Duration of the effect of breathing and speech training under excess oxygen pressure

This article presents the assessment of the duration of the effect of a 5-day course of breathing and speech training under excess oxygen pressure in 12 Vietnamese volunteer subjects. The follow-up assessment was conducted six months after the training, with rapid aircraft cabin depressurization being simulated with excess oxygen pressure (500 mm H₂O) supplied through an oxygen mask. The training and the present study were carried out using the “BARS-GD” hardware/software system developed by the Russian company Konstel. All Vietnamese volunteer subjects were found to retain high tolerance to excess oxygen pressure, maintained speech formation abilities and work capacity. A statistically significant increase in systolic and diastolic blood pressure (by 25% and 34.2%, respectively), heart rate and respiratory rate (14.4% and 41.7%, respectively) was recorded. Analysis of psychophysiological performance at the peak of excess oxygen pressure revealed a 45.2% (p < 0.01) increase in simple sensorimotor reaction time, which is 27% (p < 0.01) higher than immediately after the training. No significant changes were observed in the psychological component. Therefore, the functional state of the Vietnamese volunteer subjects under simulated rapid cabin depressurization and breathing under excess oxygen pressure was considered normal, with higher involvement of the body’s adaptive mechanisms than immediately after the training. The 5-day course of training in breathing and speech under excess oxygen pressure effectively developed sustainable psychological readiness in the volunteer subjects, breathing and speech skills, and professional reliability under extreme conditions of stratospheric cabin depressurization. Overall, this training course is considered promising for inclusion in the program of psychophysiological preparation of Vietnamese pilots for stratospheric flights.