INTRODUCTION: Although hypoxia has the potential to decrease SpO2 while ascending to high altitudes, which can cause impairments in cognitive functioning, the effects of acute hypoxia on high-order brain functions like executive processing remain unclear. AIM(S): The purpose of this study was to investigate the acute response to normobaric hypoxia and its effect on executive function and changes in BDNF (Brain Derived Neurotrophic Factor), as a protein that modulates brain health and cognition. METHOD(S): Thirty-two healthy subjects participated in a blind study where they performed two sessions of single 30 min breathing bouts under two conditions (normoxia (NOR) and normobaric hypoxia (NH)), on different days. On the first session, they breathed ambient air and on the second session, participants breathed hypoxic air (fraction of inspired oxygen (FIO2) = 0.135), which corresponded to an altitude of 3500 m. Before and after both sessions, participants performed the color-word Stroop task and level of SpO2 was monitored. RESULTS: There was no significant difference in Stroop interference in the “reading” part of the test in either conditions compared to baseline, but there was a significant increase in the “naming” part of the Stroop interference test in NH conditions (p=0.0056), which corresponded with a significant decrease in SpO2 (p<0.0001). There was also a significant increase (p<0.0001) in BDNF levels after NH conditions as compared to the baseline, what could not be seen in NOR. CONCLUSIONS: These results suggest that acute hypoxia impaired neural activity in motor executive and inhibitory processing and delayed cognitive processing for motor execution. Hypoxia has the potential to impair cognition, but the effects of acute hypoxia on cognitive function remain debatable. We investigated the effects of acute exposure to moderate hypoxic conditions, and observed decreased executive function and this negative effect was associated with decreased SpO2, irrespective of a BDNF rise.