Effects of a simulated spacewalk underwater on executive functions

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Introduction: This study explored the effects of a simulated extra-vehicular activity (EVA) during submersion involving exercise and several cognitive/motor tasks on performance of the executive functions (EF) shifting and inhibition. EVAs performed by humans in microgravity, such as on the International Space Station (ISS), call for high cognitive and motor performance during long-time physical workload with little margin for error. Executive functions (i.e., switching, inhibition, updating) are believed to form the basis for cognitive performance with influences on decision-making, shifting between tasks or the inhibition of prepotent responses, and are therefore highly relevant for productivity, safety and overall mission success in everyday life and during strenuous EVA. Lower body continuous aerobic exercise (AE) (e.g., on a bicycle ergometer) can modulate EF performance, but little knowledge exists about the application for upper-body AE (which is required during an EVA), and especially the combination of AE with cognitive/motor tasks during an EVA activity. Because astronauts’ practice for EVA in the pool for simulating weightlessness, here an underwater setting was used to implement EVA-specific AE and tasks.
Methods: In a crossover design, 8 divers (age: 25.8 ± 4.1; 4 females, 4 males) performed two conditions (e.g., EVA; Inactivity) in shallow-water submersion (3-5 m). During EVA, participants performed 30 min of moderate, followed by 30 min of high intensity upper-body AE intervals paired with cognitive/motor tasks (e.g., fast translations along underwater mock-ups following a tether protocol, transportation of payload, routing of cables, allocation of connectors...). During inactivity, participants stayed in a submerged and neutrally buoyant position. Both conditions implied cognitive testing for the times PRE, MID (after the first 30 min) and POST (after the second 30 min). For both cognitive tasks, reaction times (RT) and response accuracy (ACC) was calculated for scenarios requiring inhibition (Eriksen Flanker task) or switching (Number/Letter task) ability, respectively.
Results: Switching: RTs were shorter after Inactivity compared to EVA with no interaction of time*condition for RT and ACC scores. Inhibition: RTs were shorter for EVA compared to Inactivity. ACC showed a time*condition interaction (F(1,873, 13.108) = 5.182, p=0.023) with higher scores for MID and POST measurements during Inactivity compared to EVA.
Discussion and Conclusion: This pilot data suggests that the specific physical exercise and tasks performed during simulated EVA might affect switching and inhibition selectively, although a greater sample size is needed for confirmation. This work might help to increase the understanding of interactions between specific exercise modalities and cognitive performance. Possible applications lie within the scope of safety for EVAs outside the international space station and during long-time space travel.
Original languageEnglish
Title of host publicationBook of abstracts : 25th Annual Congress of the European College of Sport Science : 28th-30th October 2020
EditorsFlemming Dela, Erich Müller, Elias K. Tsolakidis
Number of pages2
PublisherEuropean College of Sport Science
Publication date10.2020
ISBN (Print)978-3-9818414-3-5, 978-3-9818414-2-8
Publication statusPublished - 10.2020
EventAnnual Congress of the European College of Sport Science - Online
Duration: 28.10.202030.10.2020
Conference number: 25

ID: 5929135

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