Efeito da estimulação transcraniana por corrente contínua na pressão arterial em indivíduos pré- hipertensos em um teste incremental máximo

Abstract

Hypertension is a chronic disease that affects approximately 21.4% of the world's population, increases its prevalence significantly during the late twentieth century and is one of the main causes of death in the world. Controlling hypertension may reflect a reduction in mortality and an improvement in the population's quality of life. Therefore, developing treatments to control blood pressure (BP) is of paramount importance. In this context, transcranial direct current stimulation (tDCS) is a neuronal modulation technique whose efficiency and safety have already been proven through studies carried out for the treatment of various diseases. However, there are few studies that assess the effects of tDCS on the cardiovascular system. This study aimed to verify the effects of a single session of anodic tDCS without cardiac autonomic control in necessary pre-hypertensive patients during an incremental test performed until exhaustion. Nine participants were selected with systolic BP between 121 mmHg and 139 mmHg and diastolic BP between 81 mmHg and 89 mmHg, with an anodic and sham tDCS being obtained, followed by a maximum incremental test (TiMAX). BP was measured in five moments, after 10 minutes of rest and 15, 30, 45 and 60 minutes after TiMAX. Time to exhaustion was also analyzed. For this parameter, no difference was observed between the times of the participants in the tDCS and the sham. As for heart rate variability (HRV) for the time domain, when analyzing the RMSSD, a difference was found only in the time factor in relation to rest. Likewise, the heart rate observed difference only in the time factor in relation to rest for the procedure with 2 mA. When analyzing the frequency domain for HRV, it was possible to verify the explanatory difference for LF, HF and LF / HF ratio comparing the rest procedure with 2 mA. However, no difference was found when comparing tDCS (2 mA) and sham sessions. Analyzing the results using the delta (∆) value for systolic blood pressure (SBP) and diastolic blood pressure (DBP) it was possible to observe that a tDCS does not have a significant effect on a DBP, but it did have a significant effect on a SBP. Thus, it was possible to conclude that tDCS has no effect on HRV when compared to the 2mA and sham procedure, however, the data have a hypotensive effect, requiring further studies to explore the acute effect and a possible chronic effect.