Heart Rate Variability Biofeedback in Security Forces

NCT07386951 | Recruiting

• 1 other identifier: PT-214/25
• Study Type: interventional
• Target: 50
• Locations: 1 country
• Sites: 1

Brief 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. 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.

Conditions

Well-Being, Psychological; Psychological Distress; Burnout

Keywords

Heart rate variability biofeedback; HRV biofeedback; Burnout; Stress management; Psychological distress; Mental health promotion; Workplace well-being

Outcome Measures

Primary Outcomes (3)

• 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).

  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.

  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.

  Baseline (Week 0), Post-intervention (Week 4), Follow-up (Week 10)

Secondary Outcomes (3)

• SDNN (Standard Deviation of NN Intervals) - Heart Rate Variability

  Baseline (Week 0), after each of 12 training sessions

• RMSSD (Root Mean Square of Successive Differences) - Parasympathetic Activity

  Baseline (Week 0), after each of 12 training sessions

• Stress Index - Autonomic Balance Indicator

  Baseline (Week 0), after each of 12 training sessions

Study Arms (2)

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.

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.

Interventions

Heart Rate Variability Biofeedback (HRV-BFB) Training BEHAVIORAL

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

Also known as: HRV biofeedback, Resonance frequency breathing training

HRV Biofeedback Training

Eligibility Criteria

• Age: 18 Years - 55 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Egas Moniz - Cooperativa de Ensino Superior, CRL: lead

Study Sites (1)

GNR - Comando Terrritorial de Setúbal (GNR - Setubal Territorial Command Centre)

Setúbal, Portugal

RECRUITING

MeSH Terms

Conditions

Psychological Well-Being; Burnout, Psychological

Condition Hierarchy (Ancestors)

Personal Satisfaction; Behavior; Stress, Psychological; Behavioral Symptoms

Central Study Contacts

Paulo Chaló, PhD

CONTACT

(+351) 212 946 700; pchalo@egasmoniz.edu.pt

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Masking Details: Due to the nature of the intervention, participants and investigators are aware of who receive HRV biofeedback training or not.
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: 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.

Study Record Dates

• First Submitted: January 28, 2026
• First Posted: February 4, 2026
• Study Start: January 28, 2026
• Primary Completion: April 1, 2026
• Study Completion (Estimated): August 1, 2026
• Last Updated: February 6, 2026

Record last verified: 2026-01

Locations

PT (1)