The purpose of this study is to determine if 2 weeks of nightly exposure (7-12 hours per night) to moderate hypoxia (~2,400 meters or 7,500 feet) improves glucose metabolism in people with type 2 diabetes.

Exposure to hypoxia has been advocated as a possible therapeutic aid against obesity. Indeed, our laboratory has provided the first evidence that intermittent, nightly exposure to moderate hypoxia is beneficial in improving insulin sensitivity in healthy obese patients and, therefore, lowers the risk of developing type 2 diabetes. Benefits included reduced fasting glucose levels and improved whole-body (skeletal muscle) and hepatic insulin sensitivity. Whether such intermittent hypoxia improves glucose metabolism in people with type 2 diabetes is unknown.

INCLUSION CRITERIA:

• Aged 20-65 yrs
• Body mass index (BMI) < 55 kg/m2
• Body weight 450 lbs or less (to accommodate body composition assessment)
• Have either been diagnosed with type 2 diabetes, or fasting blood glucose between 125 and 200 mg/dL, or have a hemoglobin A1c ≥ 6.5%
• Non-smokers
• Weight stable over the previous 3 months (<3 kg fluctuation)
• Known diagnosis of sleep apnea and ownership of a continuous positive airway pressure (C-PAP) device that must be worn throughout the nights spent in the tent
• If no known presence of sleep apnea, be willing to spend one night in a sleep laboratory (Louisiana Sleep Foundation) to assess presence of sleep apnea

EXCLUSION CRITERIA:

• Diagnosed with T2DM ≥ 15 years ago
• Pregnant Women
• Current insulin treatment
• Treatment with sulfonylureas or glitinides
• Treatment with a GLP-1 agonist
• Any other diabetes medication other than an oral agent is exclusionary unless otherwise cleared by medical investigator.
• Chronic Obstructive Pulmonary Disease (COPD)
• Congestive heart failure
• Prior severe cardiovascular events such as stroke or myocardial infarction
• If treated for T2DM with other oral agent, no change in the treatment for 1 month before the study and the duration of the study
• Previously known diagnosis of sleep apnea without ownership of a continuous positive airway pressure (C-PAP) device or agreement to use owned CPAP device during the nights spent in the tent
• Presence of sleep apnea following a positive home sleep test (HST), or have unsafe oxyhemoglobin saturation levels (less than 78%) during a one night sleep monitoring assessment conducted at the Louisiana Sleep Foundation without ownership of a continuous positive airway pressure (C-PAP) device or agreement to use owned C-PAP device during the nights spent in the tent
• History of high altitude sickness
• History of altitude sickness
• Does not have access to a bed or sleeping surface equivalent to or smaller than a queen size mattress

Approximately 1-month (baseline screening to end of 2-week moderate hypoxia exposure)