Inspiratory Muscle Training in Postmenopausal Women (MRS)

Mean ReSponse Time: Effects of Inspiratory Muscle Training in Postmenopausal Women (MRS)

This study is being conducted by the Department of Kinesiology within the School of Public Health at Indiana University Bloomington. The purpose of this study is to better understand how inspiratory muscle strength training affects cardiovascular health and mood disturbance in postmenopausal women.

Study Overview

• Status: Completed
• Conditions: Obesity; Aging; Postmenopausal Symptoms
• Intervention / Treatment: Device: PrO2 Fit (IMT Trainer)

Detailed Description

Inspiratory muscle training (IMT) works by strengthening the respiratory muscles through resistive airflow breathing using a handheld device. The goal being to elicit an adaptive response akin to resistance exercise for locomotor muscles. Labored breathing due to respiratory muscle weakness can detract from physical performance with attendant consequences on independent living. This may trigger a maladaptive cycle that worsens physiological and psychosocial outcomes. IMT from 6-10 weeks has been shown to increase maximal inspiratory pressure, functional capacity, and perceived breathlessness across disease states. To inform an appropriately powered randomized controlled trial, the present work proposes a 2-arm single-blind, randomized pilot study to evaluate outcomes of interest.

• Study Type: Interventional
• Enrollment (Actual): 28
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Indiana
    • Bloomington, Indiana, United States, 47405
      • Indiana University

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Postmenopausal women (self-report at least 6 years since last menstrual cycle)
• Aged 50-75 years (confirmed by birth date listed on participant's driver license at screening visit)
• English-speaking
• Body mass index between 25.0 to 39.9 kg/m2
• Able to ambulate without assistance
• Own or have access to a Bluetooth-capable phone or tablet (IOS version 12.0 or later or Android version 7.0 or later)

Exclusion Criteria:

• Unable to provide informed consent.
• Greater than stage II hypertension (i.e., >159/99 mm Hg)
• Current tobacco use (self-report)
• Habitually exercise training ≥ 2 days per week (self-report)
• Significant orthopedic limitations or other contraindications to strenuous exercise
• Live or work > 80 miles from Bloomington, Indiana
• Anticipated elective surgery during the study period.
• Surgery to the chest or abdomen in the last 6 months.
• Plan to move residence or travel out of the local area during the study period.
• History of heart attack or heart condition.
• Current use of prescription medications that affect heart rate or blood vessel dilation (e.g., systemic b-adrenergic blockers, calcium channel blockers, and hormone replacement therapy).
• Diagnosis of asthma or chronic pulmonary disease.
• Current respiratory infection.
• Diagnosis of an aneurysm in the chest, abdomen, or brain.
• Psychological or social characteristics that would interfere with their ability to fully participate in the study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Inspiratory Muscle Training (IMT) group; The test protocol requires participants to inhale maximally (maximum inspiratory pressure, MIP) against 2mm diameter leak and sustain inhalation (sustained maximal inspiratory pressure, SMIP) until task failure. Participants will complete 3 SMIP maneuvers with each training session and use the best of the three for that day's training template (corresponding to about 80% SMIP for the IMT group) via the PrO2Fit software. Participants must match or exceed the SMIP template with each increasing level of the work-rest ratio. Work at each level consists of 6 breaths, 36 breaths total. If six breaths are completed, the next level starts. Rest intervals will progressively shorten as training continues from 40-seconds to 5-seconds. The session will be terminated if participants are unable to match at least 90% of the training template for two consecutive breaths or have completed all 36 breaths. Training will be done 4 times a week, and over 8-weeks.	Device: PrO2 Fit (IMT Trainer); The device is used four times a week over a period of 8 weeks.
Sham Comparator: Sham Inspiratory Muscle Training (Sham-IMT) group; Similar to the IMT group protocol, participants will be required to complete 3 SMIP maneuvers with each training session. Participants will use the best of the three for that day's training template (corresponding to about 30% SMIP for the Sham-IMT group) via the PrO2Fit software. Participants must match or exceed the SMIP template with each increasing level of the work-rest ratio. Work at each level consists of 6 breaths, 36 breaths total. If six breaths are completed, the next level starts. Rest intervals will progressively shorten as training continues from 40-seconds to 30-, 20-, 15-, 10-, and 5-seconds. The training session will be terminated if participants are unable to match at least 90% of the training template for two consecutive breaths or have completed all 36 breaths. Training will be done 4 times a week, and over 8-weeks.	Device: PrO2 Fit (IMT Trainer); The device is used four times a week over a period of 8 weeks.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Duration	Duration, reported in seconds, to reach 63% of steady-state V̇O2 during a fixed-workload treadmill task. This technique is performed using breath-by-breath open-circuit spirometry and captures the V̇O2 fast component occurring in the transition from standing rest to treadmill walking.	Baseline, within 48 hours of completing intervention

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Distance Traveled	Distance traveled, reported in meters, during a 6-minute walk test. The assessment offers reliable and valid insight concerning exercise capacity in older women.	Baseline, within 9 days of completing intervention

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cerebral Vascular Reactivity	Cerebral vascular function will be measured in vivo evidenced by changes in cerebral blood flow velocity [i.e., reactivity (cm/s/mm Hg)] of the middle cerebral artery in response to randomized hypercapnic gas exposure.	Baseline, within 9 days of completing intervention

Collaborators and Investigators

• Sponsor: Indiana University
• Investigators: Principal Investigator: Stephen J Carter, Ph.D, Indiana University, Bloomington

Study record dates

Study Major Dates

• Study Start (Actual): April 12, 2024
• Primary Completion (Actual): September 1, 2025
• Study Completion (Actual): September 1, 2025

Study Registration Dates

• First Submitted: May 21, 2024
• First Submitted That Met QC Criteria: June 10, 2024
• First Posted (Actual): June 14, 2024

Study Record Updates

• Last Update Posted (Actual): February 12, 2026
• Last Update Submitted That Met QC Criteria: February 10, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: aging; blood pressure; postmenopausal; women's health; Inspiratory Muscle Training (IMT); mean response time
• Additional Relevant MeSH Terms: Nutrition Disorders; Overnutrition; Body Weight; Overweight; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Obesity
• Other Study ID Numbers: 20387

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: No IDP sharing plan

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: Yes