Key result
Transcutaneous auricular vagus nerve stimulation lowers blood pressure in healthy adults but fails in hypertension.
Why the study?
Does acute transcutaneous auricular vagus nerve stimulation applied to the cymba conchae or tragus reduce blood pressure and improve cardiac autonomic modulation in hypertensive and healthy individuals?
RCT (n=28)
Single-blind
Randomized crossover
No
Does acute transcutaneous auricular vagus nerve stimulation applied to the cymba conchae or tragus reduce blood pressure and improve cardiac autonomic modulation in hypertensive and healthy individuals?
Effect estimate: Wald χ2 = 19.0 for SBP and 10.0 for DBP
p-value: p=0.001 for SBP, 0.038 for DBP
A single acute session of transcutaneous auricular vagus nerve stimulation produces modest, site- and group-dependent hemodynamic responses, suggesting that short-term protocols are likely insufficient to overcome the impaired autonomic regulation characteristic of hypertension.
BACKGROUND: and PurposeTranscutaneous auricular vagus nerve stimulation (taVNS) has emerged as a promising noninvasive strategy to modulate autonomic function and reduce blood pressure (BP). However, whether the stimulation site influences acute cardiovascular responses remains unclear. OBJECTIVE: To compare the acute effects of taVNS applied to the tragus and cymba conchae on BP and cardiac autonomic modulation in hypertensive and healthy individuals. METHODS: This pilot randomized crossover clinical trial included 14 hypertensive and 14 healthy participants who underwent two taVNS sessions (tragus and cymba conchae) in randomized order, one week apart. Sessions lasted 30 min and delivered a sinusoidal current (30 Hz, 500 ms pulse width), with intensity adjusted to the individual sensory threshold. Systolic BP (SBP), diastolic BP (DBP), and heart rate variability (HRV) parameters were assessed at baseline, during stimulation, and post-stimulation. Generalized estimating equations were used for analysis. RESULTS: = 10.0, p = 0.038). Cymba conche stimulation reduced BP in healthy individuals, whereas no meaningful BP changes were observed in hypertensive participants. Tragus stimulation reduced diastolic BP only in the hypertensive group. Significant interactions were also detected for normalized spectral HRV components and sample entropy (p < 0.05), though autonomic responses were modest and not consistently indicative of enhanced parasympathetic modulation. DISCUSSION: Acute taVNS induces site- and group-dependent cardiovascular responses, with limited clinical impact after a single session. These findings suggest that short-term stimulation may be insufficient to overcome impaired autonomic regulation in hypertension and highlight the need for repeated or longer stimulation protocols in future clinical trials.
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Souza et al. (2026) conducted an RCT in Hypertension (n=28). Transcutaneous auricular vagus nerve stimulation (taVNS) at the cymba conchae vs. taVNS at the tragus was evaluated on Interaction effect of time, stimulation site, and group on systolic and diastolic blood pressure (Wald χ2 = 19.0 for SBP and 10.0 for DBP, p=0.001 for SBP, 0.038 for DBP). A single session of transcutaneous auricular vagus nerve stimulation induced site- and group-dependent cardiovascular responses (interaction p=0.001 for SBP), significantly reducing blood pressure in healthy individuals but failing to produce meaningful clinical effects in hypertensive participants.
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