The Role of Heliox in Respiratory Control

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 reducing mechanical WOB alters breathing perception and cognitive performance during inspiratory resistance. Participants will breathe either normal-density air or a low-density helium-oxygen gas mixture (heliox) to determine whether reducing mechanical WOB lowers perceived breathing effort and improves cognitive function.

NCT Number	NCT07424014
Lead Sponsor	Indiana University Collaborators: United States Department of Defense
Conditions	Work of Breathing
Enrollment	15 participants
Start Date	2026-02-03
Primary Completion	2027-05-31 (estimated)
Study Completion	2027-05-31 (estimated)
Updated on ClinicalTrials.gov	2026-03-12