Transcutaneous Electrical Nerve Stimulation on Nervous System in Patients With Hypertension.

Hypertension has high prevalence and poor control rates and is considered one of the major modifiable risk factors for cardiovascular system diseases, and one of the most important public health problems. The imbalance of the autonomic cardiovascular control, which can be considered as a major etiologic factor in the development of essential hypertension is characterized by increased sympathetic activity and reduced parasympathetic activity possible. Cardiovascular disease is the leading cause of death and disability in the world and autonomic imbalance is associated with several pathological conditions, and may be a final common pathway for the increased morbidity and mortality of cardiovascular diseases. In this sense, the heart rate variability (HRV) is a quantitative marker of sympathetic and parasympathetic activity, which can be used to assess disease and mortality as a noninvasive technique. TENS is a noninvasive therapeutic modality, easy to handle, it has no side effects or interactions with medications being used for the relief of pain by sensory stimulation through peripheral nerves and mainly for control and treatment of acute and chronic pain . Research on the effect of TENS on the sympathetic and parasympathetic nervous system activity remain controversial, especially regarding the parameters to use. The aim of this study is to investigate the effects of TENS on the sympathetic and parasympathetic nervous system in patients with hypertension by heart rate variability and blood pressure variability. This is a randomized clinical trial, double blind, where hypertensive patients were randomized to three groups: high-frequency TENS (100 Hz) n = 20, low frequency TENS (4 Hz) n = 20 and n = 20 placebo. Evaluations will be made in a single session. The results will be assessed by a blinded investigator and randomization will be done electronically. It is expected to evaluate how often TENS exerts more influence in the modulation of sympathetic and parasympathetic system.