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Sleep Is Compromised in −12◦ Head Down Tilt Position

Boschert, A.L. and Elmenhorst, D. and Gauger, P. and Li, Z. and Garcia-Gutierrez, M.T. and Gerlach, D. and Johannes, B. and Zange, J. and Bauer, A. and Rittweger, J. (2019) Sleep Is Compromised in −12◦ Head Down Tilt Position. Frontiers in Physiology, 10 (397). Frontiers Media S.A. DOI: 10.3389/fphys.2019.00397 ISSN 1664-042X

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Abstract

Recent studies are elucidating the interrelation between sleep, cranial perfusion, and cerebrospinal fluid (CSF) circulation. Head down tilt (HDT) as a simulation of microgravity reduces cranial perfusion. Therefore, our aim was to assess whether HDT is affecting sleep (clinicaltrials.gov; identifier NCT02976168). 11 male subjects were recruited for a cross-over designed study. Each subject participated in two campaigns each comprising 3 days and 2 nights. Intervention started on the second campaign day and consisted of maintenance of horizontal position or -12° HDT for 21 h. Ultrasound measurements were performed before, at the beginning and the end of intervention. Polysomnographic measurements were assessed in the second night which was either spent in horizontal posture or at -12° HDT. Endpoints were sleep efficiency, sleep onset latency, number of sleep state changes and arousals, percentages of N3, REM, light sleep stages and subjective sleep parameters. N3 and REM sleep reduced by 25.6 and 19.1 min, respectively (P = 0.002, g = -0.898; P = 0.035, g = -0.634) during -12° HDT. Light sleep (N1/2) increased by 33.0 min at -12° HDT (P = 0.002, g = 1.078). On a scale from 1 to 9 subjective sleep quality deteriorated by 1.3 points during -12° HDT (P = 0.047, g = -0.968). Ultrasonic measurement of the venous system showed a significant increase of the minimum (P = 0.009, P < 0.001) and maximum (P = 0.004, P = 0.002) cross-sectional area of the internal jugular vein at -12° HDT. The minimum cross-sectional area of the external jugular vein differed significantly between conditions over time (P = 0.001) whereas frontal skin tissue thickness was not significantly different between conditions (P = 0.077, P = 0.811). Data suggests venous congestion at -12° HDT. Since subjects felt comfortable with lying in -12° HDT under our experimental conditions, this posture only moderately deteriorates sleep. Obviously, the human body can almost compensate the several fold effects of gravity in HDT posture like an affected CSF circulation, airway obstruction, unusual patterns of propioception and effects on the cardiovascular system.

Item URL in elib:https://elib.dlr.de/129869/
Document Type:Article
Title:Sleep Is Compromised in −12◦ Head Down Tilt Position
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Boschert, A.L.Department of Muscle and Bone Metabolism, German Aerospace Center (DLR), Institute of Aerospace Medicine, Cologne,GermanyUNSPECIFIED
Elmenhorst, D.Molekulares Neuroimaging, Forschungszentrum JülichUNSPECIFIED
Gauger, P.German Aerospace Center (DLR), Institute of Aerospace Medicine, Space Physiology, Cologne, GermanyUNSPECIFIED
Li, Z.State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, ChinaUNSPECIFIED
Garcia-Gutierrez, M.T.High Studies Center Alberta Gimenez (CESAG) University of Comillas, Palma de Mallorca, SpainUNSPECIFIED
Gerlach, D.Institute of Aerospace Medicine, German Aerospace Center, Cologne, GermanyUNSPECIFIED
Johannes, B.Department of Muscle and Bone Metabolism, German Aerospace Center (DLR), Institute of Aerospace Medicine, Cologne, GermanyUNSPECIFIED
Zange, J.Department of Muscle and Bone Metabolism, German Aerospace Center (DLR), Institute of Aerospace Medicine, Cologne, GermanyUNSPECIFIED
Bauer, A.Forschungszentrum Jülich, Institute of Neuroscience and Medicine (INM-2), Jülich, GermanyUNSPECIFIED
Rittweger, J.institute of aerospace medicine, deutsches zentrum für luft- und raumfahrt, dlr e.v., cologne, germany and medical faculty, university of cologne, cologne, germany; joern.rittweger (at) dlr.deUNSPECIFIED
Date:April 2019
Journal or Publication Title:Frontiers in Physiology
Refereed publication:Yes
Open Access:Yes
Gold Open Access:Yes
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:10
DOI :10.3389/fphys.2019.00397
Publisher:Frontiers Media S.A
ISSN:1664-042X
Status:Published
Keywords:bed rest; head down tilt; polysomnography; simulated microgravity; sleep
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Research under Space Conditions
DLR - Research area:Raumfahrt
DLR - Program:R FR - Forschung unter Weltraumbedingungen
DLR - Research theme (Project):R - Vorhaben Systemphysiologie
Location: Köln-Porz
Institutes and Institutions:Institute of Aerospace Medicine
Institute of Aerospace Medicine > Cardiovascular Medicine in Aerospace
Institute of Aerospace Medicine > Muscle and Bone Metabolism
Deposited By: Schrage, Larissa
Deposited On:29 Oct 2019 14:42
Last Modified:29 Oct 2019 14:42

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