20.500.12556/DiRROS-28857 The acute effects of varying frequency and pulse width of transcutaneous auricular vagus nerve stimulation on heart rate variability in healthy adults a randomized crossover controlled trial Background/Objective: Heart rate variability (HRV) is a key biomarker of autonomic function, linked to morbidity and mortality across various diseases. Transcutaneous auricular vagus nerve stimulation (taVNS) shows therapeutic promise, but its effects on HRV and the influence of specific stimulation parameters remain unclear. This study investigated whether the acute effects of taVNS on HRV depend on combinations of stimulation frequency and pulse width. Methods: Seventy-eight healthy adults participated in seven randomized sessions, each testing one of six active taVNS protocols or an inactive sham condition applied to the cymba conchae of the left ear. The active protocols varied by frequency (10 Hz or 25 Hz) and pulse width (100 µs, 250 µs, or 500 µs). The sessions included 15 min of baseline, 15 min of taVNS or sham condition, and 10 min of recovery. HRV was calculated using the standard deviation of NN intervals (SDNN) and the root mean square of successive differences (RMSSD) from continuous ECG recordings. Results: The 10 Hz/250 µs, 10 Hz/500 µs, and 25 Hz/100 µs protocols significantly increased SDNN time series compared to the sham condition. Exploratory analysis revealed SDNN increases during the second 5 min of stimulation with the 10 Hz/500 µs protocol and during the first 5 min of recovery with the 10 Hz/250 µs and 25 Hz/100 µs protocols. No significant changes in the RMSSD were found for any protocol. Conclusions: TaVNS is safe in healthy adults, and specific frequency and pulse width combinations can acutely enhance overall HRV, as reflected in SDNN, but do not affect vagally mediated HRV, as reflected by the RMSSD. Future studies should optimize taVNS parameters to maximize physiological and clinical outcomes. auricular stimulation autonomic cardiac regulation autonomic nervous system healthy subjects heart rate variability (HRV) neuromodulation stimulation parameters transcutaneous auricular vagus nerve stimulation (taVNS) aurikularna stimulacija avtonomna regulacija srca avtonomni živčni sistem zdravi subjekti variabilnost srčnega utripa (HRV) nevromodulacija parametri stimulacije transkutana aurikularna stimulacija vagusnega živca (taVNS) true false true Angleški jezik Slovenski jezik Neznano 2026-04-09 13:49:50 2026-04-09 13:49:50 2026-04-10 03:55:40 0000-00-00 00:00:00 2025 0 0 Nasl. z nasl. zaslona; Opis vira z dne 8. 5. 2025; str. 1-18 iss. 3, [article no.] 700 Vol. 13 2025 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 616-092:616.8 2227-9059 10.3390/biomedicines13030700 235154947 RAZ_Atanackov_Peter_2025.pdf RAZ_Atanackov_Peter_2025.pdf 1 4F390D945AFC3C38FA8EE0DDC145480B cd419c61587b86f5bce95e165465da9d30718cc11d3d54c12c6239f4d83396c8 59c3530e-340a-11f1-b941-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=43010 https://www.mdpi.com/2227-9059/13/3/700 1 38e5718e-340a-11f1-b941-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=43009 Univerzitetni klinični center Ljubljana 0 0 0