The Role of Environmental Temperatures in Respiratory Control

Conditions

• Work of Breathing

Eligibility Criteria

Sex

ALL

Age

18 Years - 40 Years

Healthy Volunteers

Accepted

Interventions

• Thermoneutral temperature environment — OTHER
  During thermoneutral conditions 34°C water will be perfused through special suit while participants resting the chamber set to 24°C and 40% room humidity.
• Cold temperature environment — OTHER
  During the cold condition, 4°C water will be perfused through the special suit while participants rest in the chamber set to 4°C and 10% room humidity.
• Hot temperature environment — OTHER
  During the hot condition, 50°C water will be perfused through the special suit while participants rest in the chamber set to 40°C and 40% room humidity.

Study Details

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.

Key Dates

Start date

Oct 1, 2028

Status verified

Mar 2026

Primary completion

Dec 31, 2029

Completion

Dec 31, 2029

Study Design

Enrollment

15 participants (estimated)

Allocation

RANDOMIZED

Intervention model

CROSSOVER

Primary purpose

BASIC_SCIENCE

Arms

• Active Comparator: Thermoneutral temperature, then Cold temperature, then Hot temperature
  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.
• Active Comparator: Thermoneutral temperature, then Hold temperature, then Cot temperature
  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.
• Active Comparator: Cold temperature, then Thermoneutral temperature, then Hot temperature
  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.
• Active Comparator: Cold temperature, then Hot temperature, then Thermoneutral temperature
  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.
• Active Comparator: Hot temperature, then Thermoneutral temperature, then Cold temperature
  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.
• Active Comparator: Hot temperature, then Cold temperature, then Thermoneutral temperature
  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.

Primary Outcome Measure

Change in Stroop Color-Word Test Time Performance [ Time Frame: Before and after each breathing task on Days 1, 2, 3 (each approximately 90 minutes in duration) ]

Central Contacts

• Timothy D Mickleborough, PhD
  812-855-0753
  [email protected]

Locations (1)

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