The vagal stimulation is a promising therapy for a lot of disorders as well as hemodynamic regulatory way. In order to minimize the harm of a surgery chip implantation, actually it was developing a non-invasive device that is able to stimulate the auricular branch of vagal nerve. It has been shown that trans-auricular vagal stimulation (tVNS) causes direct stimulation of the vagal nerve. However, there are still no strong evidences about it actions regarding the autonomic modulation. The aim of this study is to evaluate effects of tVNS on heart rate, blood pressure and the autonomic control in healthy and hypertensive subjects, at rest and after orthostatic position

Normotensive group Inclusion Criteria:

• healthy volunteers
• sign the consent term

Normotensive group Exclusion Criteria:

• smokers
• alcoholism
• drug treatment
• skin lesion in the ear region
• chronic or acute diseases
• pregnancy
• be participating in another research protocol
• high performance athletes
• recent surgery
• vaso-vagal syndrome

Hypertensive group Inclusion Criteria:

• hypertensive diagnosis (with or without anti-hypertensive drugs treatment) or
• ambulatory blood pressure monitoring (ABPM) >130/85
• sign the consent term

Hypertensive group Exclusion Criteria:

• smokers
• alcoholism
• beta-blockers treatment
• skin lesion in the ear region
• associated diseases
• pregnancy
• be participating in another research protocol
• high performance athletes
• recent surgery
• vaso-vagal syndrome