Environmental Temperatures for Work of Breathing

Overseen By Timothy D Mickleborough, PhD

Age: 18 - 65

Sex: Any

Trial Phase: Academic

Sponsor: Indiana University

Must not be taking: SSRIs, Stimulants, Antibiotics, Painkillers

Disqualifiers: Smoking, Cardiovascular, Pulmonary, Neurological, Metabolic, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 4

What You Need to Know Before You Apply

What is the purpose of this trial?

Warfighters are frequently exposed to environments and life-support systems that increase breathing resistance and the work of breathing (WOB), such as aircraft on-board oxygen generation systems and underwater breathing apparatuses. Elevated WOB increases the perception of breathing difficulty (dyspnea) and has been associated with impaired cognitive performance, including slower reaction time and reduced accuracy during attention-demanding tasks. These effects are particularly concerning in operational settings that require rapid decision-making and precise motor responses.

Despite growing recognition of this issue, critical gaps remain regarding strategies to mitigate the perceptual and cognitive consequences of elevated inspiratory resistance, especially under realistic operational stressors. The objective of this study is to determine whether exposing individuals to thermal stress alters breathing perception and cognitive performance during inspiratory resistance. Participants will perform inspiratory resistance breathing under thermoneutral, heat, and cold conditions to determine whether thermal stress amplifies WOB, breathing perception, and cognitive impairment.

Are You a Good Fit for This Trial?

Inclusion Criteria

English speaking and reading

Normal cognitive function assessed using the Montreal cognitive function test [18]

I am between 18 and 40 years old.

Exclusion Criteria

History of smoking or recreational smoking, cardiovascular disease, renal disease, pulmonary disease (including asthma or exercise-induced asthma), neurological disease, and metabolic disease

Are pregnant or could possibly be pregnant by self-report

Are color blind

Timeline for a Trial Participant

Screening/Familiarization

Participants are screened for eligibility to participate in the trial

1 day

1 visit (in-person)

Experimental Visits

Participants complete breathing tasks under different temperature conditions (thermoneutral, heat, cold) with cognitive and physiological assessments

3 days (with 7-day washout between visits)

3 visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness after experimental visits

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Thermal Stress Exposure

How Is the Trial Designed?

Group I: Thermoneutral temperature, then Cold temperature, then Hot temperature Active Control 3 Interventions

Participants will complete 3 experimental visits at which they will complete a breathing task under an assigned temperature condition. The order of condition exposure will be assigned via randomization.

Group II: Thermoneutral temperature, then Hold temperature, then Cot temperature Active Control 3 Interventions

Participants will complete 3 experimental visits at which they will complete a breathing task under an assigned temperature condition. The order of condition exposure will be assigned via randomization.

Group III: Cold temperature, then Thermoneutral temperature, then Hot temperature Active Control 3 Interventions

Participants will complete 3 experimental visits at which they will complete a breathing task under an assigned temperature condition. The order of condition exposure will be assigned via randomization.

Group IV: Cold temperature, then Hot temperature, then Thermoneutral temperature Active Control 3 Interventions

Participants will complete 3 experimental visits at which they will complete a breathing task under an assigned temperature condition. The order of condition exposure will be assigned via randomization.

Group V: Hot temperature, then Thermoneutral temperature, then Cold temperature Active Control 3 Interventions

Participants will complete 3 experimental visits at which they will complete a breathing task under an assigned temperature condition. The order of condition exposure will be assigned via randomization.

Group VI: Hot temperature, then Cold temperature, then Thermoneutral temperature Active Control 3 Interventions

Participants will complete 3 experimental visits at which they will complete a breathing task under an assigned temperature condition. The order of condition exposure will be assigned via randomization.

Who Is Running the Clinical Trial?

Indiana University

Lead Sponsor

Trials

1,063

Recruited

1,182,000+

United States Department of Defense

Collaborator

Trials

940

Recruited

339,000+