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Cardiorespiratory and Neuromuscular Demand of Daily Centrifugation: Results From the 60-Day AGBRESA Bed Rest Study

Kramer, A. and Venegas-Carro, M. and Mulder, E. and Lee, J.K. and Moreno-Villanueva, M. and Bürkle, A. and Gruber, M. (2020) Cardiorespiratory and Neuromuscular Demand of Daily Centrifugation: Results From the 60-Day AGBRESA Bed Rest Study. Frontiers in Physiology, 11, p. 562377. Frontiers Media S.A. doi: 10.3389/fphys.2020.562377. ISSN 1664-042X.

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Official URL: https://www.frontiersin.org/articles/10.3389/fphys.2020.562377/full

Abstract

Purpose: Long stays in space require countermeasures for the degrading effects of weightlessness on the human body, and artificial gravity (AG) has been proposed as an integrated countermeasure. The aim of this study was to assess the cardiorespiratory and neuromuscular demand of AG elicited via daily centrifugation during 60 days of bed rest. Methods: Twenty four participants (33 ± 9 y, 175 ± 9 cm, 74 ± 10 kg, 8 female) were subjected to 60 days of strict six-degree head-down tilt (HDT) bed rest and were randomly allocated to one of three experimental groups: 30 min of daily centrifugation with an acceleration of 1 g at the center of mass and 2 g at the feet applied continuously (cAG) or intermittently in 6 epochs of 5 min each, separated by 3 min breaks (iAG), or non-centrifuged control (CTRL). Cardiorespiratory demand during centrifugation was assessed at the beginning (HDT3) and end (HDT60) of the bed rest phase via spirometry and heart rate monitoring, leg muscle activation was monitored via electromyography. Results: On average, analyses of variance revealed that heart rate during centrifugation increased by 40% (iAG) and 60% (cAG) compared to resting values (p < 0.001), while oxygen uptake did not change significantly (p = 0.96). There was a preference for calf over knee extensor muscle activation (active time soleus 57 ± 27%, gastrocnemius medialis 45 ± 27% and vastus lateralis 27 ± 27%, p < 0.001), with large inter-individual differences in leg muscle active time. AG could not prevent the increase in resting heart rate after bed rest. For most of the recorded parameters, there were little differences between cAG and iAG, with the increase in heart rate during centrifugation being a notable exception (greater increase for cAG, p = 0.01). Conclusion: Daily 30 min bouts of artificial gravity elicited by centrifugation put a substantial demand on the heart as a pump without increasing oxygen consumption. If centrifugation is to be used as a countermeasure for the deteriorating effects of microgravity on physical performance, we recommend combining it with strenuous exercise.

Item URL in elib:https://elib.dlr.de/137102/
Document Type:Article
Title:Cardiorespiratory and Neuromuscular Demand of Daily Centrifugation: Results From the 60-Day AGBRESA Bed Rest Study
Authors:
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Kramer, A.University of KonstanzUNSPECIFIED
Venegas-Carro, M.Department of Sport Science, University of Konstanz, Konstanz, GermanyUNSPECIFIED
Mulder, E.German Aerospace Center (DLR), Institute of Aerospace Medicine, Space Physiology, Cologne, GermanyUNSPECIFIED
Lee, J.K.German Aerospace Center, Cologne, GermanyUNSPECIFIED
Moreno-Villanueva, M.Department of Biology, University of Konstanz, Konstanz, GermanyUNSPECIFIED
Bürkle, A.Department of Biology, University of Konstanz, Konstanz, GermanyUNSPECIFIED
Gruber, M.Universität KonstanzUNSPECIFIED
Date:September 2020
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:11
DOI :10.3389/fphys.2020.562377
Page Range:p. 562377
Publisher:Frontiers Media S.A
Series Name:Embryonic and Developmental Physiology
ISSN:1664-042X
Status:Published
Keywords:exercise, countermeasure, heart rate, oxygen consumption, artificial gravity
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 - Research under Space Conditions
DLR - Research theme (Project):R - Vorhaben Systemphysiologie (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Aerospace Medicine > Muscle and Bone Metabolism
Institute of Aerospace Medicine > Leitungsbereich ME
Deposited By: Arndt, Carina
Deposited On:05 Nov 2020 16:58
Last Modified:05 Nov 2020 16:58

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