A preliminary investigation on the effects of intermittent exposure to hypoxia on glucose homeostasis

• Register: ANZCTR
• Last refreshed on: 13 January 2020
• Main ID: ACTRN12616000525482
• Date of registration: 22/04/2016
• Prospective Registration: Yes
• Primary sponsor: Southern Cross University
• Public title: A preliminary investigation on the effects of intermittent exposure to hypoxia on glucose homeostasis
• Scientific title: A preliminary investigation on the effects of intermittent exposure to hypoxia on glucose homeostasis in overweight adults with impaired fasting blood glucose
• Date of first enrolment: 27/04/2016
• Target sample size: 25
• Recruitment status: Recruiting
• URL: https://anzctr.org.au/ACTRN12616000525482.aspx
• Study type: Interventional
• Study design: Purpose: Treatment; Allocation: Randomised controlled trial; Masking: Blinded (masking used);Assignment: Crossover;Type of endpoint: Efficacy;
• Phase: Not Applicable

Countries of recruitment

Australia

Contacts

• Name: Mr Charl Neuhoff

• Name: Prof Shi Zhou

Key inclusion & exclusion criteria

Inclusion criteria: Fasting blood glucose greater than 6.0 mM
Body mass index >25 (i.e. overweight or obese);
No planned changes to medication regimen for hyperglycaemia (e.g. metformin, acarbose) or other metabolic diseases (e.g. lipid lowering drugs); and
No planned major lifestyle changes during the testing period (i.e. commencement/ceasing of exercise regimen, pregnancy, etc.)

Exclusion criteria: Cardiovascular diseases;
Anemia or blood donation within past 3 months;
Severe chronic obstructive pulmonary disease;
Smoking;
Alcohol consumption for more than 3 standard drinks per day;
Obstructive sleep apnea;
Uncontrolled asthma;
Inflammatory and/or infectious diseases;
Intolerance to oxygen insufficiency;
Disease with symptoms of decompensation;
Terminal illness;
Cancer;
Pregnant;
Neurological diseases; or
Mental illness.


Age minimum: 18 Years
Age maximum: 65 Years
Gender: Both males and females

Health Condition(s) or Problem(s) studied

Impaired fasting blood glucose;Pre-diabetes;Overweight;Type 2 diabetes;
Impaired fasting blood glucose
Pre-diabetes
Overweight
Type 2 diabetes

Metabolic and Endocrine - Diabetes

Intervention(s)

Participants with impaired fasting blood glucose will be given intermittent exposure to hypoxic air from a hypoxicator via a breathing mask. The biofeedback mode of the hypoxicator will be used with the target hypoxia level set as blood oxygen saturation at 90% (corresponding oxygen level in the air at approximately 15%). The blood oxygen saturation is monitored by a pulse oximeter. Each intervention session is for 1 hour that includes four cycles of breathing hypoxic air for 10 minutes followed by normal air for 5 minutes. The intervention will be administered by research scientists and accredited exercise physiologists. Each intervention session will be delivered individually at the research laboratory in School of Health and Human Sciences, Lismore Campus of Southern Cross University.
The research has two phases. The first phase is a pilot investigation that will use a single system research design to examine the acute effects of 1 hour hypoxia or normoxia exposure on blood glucose. Each participant will be randomly allocated into two hypoxia and two normoxia sessions each is separated by one week. The phase two of the research will be a randomised controlled trial that uses a single-blind crossover design to investigate the effects of four weeks (three 1 hour sessions per week in non-consecutive days) hypoxia or placebo intervention on blood glucose homeostasis and insulin sensitivity. A 4-week wash-out period will be inserted between the two 4-week hypoxia or normoxia (placebo) intervention periods).

Primary Outcome(s)

Phase 2: Changes in fasting blood glucose (veni-puncture samples), assessed by serum assay at an accredited pathology lab..[Pre and post four weeks hypoxia and four weeks placebo intervention periods.]

Phase 2: Changes in glucose tolerance (veni-puncture samples), assessed by serum assay at an accredited pathology lab..[Pre and post four weeks hypoxia and four weeks placebo intervention periods.]

Phase 1: Acute changes in blood glucose (skin-puncture samples), assessed by a hand-hold glucometer..

[Phase 1: Pre, 30 min and 60 min during, and 30 min, 1 hour and 24 hour post an intervention trial.

]

Secondary Outcome(s)

Phase 2: Changes in blood insulin (veni-puncture samples), assessed by serum assay at an accredited pathology lab.[Phase 2: Pre and post four weeks hypoxia and four weeks placebo intervention periods.]

Blood pressure, monitored using a sphygmomanometer. [Every 15 minutes during each intervention session. ]

Heart rate, monitored by a pulse oximeter.[Monitored continuously and recorded every 5 minutes during each intervention session. ]

Phase 2: Changes in HbA1c, assessed by ion-exchange high-performance liquid chromatography at an accredited pathology lab.[Pre and post four weeks hypoxia and four weeks placebo intervention periods.]

Blood oxygen saturation (SpO2), monitored by a pulse oximeter in all intervention sessions.[Monitored continuously during each intervention session to provide biofeedback to the hypoxicator. ]

Secondary ID(s)

Nil known

Source(s) of Monetary Support

Southern Cross University

Ethics review

Status: Approved
Approval date:
Contact:

Southern Cross University Human Research Ethics Committee