An interventional study of Inspired gas in Hypercapnia, sponsored by United States Army Research Institute of Environmental Medicine. Completed at 1 site in United States. Open to participants aged 18 Years to 45 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2022-05-31.
Sponsored by United States Army Research Institute of Environmental Medicine · Not applicable, Interventional, and Other
The aim of this randomized, single-blind, placebo-controlled crossover trial is to determine the effects of graded hypercapnia (0, 2, and 4% inspired CO2) on endurance performance. Twelve healthy and fit young adults (men and women) will complete this study. Participants will perform experimental trials on 3 separate days (one each breathing 0%, 2%, and 4% inspired CO2-all with normal 21% oxygen). During each trial, they will perform 10 minutes of submaximal treadmill walking exercise and then complete a self-paced 2-mile treadmill run time-trial.
Participants will undergo baseline measurements of pulmonary function and maximal oxygen uptake (VO2max). They will then complete two familiarization trials, with 10 minutes of submaximal exercise (\~40%VO2max) followed by a self-paced 2-mile treadmill time trial. Lastly, they will complete three experimental trials, repeating the same submaximal and time-trial exercise procedures while breathing the test gas (0%, 2%, or 4% CO2-all with normal 21% oxygen). During the experimental trials, arterialized capillary blood samples will be collected at rest breathing room air, at rest breathing the test gas, and during submaximal exercise at 40% VO2max breathing the test gas. The primary outcome is 2-mile treadmill time-trial performance. Secondary outcomes include ventilation, metabolic rate, heart rate, arterialized capillary pH/PCO2/HCO3, perceived exertion, dyspnea, leg discomfort, breathing descriptors, and headache ratings.
186 studies on the registry are indexed under Hypercapnia; 34 are open to participants now.
This study's enrollment of 15 is below the median of 49 across 140 interventional studies indexed under Hypercapnia.
Browse Hypercapnia studies →United States Army Research Institute of Environmental Medicine is the lead sponsor of 67 studies on the registry; 9 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Inspired gas containing 4% CO2, 21% O2, balance N2
Other: Inspired gas
Inspired gas containing 2% CO2, 21% O2, balance N2
Other: Inspired gas
Inspired gas containing 0% CO2, 21% O2, balance N2
Other: Inspired gas
Inspired gas content
2 mile self-paced treadmill time trial performance
Time to complete self-paced 2 mile treadmill time trial (min:sec)
Time frame: 30 minutes
Ventilation rate
Ventilation rate will be assessed using a pneumotachometer \[L/min\]
Time frame: 30 minutes
Oxygen consumption
Oxygen consumption will be assessed using computerized indirect calorimetry \[ml/kg/min\]
Time frame: 30 minutes
Heart rate
Heart rate will be assessed using telemetry \[beats per min\]
Time frame: 30 minutes
Arterialized capillary pH
Arterialized capillary pH will be assessed using a blood gas analyzer \[Unitless\]
Time frame: 30 minutes
Arterialized capillary pCO2
Arterialized capillary pCO2 will be assessed using a blood gas analyzer \[mmHg\]
Time frame: 30 minutes
Arterialized capillary HCO3
Arterialized capillary HCO3 will be assessed using a blood gas analyzer \[mEq/L\]
Time frame: 30 minutes
Rating of perceived exertion
Rating of perceived exertion will be assessed using Borg's 6-20 scale \[AU\]
Time frame: 30 minutes
Dyspnea
Rating of perceived dyspnea will be assessed using Borg's 0-10 scale \[AU\]
Time frame: 30 minutes
Leg discomfort
Rating of perceived leg discomfort will be assessed using Borg's 0-10 scale \[AU\]
Time frame: 30 minutes
Headache
Headache will be assessed using a visual analog scale \[AU\]
Time frame: 30 minutes
Breathing descriptors
Breathing descriptors will be assessed by having participants check statements that apply to their breathing (e.g., breathing out requires more effort) \[unitless\]
Time frame: 30 minutes
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Plan to share: No
This study is completed, as verified in May 2022. You cannot join it, but the record below documents what was studied.
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United States Army Research Institute of Environmental Medicine