Healthy VolunteerstaVNS-HRVNCT07526415
Effect of Recording Duration on Heart Rate Variability During taVNS
A study testing Transcutaneous Auricular Vagus Nerve Stimulation in people with Healthy Volunteers, run by Sinop University at 1 site in Turkey (Türkiye).
Trial summary
This study aims to evaluate how different heart rate variability (HRV) recording durations reflect autonomic nervous system responses during transcutaneous auricular vagus nerve stimulation (taVNS) in healthy adults. Read more about this study
- Who is it for?
- Ages 18 to 40 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy Volunteers
- What is being tested?
- Transcutaneous Auricular Vagus Nerve Stimulation
- Type of treatment
- Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 40 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 1 May 2026to 15 Sep 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 40 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy volunteers aged 18 to 40 years
- Able and willing to provide informed consent
- Able to tolerate active transcutaneous auricular vagus nerve stimulation and sham stimulation
- Able to comply with study instructions, including restrictions related to caffeine, nicotine, and heavy exercise before assessment
- No condition preventing heart rate variability, blood pressure, or pulse measurements
Who cannot join
- Diagnosed cardiovascular disease, arrhythmia, or pacemaker use
- History of neurologic disease that may affect autonomic nervous system function
- Regular use of medications that may affect heart rate variability or autonomic responses, including beta blockers, antiarrhythmics, or anticholinergic drugs
- Active ear infection, dermatologic lesion, or any ear condition that may interfere with stimulation
- Marked pain, discomfort, or intolerance during stimulation
- Acute infection, fever, or other acute health problem on the measurement day
- Heart rate variability data that cannot be evaluated because of excessive motion artifact
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Turkey (Türkiye)1 site
Artvin Coruh University, Artvin Vocational School, Disabled Care and Rehabilitation Laboratory, Artvin,
Artvin
Ömer Dicle Kızıl, MSc, +90 541 523 36 91, omerdiclekizil@gmail.com
Ömer Dicle Kızıl, MSc
About this study
Official title: Effect of Recording Duration on Heart Rate Variability During Transcutaneous Auricular Vagus Nerve Stimulation: A Randomized, Sham-Controlled Crossover Study
This study aims to evaluate how different heart rate variability (HRV) recording durations reflect autonomic nervous system responses during transcutaneous auricular vagus nerve stimulation (taVNS) in healthy adults. In a randomized, sham-controlled crossover design, participants will attend two separate sessions and receive both active taVNS and sham stimulation in randomized order. During each session, a continuous 10-minute HRV recording will be obtained, and 1-minute, 5-minute, and 10-minute analysis windows will be compared. Blood pressure and pulse will also be measured before and after stimulation. The study will investigate whether shorter or longer HRV recording durations provide results comparable to the standard 5-minute recording and which duration most reliably detects autonomic changes during taVNS.
Read the detailed description
The vagus nerve plays a central role in autonomic regulation, and heart rate variability (HRV) is a widely used noninvasive marker of autonomic nervous system activity. Transcutaneous auricular vagus nerve stimulation (taVNS) has increasingly been used in experimental and clinical research as a noninvasive method to modulate vagal activity. Although previous studies suggest that taVNS may influence parasympathetic activity, HRV measurement duration remains an important methodological issue. Standard short-term HRV analysis is commonly based on 5-minute recordings, but ultra-short and longer recordings are also used, and their validity during taVNS has not been sufficiently clarified.
This study is designed to determine whether different HRV recording durations provide comparable and reliable information during taVNS. The study will use a randomized, sham-controlled crossover design. Healthy adult participants will attend two sessions separated by a washout period of 48 to 72 hours. In one session, participants will receive active taVNS; in the other, they will receive sham stimulation. The order of sessions will be randomized.
During each session, HRV data will be collected continuously for 10 minutes using a Polar H10 chest strap. From this single uninterrupted recording, 1-minute, 5-minute, and 10-minute analysis windows will be derived. HRV parameters from time-domain and frequency-domain analyses will be calculated. Blood pressure and pulse will be measured before and after the intervention using an automated upper-arm blood pressure monitor.
Active taVNS will be applied to the cymba conchae region of the ear using commonly reported stimulation parameters. Sham stimulation will be delivered with the same device and similar sensory conditions, but at a non-vagal ear location to minimize physiologic vagal effects. This design is intended to control for nonspecific sensory and expectation-related effects.
The primary objective is to assess whether the standard 5-minute HRV recording during taVNS detects autonomic effects compared with sham stimulation. Secondary objectives are to examine the agreement between 1-minute, 5-minute, and 10-minute HRV measurements and to evaluate whether shorter or longer recordings provide additional methodological value. The relationship between HRV findings and hemodynamic responses, including blood pressure and pulse, will also be explored. This study may help identify the most appropriate HRV recording duration for future taVNS research and contribute to methodological standardization in this field.
- Conditions
- Healthy Volunteers
- Being tested
- Transcutaneous Auricular Vagus Nerve Stimulation, Sham Stimulation
- Keywords
- Transcutaneous Auricular Vagus Nerve Stimulation, taVNS, Autonomic Nervous System
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Transcutaneous Auricular Vagus Nerve StimulationDevice
Also called taVNS
Active transcutaneous auricular vagus nerve stimulation will be applied bilaterally to the cymba conchae region of the ear using a transcutaneous stimulation device. Stimulation will be delivered for 10 minutes with a frequency of 25 Hz, a pulse width of 200 to 300 microseconds, and an individually adjusted intensity that is clearly perceptible but not painful. Heart rate variability will be recorded continuously during the intervention.
Sham StimulationDevice
Also called Sham taVNS
Sham stimulation will be delivered for 10 minutes using the same transcutaneous stimulation device and similar stimulation settings as the active intervention, but the stimulation will be applied to a non-vagal ear region, such as the earlobe or helix, to minimize physiologic vagal effects while maintaining similar sensory input. Heart rate variability will be recorded continuously during the intervention.
| Study group | Role | What they receive |
|---|---|---|
| taVNS First | Experimental | Participants assigned to this sequence will receive active transcutaneous auricular vagus nerve stimulation (taVNS) during the first session and sham stimulation during the second session, with a 48- to 72-hour washout period between sessions. Receives: Device: Transcutaneous Auricular Vagus Nerve Stimulation |
| Sham First | Sham comparator | Participants assigned to this arm will receive sham stimulation during the first session and active transcutaneous auricular vagus nerve stimulation (taVNS) during the second session, with a 48- to 72-hour washout period between sessions. Receives: Device: Sham Stimulation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Difference in 5-minute lnRMSSD During Active taVNS Compared With Sham Stimulation
The primary outcome is the between-condition difference in 5-minute heart rate variability, assessed by lnRMSSD derived from the continuous RR interval recording obtained during the 10-minute intervention period. The 5-minute analysis window is the prespecified standard short-term HRV measure used to compare active transcutaneous auricular vagus nerve stimulation with sham stimulation.
Measured: During the 10-minute intervention period at each study session
Secondary outcomes (5)
Agreement Between 1-minute and 5-minute HRV Measurements During Active taVNS
Agreement between ultra-short 1-minute and standard 5-minute HRV measurements obtained from the same continuous RR recording during active taVNS will be assessed using predefined agreement analyses.
Measured: During the 10-minute intervention period at each active taVNS session
Comparison of 10-minute and 5-minute HRV Measurements During Active taVNS
HRV parameters derived from 10-minute and 5-minute analysis windows of the same continuous RR recording during active taVNS will be compared to determine whether the longer recording provides additional physiologic sensitivity or discriminatory value.
Measured: During the 10-minute intervention period at each active taVNS session
Effect of Recording Duration on HRV Differences Between Active taVNS and Sham Stimulation
Differences between active taVNS and sham stimulation will be evaluated across 1-minute, 5-minute, and 10-minute HRV analysis windows to determine whether recording duration influences the detection of autonomic effects.
Measured: During the 10-minute intervention period at each study session
Change in Systolic and Diastolic Blood Pressure After Active taVNS Compared With Sham Stimulation
Systolic and diastolic blood pressure will be measured before and immediately after each intervention session to assess hemodynamic responses to active taVNS and sham stimulation.
Measured: Immediately before and immediately after each 10-minute intervention session
Change in Pulse Rate After Active taVNS Compared With Sham Stimulation
Pulse rate will be measured before and immediately after each intervention session to assess hemodynamic responses to active taVNS and sham stimulation.
Measured: Immediately before and immediately after each 10-minute intervention session
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 Apr 2026
- Study start1 May 2026 (estimated)
- Primary completion31 Aug 2026 (estimated)
- Study completion15 Sep 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (4)Papers the sponsor has linked to this study.
- Other trials for Healthy VolunteersStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- A randomized, sham-controlled crossover design will be used. Each participant will attend two separate sessions and receive both active transcutaneous auricular vagus nerve stimulation (taVNS) and sham stimulation in randomized order, with a 48- to 72-hour washout period between sessions. Continuous 10-minute heart rate variability recordings will be obtained during each intervention session.
- Masking
- Double blind
- Who is masked
- Investigator, Outcomes assessor
- Enrolment
- 40 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Sinop University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, SEFA HAKTAN HATIK, Sinop University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07526415
- Sponsor's protocol ID
- TAVNS6
- Acronym
- taVNS-HRV
- Status last verified
- Apr 2026
- First submitted
- 6 Apr 2026
- Last updated
- 16 Apr 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Frangos E, Ellrich J, Komisaruk BR. Non-invasive Access to the Vagus Nerve Central Projections via Electrical Stimulation of the External Ear: fMRI Evidence in Humans. Brain Stimul. 2015 May-Jun;8(3):624-36. doi: 10.1016/j.brs.2014.11.018. Epub 2014 Dec 6.
PubMed 25573069Shaffer F, Ginsberg JP. An Overview of Heart Rate Variability Metrics and Norms. Front Public Health. 2017 Sep 28;5:258. doi: 10.3389/fpubh.2017.00258. eCollection 2017.
PubMed 29034226Clancy JA, Mary DA, Witte KK, Greenwood JP, Deuchars SA, Deuchars J. Non-invasive vagus nerve stimulation in healthy humans reduces sympathetic nerve activity. Brain Stimul. 2014 Nov-Dec;7(6):871-7. doi: 10.1016/j.brs.2014.07.031. Epub 2014 Jul 16.
PubMed 25164906Peuker ET, Filler TJ. The nerve supply of the human auricle. Clin Anat. 2002 Jan;15(1):35-7. doi: 10.1002/ca.1089.
PubMed 11835542
Study at a glance
From the registry record, last updated by the sponsor on 16 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of Recording Duration on Heart Rate Variability During Transcutaneous Auricular Vagus Nerve Stimulation: A Randomized, Sham-Controlled Crossover Study
- ClinicalTrials.gov ID
- NCT07526415
- Acronym / sponsor ID
- taVNS-HRV / TAVNS6
- Conditions
- Healthy Volunteers
- Keywords
- Transcutaneous Auricular Vagus Nerve Stimulation, taVNS, Autonomic Nervous System
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 40 participants (estimated)
- Lead sponsor
- Sinop UniversityUniversity, hospital or other
- Study start
- 1 May 2026 (estimated)
- Primary completion
- 31 Aug 2026 (estimated)
- Study completion
- 15 Sep 2026 (estimated)
- First posted
- 13 Apr 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study aims to evaluate how different heart rate variability (HRV) recording durations reflect autonomic nervous system responses during transcutaneous auricular vagus nerve stimulation (taVNS) in healthy adults. In a randomized, sham-controlled crossover design, participants will attend two separate sessions and receive both active taVNS and sham stimulation in randomized order. During each session, a continuous 10-minute HRV recording will be obtained, and 1-minute, 5-minute, and 10-minute analysis windows will be compared. Blood pressure and pulse will also be measured before and after stimulation. The study will investigate whether shorter or longer HRV recording durations provide results comparable to the standard 5-minute recording and which duration most reliably detects autonomic changes during taVNS.
Detailed description
The vagus nerve plays a central role in autonomic regulation, and heart rate variability (HRV) is a widely used noninvasive marker of autonomic nervous system activity. Transcutaneous auricular vagus nerve stimulation (taVNS) has increasingly been used in experimental and clinical research as a noninvasive method to modulate vagal activity. Although previous studies suggest that taVNS may influence parasympathetic activity, HRV measurement duration remains an important methodological issue. Standard short-term HRV analysis is commonly based on 5-minute recordings, but ultra-short and longer recordings are also used, and their validity during taVNS has not been sufficiently clarified.
This study is designed to determine whether different HRV recording durations provide comparable and reliable information during taVNS. The study will use a randomized, sham-controlled crossover design. Healthy adult participants will attend two sessions separated by a washout period of 48 to 72 hours. In one session, participants will receive active taVNS; in the other, they will receive sham stimulation. The order of sessions will be randomized.
During each session, HRV data will be collected continuously for 10 minutes using a Polar H10 chest strap. From this single uninterrupted recording, 1-minute, 5-minute, and 10-minute analysis windows will be derived. HRV parameters from time-domain and frequency-domain analyses will be calculated. Blood pressure and pulse will be measured before and after the intervention using an automated upper-arm blood pressure monitor.
Active taVNS will be applied to the cymba conchae region of the ear using commonly reported stimulation parameters. Sham stimulation will be delivered with the same device and similar sensory conditions, but at a non-vagal ear location to minimize physiologic vagal effects. This design is intended to control for nonspecific sensory and expectation-related effects.
The primary objective is to assess whether the standard 5-minute HRV recording during taVNS detects autonomic effects compared with sham stimulation. Secondary objectives are to examine the agreement between 1-minute, 5-minute, and 10-minute HRV measurements and to evaluate whether shorter or longer recordings provide additional methodological value. The relationship between HRV findings and hemodynamic responses, including blood pressure and pulse, will also be explored. This study may help identify the most appropriate HRV recording duration for future taVNS research and contribute to methodological standardization in this field.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- A randomized, sham-controlled crossover design will be used. Each participant will attend two separate sessions and receive both active transcutaneous auricular vagus nerve stimulation (taVNS) and sham stimulation in randomized order, with a 48- to 72-hour washout period between sessions. Continuous 10-minute heart rate variability recordings will be obtained during each intervention session.
| Arm | Type | Receives |
|---|---|---|
| taVNS First | Experimental | Device: Transcutaneous Auricular Vagus Nerve StimulationParticipants assigned to this sequence will receive active transcutaneous auricular vagus nerve stimulation (taVNS) during the first session and sham stimulation during the second session, with a 48- to 72-hour washout period between sessions. |
| Sham First | Sham comparator | Device: Sham StimulationParticipants assigned to this arm will receive sham stimulation during the first session and active transcutaneous auricular vagus nerve stimulation (taVNS) during the second session, with a 48- to 72-hour washout period between sessions. |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- Healthy volunteers aged 18 to 40 years
- Able and willing to provide informed consent
- Able to tolerate active transcutaneous auricular vagus nerve stimulation and sham stimulation
- Able to comply with study instructions, including restrictions related to caffeine, nicotine, and heavy exercise before assessment
- No condition preventing heart rate variability, blood pressure, or pulse measurements
Key exclusion criteria (7 listed)
- Diagnosed cardiovascular disease, arrhythmia, or pacemaker use
- History of neurologic disease that may affect autonomic nervous system function
- Regular use of medications that may affect heart rate variability or autonomic responses, including beta blockers, antiarrhythmics, or anticholinergic drugs
- Active ear infection, dermatologic lesion, or any ear condition that may interfere with stimulation
- Marked pain, discomfort, or intolerance during stimulation
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Transcutaneous Auricular Vagus Nerve StimulationAlso: taVNSActive transcutaneous auricular vagus nerve stimulation will be applied bilaterally to the cymba conchae region of the ear using a transcutaneous stimulation device. Stimulation will be delivered for 10 minutes with a frequency of 25 Hz, a pulse width of 200 to 300 microseconds, and an individually adjusted intensity that is clearly perceptible but not painful. Heart rate variability will be recorded continuously during the intervention. | Device | taVNS First |
| Sham StimulationAlso: Sham taVNSSham stimulation will be delivered for 10 minutes using the same transcutaneous stimulation device and similar stimulation settings as the active intervention, but the stimulation will be applied to a non-vagal ear region, such as the earlobe or helix, to minimize physiologic vagal effects while maintaining similar sensory input. Heart rate variability will be recorded continuously during the intervention. | Device | Sham First |
Primary outcome
Difference in 5-minute lnRMSSD During Active taVNS Compared With Sham Stimulation
Time frame: During the 10-minute intervention period at each study session
The primary outcome is the between-condition difference in 5-minute heart rate variability, assessed by lnRMSSD derived from the continuous RR interval recording obtained during the 10-minute intervention period. The 5-minute analysis window is the prespecified standard short-term HRV measure used to compare active transcutaneous auricular vagus nerve stimulation with sham stimulation.
5 secondary outcomes
Agreement Between 1-minute and 5-minute HRV Measurements During Active taVNS
Time frame: During the 10-minute intervention period at each active taVNS session
Comparison of 10-minute and 5-minute HRV Measurements During Active taVNS
Time frame: During the 10-minute intervention period at each active taVNS session
Effect of Recording Duration on HRV Differences Between Active taVNS and Sham Stimulation
Time frame: During the 10-minute intervention period at each study session
Change in Systolic and Diastolic Blood Pressure After Active taVNS Compared With Sham Stimulation
Time frame: Immediately before and immediately after each 10-minute intervention session
Change in Pulse Rate After Active taVNS Compared With Sham Stimulation
Time frame: Immediately before and immediately after each 10-minute intervention session
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 16 Apr 2026.
- Background: PubMed 25573069Frangos E, Ellrich J, Komisaruk BR. Non-invasive Access to the Vagus Nerve Central Projections via Electrical Stimulation of the External Ear: fMRI Evidence in Humans. Brain Stimul. 2015 May-Jun;8(3):624-36. doi: 10.1016/j.brs.2014.11.018. Epub 2014 Dec 6.
- Background: PubMed 29034226Shaffer F, Ginsberg JP. An Overview of Heart Rate Variability Metrics and Norms. Front Public Health. 2017 Sep 28;5:258. doi: 10.3389/fpubh.2017.00258. eCollection 2017.
- Background: PubMed 25164906Clancy JA, Mary DA, Witte KK, Greenwood JP, Deuchars SA, Deuchars J. Non-invasive vagus nerve stimulation in healthy humans reduces sympathetic nerve activity. Brain Stimul. 2014 Nov-Dec;7(6):871-7. doi: 10.1016/j.brs.2014.07.031. Epub 2014 Jul 16.
- Background: PubMed 11835542Peuker ET, Filler TJ. The nerve supply of the human auricle. Clin Anat. 2002 Jan;15(1):35-7. doi: 10.1002/ca.1089.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Transcutaneous Auricular Vagus Nerve Stimulation in people with Healthy Volunteers, run by Sinop University at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 16 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Sefa Haktan Hatık, PhD (+90 368 271 55 28, haktanhtk@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Difference in 5-minute lnRMSSD During Active taVNS Compared With Sham Stimulation (time frame: During the 10-minute intervention period at each study session). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07526415, which also lists 4 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 16 Apr 2026.