Acetazolamide and Exercise Performance at Altitude
Condition: Hypoxia; Exercise Performance; Cognitive Function; Dexterity
MeSH terms: Hypoxia
Study type: Interventional
Phase: Early Phase 1

Summary: 
      The goals of the present study are to evaluate whether the most common, and effective,
      treatment for acute mountain sickness (AMS), acetazolamide (AZ), has a negative, positive, or
      no influence on exercise performance, cognitive performance, or manual dexterity in young
      healthy subjects during simulated altitude exposure. AMS represents a serious challenge to
      the health and performance of the Warfighter who may need to rapidly deploy to high altitude.
      However, there have been concerns that AZ might alter or impair endurance exercise
      performance, and possibly fine motor skills. These would represent major limitations to the
      use of this drug in a Warfighter who has a specific timeframe in which to accomplish mission
      tasks. In the present project, we will use exposure to simulated altitude in the USARIEM
      hypobaric chamber to quantify the impact, if any, of AZ on endurance exercise performance
      following rapid ascent to 3500 meters (m) in unacclimatized lowlander volunteers. The study
      will be conducted using a randomized, single-blind, placebo-controlled crossover study
      design. Ten male and female volunteers will complete one orientation day, one VO2peak day,
      three days of familiarization testing at sea level (SL), then two rounds of experimental
      testing. Each round of experimental testing consists of six days including four days to
      establish baseline euhydration, followed by a 30 hour (hr) exposure to 3500 m. Volunteers
      will have a two week break between experimental testing rounds for washout of any effects of
      altitude acclimation. During one experimental round, volunteers will take two doses of AZ
      each day (Phase 1: 250 mg/dose,500 mg/day, Phase 2: 125 mg/dose, 250 mg/day) starting 48 hr
      prior to their altitude exposure and continuing for the 30 hr stay at high altitude. During
      the other experimental condition, volunteers will be given a placebo at the same time points
      as the doses of AZ. Prior to altitude exposure, AMS will be evaluated and volunteers will
      then ascend to a simulated altitude of 3500 m, where they will remain for 30 hr. Volunteers
      will rest at altitude for an hr, after which they will complete an AMS questionnaire, resting
      ventilation measurements, provide a blood sample and complete cognitive and finger dexterity
      testing. Subjects will then perform 15 minutes (min) of steady state (SS) treadmill exercise
      at 40-45% of SL VO2peak and a 2 mile treadmill time trial (TT). Volunteers will stay
      overnight in the hypobaric chamber with research staff supervision. The following morning,
      metabolic and blood measurements will again be completed, after which volunteers will perform
      the exercise testing for a second time. Cognitive and finger dexterity testing will be
      performed before volunteers return to sea level (i.e., "descend" from the simulated
      altitude). The results of the proposed study will, for the first time, provide quantitative
      evidence regarding whether AZ treatment impairs endurance exercise performance in the context
      of a Warfighter-relevant endurance exercise task.
    


Intervention name(s): Acetazolamide Pill; Placebo pill
Intervention type(s): Drug; Drug
Intervention description(s): Subjects will take acetazolamide pill (Diamox), 500 mg/ day, and assess effect on exercise performance during 30-hour exposure to 3,500 m simulated altitude.; Subjects will take placebo pill and then we will assess exercise performance during 30-hour exposure to 3,500 m simulated altitude.
Other intervention name(s): Diamox
Intervention MeSH terms: Acetazolamide
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: Subjects will serve as their own controls. Will exercise during simulated altitude exposure twice, once with acetazolamide and once with placebo.
Masking: Single (Participant)
Primary purpose: Basic Science