Yoga-Based Breathing Exercises in a Salt-Cave Environment Versus a Standard Clinical Setting in Smokers (SPELEO-SMOKERS)

July 27, 2026 updated by: SEFA HAKTAN HATIK, Sinop University

Yoga-Based Breathing Exercises Performed in a Salt-Cave Environment Versus a Standard Clinical Setting in Smokers: A Randomized Controlled Trial

This randomized controlled trial evaluated whether performing the same yoga-based breathing exercise program in a salt-cave environment produced different respiratory, functional, physical activity, and quality-of-life outcomes compared with the same program performed in a standard clinical setting in adult smokers. Sixty adult smokers were randomized to either a salt-cave group or a control group. Both groups received a physiotherapist-supervised yoga-based breathing exercise program for 6 weeks, twice weekly, in 50-minute sessions. The intervention content, frequency, duration, and physiotherapist supervision were identical in both groups; the only planned between-group difference was the intervention setting. Spirometric outcomes were assessed at baseline, week 3, and week 6. Functional exercise capacity, physical activity, and quality of life were assessed at baseline and week 6.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Eligible participants were adult daily smokers aged 18 to 65 years who had smoked for at least the previous 12 months. After baseline assessments, participants were randomized in a 1:1 ratio to the salt-cave group or the standard clinical setting group. Allocation was generated by an independent researcher and concealed using sequentially numbered, opaque, sealed envelopes. Both groups completed the same 6-week yoga-based breathing exercise program, delivered twice weekly under physiotherapist supervision. Each standardized session lasted approximately 50 minutes and included preparatory breathing control, diaphragmatic breathing, Suusi breathing, Kapalabhati, Ujjayi, Anuloma-Viloma/Nadi Shodhana, Bhastrika, Bhramari, Agni Sar, and relaxation. The salt-cave group received the program at the Tuzluca Salt Therapy Center, whereas the control group received the program in a standard private clinical setting. Spirometric parameters included forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF), and the FEV1/FVC ratio. Secondary assessments included the 6-minute walk test, the International Physical Activity Questionnaire-Short Form, and the World Health Organization Quality of Life-BREF. Participant and provider blinding was not feasible because the settings were visibly different. Statistical analysis was conducted using coded group labels.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
60

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Turkey (Türkiye)
      • Iğdır, Turkey (Türkiye), 76900
        • Tuzluca Rock Salt Mine Salt Therapy Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Adults aged 18 to 65 years
  • Voluntary participation and written informed consent
  • Ability to ambulate and cooperate with assessments
  • Literacy
  • Daily smoking for at least the previous 12 months
  • Body mass index below 30 kg/m²

Exclusion Criteria:

  • Adults aged 18 to 65 years
  • Voluntary participation and written informed consent
  • Ability to ambulate and cooperate with assessments
  • Literacy
  • Daily smoking for at least the previous 12 months
  • Body mass index below 30 kg/m²

Withdrawal Criteria

  • Participant request to discontinue
  • Pregnancy or suspected pregnancy
  • Occurrence of a sports-related injury during assessments

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Salt-Cave Yoga-Based Breathing Exercise Group
Participants completed the physiotherapist-supervised yoga-based breathing exercise program at the Tuzluca Salt Therapy Center for 6 weeks, twice weekly. The program content, session duration, frequency, and supervision were identical to those of the comparator group; the planned between-group difference was the intervention setting.
Behavioral: Yoga-Based Breathing Exercise Program in a Salt-Cave Environment
Participants received a physiotherapist-supervised yoga-based breathing exercise program at the Tuzluca Salt Therapy Center. The intervention lasted 6 weeks and included two sessions per week, for a total of 12 sessions. Each standardized session lasted approximately 50 minutes and included preparatory breathing control, diaphragmatic breathing, Suusi breathing, Kapalabhati, Ujjayi, Anuloma-Viloma/Nadi Shodhana, Bhastrika, Bhramari, Agni Sar, and relaxation. The exercise content, session frequency, duration, and physiotherapist supervision were identical to those provided in the standard clinical setting group; the planned difference was the intervention setting.
Active Comparator: Standard Clinical Setting Yoga-Based Breathing Exercise Group
Participants completed the same physiotherapist-supervised yoga-based breathing exercise program at the Iğdır Fizyodinamik Wellness Center for 6 weeks, twice weekly. The program content, session duration, frequency, and supervision were identical to those of the experimental group.
Behavioral: Yoga-Based Breathing Exercise Program in a Standard Clinical Setting
Participants received the same physiotherapist-supervised yoga-based breathing exercise program in a standard clinical setting at the Iğdır Fizyodinamik Wellness Center. The intervention lasted 6 weeks and included two sessions per week, for a total of 12 sessions. Each standardized session lasted approximately 50 minutes and included preparatory breathing control, diaphragmatic breathing, Suusi breathing, Kapalabhati, Ujjayi, Anuloma-Viloma/Nadi Shodhana, Bhastrika, Bhramari, Agni Sar, and relaxation. The exercise content, session frequency, duration, and physiotherapist supervision were identical to those provided in the salt-cave group.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Change in Forced Expiratory Volume in 1 Second (FEV1) From Baseline to Week 6
Time Frame: Baseline, week 3, and week 6; primary endpoint at week 6
FEV1 was measured in liters using pre-bronchodilator spirometry. Participants performed three forced expiratory maneuvers under standardized instruction, and the best acceptable value was recorded. The primary comparison was the between-group difference in change from baseline to week 6. An interim measurement was also obtained at week 3
Baseline, week 3, and week 6; primary endpoint at week 6

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change in Forced Vital Capacity (FVC) From Baseline to Week 6
Time Frame: Baseline, week 3, and week 6
FVC in liters, measured by pre-bronchodilator spirometry; baseline, week 3, and week 6.
Baseline, week 3, and week 6
Change in Peak Expiratory Flow (PEF) From Baseline to Week 6
Time Frame: Baseline, week 3, and week 6
PEF in L/s, measured by pre-bronchodilator spirometry; baseline, week 3, and week 6.
Baseline, week 3, and week 6
Change in FEV1/FVC Ratio From Baseline to Week 6
Time Frame: Baseline, week 3, and week 6
FEV1/FVC expressed as a percentage; baseline, week 3, and week 6.
Baseline, week 3, and week 6
Change in 6-Minute Walk Distance From Baseline to Week 6
Time Frame: Baseline and week 6
Distance walked in meters during the 6-minute walk test. Two tests were administered and the longest distance was used; baseline and week 6.
Baseline and week 6
Change in Physical Activity Assessed by IPAQ-SF From Baseline to Week 6
Time Frame: Baseline and week 6
Total physical activity expressed as MET-min/week using the standard IPAQ-SF scoring protocol; baseline and week 6.
Baseline and week 6
Change in WHOQOL-BREF Scores From Baseline to Week 6
Time Frame: Baseline and week 6
Changes in General Health, Physical Health, Psychological, Social Relationships, and Environment scores; baseline and week 6.
Baseline and week 6
Participants With Intervention-Related Adverse Events
Time Frame: 6-week study period
Number of participants experiencing intervention-related or spirometry-related adverse events during the 6-week study period.
6-week study period

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Sinop University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 1, 2022

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
February 20, 2023

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
February 28, 2023

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
July 27, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 27, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
July 30, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 30, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 27, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • SPELEO-SMOKERS-2022

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be shared with external researchers.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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