Optimizing Mind-Body Interactions in Respiratory Control During Operationally Relevant Environmental Stressors
Indiana University
Summary
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.
Description
Warfighters often face thermal stressors that increase the WOB, even with life-support systems in place. Both cold and heat stress elevate the WOB independently, without requiring increased inspiratory resistance. Cold stress stimulates ventilation and causes a biphasic bronchiolar response: inhaling cold air during hyperventilation leads to initial bronchodilation followed by bronchoconstriction, tightening the bronchioles and increasing airflow resistance, and thus the WOB. Warfighters are also exposed to extreme heat and hyperthermia-induced hyperventilation occurs when core body temperatur…
Eligibility
- Age range
- 18–40 years
- Sex
- All
- Healthy volunteers
- Yes
Inclusion Criteria: * Between the ages of 18-40 years old. * English speaking and reading. * Self-reported weekly activity of at least 120 minutes/week of high intensity exercise for the previous 2 years. * Normal pulmonary function assessed by a resting forced expiratory volume in 1 second over forced vital capacity (FEV1/FVC) \> 75% of predicted. * Normal cognitive function assessed using the Montreal cognitive function test \[18\]. * Body mass index (BMI) ≤ 35 kg/m2. * Females with a regular menstrual cycle that ranges from 21-35 days (eumenorrhea) Exclusion Criteria: * History of smokin…
Interventions
- OtherThermoneutral temperature environment
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.
- OtherCold temperature environment
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.
- OtherHot temperature environment
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.
Location
- Multidisciplinary Engineering and Sciences Hall (MESH)Bloomington, Indiana