Acetazolamide and Exercise Performance at Altitude
Status:
Completed
Trial end date:
2019-05-15
Target enrollment:
Participant gender:
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.
Phase:
Early Phase 1
Details
Lead Sponsor:
United States Army Research Institute of Environmental Medicine