High Altitude and Exogenous Carbohydrate Oxidation

Completed · Not applicable

Conditions studied: Glucose Metabolism, High Altitude

In brief

Recent studies have reported that oxidation of exogenous carbohydrate is reduced under acute hypobaric hypoxic (high altitude; HA) conditions compared to normoxia (sea level; SL) in native lowlanders. However, the mechanisms by which HA suppresses exogenous carbohydrate oxidation are not known. This study will seek to confirm that acute HA exposure decreases exogenous carbohydrate oxidation during steady-state aerobic exercise compared to SL, and explore if the mechanism inhibiting plasma glucose uptake is insulin dependent or independent.

Key facts

Study ID

NCT03851744

Run by

United States Army Research Institute of Environmental Medicine

People needed

10

Starts

2018-11-28

Expected to finish

2020-09-01

Last updated by the study team

2021-09-02

Who can join

Age: 18 and older, up to 39. Sex: male. Healthy volunteers: accepted.

You may qualify if…

• Men aged 18 - 39 years
• Born at altitudes less than 2,100 m (\~7,000 feet; Examples include Santa Fe, New Mexico; Laramie, Wyoming; Etc.)
• Physically active based on assessment of physical activity history (2-4 days per week aerobic and/or resistance exercise)
• Have supervisor approval (permanent party military and civilians)
• Willing to refrain from alcohol, smokeless nicotine products and dietary supplement use during study periods
• Refrain from taking any nonsteroidal anti-inflammatory drugs (NSAIDs; e.g. aspirin, Advil®, Aleve®, Naprosyn®, or any aspirin-containing product) for 10 days before and at least 5 days AFTER each muscle biopsy. (*Tylenol® or acetaminophen is ok to use if needed for discomfort)

You may not qualify if…

• Born at altitudes greater than 2,100 m (\~7,000 feet; Examples include Santa Fe, New Mexico; Laramie, Wyoming; Etc.)
• Living in areas that are more than 1,200 m (\~4,000 feet), or have traveled to areas that are more than 1,200 m for five days or more within the last 2 months (Examples include Ft. Huachuca, Arizona; Lima, Peru; Feldberg, Germany, Etc.)
• Musculoskeletal injuries that compromise exercise capability
• Metabolic or cardiovascular abnormalities (determined by resting ECG), gastrointestinal disorders (e.g., kidney disease, diabetes, cardiovascular disease, etc.)
• Medication that affects macronutrient metabolism (i.e., diabetes medications, statins, corticosteroids, etc) and/or the ability to participate in strenuous exercise
• Evidence of apnea or other sleeping disorders
• Prior diagnosis of high altitude pulmonary edema (HAPE) or high altitude cerebral edema (HACE)
• Presence of asthma or respiratory tract infections (< 1 month prior)
• Allergies or intolerance to foods (including but not limited to lactose intolerance/milk allergy), vegetarian practices, or medications (including, but not limited to, lidocaine ) to be utilized in the study
• Smoking or vaping
• History of complications with lidocaine
• Taking medications that interfere with oxygen delivery and transport (Includes sedatives, sleeping aids, tranquilizers and/or any medication that depresses ventilation, diuretics, alpha and beta blockers)
• Evidence of any physical, mental, and/or medical conditions that would make the proposed studies relatively more hazardous as determined by the Office of Medical Support and Oversight
• Present condition of alcoholism, anabolic steroids, or other substance abuse issues
• Anemia (hematocrit <38% and hemoglobin <12.5 g/dL) and Sickle Cell Anemia/Trait
• Abnormal prothrombin time (PT)/ partial thromboplastin time (PTT) test or problems with blood clotting
• Blood donation within 8 weeks of beginning the study

Where it is running

• USARIEM — Natick, Massachusetts, United States

Full record on ClinicalTrials.gov

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