Respiratory and Exercise Responses by Body Roundness Index in Obesity

Evaluation of Respiratory Performance and Exercise Responses According to Body Roundness Index in Individuals With Obesity

This observational study aims to evaluate respiratory performance and exercise responses according to Body Roundness Index (BRI) in individuals with obesity. Participants will undergo anthropometric and body composition assessments, respiratory muscle strength testing, pulmonary function evaluation, and a six-minute walk test. Exercise-related ventilatory responses, dyspnea, fatigue perception, oxygen saturation, and heart rate responses will also be assessed. The study seeks to investigate the relationship between BRI and cardiopulmonary performance and to determine whether BRI may serve as a useful indicator of obesity-related functional limitations and exercise capacity.

Study Overview

• Status: Not yet recruiting
• Conditions: Obesity
• Intervention / Treatment: Other: Observational

• Study Type: Observational
• Enrollment (Estimated): 120

Contacts and Locations

• Study Contact: Name: Buket Akinci, Prof. Dr.; Phone Number: +90 505 641 56 92; Email: bakinci@biruni.edu.tr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

The study population will consist of adults with obesity between 25 and 60 years of age with a body mass index (BMI) ≥ 30 kg/m² according to the World Health Organization classification. Participants will be recruited on a voluntary basis and will undergo anthropometric, respiratory, and exercise capacity assessments.

Description

Inclusion Criteria:

• Individuals between 25 and 60 years of age
• Individuals with a body mass index (BMI) ≥ 30 kg/m² according to the World Health Organization (WHO) classification
• Individuals who voluntarily agree to participate in the study

Exclusion Criteria:

• Individuals with a Charlson Comorbidity Index (CCI) score of 3 or higher
• Individuals with uncontrolled arrhythmia, hypertension, heart failure, diabetes mellitus, or unstable angina pectoris
• Individuals with cooperation difficulties, orthopedic disorders, or neurological problems that may interfere with assessment procedures
• Individuals with a history of lower extremity injury or surgery within the last six months
• Individuals diagnosed with diabetes mellitus and presenting complications such as nephropathy, retinopathy, or neuropathy
• Individuals with concomitant chronic respiratory disease
• Individuals with acute infection
• Individuals with middle ear pathologies (e.g., tympanic membrane rupture or otitis)
• Individuals with a history of spontaneous or trauma-related pneumothorax
• Current smokers
• Pregnant individuals
• Individuals with a STOP-Bang score of 3 or higher
• Individuals currently participating in a structured weight-loss diet program or receiving medical treatment for weight reduction during the assessment period
• Individuals who underwent endoscopic intervention and/or bariatric surgery within the last year

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Individuals with obesity	Other: Observational; Participants will not receive any therapeutic or experimental intervention; only observational and functional assessments will be performed.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Forced vital capacity (FVC)	The assessment will be performed in accordance with the American Thoracic Society (ATS) and European Respiratory Society (ERS) criteria. Assessments will be conducted in a seated position with back support. To prevent the risk of infection, disposable mouthpieces and filters will be used for each participant. Forced vital capacity (FVC) will be measured. Values will be recorded in liter and as percentage (%) of predicted values. Measurements will be repeated three times, and the best value meeting measurement standardization criteria will be recorded.	Day 1
Maximum Inspiratory Pressure (MIP)	Respiratory muscle strength assessment will be performed using an intraoral pressure measurement device (MicroRPM, Micro Medical, United Kingdom) in accordance with the American Thoracic Society (ATS) and European Respiratory Society (ERS) criteria (ATS/ERS, 2002). Measurements will be conducted in a seated position while wearing a nose clip. To prevent the risk of infection, disposable mouthpieces and filters will be used for each participant. For maximal inspiratory pressure (MIP) measurement, participants will perform a maximal inspiratory effort through the mouth for a few seconds. Measurements will be repeated three times, and the best value meeting standardization criteria will be recorded in cmH₂O.	Day 1
Forced Expiratory Volume in 1 second (FEV1)	The assessment will be performed in accordance with the American Thoracic Society (ATS) and European Respiratory Society (ERS) criteria. Assessments will be conducted in a seated position with back support. To prevent the risk of infection, disposable mouthpieces and filters will be used for each participant. FEV1 ratio will be measured. Values will be recorded percentage (%) of predicted values. Measurements will be repeated three times, and the best value meeting measurement standardization criteria will be recorded.	Day 1
FEV1/FVC ratio	The assessment will be performed in accordance with the American Thoracic Society (ATS) and European Respiratory Society (ERS) criteria. Assessments will be conducted in a seated position with back support. To prevent the risk of infection, disposable mouthpieces and filters will be used for each participant. FEV1/FVC ratio will be measured. Values will be recorded percentage (%) of predicted values. Measurements will be repeated three times, and the best value meeting measurement standardization criteria will be recorded.	Day 1
Maximal expiratory pressure (MEP)	Respiratory muscle strength assessment will be performed using an intraoral pressure measurement device (MicroRPM, Micro Medical, United Kingdom) in accordance with the American Thoracic Society (ATS) and European Respiratory Society (ERS) criteria (ATS/ERS, 2002). Measurements will be conducted in a seated position while wearing a nose clip. To prevent the risk of infection, disposable mouthpieces and filters will be used for each participant. For maximal expiratory pressure (MEP) measurement, a maximal expiratory effort will be performed for a few seconds, and the values will be recorded. Measurements will be repeated three times, and the best value meeting standardization criteria will be recorded in cmH₂O.	Day 1

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Exercise capacity	Exercise capacity will be evaluated using the Six-Minute Walk Test (6MWT) according to the American Thoracic Society (ATS) guidelines with the Spiropalm 6MWT device (COSMED, Italy) (ATS, 2002). Before the test, participants will rest for at least 10 minutes, and baseline measurements including heart rate, blood pressure, oxygen saturation, dyspnea, and leg fatigue will be recorded. The test will be performed in a 30-meter indoor corridor, and participants will be instructed to walk as fast as possible for six minutes. Total walking distance will be recorded in meters. Heart rate, oxygen saturation, dyspnea, and fatigue levels will be reassessed after the test.	Day 1
Ventilation (VE)	Ventilation (Unit of Measure: L/min) during the 6MWT will be assessed using the Spiropalm device.	Day 1
Body fat mass index (kg)	Body fat mass (kg) will be measured using Bioelectrical Impedance Analysis (BIA). Participants will be informed about the test protocol and instructed to fast for 8-12 hours before the assessment, arrive with an empty bladder, and avoid fluid intake, food consumption, and vigorous physical activity prior to the measurements. Assessments will be performed during daytime at a room temperature of 25°C. Participants will be measured while clothed and barefoot after removing their shoes, socks, and all metal accessories.	Day 1
Body Roundness Index	Body Roundness Index (BRI) will be calculated using waist circumference and height measurements according to the standardized BRI formula. The BRI is a continuous index with no fixed minimum or maximum value. Higher BRI values indicate greater body roundness and higher adiposity (worse outcome).	Day 1
Peak ventilation (VEpeak)	Peak ventilation (VEpeak) during the 6MWT will be assessed using the Spiropalm device.	Day 1
Peak breathing reserve (BRpeak)	Peak breathing reserve (BRpeak) (Unit of Measure: %) during the 6MWT will be assessed using the Spiropalm device.	Day 1
Inspiratory capacity (IC)	Inspiratory capacity (IC) during the 6MWT will be assessed using the Spiropalm device.	Day 1
Body muscle mass (kg)	Body muscle mass (kg) will be measured using Bioelectrical Impedance Analysis (BIA). Participants will be informed about the test protocol and instructed to fast for 8-12 hours before the assessment, arrive with an empty bladder, and avoid fluid intake, food consumption, and vigorous physical activity prior to the measurements. Assessments will be performed during daytime at a room temperature of 25°C. Participants will be measured while clothed and barefoot after removing their shoes, socks, and all metal accessories.	Day 1

Collaborators and Investigators

• Sponsor: Biruni University

Study record dates

Study Major Dates

• Study Start (Estimated): June 20, 2026
• Primary Completion (Estimated): November 20, 2026
• Study Completion (Estimated): December 9, 2026

Study Registration Dates

• First Submitted: May 7, 2026
• First Submitted That Met QC Criteria: May 12, 2026
• First Posted (Actual): May 19, 2026

Study Record Updates

• Last Update Posted (Actual): May 19, 2026
• Last Update Submitted That Met QC Criteria: May 12, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Nutrition Disorders; Overnutrition; Body Weight; Overweight; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Obesity; Health Services Administration; Quality of Health Care; Outcome Assessment, Health Care; Outcome and Process Assessment, Health Care; Watchful Waiting
• Other Study ID Numbers: Obesity1052026

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No