Effects of U.S. Navy Diver Training on Physiological Parameters, Time of Useful Consciousness and Cognitive Performance During Periods of Normobaric Hypoxia

Abstract

Abstract : Purpose: To investigate if U.S. Navy diver training has an effect on physiological parameters (i.e., heart rate [HR] and SpO2 levels), time of useful consciousness (TUC), and cognitive performance during periods of normobaric hypoxia. Methods: Each subject completed a helmet and aviator mask fitting, SynWin multitask battery training, a normobaric hypoxia symptom familiarization session, and a data collection session which consisted of simulated altitudes of 0 feet above MSL (0k), 18,000 feet (5,486 m) above MSL (18k), and 25,000 feet (7,620 m) above MSL (25k). Three separate two-way multivariate analysis of variance (MANOVA) were run for each simulated altitude with GRP (diver, non-diver) as the between-subjects variable were conducted for SpO2, HR, TUC, and SynWin composite score (SCS) data. Bonferonni corrections were applied as necessary to maintain a family-wise alpha of 0.05. Results: The results of the MANOVAs indicated that USN diver training had no effect on Fg-SpO2, HR, TUC, or SCS for the 0k, 18k, and 25k exposures. Conclusions: There were no significant differences between diver and non-diver physiological parameter measurements, TUC, and cognitive performance during any of the normobaric hypoxic exposures. The results of this study will help to validate the use of a 60% cut-point for SpO2 levels as one input for a physiological based definition of TUC. Future research should focus on developing a model that incorporates a 60% SpO2 cut-point, as well as changes in HR and blood pressure data that are based on the subject's individualized normative data.