RecruitingACTRN12616000525482

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

A preliminary investigation on the effects of intermittent exposure to hypoxia on glucose homeostasis in overweight adults with impaired fasting blood glucose

Sponsor

Southern Cross University

Enrollment

25 participants

Start Date

Apr 27, 2016

Study Type

Interventional

Conditions

Impaired fasting blood glucose Overweight Pre-diabetes

Summary

Obesity and diabetes have become global epidemics. It is known that adequate physical activity and a healthy diet are among the key factors in weight control and management of type 2 diabetes. However, participation in regular exercise could be a challenge to some individuals with various capacities. There have been reports in the literature that hypoxia interventions, alone or combined with exercise, may have beneficial effects on weight control and blood glucose homeostasis in individuals with obesity and hyperglycaemia. With advancement of technology, hypoxia chambers and breathing devices (hypoxicators) have become available to provide air with various levels of oxygen. Whether hypoxia can be validated as an alternative or complementary intervention for obesity and diabetes requires further research. The aim of this research is to conduct a preliminary investigation on the effect of four weeks intermittent exposure to mild hypoxia (with the target blood oxygen saturation level at approximately 90%) on blood glucose homeostasis and insulin sensitivity in individuals with impaired fasting blood glucose. The participants’ responses (including blood oxygen saturation level, heart rate, and blood pressure) during the intervention sessions will be closely monitored, and their blood glucose, insulin and HbA1c levels, and glucose tolerance will be assessed pre and post the intervention period to determine the effects.

Eligibility

Sex: Both males and femalesMin Age: 18 YearssMax Age: 65 Yearss

Plain Language Summary

Simplified for easier understanding

This study is looking at whether brief, repeated sessions of breathing slightly lower-oxygen air (called intermittent hypoxia) can help improve blood sugar levels in people who have higher-than-normal fasting blood glucose but haven't yet developed full diabetes. Participants will breathe through a special device that lowers their oxygen level slightly — similar to being at altitude — for short sessions over 4 weeks. Blood sugar, insulin, and other markers will be measured before and after. You may be eligible if: - You are aged 18 to 65 years - Your fasting blood glucose is above 6.0 mmol/L - Your BMI is above 25 (overweight or obese) - You are not planning to change your diabetes medications or lifestyle significantly during the study You may NOT be eligible if: - You have a diagnosed cardiovascular disease - You have anaemia or have donated blood in the past 3 months - You have severe COPD, uncontrolled asthma, or obstructive sleep apnoea - You currently smoke or drink more than 3 standard alcoholic drinks per day - You are pregnant - You have a neurological or mental illness Talk to your doctor about whether this trial might be right for you.

This is a simplified summary. Always discuss eligibility with your doctor before enrolling in a clinical trial.

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Interventions

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).