HypercapniaC3FNCT06636825
Influence of Caffeine on Psychomotor Vigilance and Carbon Dioxide Tolerance During Graded Hypercapnia
A study testing Graded hypercapnia and Caffeine in people with Hypercapnia, run by United States Army Research Institute of Environmental Medicine at 1 site in United States.
Trial summary
The aim of this randomized, double-blind, placebo-controlled crossover trial is to determine the effects of caffeine vs. placebo on psychomotor vigilance and carbon dioxide tolerance during graded hypercapnia. Read more about this study
- Who is it for?
- Ages 18 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Hypercapnia
- What is being tested?
- Graded hypercapnia and Caffeine
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 29 participants
- Where
- 1 siteUnited States
- Study dates
- 9 Nov 2023to 17 Sep 2024
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Male or female, age 18-45
- Body mass index 18.5-30.0 kg m-2
- Body mass 50-100 kg
- In good health as determined by the Office of Medical Support \& Oversight (OMSO) General Medical Clearance
- Perform exercise at least 2 times per week
- Willing to abstain from exercise and alcoholic beverages for 24 hours before each study visit.
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- Willing to abstain from caffeine for 12 hours prior to all study visits
- Willing to abstain from caffeine for 12 hours after visits 3 and 4
- Willing to remain fasted (no food or fluid other than water) from lights out until after arrival at the laboratory the following morning on each study day (~10 hours)
- Have supervisor approval if permanent party military or a federal employee at U.S. Army Natick Soldier System Center
Who cannot join
- Females who are pregnant or planning to become pregnant during the study
- Females who are surgically sterile
- History of severe adverse reaction to caffeine (e.g., headache, dizziness, diarrhea, insomnia)
- Taking dietary supplements, prescriptions, or over the counter medication, other than a contraceptive (unless approved by OMSO \& PI)
- Abnormal blood count (For example: hemoglobin (Hb) outside of the typical normal values reported by LabCorp in accordance with OMSO (Normal [Hb] Males = 12.6-17.7 g/dL; Females = 11.1-15.9 g/dL) or hematocrit (Hct) outside of the normal ranges (Normal Hct Males = 37.5-51.0%; Females = 34.0-46.6%) levels, presence of abnormal blood chemicals (hemoglobin S or sickle cell traits)
- Any history of pulmonary or cardiovascular disease
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- Current diagnosis of asthma (childhood asthma with no recurrence in the last 5 years ok)
- Smokers or nicotine users (unless have quit >1 month prior)
- Current or recent respiratory tract or sinus infections (< 1 month prior)
- Current diagnosis of migraine or recurrent headaches (previous diagnosis with no recurrence in the last 5 years ok)
- Any history of seizures
- Any history of panic disorder
- Blood donation in the previous 8 weeks
- Positive Covid-19 test within the last month (based on self-report)
Trial locations and contacts
1 site in 1 country.
United States1 site
US Army Research Institute of Environmental Medicine
Natick, Massachusetts, 01760
About this study
The aim of this randomized, double-blind, placebo-controlled crossover trial is to determine the effects of caffeine vs. placebo on psychomotor vigilance and carbon dioxide tolerance during graded hypercapnia.
Read the detailed description
Healthy and fit young adults (men and women) will participate in this study. Participants will perform two primary experimental trials on separate days, one after consuming 400 mg caffeine, and the other after consuming a non-caffeinated placebo. During each trial, participants will breathe increasing levels of inspired CO2 in a stepwise manner (0%, 2%, 4%, 6%, 8% CO2; all with 21% oxygen) during successive 12-minute stages. The endpoints of the graded hypercapnia protocol will be completion of the 8% CO2 stage, voluntary subject termination due to discomfort, or end-tidal CO2 greater than 70 mmHg. The investigators hypothesize that, compared to placebo, caffeine will lower end tidal and arterialized PCO2 and mitigate CO2-mediated decrements in psychomotor vigilance.
- Conditions
- Hypercapnia
- Being tested
- Graded hypercapnia, Caffeine, Placebo
- Keywords
- Caffeine, Carbon dioxide, Cognitive Function
- Medical subject headings
- Hypercapnia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Graded hypercapniaOther
Volunteers breathe 0%, 2%, 4%, 6%, and 8% CO2 (with 21% O2, balance nitrogen) for 12 minutes each
CaffeineDrug
400 mg caffeine capsule taken in a single dose 1 hour prior to graded hypercapnia
PlaceboDrug
Placebo (microcrystalline cellulose) capsule taken in a single dose 1 hour prior to graded hypercapnia
| Study group | Role | What they receive |
|---|---|---|
| Placebo | Placebo comparator | Placebo (microcrystalline cellulose) capsule taken in a single dose 1 hour prior to graded hypercapnia Receives: Other: Graded hypercapnia; Drug: Placebo |
| Experimental | Experimental | 400 mg caffeine capsule taken in a single dose 1 hour prior to graded hypercapnia Receives: Other: Graded hypercapnia; Drug: Caffeine |
What is being measured
The primary outcome is the main question the study is designed to answer.
End-tidal CO2
End-tidal CO2 (mmHg)
Measured: 60 minutes
PVT Performance
Psychomotor vigilance (mean reaction time in s)
Measured: 60 minutes
Carbon dioxide tolerance
Time spent in graded hypercapnia protocol (minutes)
Measured: 60 minutes
Secondary outcomes (18)
Ventilation
Ventilation (L/min)
Measured: 60 minutes
Respiratory Rate
Breaths per minute
Measured: 60 minutes
Tidal volume
Tidal volume (L)
Measured: 60 minutes
Oxygen Consumption
Oxygen consumption (L/min)
Measured: 60 minutes
Carbon dioxide release
Carbon dioxide release (L/min)
Measured: 60 minutes
Heart Rate
Heart Rate (Beats per minute)
Measured: 60 minutes
Blood Pressure
Blood pressure (mmHg)
Measured: 60 minutes
Total Mood Disturbance
Profile of Mood States (AU); higher number is worse mood
Measured: 60 minutes
Arterialized capillary pH
pH (unitless)
Measured: 60 minutes
Arterialized capillary PCO2
Partial pressure of carbon dioxide (mmHg)
Measured: 60 minutes
Arterialized capillary bicarbonate
Bicarbonate (mmol/L))
Measured: 60 minutes
Dyspnea
Borg 0-10 Scale (higher number is more dyspnea)
Measured: 60 minutes
Discomfort
Borg 0-10 Scale (higher number is more discomfort)
Measured: 60 minutes
Headache
100mm visual analog scale (higher number is worse headache)
Measured: 60 minutes
Plasma caffeine
Plasma caffeine (ug/mL)
Measured: 60 minutes
Plasma theobromine
Plasma theobromine (ug/mL)
Measured: 60 minutes
Plasma theophylline
Plasma theophylline (ug/mL)
Measured: 60 minutes
Plasma paraxanthine
Plasma paraxanthine (ug/mL)
Measured: 60 minutes
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Oct 2024
- Study start9 Nov 2023
- Primary completion17 Sep 2024
- Study completion17 Sep 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HypercapniaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Randomized, double-blind, placebo-controlled crossover trial
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 29 participants (actual)
Sponsor and investigators
- Lead sponsor
- United States Army Research Institute of Environmental Medicine
- Sponsor type
- US federal agency
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06636825
- Sponsor's protocol ID
- 23-05
- Acronym
- C3F
- Status last verified
- Oct 2024
- First submitted
- 4 Oct 2024
- Last updated
- 15 Oct 2024
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 15 Oct 2024. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Influence of Caffeine on Psychomotor Vigilance and Carbon Dioxide Tolerance During Graded Hypercapnia
- ClinicalTrials.gov ID
- NCT06636825
- Acronym / sponsor ID
- C3F / 23-05
- Conditions
- Hypercapnia
- Keywords
- Caffeine, Carbon dioxide, Cognitive Function
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 29 participants (actual)
- Lead sponsor
- United States Army Research Institute of Environmental MedicineUS federal agency
- Study start
- 9 Nov 2023 (actual)
- Primary completion
- 17 Sep 2024 (actual)
- Study completion
- 17 Sep 2024 (actual)
- First posted
- 15 Oct 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The aim of this randomized, double-blind, placebo-controlled crossover trial is to determine the effects of caffeine vs. placebo on psychomotor vigilance and carbon dioxide tolerance during graded hypercapnia.
Detailed description
Healthy and fit young adults (men and women) will participate in this study. Participants will perform two primary experimental trials on separate days, one after consuming 400 mg caffeine, and the other after consuming a non-caffeinated placebo. During each trial, participants will breathe increasing levels of inspired CO2 in a stepwise manner (0%, 2%, 4%, 6%, 8% CO2; all with 21% oxygen) during successive 12-minute stages. The endpoints of the graded hypercapnia protocol will be completion of the 8% CO2 stage, voluntary subject termination due to discomfort, or end-tidal CO2 greater than 70 mmHg. The investigators hypothesize that, compared to placebo, caffeine will lower end tidal and arterialized PCO2 and mitigate CO2-mediated decrements in psychomotor vigilance.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
- Model description
- Randomized, double-blind, placebo-controlled crossover trial
| Arm | Type | Receives |
|---|---|---|
| Placebo | Placebo comparator | Other: Graded hypercapnia, Drug: PlaceboPlacebo (microcrystalline cellulose) capsule taken in a single dose 1 hour prior to graded hypercapnia |
| Experimental | Experimental | Other: Graded hypercapnia, Drug: Caffeine400 mg caffeine capsule taken in a single dose 1 hour prior to graded hypercapnia |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (10 listed)
- Male or female, age 18-45
- Body mass index 18.5-30.0 kg m-2
- Body mass 50-100 kg
- In good health as determined by the Office of Medical Support \& Oversight (OMSO) General Medical Clearance
- Perform exercise at least 2 times per week
Key exclusion criteria (14 listed)
- Females who are pregnant or planning to become pregnant during the study
- Females who are surgically sterile
- History of severe adverse reaction to caffeine (e.g., headache, dizziness, diarrhea, insomnia)
- Taking dietary supplements, prescriptions, or over the counter medication, other than a contraceptive (unless approved by OMSO \& PI)
- Abnormal blood count (For example: hemoglobin (Hb) outside of the typical normal values reported by LabCorp in accordance with OMSO (Normal [Hb] Males = 12.6-17.7 g/dL; Females = 11.1-15.9 g/dL) or hematocrit (Hct) outside of the normal ranges (Normal Hct Males = 37.5-51.0%; Females = 34.0-46.6%) levels, presence of abnormal blood chemicals (hemoglobin S or sickle cell traits)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Graded hypercapniaVolunteers breathe 0%, 2%, 4%, 6%, and 8% CO2 (with 21% O2, balance nitrogen) for 12 minutes each | Other | Experimental, Placebo |
| Caffeine400 mg caffeine capsule taken in a single dose 1 hour prior to graded hypercapnia | Drug | Experimental |
| PlaceboPlacebo (microcrystalline cellulose) capsule taken in a single dose 1 hour prior to graded hypercapnia | Drug | Placebo |
Primary outcome
End-tidal CO2
Time frame: 60 minutes
End-tidal CO2 (mmHg)
PVT Performance
Time frame: 60 minutes
Psychomotor vigilance (mean reaction time in s)
Carbon dioxide tolerance
Time frame: 60 minutes
Time spent in graded hypercapnia protocol (minutes)
18 secondary outcomes
Ventilation
Time frame: 60 minutes
Respiratory Rate
Time frame: 60 minutes
Tidal volume
Time frame: 60 minutes
Oxygen Consumption
Time frame: 60 minutes
Carbon dioxide release
Time frame: 60 minutes
Heart Rate
Time frame: 60 minutes
Blood Pressure
Time frame: 60 minutes
Total Mood Disturbance
Time frame: 60 minutes
Arterialized capillary pH
Time frame: 60 minutes
Arterialized capillary PCO2
Time frame: 60 minutes
Arterialized capillary bicarbonate
Time frame: 60 minutes
Dyspnea
Time frame: 60 minutes
Discomfort
Time frame: 60 minutes
Headache
Time frame: 60 minutes
Plasma caffeine
Time frame: 60 minutes
Plasma theobromine
Time frame: 60 minutes
Plasma theophylline
Time frame: 60 minutes
Plasma paraxanthine
Time frame: 60 minutes
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 Oct 2024.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Graded hypercapnia and Caffeine in people with Hypercapnia, run by United States Army Research Institute of Environmental Medicine at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 10 inclusion and 14 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 15 Oct 2024. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
End-tidal CO2 (time frame: 60 minutes). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 15 Oct 2024; AzTrials last refreshed its copy on 8 Nov 2026.