Effects of Inspired CO2 and Breathing Resistance on Neurocognitive and Postural Stability in U.S. Navy Divers
Technical Report,06 Apr 2013,02 Nov 2014
Navy Experimental Diving Unit Panama City United States
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Purpose The aim of this investigation was to evaluate the effects on neurocognitive performance and postural stability of inspired CO2 and breathing resistance during endurance exercise. Methods Subjects N16 completed five dives. Each dive involved a different combination of inspired CO2 0, 1, and 2 SEV CO2 and breathing resistance work of breathing per tidal volume of 1.0 kPa and 1.8 kPa at a minute ventilation of 62.5 Lmin. Neurocognitive functioning was assessed prepost each dive using a subset of Automated Neuropsychological Assessment Metrics ANAM. Postural stability was assessed post each dive through the use of a Wii Balance Board. Amplitude and sample entropy SampEn were calculated for the center of pressure COP in both the anterior-posterior X and medial-lateral Y directions. A general linear model multivariate analysis of variance GLM MANOVA with repeated measures was conducted to evaluate the effect of exercise and breathing conditions on ANAM performance. Four GLM MANOVAs with repeated measures were conducted to evaluate the effect of breathing conditions on postural stability. Alpha was set at p 05. Results There were no significant differences found. Conclusions The results of this study can be interpreted as the various combinations of high CO2 levels and high breathing resistance did not impair neurocognitive performance and postural stability. Future studies should focus on other neurocognitive and neurophysiological tests to verify these results. However, it should be noted that the individuals who were most likely to have shown neurocognitive effects from the CO2 exposures did not complete post-exercise neurocognitive assessments.