Psychological DistressGNR-HRVBNCT07386951
Heart Rate Variability Biofeedback in Security Forces
A study testing Heart Rate Variability Biofeedback (HRV-BFB) Training in people with Psychological Distress and Well-Being, Psychological, run by Egas Moniz - Cooperativa de Ensino Superior, CRL at 1 site in Portugal.
Trial summary
This exploratory study evaluates the effectiveness of a 12-session Heart Rate Variability Biofeedback (HRV-BFB) protocol in reducing distress and burnout while promoting psychological well-being among Portuguese National Republican Guard (GNR) professionals. Read more about this study
- Who is it for?
- Ages 18 to 55 yearsHealthy volunteers can take part
- Conditions the study is for
- Psychological Distress, Well-Being, Psychological, Burnout
- What is being tested?
- Heart Rate Variability Biofeedback (HRV-BFB) Training
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 50 participants
- Where
- 1 sitePortugal
- Study dates
- 28 Jan 2026to 1 Aug 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 55 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Operational military personnel of the Guarda Nacional Republicana (GNR) performing security, patrol, criminal investigation, or road safety duties
- Any military rank or professional category within operational roles
- Age between 18 and 55 years, inclusive
- Both males and females
- Capable of providing informed consent in Portuguese language
Who cannot join
- Extended sick leave or medical absence
- Currently involved in serious disciplinary proceedings
- Use, modification, or initiation of psychotropic medication (including antidepressants, anti-anxiety medications, antipsychotics, mood stabilizers) within the past 6 months
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Portugal1 site, 1 recruiting
- Recruiting
GNR - Comando Terrritorial de Setúbal (GNR - Setubal Territorial Command Centre)
Setúbal
Paulo Chaló, PhD, (+351) 212 946 700, pchalo@egasmoniz.edu.pt
Clauda Carrilho
About this study
Official title: Heart Rate Variability Biofeedback in Distress Regulation and Burnout Prevention Among Security Forces
This exploratory study evaluates the effectiveness of a 12-session Heart Rate Variability Biofeedback (HRV-BFB) protocol in reducing distress and burnout while promoting psychological well-being among Portuguese National Republican Guard (GNR) professionals. Exposed to high occupational stress from unpredictable risks, shift work, and limited resources, these individuals face elevated vulnerability to chronic stress outcomes. The intervention leverages real-time HRV feedback to enhance autonomic regulation, breathing techniques, and emotional self-regulation.
Read the detailed description
Security forces like the GNR play a critical role in public safety but endure chronic stress from violence exposure, rapid decisions, shift rotations, and institutional resource shortages, heightening risks of distress, burnout, and impaired well-being. Distress arises when perceived threats exceed coping resources, leading to persistent negative emotions and health disruptions. Burnout manifests as exhaustion, mental distancing, and reduced efficacy from unmanaged chronic stress, with organizational impacts including absenteeism and eroded public trust. Psychological well-being encompasses multidimensional aspects like autonomy, relationships, and purpose beyond mere absence of illness. Traditional interventions face barriers such as stigma and access issues in rural GNR contexts, necessitating flexible, self-administered tools.
Intervention: HRV-BFB Protocol HRV-BFB trains participants to consciously modulate physiological responses via real-time monitoring of heart rate variability (HRV), reflecting sympathetic-parasympathetic balance. Low HRV links to mental health risks, while training targets resonance frequency breathing (~6 breaths/min or 0.1 Hz) to boost HRV amplitude, cardiac coherence, and baroreflex strength. Delivered autonomously via app post-initial guidance, the 12-session protocol requires no daily clinician oversight, enhancing accessibility for dispersed GNR personnel. Evidence shows HRV-BFB reduces stress, anxiety, depression, and burnout while fostering well-being in high-stress groups like emergency workers.
Study Objectives This exploratory trial tests whether HRV-BFB significantly lowers distress (multidimensional: physical, cognitive, emotional, behavioral), burnout levels, and boosts psychological well-being in GNR professionals. It aims to inform scalable interventions tailored to Portuguese police realities, addressing gaps in institutional support.
- Conditions
- Psychological Distress, Well-Being, Psychological, Burnout
- Being tested
- Heart Rate Variability Biofeedback (HRV-BFB) Training
- Keywords
- Heart rate variability biofeedback, HRV biofeedback, Burnout, Stress management, Psychological distress, Mental health promotion, Workplace well-being
- Medical subject headings
- Psychological Well-Being, Burnout, Psychological
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Heart Rate Variability Biofeedback (HRV-BFB) TrainingBehavioural
Also called HRV biofeedback, Resonance frequency breathing training
Participants receive a structured heart rate variability biofeedback (HRV-BFB) training protocol delivered over 4 weeks. The intervention uses a portable chest-worn ECG sensor (eSense Pulse) connected via Bluetooth to a mobile application that provides real-time visual feedback of heart rate variability. Each participant completes 12 individual sessions of 12 minutes each (one session every 2 days). Sessions take place in a quiet room and follow a standardized format: a brief preparation phase, followed by approximately 10 minutes of guided breathing at resonance frequency (around 6 breaths per minute) using a visual breathing guide. The application displays color-coded feedback indicating how closely the participant's physiological response matches the target HRV pattern, and participants are instructed to adjust their breathing and recall positive memories to maximize time in the desired state. The aim is to increase HRV, strengthen parasympathetic activation, and improve stress and
| Study group | Role | What they receive |
|---|---|---|
| HRV Biofeedback Training | Experimental | Participants receive 12 individual sessions of heart rate variability biofeedback (HRV-BFB) over 4 weeks (one 12-minute session every 2 days). Training is delivered using a chest-worn ECG sensor (eSense Pulse) connected to a mobile application that provides real-time visual feedback. Receives: Behavioral: Heart Rate Variability Biofeedback (HRV-BFB) Training |
| Control: No Intervention | No intervention | Participants receive no active intervention during the 4-week study intervention period and continue their usual duties and routines. They complete the same assessment schedule as the experimental group at baseline, 4 weeks, and 10 weeks. After completion of the final follow-up assessment, they are offered the opportunity to receive the HRV biofeedback training protocol. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Psychological Distress (Kessler Psychological Distress Scale - K10)
The Kessler Psychological Distress Scale (K-10) is a 10-item self-report measure assessing psychological distress over the past 30 days. Items measure anxiety and depressive symptoms on a 5-point Likert scale (1=never to 5=always). Total score range: 10-50 (higher scores indicate greater distress). Portuguese validation: α=0.91. Primary outcome is change from baseline to post-intervention (week 4) and follow-up (week 10).
Measured: Baseline (Week 0), Post-intervention (Week 4), Follow-up (Week 10)
Change in Occupational Burnout (Burnout Assessment Tool - BAT-12)
The Burnout Assessment Tool Short Form (BAT-12) is a 12-item self-report measure of occupational burnout across 4 dimensions: exhaustion (3 items), mental distance (3 items), cognitive impairment (3 items), emotional impairment (3 items). 5-point Likert scale (1=never to 5=always). Total score range: 12-60. Portuguese validation: α=0.85. Primary outcome is change from baseline to post-intervention and follow-up.
Measured: Baseline (Week 0), Post-intervention (Week 4), Follow-up (Week 10)
Change in Psychological Well-Being (WHO-5 Well-Being Index)
The WHO-5 Well-Being Index is a 5-item self-report measure of psychological well-being over the past 2 weeks. Items assess positive mood, vitality, sleep, daily functioning, and life satisfaction on a 0-5 scale. Total score range: 0-25 (higher=higher well-being). Primary outcome is change from baseline to post-intervention and follow-up.
Measured: Baseline (Week 0), Post-intervention (Week 4), Follow-up (Week 10)
Secondary outcomes (3)
SDNN (Standard Deviation of NN Intervals) - Heart Rate Variability
SDNN measures the standard deviation of the average NN (R-R) intervals in milliseconds during a recording period. It is a general indicator of overall heart rate variability and reflects the body's overall capacity for physiological adaptation and autonomic flexibility. Higher SDNN values indicate better autonomic regulation.
Measured: Baseline (Week 0), after each of 12 training sessions
RMSSD (Root Mean Square of Successive Differences) - Parasympathetic Activity
RMSSD measures the root mean square of successive differences between adjacent NN (R-R) intervals in milliseconds. It is a primary time-domain measure of high-frequency heart rate variability and specifically reflects parasympathetic (vagal) nervous system activity and the body's recovery capacity. Higher RMSSD indicates stronger parasympathetic tone.
Measured: Baseline (Week 0), after each of 12 training sessions
Stress Index - Autonomic Balance Indicator
The Stress Index is a proprietary metric derived from heart rate variability analysis that quantifies autonomic nervous system balance. Lower values indicate better autonomic regulation and lower physiological stress levels. Higher values reflect sympathetic dominance and poorer stress adaptation.
Measured: Baseline (Week 0), after each of 12 training sessions
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Feb 2026
- Study start28 Jan 2026
- Primary completionApr 2026 (estimated)
- Study completion1 Aug 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Psychological DistressStudies 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
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- A randomized, parallel-group clinical trial in which participants are allocated to either a 4-week heart rate variability biofeedback (HRV-BFB) training program or to a no-intervention control condition, with assessments at baseline, post-intervention (4 weeks), and 10-week follow-up.
- Masking
- None (open label)
- Enrolment
- 50 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Egas Moniz - Cooperativa de Ensino Superior, CRL
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07386951
- Sponsor's protocol ID
- PT-214/25
- Acronym
- GNR-HRVB
- Status last verified
- Jan 2026
- First submitted
- 28 Jan 2026
- Last updated
- 6 Feb 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 6 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Heart Rate Variability Biofeedback in Distress Regulation and Burnout Prevention Among Security Forces
- ClinicalTrials.gov ID
- NCT07386951
- Acronym / sponsor ID
- GNR-HRVB / PT-214/25
- Conditions
- Psychological Distress, Well-Being, Psychological, Burnout
- Keywords
- Heart rate variability biofeedback, HRV biofeedback, Burnout, Stress management, Psychological distress, Mental health promotion, Workplace well-being
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 50 participants (estimated)
- Lead sponsor
- Egas Moniz - Cooperativa de Ensino Superior, CRLUniversity, hospital or other
- Study start
- 28 Jan 2026 (actual)
- Primary completion
- Apr 2026 (estimated)
- Study completion
- 1 Aug 2026 (estimated)
- First posted
- 4 Feb 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 exploratory study evaluates the effectiveness of a 12-session Heart Rate Variability Biofeedback (HRV-BFB) protocol in reducing distress and burnout while promoting psychological well-being among Portuguese National Republican Guard (GNR) professionals. Exposed to high occupational stress from unpredictable risks, shift work, and limited resources, these individuals face elevated vulnerability to chronic stress outcomes. The intervention leverages real-time HRV feedback to enhance autonomic regulation, breathing techniques, and emotional self-regulation.
Detailed description
Security forces like the GNR play a critical role in public safety but endure chronic stress from violence exposure, rapid decisions, shift rotations, and institutional resource shortages, heightening risks of distress, burnout, and impaired well-being. Distress arises when perceived threats exceed coping resources, leading to persistent negative emotions and health disruptions. Burnout manifests as exhaustion, mental distancing, and reduced efficacy from unmanaged chronic stress, with organizational impacts including absenteeism and eroded public trust. Psychological well-being encompasses multidimensional aspects like autonomy, relationships, and purpose beyond mere absence of illness. Traditional interventions face barriers such as stigma and access issues in rural GNR contexts, necessitating flexible, self-administered tools.
Intervention: HRV-BFB Protocol HRV-BFB trains participants to consciously modulate physiological responses via real-time monitoring of heart rate variability (HRV), reflecting sympathetic-parasympathetic balance. Low HRV links to mental health risks, while training targets resonance frequency breathing (~6 breaths/min or 0.1 Hz) to boost HRV amplitude, cardiac coherence, and baroreflex strength. Delivered autonomously via app post-initial guidance, the 12-session protocol requires no daily clinician oversight, enhancing accessibility for dispersed GNR personnel. Evidence shows HRV-BFB reduces stress, anxiety, depression, and burnout while fostering well-being in high-stress groups like emergency workers.
Study Objectives This exploratory trial tests whether HRV-BFB significantly lowers distress (multidimensional: physical, cognitive, emotional, behavioral), burnout levels, and boosts psychological well-being in GNR professionals. It aims to inform scalable interventions tailored to Portuguese police realities, addressing gaps in institutional support.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- A randomized, parallel-group clinical trial in which participants are allocated to either a 4-week heart rate variability biofeedback (HRV-BFB) training program or to a no-intervention control condition, with assessments at baseline, post-intervention (4 weeks), and 10-week follow-up.
| Arm | Type | Receives |
|---|---|---|
| HRV Biofeedback Training | Experimental | Behavioral: Heart Rate Variability Biofeedback (HRV-BFB) TrainingParticipants receive 12 individual sessions of heart rate variability biofeedback (HRV-BFB) over 4 weeks (one 12-minute session every 2 days). Training is delivered using a chest-worn ECG sensor (eSense Pulse) connected to a mobile application that provides real-time visual feedback. |
| Control: No Intervention | No intervention | –Participants receive no active intervention during the 4-week study intervention period and continue their usual duties and routines. They complete the same assessment schedule as the experimental group at baseline, 4 weeks, and 10 weeks. After completion of the final follow-up assessment, they are offered the opportunity to receive the HRV biofeedback training protocol. |
Who may qualify
- Ages
- 18 to 55 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- Operational military personnel of the Guarda Nacional Republicana (GNR) performing security, patrol, criminal investigation, or road safety duties
- Any military rank or professional category within operational roles
- Age between 18 and 55 years, inclusive
- Both males and females
- Capable of providing informed consent in Portuguese language
Key exclusion criteria (3 listed)
- Extended sick leave or medical absence
- Currently involved in serious disciplinary proceedings
- Use, modification, or initiation of psychotropic medication (including antidepressants, anti-anxiety medications, antipsychotics, mood stabilizers) within the past 6 months
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 |
|---|---|---|
| Heart Rate Variability Biofeedback (HRV-BFB) TrainingAlso: HRV biofeedback, Resonance frequency breathing trainingParticipants receive a structured heart rate variability biofeedback (HRV-BFB) training protocol delivered over 4 weeks. The intervention uses a portable chest-worn ECG sensor (eSense Pulse) connected via Bluetooth to a mobile application that provides real-time visual feedback of heart rate variability. Each participant completes 12 individual sessions of 12 minutes each (one session every 2 days). Sessions take place in a quiet room and follow a standardized format: a brief preparation phase, followed by approximately 10 minutes of guided breathing at resonance frequency (around 6 breaths per minute) using a visual breathing guide. The application displays color-coded feedback indicating how closely the participant's physiological response matches the target HRV pattern, and participants are instructed to adjust their breathing and recall positive memories to maximize time in the desired state. The aim is to increase HRV, strengthen parasympathetic activation, and improve stress and | Behavioural | HRV Biofeedback Training |
Primary outcome
Change in Psychological Distress (Kessler Psychological Distress Scale - K10)
Time frame: Baseline (Week 0), Post-intervention (Week 4), Follow-up (Week 10)
The Kessler Psychological Distress Scale (K-10) is a 10-item self-report measure assessing psychological distress over the past 30 days. Items measure anxiety and depressive symptoms on a 5-point Likert scale (1=never to 5=always). Total score range: 10-50 (higher scores indicate greater distress). Portuguese validation: α=0.91. Primary outcome is change from baseline to post-intervention (week 4) and follow-up (week 10).
Change in Occupational Burnout (Burnout Assessment Tool - BAT-12)
Time frame: Baseline (Week 0), Post-intervention (Week 4), Follow-up (Week 10)
The Burnout Assessment Tool Short Form (BAT-12) is a 12-item self-report measure of occupational burnout across 4 dimensions: exhaustion (3 items), mental distance (3 items), cognitive impairment (3 items), emotional impairment (3 items). 5-point Likert scale (1=never to 5=always). Total score range: 12-60. Portuguese validation: α=0.85. Primary outcome is change from baseline to post-intervention and follow-up.
Change in Psychological Well-Being (WHO-5 Well-Being Index)
Time frame: Baseline (Week 0), Post-intervention (Week 4), Follow-up (Week 10)
The WHO-5 Well-Being Index is a 5-item self-report measure of psychological well-being over the past 2 weeks. Items assess positive mood, vitality, sleep, daily functioning, and life satisfaction on a 0-5 scale. Total score range: 0-25 (higher=higher well-being). Primary outcome is change from baseline to post-intervention and follow-up.
3 secondary outcomes
SDNN (Standard Deviation of NN Intervals) - Heart Rate Variability
Time frame: Baseline (Week 0), after each of 12 training sessions
RMSSD (Root Mean Square of Successive Differences) - Parasympathetic Activity
Time frame: Baseline (Week 0), after each of 12 training sessions
Stress Index - Autonomic Balance Indicator
Time frame: Baseline (Week 0), after each of 12 training sessions
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 6 Feb 2026.
- Individual participant dataSharing planned: Undecided
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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 Heart Rate Variability Biofeedback (HRV-BFB) Training in people with Psychological Distress and Well-Being, Psychological, run by Egas Moniz - Cooperativa de Ensino Superior, CRL at 1 site in Portugal.
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 3 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: looking for participants now, as of the sponsor's last update on 6 Feb 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 Portugal. 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. 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 Paulo Chaló, PhD ((+351) 212 946 700, pchalo@egasmoniz.edu.pt), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Psychological Distress (Kessler Psychological Distress Scale - K10) (time frame: Baseline (Week 0), Post-intervention (Week 4), Follow-up (Week 10)). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 6 Feb 2026.