Alternating Days of Intermittent Hypoxic Exposure (IHE) on Physical and Cognitive Performance

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Alternating Days of Intermittent Hypoxic Exposure (IHE) on Physical and Cognitive Performance
Zupan, Michael F. ; Lennemann, Lynette M. ; Herrera, Monica ; Walker, Thomas B.

Rapid deployments do not allow our airmen to slowly progress to high altitudes, so predeployment strategies for the optimal use of hypoxic tents need to be developed. The primary objective of this study was to determine if alternating days of intermittent normobaric hypoxic exposures (IHE) for previously unacclimatized, sea-level residents (SLR) would work as a training strategy to minimize physical and cognitive impairments, and possibly reduce acute mountain sickness (AMS) incidence in our battlefield airmen during deployment. A secondary objective was to compare the physical and cognitive performance results between normobaric hypoxic and hypobaric hypoxic conditions. We conducted a crossover style, randomized study to assess the efficacy of IHE on physical and cognitive performance decrements. Baseline physical tests were conducted at SL, normobaric hypoxic (NH), and hypobaric hypoxic (HH) environments. Subjects were randomly assigned to either five consecutive (C-IHE) or five alternating (A-IHE) days of IHE. All tests were repeated post-IHE exposure. Following a four-week washout interval, all subjects repeated the process again under the opposite IHE exposure schedule. Intra-subject differences between training regimens (C-IHE vs. A-IHE) and the three environments (SL vs. NH vs. HH) were analyzed. Seven well-conditioned (average VO2 max = 57 mL-1.Kg-1.min) male subjects (30.4 ? 8.7 yrs) completed the study. Significant physiological differences in VO2 max (p<0.001) and oxygen saturation (p<0.01) between SL and NH or HH were observed. There were no significant differences in the HH environment for any performance variables following C-IHE and A-IHE training regimens. A-IHE produces the same altitude adaptations as C-IHE, which may allow our battlefield airmen to better prepare themselves for moderate altitude (MA) deployments.
Descriptors : *HYPOXIA, STRATEGY, PERFORMANCE(HUMAN), COGNITION, ALTITUDE SICKNESS, OXYGEN, EXPOSURE(PHYSIOLOGY), DEPLOYMENT, AIR FORCE PERSONNEL