Transcutaneous electrical nerve stimulation at different frequencies on heart rate variability in healthy subjects

Abstract

Sympathetic and parasympathetic nervous system imbalance has been strongly associated to sudden cardiac death. Among the non-pharmacological treatment, transcutaneous electrical nerve stimulation (TENS) represents a possible therapeutic intervention to reduce sympathetic excitation and improve the sympatho-vagal balance in different clinical conditions. We aimed to verify acute effects of high and low transcutaneous electrical nerve stimulation (TENS) frequencies by the evaluation of heart rate variability. Seven healthy volunteers received an application of low frequency (10-Hz) and high frequency (100-Hz) TENS. After 10-Hz, there was decrease of LF normalized units (n.u.) component (32.7±5.9 vs 18.3±3.4, p<0.002) and increase of HF n.u. (60.9±4.3 vs 72.6±8.9, p<0.016). In contrast, after 100-Hz there was increase of LF n.u. (31.5±16.1 vs 41.6±12.2, p<0.019) and reduction of HF n.u. (63.9±15.3 vs 53.7±12.3, p<0.031). In conclusion, TENS modulates sympathetic and parasympathetic activity in a frequency dependent manner.

<b>Different frequencies of transcutaneous electrical nerve stimulation on sympatho-vagal balance

“…The hypothesis is that this therapeutic applied in the trajectory of the brachial nerve plexus (Franco et al, 2014) resource modifies the autonomic balance, with the high frequency being responsible for the decrease of the sympathetic activity, demonstrating that this application site presents opposite results to previous studies (Stein et al, 2011;Vieira et al, 2012;Ngai & Jones, 2013). The aim of this study was to evaluate the effects of TENS at low (10 Hz) and high (100 Hz) frequencies on autonomic balance in healthy subjects.…”

“…HRV was analyzed in the time and frequency domain, using the area of greatest stability in RR intervals corresponding to 5 min of recordings (containing at least 256 consecutive beats) during controlled breathing. Volunteers remained in a supine position at rest for 10 min and afterwards, data were collected with controlled breathing (12 breaths per minute; I/E:2/3) (Stein et al, 2011). Previously, there was training for the adaptation of the voluntary procedures.…”

“…Stein et al (2011) have demonstrated that the TENS low frequency (10 Hz) applied on paravertebral ganglionar region decreased sympathetic activity, and high frequency (100 Hz) increased this activity in healthy youngs (Stein et al, 2011). The TENS low frequency (2 Hz) applied to acupuncture point (BL 13 Feishu located lateral to the lower border of the T3 vertebra) also reduces the sympathetic activity (Ngai & Jones, 2013).…”

“…Therapeutic techniques that correct this imbalance are associated with reduced cardiovascular mortality (European Society of Cardiology [ESC], 1996). TENS is presented as a potential non-pharmacological resource that can be applied in the management of some cardiovascular diseases, such as hypertension (Chauhan et al, 1994;Cramp, Gilsenan, Lowe, & Walsh, 2000;Raimundo et al, 2009;Stein et al, 2011). Previous studies have demonstrated that TENS application reduced the systemic blood pressure of healthy volunteers (Sherry, Oehrlein, Hegge, & Morgan, 2001;Nitz, 2003;Vieira et al, 2012) and hypertensive patients (Kaada, Flatheim, & Woie, 1991;Jacobsson, Himmelmann, Bergbrant, Svensson, & Mannheimer, 2000).…”

“…autonomic nervous system (ANS) (Stein, Dal Lago, Ferreira, Casali, & Plentz, 2011;Vieira et al, 2012;Franco et al, 2014). Sympatho-vagal imbalance, especially the hyperexcitation is associated to the development of hypertension, cardiac arrhythmias and sudden death (Marmar & Shivkumar, 2008;Rizas et al, 2014).…”