Mountain Sickness Acute
Conditions
Keywords
Exercise, Aerobic, Cognitive Function
Brief summary
Individuals traveling to altitudes above 8,000 feet may suffer from impaired exercise and cognitive performance, and acute mountain sickness (AMS). Decreased barometric pressure, which leads to low blood oxygen levels, is the primary cause of these disorders. Symptoms of AMS are characterized by headache, nausea, vomiting, dizziness, fatigue, and difficulty sleeping. The goal of this research is to identify whether Respiratory Muscle Training will improve physical and cognitive performance, and reduce the symptoms of AMS, at simulated high altitude.
Interventions
DEVICERespiratory Muscle Training
Subjects will breathe through a custom isocapnic Respiratory Muscle Training method developed in-house. The initial breathing frequency will be 30 breaths per minute. Subsequent sessions will begin with 20 minutes of breathing at the highest rate attained on the previous training day. During the last 10 minutes of each session, breathing rate will increase by 1-2 breaths/min.
DEVICESham Breathing Training
Each subject in the sham group will be prompted to hold his breath for 10 seconds every 30 seconds (two times each minute) while breathing on a circuit visibly identical to that used in Respiratory Muscle Training. The subject will breathe ambient air normally after each breath hold. Each sham session will last 30 minutes total.
Sponsors
United States Department of Defense
University of Colorado, Denver
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
SINGLE (Subject)
Masking description
Participants will be masked from knowing whether they are performing the Respiratory Muscle Training or sham training.
Eligibility
Sex/Gender
MALE
Age
18 Years to 45 Years
Healthy volunteers
Yes
Inclusion criteria
* Healthy * Men, ages 18-45 who are able to achieve at least 3.5 watts/kg of body weight during the peak oxygen uptake test
Exclusion criteria
* Less than 18 years old * Greater than 45 years old * Have a body mass index greater than or equal to 30 * Have been recent smokers (tobacco or e-cigarettes) * Current recreational or medical marijuana users * Currently taking any medication (over-the-counter or prescription) or herbal supplements * Participants who are unable to tolerate drinking only two, 6-ounce caffeinated beverages per day of the study * Participants who are legally blind * Participants who have been to altitudes above Denver (1609m or 5280ft), including air travel, in the 3 weeks prior to the start of the study or with plans to do so during the study * Participants who have suffered a significant head injury, have anemia or sickle cell trait or disease, have active peptic ulcer disease, diabetes, hypertension, heart disease, HIV/AIDS, glaucoma, kidney disease, liver disease/cirrhosis, adrenal gland failure, hyponatremia/hypokalemia, tuberculosis * Participants who have a current herpes infection or any other current type of viral or bacterial infection * Participants with seizure disorders or history of migraines
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in exercise performance during acute simulated high-altitude exposure as measured by a peak oxygen uptake test and time to complete a 720kJ (40km) time trial on a Velotron cycle ergometer. | Baseline and during acute simulated high-altitude exposure. (2 days, 12 hours per day) | Determine whether Respiratory Muscle Training performed 3x a week for 30 minutes per session is effective in improving exercise performance during acute simulated high-altitude exposure. |
| Change in cognitive function during acute simulated high-altitude exposure as measured by the DANA cognitive test battery. | Baseline and during acute simulated high-altitude exposure. (2 days, 12 hours per day) | Determine whether Respiratory Muscle Training performed 3x a week for 30 minutes per session improves cognitive function during simulated high-altitude exposure. |
| Change in incidence and severity of acute mountain sickness during acute simulated high-altitude exposure as determined by the Lake Louise Questionnaire (a diagnostic survey of acute mountain sickness). | Baseline and during acute simulated high-altitude exposure. (2 days, 12 hours per day) | Determine whether Respiratory Muscle Training performed 3x a week for 30 minutes per session is effective in reducing incidence and severity of AMS during acute simulated high-altitude exposure. |
Countries
United States
Outcome results
None listed