Influence of Graded Hypercapnia on Endurance Exercise Performance

May 24, 2022 updated by: United States Army Research Institute of Environmental Medicine
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.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

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.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
15

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Massachusetts
      • Natick, Massachusetts, United States, 01760
        • USARIEM

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

14 years to 41 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Male or female, age 18-45
  • In good health as determined by medical screening
  • Passed his/her most recent Army Combat Fitness Test (ACFT) (Military Volunteers Only) or performs aerobic exercise at least 2 times per week and able to complete two mile run in ≤ 21 minutes (Civilian Volunteers)
  • Willing to not participate in any exercise or drink alcoholic beverages for 24 hours before each study visit.
  • Willing to not take part in any strenuous exercise in the 36 hours before each visit.
  • Willing not to drink caffeine or eat food until after testing on familiarization and performance testing visits (visits 2-6).
  • Willing to maintain a similar dietary pattern in the 2 days before each familiarization and performance visits.
  • Have supervisor approval if permanent party military or a federal employee at U.S. Army Natick Soldier System Center
  • Able to speak and read English fluently

Exclusion Criteria:

  • Females who are pregnant or planning to become pregnant during the study
  • Taking dietary supplements, prescriptions, or over the counter medication, other than a contraceptive (unless approved by medical staff & PI)
  • Musculoskeletal injuries that compromise ability to run on a treadmill
  • Abnormal blood count, presence of abnormal blood chemicals (hemoglobin S or sickle cell traits)
  • Smokers or tobacco/nicotine users (unless have quit > 1 month prior)
  • Any history of asthma
  • Current or recent respiratory tract or sinus infections (< 1 month prior)
  • Allergy to skin adhesive
  • Any history of migraine or recurrent headaches
  • Any history of panic disorder
  • Blood donation in the previous 8 weeks
  • Positive Covid-19 test within the last month

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: 4% CO2
Inspired gas containing 4% CO2, 21% O2, balance N2
Other: Inspired gas
Inspired gas content
Experimental: 2% CO2
Inspired gas containing 2% CO2, 21% O2, balance N2
Other: Inspired gas
Inspired gas content
Sham Comparator: 0% CO2
Inspired gas containing 0% CO2, 21% O2, balance N2
Other: Inspired gas
Inspired gas content

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
2 mile self-paced treadmill time trial performance
Time Frame: 30 minutes
Time to complete self-paced 2 mile treadmill time trial (min:sec)
30 minutes

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Ventilation rate
Time Frame: 30 minutes
Ventilation rate will be assessed using a pneumotachometer [L/min]
30 minutes
Oxygen consumption
Time Frame: 30 minutes
Oxygen consumption will be assessed using computerized indirect calorimetry [ml/kg/min]
30 minutes
Heart rate
Time Frame: 30 minutes
Heart rate will be assessed using telemetry [beats per min]
30 minutes
Arterialized capillary pH
Time Frame: 30 minutes
Arterialized capillary pH will be assessed using a blood gas analyzer [Unitless]
30 minutes
Arterialized capillary pCO2
Time Frame: 30 minutes
Arterialized capillary pCO2 will be assessed using a blood gas analyzer [mmHg]
30 minutes
Arterialized capillary HCO3
Time Frame: 30 minutes
Arterialized capillary HCO3 will be assessed using a blood gas analyzer [mEq/L]
30 minutes
Rating of perceived exertion
Time Frame: 30 minutes
Rating of perceived exertion will be assessed using Borg's 6-20 scale [AU]
30 minutes
Dyspnea
Time Frame: 30 minutes
Rating of perceived dyspnea will be assessed using Borg's 0-10 scale [AU]
30 minutes
Leg discomfort
Time Frame: 30 minutes
Rating of perceived leg discomfort will be assessed using Borg's 0-10 scale [AU]
30 minutes
Headache
Time Frame: 30 minutes
Headache will be assessed using a visual analog scale [AU]
30 minutes
Breathing descriptors
Time Frame: 30 minutes
Breathing descriptors will be assessed by having participants check statements that apply to their breathing (e.g., breathing out requires more effort) [unitless]
30 minutes

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
United States Army Research Institute of Environmental Medicine

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Benjamin J Ryan, Ph.D., United States Army Research Institute of Environmental Medicine

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 10, 2021

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
April 14, 2022

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
April 14, 2022

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
October 13, 2021

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 30, 2021

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
November 11, 2021

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 31, 2022

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 24, 2022

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2022

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • USARIEM

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

No

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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