P 61. Effects of acute normobaric hypoxia on memory and attention in young adults

Abstract

Objective. An increasing number of sea-level residents takes part in alpine sports such as trekking or skiing. This has inspired a growing research interest on the effects of high altitude and hypoxic conditions on cognition. The aim of this study was to assess the effects of an acute normobaric hypoxia intervention (90 minutes) on cognition in healthy young adults. Methods . Twenty-five healthy, high-altitude-naive adults (25,8 ± 3,3 years; 15 females) were analysed in a randomized cross-over study. Participants received one acute normobaric hypoxic and one normobaric normoxic intervention separated by at least 2 weeks. Heart frequency and saturation of arterial blood oxygenation (SaO2) were continuously monitored while participants lay down for 120 minutes. After 30 minutes, either normobaric hypoxia (SaO2 of 80-85%) or normobaric normoxia was applied for the following 90 minutes. Cognitive parameters related to working memory and sustained attention (d2-Test, N-Back and Digit Span Test) were collected before and after each intervention session. Results . Normobaric hypoxia led to a significant decrease of SaO2 compared to normobaric normoxia (82,7 ± 4,3% vs. 98,1 ± 0,5%, p < .001). Regarding cognitive parameters, no significant time × group interactions were observed. Post hoc t-tests revealed a significant improvement in the d2-Test in both groups. Conclusion . In contrast to previous studies (Malle et al., 2013; Pilmanis, Balldin & Fischer, 2016; Ochi et al., 2018) our results indicate that acute normobaric hypoxia has no effects on working memory and sustained attention. One potential explanation for the absence of effects is the short duration and/or the rather high O2 concentration of the hypoxic condition. In this regard, Ochi et al. have found dose-dependent effects of hypoxia on cognition with the most pronounced results under the severe condition (5000 m). Future studies are needed that investigate dose-response mechanisms of acute hypoxia on cognition.