Evaluation of the Physiological Challenges in Extreme Environments: Implications for Enhanced Training, Operational Performance and Sex Specific Responses
Abstract
The specific aim of this project series was to determine the impacts of environmental conditions on specific markers of exercise response under normobaria sea level, hypoxic, and high altitude derived hypobaria.This has culminated in the design of a final field trial that took place in Kailua-Kona, HI chosen because of its accessibility to both sea level and high altitude (~14,000 feet elevations. This trial effectively examined the translation of training/operational environments in reference to hypobaric and hypoxic environments. Recreationally active males (n=8) and females (n=8) served as study participants. Briefly, subjects were flown from the mainland United States to Kailua-Kona, HI. Subjects were studied on days 2, 3 and 4 after arrival. Subjects did not have their diets or physical activity controlled outside of time spent exercising restriction. In a repeated measures crossover design, three 90-minute altitude exposures were employed. It takes approximately 90 minutes to ascend Mauna Kea (~14,000 feet) by 4WD automobile. Therefore, the three interventions were a normobaric normoxia (sea-level control), graded hypoxic exposure (normobaric hypoxia) designed to mimic the gradual ascent to 14,000 feet, and a high altitude exposure (hypobaric hypoxia) inclusive of the time spent reaching 14,000 feet. Following baseline measurements, participants then completed 3 minutes of bench step exercise (39 cm step, 22 steps/min, estimated VO2=25 ml/kg/min). Key dependent variables included measures of muscle and brain oxygenation, HR, SV, CO, SpO2 and fluid shifts. Data were analyzed using 2-way (sex x trial) and 3-way (sex x trial x exercise time). A type I probability error of less than 5 was considered significant (p < 0.05). At the time of this report, data specific to main effects of trial and time have been evaluated. Specific sex comparisons have not yet been considered.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 2019
- Accession Number
- AD1130819
Entities
People
- Brent C. Ruby
Organizations
- University of Montana