducing the risk of cardiovascular events), heart failure and is also indicated for kidney protection. It has a mechanism of action that blocks the AT1 receptor for angiotensin 2 – a peptide that causes the muscular walls of small arteries (arterioles) to contract, increasing blood pressure.
According to the study, published in the scientific journal Clinical and Experimental Hypertensionlosartan is able to reduce blood pressure, bringing it to normal levels, but without physical exercise, cardiac autonomic control remains very poor.
“Heart rate variability is not adequately restored with the drug alone. So much so that one of the interesting points observed is that the patient treated with losartan has less heart rate variability than the untreated individual. This means that the regulation of pumping blood through the cardiovascular system is not at an adequate level. Reducing blood pressure is necessary and essential, but medication alone is not enough. Exercise complements the effect”, says Hugo Celso Dutra de Souza, professor at FMRP-USP and corresponding author of the article .
The research received support from Fapesp and its first author is Tábata de Paula Facioli, who was a student at the Laboratory of Physiotherapy and Cardiovascular Physiology, coordinated by Souza.
cases
A global analysis of trends in the prevalence, detection, treatment and control of hypertension, led by Imperial College London and the WHO (World Health Organization), showed that the number of adults (between 30 and 79 years old) with the disease increased from 650 million to 1.28 billion in the last 30 years.
Almost half of these people did not know they had this condition. In Brazil, about 30% of adults are hypertensive, according to data from the Brazilian Society of Cardiology (SBC).
Hypertension increases the risk of heart, brain and kidney disease. It is one of the main causes of death and disease worldwide and can be easily detected by measuring blood pressure. In many cases it is effectively treated with low-cost drugs, including losartan, enalapril maleate, hydrochlorothiazide, propranolol and amlodipine.
Souza recalls that, in 2015, another study published by his group, also supported by FAPESP, had investigated heart rate variability in animal models.
“At the time, we were working with spontaneously hypertensive rats (SHR) to understand whether aerobic exercise was better suited to certain pharmacological therapies. We saw that the drugs had discrepant results between them. As many patients use these drugs, we decided to study in humans to analyze the effect”, says the professor.
Method
The researchers had a sample of 32 men (between 40 and 60 years old), divided into two groups: people with normal blood pressure (normotensives) and hypertensive people treated with losartan.
They underwent aerobic physical training for 16 weeks. Hemodynamic parameters, heart rate variability, blood pressure variability, and spontaneous baroreflex sensitivity (a short-term blood pressure control mechanism) were measured before and after exercise.
Before training, both groups recorded similar values ??of hemodynamic parameters. However, hypertensive patients had reduced spontaneous baroreflex sensitivity and heart rate variability, characterized by decreased sympathetic and vagal modulation.
After exercise, normotensive subjects had a decrease in resting heart rate, as did hypertensive subjects. However, this last group also showed a reduction in blood pressure and sympathetic modulation; increased vagal modulation and spontaneous baroreflex sensitivity, but with lower heart rate variability compared to normotensive individuals.
The autonomic nervous system controls the body’s internal processes through two branches: sympathetic and parasympathetic (also called vagal).
Sometimes the two can have opposite effects on the same organ. For example, the sympathetic division increases heart rate and the parasympathetic division reduces it. Overall, together, they ensure that the body responds appropriately to different situations, such as stress.
As women have different modulation of the autonomic nervous system from men, mainly as a result of ovarian hormones, Souza explains that there was a separation to develop the research.
“The study with women is in its final phase. We have already observed interesting results, especially comparing the effect of hypertension in women before and after menopause”, says the professor.
The researchers are also working on a paper comparing losartan with enalapril maleate to show the differences. The former blocks the angiotensin receptor and enalapril acts on the angiotensin-converting enzyme.
“Physical exercise is important, and has been seen as a kind of magic pill. However, we need to understand what it really does in the body so that, who knows, in the future, we may try to pharmacologically simulate its effects”, concludes Souza.