Each volunteer will perform three assessments with a one-week interval. Each assessment will include assessment of autonomic balance, blood pressure, and blood collection (catecholamines). Interventions (placebo, low frequency TENS and IES) will be randomized. Volunteers will be accommodated in the supine position. With properly sanitized skin (70% alcohol) and self-adhesive electrodes (5x5 area) will be positioned in the cervical paravertebral region. All participants will be submitted to a placebo TENS session, a low frequency TENS session (TENS, 10 Hz/200μs) and an IES session (STEIN et al., 2012). The sessions will take place in the morning in a 12-hour fast, lasting 30 minutes, in an air-conditioned place (23ºC).
