Rebreathing-induced Hypoxia and Glucose Levels

May 5, 2026 updated by: Sophie Lalande, University of Texas at Austin

Effect of Rebreathing-induced Hypoxia on the Response to an Oral Glucose Tolerance Test

The aim of this research project is to determine the effect of repeated maximal voluntary apneas on glucose uptake during an oral glucose tolerance test in healthy individuals, individuals with prediabetes and patients with type 2 diabetes.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

It is predicted that 1 in 3 adults will develop diabetes by 2050, implying that a large percentage of the population will become at high risk for cardiovascular disease, the most common cause of death in patients with type 2 diabetes. While regular exercise reduces insulin resistance and the elevated glucose levels associated with type 2 diabetes, only 28% of the adult population with diabetes meet physical activity recommendations. There is therefore an urgent need to identify alternative, non-pharmacological interventions that prevent and treat type 2 diabetes.

A reduced oxygen availability, or hypoxia, is widely implicated in the development of insulin resistance. Paradoxically, hypoxia also triggers glucose uptake independently from the actions of insulin. Indeed, breathing low levels of oxygen stimulates glucose uptake in skeletal muscles by activating 5' adenosine monophosphate-activated protein kinase (AMPK). Discrepancies on the effect of hypoxia on glucose homeostasis may be attributed to the duration and type (nocturnal vs. diurnal) of hypoxic exposure. For example, the many severe hypoxic bouts associated with obstructive sleep apnea are associated with a worsened glycemic control while hypoxic exposure consisting of a limited number of short bouts of moderate hypoxia improves glycemic control. Therefore, an intervention that can induce brief hypoxic conditions, as observed through a reduced fraction of inspired oxygen, could attenuate the postprandial increase in glucose levels.

Fraction of inspired oxygen can be reduced by rebreathing into a low-volume closed-circuit system containing ambient air for few minutes. Thus, the aim of this research project is to determine the effect of few bouts of rebreathing-induced hypoxia on glucose uptake during an oral glucose tolerance test in healthy individuals, individuals with prediabetes and patients with type 2 diabetes. If our expected outcomes are met, our next step will be to determine whether repeated sessions of rebreathing-induced hypoxia (5 sessions per week over 1-3 months) results in improvements in glycemic control.

Study Type

Interventional

Enrollment (Actual)

20

Phase

  • 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

  • United States
    • Texas
      • Austin, Texas, United States, 78712
        • The Unviersity of Texas at Austin

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

Ages Eligible for Study

18 years to 80 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Men and women aged 18 to 80 years old

Exclusion Criteria:

  • Have uncontrolled stage 2 hypertension (˃140/90 mmHg)
  • Are smokers
  • Are pregnant
  • Have a history of cardiovascular disease or indication of cardiovascular disease such as myocardial infarction, left ventricular hypertrophy, ischemic heart disease (or prior ischemia), stroke, and/or other vascular disease
  • Have a history of lung disease
  • Are taking insulin or more than one antihypertensive medication
  • Have poorly controlled diabetes: HbA1c levels ˃ 9%
  • Have been previously diagnosed with diabetic complications (nephropathy, neuropathy, retinopathy) by their family doctor

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: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Sham Comparator: Spontaneous breathing
Participants will be spontaneously breathing during an oral glucose tolerance test.
Behavioral: Spontaneous breathing
Participants will be spontaneously breathing during an oral glucose tolerance test.
Experimental: Rebreathing-induced hypoxia
Participants will rebreathe room air from a low-volume closed-circuit system for a period of 2 minutes.
Behavioral: Rebreathing-induced hypoxia
Participants will rebreathe room air from a low-volume closed-circuit system for a period of 2 minutes.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in plasma glucose levels
Time Frame: Collected at min 0, 30, 60, 90 and 120 minutes of the oral glucose tolerance test
Plasma glucose levels obtained from a venous catheter during a 2-hour oral glucose tolerance test
Collected at min 0, 30, 60, 90 and 120 minutes of the oral glucose tolerance test

Collaborators and Investigators

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

Sponsor

University of Texas at Austin

Investigators

  • Principal Investigator: Sophie Lalande, UT Austin

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)

October 21, 2021

Primary Completion (Actual)

September 4, 2023

Study Completion (Actual)

October 13, 2025

Study Registration Dates

First Submitted

May 8, 2022

First Submitted That Met QC Criteria

June 13, 2022

First Posted (Actual)

June 16, 2022

Study Record Updates

Last Update Posted (Actual)

May 6, 2026

Last Update Submitted That Met QC Criteria

May 5, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • STUDY00001555

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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