Insulin Resistance
Conditions
Keywords
obesity, hypoxia, insulin sensitivity, altitude
Brief summary
The purpose of this study is to look at how a reduction in oxygen levels (hypoxia) influences insulin sensitivity and carbohydrate metabolism. It is expected that 10 nights of exposure to moderate hypoxia (\ 15% O2, similar to conditions at an altitude of \ 7500 feet) will improve glucose metabolism.
Interventions
OTHERHypoxia Exposure
Participants spent 10 consecutive nights (approximately 100 hours of exposure) in a hypoxic tent at \ 15% O2 (ca. 2400 m elevation).
Sponsors
Pennington Biomedical Research Center
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
PREVENTION
Masking
NONE
Eligibility
Sex/Gender
MALE
Age
20 Years to 45 Years
Healthy volunteers
Yes
Inclusion criteria
* Aged 20-45 years * Male * Obese category (BMI \> 30 kg/m2) * Healthy as assessed by a self-reported health questionnaire * Non-smokers * Weight stable over the past 3 months (\<2kg fluctuation)
Exclusion criteria
* Female * Diabetes * Sleep apnea * Hypertension * History of altitude sickness * Individuals taking any chronic medications * Individuals taking any stimulants * Individuals taking beta-blockers * Individuals with chronic alcohol consumption (\>3 drinks per day) or drug abuse. * Individuals unable to abstain from caffeinated beverage or alcohol the days of study testing * Individuals with history disease or history of stroke
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Insulin sensitivity | Change from baseline to 10 nights of hypoxia exposure | Glucose disposal and oxidation were measured using a two-step hyperinsulinemic euglycemic clamp and indirect calorimetry. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in oxygen tension in adipose tissue | Before and after 10 nights of hypoxia exposure | pO2 levels were measured in adipose tissue both under hypoxia and normal oxygen conditions (normoxia) via a dual temperature-oxygen tension probe. |
| Glucose uptake in myotubes | Before 10 nights of hypoxia exposure | Glucose uptake assays were performed in the presence or absence of hypoxia on myotubes harvested from muscle biopsies. |
| Change in gene and protein expression | Before and after 10 nights of hypoxia exposure | Gene and protein expression of some hypoxia-responsive and insulin-signaling markers were measured in biopsied muscle and adipose tissue via RT-PCR and Western blotting, respectively. |
Countries
United States
Outcome results
None listed