Effect of intermittent normobaric hypoxia on executive functions assessed with different cognitive tests in healthy young subjects.

Objective: The main objective of this study was to analyze the effects of an intermittent normobaric hypoxia session on executive functions assessed with different cognitive tests given to healthy young subjects. Methods: In this randomized trial with a between-subject design, 27 healthy volunteers were divided into an experimental group (EG; n = 13) and a control group (CG; n = 14). Participants completed tasks assessing deductive reasoning, response inhibition, and visuospatial working memory. The experimental group performed these tasks before and after an intermittent hypoxia session (12%, 4,400 m) with the iAltitude simulator, while the control group completed them before and after normoxic conditions without hypoxia exposure. Results: Both groups showed an increase in the score obtained in the Double Trouble test (p = 0.001-0.002; 95%CI = -19.11, -4.23; η 2 = 0.552-0.660), the CG showed also improvement in the level in the Odd One Out test (p = 0.034; 95%CI = 3.69, -0.17; η 2 = 0.301). However, the Group (IH vs. Control) × Time (Pre vs. Post) interaction was not significant for any of the executive function variables, indicating similar patterns of change across groups both in the overall sample and when analyses were conducted separately by sex. Significant differences were found in SaO₂ (p = 0.001; 95%CI = 2.89, 10.18) and HR (p = 0.012; 95%CI = -15.55, -1.37) after hypoxia in the EG. Conclusion: A single session of intermittent hypoxia did not produce clear changes in executive function against control group, which suggests that it may not alter cognitive function at the acute level.