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CompletedNCT07445113Updated Sep 17, 2026

Diaphragmatic Breathing and Stimulation of the Autonomic Nervous System

An interventional study of Guided breathing at 6 breaths per minute (bpm) with an inspiration (I) to expiration (E) and Guided breathing at 6 bpm with apnea (A) in Healthy Adult Male and Female Volunteers, sponsored by University of Jaén. Completed at 1 site in Spain. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-09-17.

Sponsored by University of Jaén · Not applicable, Interventional, and Treatment

Phase
Not applicable
Study type
Interventional
Enrollment
60
Allocation
Randomized
Ages
18 Years and older
Sex
All
01

Study summary

Introduction:

Slow, deep breathing has demonstrated beneficial effects on the autonomic nervous system, particularly by increasing parasympathetic activity through vagal nerve modulation. Previous studies suggest that this breathing pattern optimizes the sympathovagal balance, modifies physiological parameters such as heart rate, blood pressure, and oxygen saturation, and influences variables including heart rate variability (HRV) and RR intervals.

Objectives:

To analyze the effects of different slow deep breathing (SDB) training modalities on vagal tone regulation. Secondary objectives include evaluating their impact on heart rate and rhythm, HRV, cardiac beat intervals, blood pressure, and oxygen saturation.

Methodology:

A randomized, controlled, single-blind, parallel-design clinical trial will be conducted. Sixty healthy participants will be enrolled and allocated into three groups: two experimental groups (SDB with and without apnea) and one control group (breathing education). Pre- and post-intervention measurements will include HRV, RR intervals, heart rate, blood pressure, oxygen saturation, and cervical joint variables. Data will be analyzed using repeated-measures ANOVA and statistical tests appropriate for each variable type, with a significance level set at 5%.

Expected Results:

SDB-based interventions are expected to produce significant improvements in vagal regulation, increasing heart rate variability and favorably modifying the aforementioned physiological parameters compared with the control group.

02

Conditions studied

  • Healthy Adult Male and Female Volunteers

Keywords

  • Slow diaphragmatic breathing
  • autonomic nervous system
  • heart rate variability
03

Who can participate

Ages eligible
18 Years and older
Sexes eligible
All
Accepts healthy volunteers
Yes

Inclusion criteria

  • Healthy individuals who have not smoked during the 24 hours prior to the study.
  • Healthy individuals who have not drunk alcohol during the 24 hours prior to the study.
  • Healthy individuals who have not drunk coffee during the 24 hours prior to the study.

Exclusion criteria

Exclusion Criteria:

  • Individuals with cardiovascular diseases or neurological disorders.
  • Individuals with cognitive impairment.
  • Individuals taking medications that affect autonomic nervous system function, such as: benzodiazepines, beta-blockers or beta-adrenergic agents.
04

Study design

Phase
Not applicable
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Triple (Participant, Investigator, Outcomes assessor)
Enrollment
60 participants (actual)

Study arms

  • Experimental
    Experimental Group 1. SDB 6x6

    5-minute guided slow deep breathing consisting of a 6-second inhalation and 6-second exhalation. Ratio of 1:1

    Procedure: Guided breathing at 6 bpm with apnea (A)

  • Experimental
    Experimental Group 2. SDB 6x6x6

    5-minute guided slow deep breathing consisting of a 6-second inhalation, 6-second inspiratory hold, and 6-second exhalation (1:1:1 ratio)

    Procedure: Guided breathing at 6 breaths per minute (bpm) with an inspiration (I) to expiration (E)

  • Placebo comparator
    Control Group

    Breathing education

    Procedure: Breathing education

Interventions

  • ProcedureGuided breathing at 6 breaths per minute (bpm) with an inspiration (I) to expiration (E)

    Spontaneous breathing in adults typically ranges between 12 and 20 breaths per minute (bpm), whereas slow, deep breathing (SDB) is usually performed as guided breathing at approximately 4 to 6 bpm.

    Also known as: Experimental Group 1. SDB 6x6

  • ProcedureGuided breathing at 6 bpm with apnea (A)

    Spontaneous breathing in adults typically ranges between 12 and 20 breaths per minute (bpm), whereas slow, deep breathing (SDB) is usually performed as guided breathing at approximately 4 to 6 bpm.

    Also known as: Experimental Group 2.SDB 6x6x6

  • ProcedureBreathing education

    Breathing education consists of teaching individuals to understand, control, and optimize their breathing patterns.

    Also known as: Control Group

05

What researchers measure

Primary outcomes

  1. Heart rate variability (HRV)

    Heart rate variability (HRV): measured using the Polar H10 heart rate sensor.

    Time frame: Baseline

  2. Heart rate variability (HRV)

    Heart rate variability (HRV): measured using the Polar H10 heart rate sensor

    Time frame: Immediately after treatment

Secondary outcomes

  1. Anthropometric variables: Weight

    Weight was measured using a calibrated digital scale

    Time frame: Baseline

  2. RMSSD (root mean square of successive differences)

    RMSSD (root mean square of successive differences) measured using the validated Elite HRV application

    Time frame: Baseline

  3. SDRR (standard deviation of RR intervals)

    SDRR (standard deviation of RR intervals): assessed using the validated Elite HRV application.

    Time frame: Baseline

  4. Pressure pain thresholds (PPTs)

    Pressure pain sensitivity was evaluated using a digital algometer (FPIX; Wagner Instruments, Greenwich, CT, EE.UU). PPTs were measured at the spinous process of C3-C4.

    Time frame: Baseline

  5. RMSSD (root mean square of successive differences)

    RMSSD (root mean square of successive differences) measured using the validated Elite HRV application

    Time frame: Immediately after treatment

  6. SDRR (standard deviation of RR intervals)

    SDRR (standard deviation of RR intervals) assessed using the validated Elite HRV application

    Time frame: Immediately after treatment

  7. Pressure pain thresholds (PPTs)

    Pressure pain sensitivity was evaluated using a digital algometer (FPIX; Wagner Instruments, Greenwich, CT, EE.UU). PPTs were measured at the spinous process of C3-C4

    Time frame: Immediately after treatment

  8. Anthropometric variables: height

    Height was measured with a calibrated stadiometer

    Time frame: Baseline

  9. Characteristics demographics: Age

    Age was self-reported by the participants

    Time frame: Baseline

  10. Characteristics demographics: Gender

    Gender was self-reported by the participants

    Time frame: Baseline

06

Study locations

1 site
  • University of Jaen
    Jaén, Jaén 23071, Spain
07

References and documents

Publications

  • Jafari H, Gholamrezaei A, Franssen M, Van Oudenhove L, Aziz Q, Van den Bergh O, Vlaeyen JWS, Van Diest I. Can Slow Deep Breathing Reduce Pain? An Experimental Study Exploring Mechanisms. J Pain. 2020 Sep-Oct;21(9-10):1018-1030. doi: 10.1016/j.jpain.2019.12.010. Epub 2020 Jan 22. PubMed 31978501 ↗
  • Gholamrezaei A, Van Diest I, Aziz Q, Pauwels A, Tack J, Vlaeyen JWS, Van Oudenhove L. Effect of slow, deep breathing on visceral pain perception and its underlying psychophysiological mechanisms. Neurogastroenterol Motil. 2022 Apr;34(4):e14242. doi: 10.1111/nmo.14242. Epub 2021 Aug 11. PubMed 34378834 ↗
  • Cai Y, Wang Z, Zhang W, Kong W, Jiang J, Zhao R, Wang D, Feng L, Ni G. Estimation of Heart Rate and Energy Expenditure Using a Smart Bracelet during Different Exercise Intensities: A Reliability and Validity Study. Sensors (Basel). 2022 Jun 21;22(13):4661. doi: 10.3390/s22134661. PubMed 35808157 ↗
  • Alabdo A, Oflazoglu B, Kus MM, Cakan P, Ugras S, Yildiz S. Cardiac Autonomic Control Reflects Sympathovagal Changes Associated With Withholding Urination. Neurourol Urodyn. 2025 Sep;44(7):1512-1520. doi: 10.1002/nau.70105. Epub 2025 Jun 27. PubMed 40575945 ↗

Individual participant data

Plan to share: Yes — The data of the study will be available under reasonable request to the corresponding author or published in the Repository of the university of Jaen (www.ruja.es)

Supporting information: Study protocol, Sap, Csr

08

Registry details

Key details

Study ID
NCT07445113
Lead sponsor
University of Jaén
Responsible party
Ana Sedeño Vidal (Full Professor, University of Jaén) — Principal investigator
First posted
Mar 3, 2026
Start date
Dec 26, 2025
Primary completion
Jan 30, 2026
Completion
Jan 30, 2026
Last update
Sep 17, 2026

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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