Acute Normobaric Hypoxia Lowers Executive Functions among Young Men despite Increase of BDNF Concentration

Abstract

Background: Decreased SpO2 during hypoxia can cause cognitive function impairment, and the effects of acute hypoxia on high-order brain functions such as executive processing remain unclear. This study’s goal was to examine the impact of an acute normobaric hypoxia breathing session on executive function and biological markers. Methods: Thirty-two healthy subjects participated in a blind study performing two sessions of single 30 min breathing bouts under two conditions (normoxia (NOR) and normobaric hypoxia (NH), FIO2 = 0.135). The Stroop test was applied to assess cognitive function. Results: No significant difference was observed in the Stroop interference in the “reading” part of the test in either condition; however, there was a significant increase in the “naming” part under NH conditions (p = 0.003), which corresponded to a significant decrease in SpO2 (p < 0.001). There was a significant increase (p < 0.013) in the brain-derived neurotrophic factor (BDNF) level after NH conditions compared to the baseline, which was not seen in NOR. In addition, a significant drop (p < 0.001) in cortisol levels in the NOR group and a slight elevation in the NH group was noticed. Conclusions: According to these findings, acute hypoxia delayed cognitive processing for motor execution and reduced the neural activity in motor executive and inhibitory processing. We also noted that this negative effect was associated with decreased SpO2 irrespective of a rise in BDNF.

Brain-Derived neurotrophic factor and inflammatory biomarkers are unaffected by acute and chronic intermittent hypoxic-hyperoxic exposure in geriatric patients: a randomized controlled trial

“…[ 107 ] and Chroboczek et al. [ 108 ] examined the effect of a brief hypoxic exposure (30 min of continuous normobaric hypoxia) on BDNF P levels in young healthy males in comparison to normoxic control. Interestingly, the results from Hubold et al.…”

“…Chroboczek et al. showed an increase in BDNF P level 5–6 min after acute exposure to hypoxia (F i O 2 = 0.130) compared to baseline, which was not seen in the normoxic control condition [ 108 ]. Furthermore, blood cortisol concentration was decreased after the normoxic control compared to the hypoxia condition [ 108 ].…”

Exercise-Induced Elevated BDNF Concentration Seems to Prevent Cognitive Impairment after Acute Exposure to Moderate Normobaric Hypoxia among Young Men

“…This experiment is part of a larger project in which previous results have shown negative effects of hypoxic breathing sessions on cognitive functions [ 7 ]. The main result of this work was a significant increase in BDNF concentration after a single bout of exercise in normobaric hypoxic conditions with a corresponding lack of deterioration in executive functions, even though this impairment was expected based on previous results.…”

“…DBNT00; Ray Biotech Inc., Cambridge, UK). A 1 h clotting period was permitted for the proper serum BDNF dosage based on our prior experiences and recommendations in the literature [ 7 , 35 , 36 ].…”

“…Conditions of hypoxia are more complex. It has been shown that exposure to hypoxia itself usually causes cognitive decline, and this is related to either the time of exposure, the level of hypoxia, or both [ 6 , 7 ].…”