Inspiratory Muscle Strength Training in Adults With Type 2 Diabetes (DIT)

Effects of Inspiratory Muscle Strength Training on Metabolic and Cardiovascular Health in Adults With Type 2 Diabetes

This clinical research study will investigate the effects of 6 weeks of inspiratory muscle strength training on metabolic and cardiovascular outcomes in adults with recent-onset type 2 diabetes.

Study Overview

• Status: Completed
• Conditions: Hypertension; Diabetes Mellitus, Type 2
• Intervention / Treatment: Behavioral: Inspiratory muscle strength training (IMST)

Detailed Description

Type 2 diabetes mellitus (T2DM) is at epidemic proportions in the United States and worldwide. It is a chronic obesity-associated metabolic disorder characterized by glucose dysregulation combined with insulin resistance and beta-cell defects. First-line T2DM treatments include lifestyle remedies, such as dietary modifications and exercise. Exercise, whether aerobic and/or resistance training, increases whole-body insulin sensitivity and stimulates muscle glucose uptake independent of insulin. The acute effects of exercise on muscle in patients with abnormal glucose regulation produce immediate improvements in blood glucose levels. In addition, when exercise is repeated over time, adaptations occur that include more long-lasting increases in insulin sensitivity. The effects of traditional exercise on glycemic control and insulin sensitivity in patients with T2DM are well established. However, adherence to traditional exercise programs is low, in part, due to lack of time and physical discomfort, and new regimens for T2DM treatment are needed.

Recently, a novel time-efficient respiratory exercise called Inspiratory Muscle Strength Training (IMST) was developed. IMST is distinct from other traditional forms of exercise as it is only 5 minutes per session and performed on a hand-held device during stationary sitting or standing. Typically, IMST comprises 5 sets of 6 inspiratory maneuvers with 1-minute rests between sets. Previous studies demonstrate that 6 weeks of IMST improve systolic blood pressure (SBP), sympathetic nervous system activity, and endothelial function in healthy individuals, middle-aged and older people, and adults with obstructive sleep apnea. These BP-lowering effects of IMST are significant for reducing the risks of cardiovascular disease (CVD), the number one cause of death in people living with diabetes. IMST is safe and tolerable, with adherence rates >90% in diverse populations, and presents a manageable program for improving metabolic health in T2DM patients who have difficulty maintaining a traditional exercise program requiring a large amount of time and physical exertion. It is unknown if IMST, a highly-abbreviated respiratory exercise that is not physically demanding, has beneficial effects on glycemic control and insulin sensitivity, in combination with its improvements on BP measures, in patients with T2DM. The potential for IMST to exert metabolic benefits in diabetic patients warrants assessment

• Study Type: Interventional
• Enrollment (Actual): 11
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Arizona
    • Tucson, Arizona, United States, 85724
      • Arizona Respiratory and Neurophysiology Laboratory

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• diagnosed with type 2 diabetes by physician
• fasting plasma glucose levels ≥126 mg/dl and ≤240 mg/dl
• systolic blood pressure between 120-169 mmHg
• stable dose of medication (three months on the same dose)
• weight stable in the prior 3 months (<3.0 kg weight change) and willing to remain weight stable throughout the study
• absence of unstable clinical disease as determined by medical history

Exclusion Criteria:

• current smoker (including tobacco products, vaping devices, THC, etc…)
• have an uncontrolled medical condition (e.g., cancer)
• myocardial infarction or stroke within the previous 12 months
• performs regular aerobic exercise (>4 bouts/week)
• BMI ≥ 40 kg/m2
• systolic blood pressure <120 or ≥170 mmHg
• diastolic blood pressure >100 or <60 mmHg
• Cheyne-Stokes respiration
• history of perforated eardrum
• history of glaucoma or retinopathy
• history of collapsed lung
• diagnosed with asthma
• pregnant, breastfeeding, or trying to become pregnant (self-reported)
• medications that, in the opinion of the study physician or nurse practitioner, may impact the outcomes of the study (e.g., steroids)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: High-resistance IMST; 30 breaths/day (5 sets of 6 breaths, one minute of rest between sets), 5 days/week, 6 weeks	Behavioral: Inspiratory muscle strength training (IMST); 30 breaths/day, 5 days/week, 6 weeks; Other Names: inspiratory resistance training; vascular conditioning exercise; inspiratory muscle training
Active Comparator: Low-resistance IMST; 30 breaths/day (5 sets of 6 breaths, one minute of rest between sets), 5 days/week, 6 weeks	Behavioral: Inspiratory muscle strength training (IMST); 30 breaths/day, 5 days/week, 6 weeks; Other Names: inspiratory resistance training; vascular conditioning exercise; inspiratory muscle training

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from baseline fasting blood plasma glucose after 6 weeks of IMST	A blood sample will be collected after 12 hours of fasting. Blood and plasma will be separated and plasma glucose levels will be quantified.	Blood plasma collected and analyzed at baseline and after 6 weeks of training
Change from baseline fasting blood plasma Insulin after 6 weeks of IMST	A blood sample will be collected after 12 hours of fasting. Blood and plasma will be separated and plasma insulin levels will be quantified.	Blood plasma collected and analyzed at baseline and after 6 weeks of training
Change from baseline insulin sensitivity after 6 weeks of IMST	A blood sample will be collected after 12 hours of fasting. Insulin sensitivity will be calculated using the homeostatic model assessment of insulin resistance (HOMA-IR): (fasting serum insulin (mU/L) × fasting plasma glucose (mmol/L) × 22.5).	Blood plasma collected and analyzed at baseline and after 6 weeks of training

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from baseline systolic blood pressure after 6 weeks of IMST	Change in systolic blood pressure (SBP) will be measured by both relative and absolute changes from baseline. SBP will be assessed in accordance with American College of Cardiology/American Heart Association guidelines. Measurements will be taken using an automated oscillometric sphygmomanometer and will be performed in triplicate over the brachial artery of the left arm after 5 minutes of quiet rest, with 1 minute of recovery between measures. SBP will be defined as the average of the 3 pressures.	Blood pressure will be assessed at baseline and after 6 weeks of training
Change from baseline Nitric Oxide-mediated Endothelial Dependent Dilation (EDD)	Brachial artery Flow Mediated Dilation (BA-FMD), a well-established measure of NO-mediated endothelial function, will be measured by both relative and absolute changes from baseline. BA-FMD will be determined using high-resolution ultrasonography and analyzed with a commercially available software package. An ultrasound probe will be placed 3-6 cm proximal to the antecubital crease on the right arm and a baseline image of the right brachial artery will be obtained. Following baseline, reactive hyperemia will be produced by inflating a rapid-inflating blood pressure cuff. Brachial artery diameter change will be measured for 2 minutes following 5-min of forearm blood flow occlusion.	EDD will be assessed at baseline and after 6 weeks of training

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from baseline proteomic analysis	Isolated plasma proteins will be subjected to sequential in-solution digestion (Lys-C and trypsin) followed by analysis with tandem mass spectrometry for pre/post changes. Quantitative proteomics using extracted ion abundance, including statistical analysis, will be performed in Progenesis. The resulting quantitative proteomic data sets will be analyzed using DAVID (david.ncifcrf.gov), a well-established tool for gene ontology enrichment analysis.	Proteomics will be performed at baseline and after 6 weeks of training

Collaborators and Investigators

• Sponsor: University of Arizona
• Investigators: Principal Investigator: Dallin Tavoian, PhD, University of Arizona

Publications and helpful links

General Publications

• Craighead DH, Tavoian D, Freeberg KA, Mazzone JL, Vranish JR, DeLucia CM, Seals DR, Bailey EF. A multi-trial, retrospective analysis of the antihypertensive effects of high-resistance, low-volume inspiratory muscle strength training. J Appl Physiol (1985). 2022 Oct 1;133(4):1001-1010. doi: 10.1152/japplphysiol.00425.2022. Epub 2022 Sep 15.

Study record dates

Study Major Dates

• Study Start (Actual): June 30, 2023
• Primary Completion (Actual): May 6, 2024
• Study Completion (Actual): May 6, 2024

Study Registration Dates

• First Submitted: November 30, 2022
• First Submitted That Met QC Criteria: November 30, 2022
• First Posted (Actual): December 9, 2022

Study Record Updates

• Last Update Posted (Actual): June 14, 2024
• Last Update Submitted That Met QC Criteria: June 13, 2024
• Last Verified: June 1, 2024

More Information

Terms related to this study

• Keywords: insulin sensitivity; blood pressure; blood glucose; non-pharmacological; inspiratory resistance training
• Additional Relevant MeSH Terms: Pathologic Processes; Glucose Metabolism Disorders; Metabolic Diseases; Respiratory Tract Diseases; Respiration Disorders; Endocrine System Diseases; Diabetes Mellitus; Diabetes Mellitus, Type 2; Respiratory Aspiration
• Other Study ID Numbers: 00002239

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: There is no plan to make IPD available

Drug and device information, study documents

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