Short-term isolation effects on the brain, cognitive performance, and sleep-The role of exercise

Timo Klein; Leonard Braunsmann; Jessica Koschate; Uwe Hoffmann; Tina Foitschik; Stephanie Krieger; Brian Crucian; Stefan Schneider; Vera Abeln

doi:10.3389/fphys.2023.903072

Short-term isolation effects on the brain, cognitive performance, and sleep-The role of exercise

Front Physiol. 2023 Jan 30:14:903072. doi: 10.3389/fphys.2023.903072. eCollection 2023.

Authors

Timo Klein^{1

2

3

4}, Leonard Braunsmann¹, Jessica Koschate⁵, Uwe Hoffmann³, Tina Foitschik¹, Stephanie Krieger⁶, Brian Crucian⁷, Stefan Schneider^{8

9

10}, Vera Abeln^{1

3}

Affiliations

¹ Institute of Movement and Neuroscience, German Sport University Cologne, Cologne, Germany.
² University of Rostock, Institute of Sport Science, Rostock, Germany.
³ Centre for Health and Integrative Physiology in Space (CHIPS), German Sport University Cologne, Cologne, Germany.
⁴ VasoActive Research Group, School of Health and Sport Sciences, University of the Sunshine Coast, Maroochydore, QLD, Australia.
⁵ Geriatric Medicine, Department for Health Services Research, School of Medicine and Health Sciences, University of Oldenburg, Cologne, Germany.
⁶ KBR, Houston, TX, United States.
⁷ NASA-Johnson Space Center, Houston, TX, United States.
⁸ Institute of Movement and Neurosciences, Center for Health and Integrative Physiology in Space, German Sport University Cologne, Cologne, Germany.
⁹ School of Maritime Studies, Memorial University of Newfoundland, St. Johns, NL, Canada.
¹⁰ Faculty for Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore, QLD, Australia.

Abstract

Isolation is stressful and negatively affects sleep and mood and might also affect the structure and function of the brain. Physical exercise improves brain function. We investigated the influence of physical exercise during isolation on sleep, affect, and neurobehavioral function. N = 16 were isolated for 30 days with daily exercise routines (ISO₁₀₀) and n = 16 isolated for 45 days with every second day exercise (ISO₅₀). N = 27 were non-isolated controls who either exercised on a daily basis (CTRL_Ex) or refused exercise (CTRL_NonEx) for 30 days. At the beginning and the end of each intervention, intravenous morning cortisol, melatonin, brain-derived neurotrophic factor and IGF-1, positive and negative affect scales, electroencephalography, cognitive function, and sleep patterns (actigraphy) were assessed. High levels of cortisol were observed for the isolated groups (p < .05) without negative effects on the brain, cognitive function, sleep, and mood after 4 to 6 weeks of isolation, where physical exercise was performed regularly. An increase in cortisol and impairments of sleep quality, mood, cognitive function, and neurotrophic factors (p < .05) were observed after 4 weeks of absence of physical exercise in the CTRL_NonEx group. These findings raise the assumption that regular physical exercise routines are a key component during isolation to maintain brain health and function.

Keywords: cognition; confinement; cortisol; mental health; neurotrophic factors; physical activity; space flight; stress.

Grants and funding

This study was supported by a grant from the German Ministry of Economic Affairs and Energy (BMWi) as handled by the German Space Agency (DLR), grant No. 50WB1516 to VA.