| Summary: | <i>Background and objective</i>:<b> </b>This is the first study to investigate the effect of high-flow oxygen therapy, using a normobaric chamber on cognitive, biochemical (oxidative stress parameters and the level of neurotrophins), cardiovascular and autonomic functioning. <i>Materials and methods</i>: 17 healthy volunteers, eight males and nine females, with a mean age of 37.5 years, were examined. The experimental study involved ten two-hour exposures in a normobaric chamber with a total pressure of 1500 hPa, in air adjusted to 37% oxygen, 1.079% carbon dioxide and 0.44% hydrogen. Cognitive function was assessed by using Trail Making Test parts A, B and difference in results of these tests (TMT A, TMT B and TMT B-A); California Verbal Learning Test (CVLT); Digit symbol substitution test (DSST); and Digit Span (DS). Fatigue (Fatigue Severity Scale (FSS)), cardiovascular, autonomic and baroreceptor functioning (Task Force Monitor) and biochemical parameters were measured before and after intervention. <i>Results</i>: After 10 sessions in the normobaric chamber, significant decreases in weight, caused mainly by body fat % decrease (24.86 vs. 23.93%, <i>p</i> = 0.04 were observed. TMT part A and B results improved (<i>p</i> = 0.0007 and <i>p</i> = 0.001, respectively). In contrast, there was no statistically significant influence on TMT B-A. Moreover, decrease in the number of symbols left after a one-minute test in DSST was noted (<i>p</i> = 0.0001). The mean number of words correctly recalled in the CVLT Long Delay Free Recall test improved (<i>p</i> = 0.002), and a reduction in fatigue was observed (<i>p</i> = 0.001). Biochemical tests showed a reduction in levels of malondialdehyde (<i>p</i> < 0.001), with increased levels of Cu Zn superoxide dismutase (<i>p</i> < 0.001), Neurotrophin 4 (<i>p</i> = 0.0001) and brain-derived neurotrophic factor (p = 0.001). A significant increase in nitric oxide synthase 2 (Z = 2.29, <i>p</i> = 0.02) and Club cell secretory protein (<i>p</i> = 0.015) was also noted. Baroreceptor function was significantly improved after normobaric exposures (<i>p</i> = 0.003). Significant effect of normobaric exposures and BDNF in CVLT Long Delay Free Recall was noted. <i>Conclusions</i>: This study demonstrates that 10 exposures in a normobaric chamber have a positive impact on visual information and set-shifting processing speed and increase auditory-verbal short-term memory, neurotrophic levels and baroreceptor function. A response of the respiratory tract to oxidative stress was also noted. There is a need to rigorously examine the safety of normobaric therapy. Further studies should be carried out with physician examination, both pre and post treatment.
|
|---|