Universität zu Köln

Laing, Charles ORCID: 0000-0002-2367-2323, Green, David A., Mulder, Edwin, Hinghofer-Szalkay, Helmut, Blaber, Andrew P., Rittweger, Joern and Goswami, Nandu ORCID: 0000-0002-6704-0723 (2020). Effect of novel short-arm human centrifugation-induced gravitational gradients upon cardiovascular responses, cerebral perfusion and g-tolerance. J. Physiol.-London, 598 (19). S. 4237 - 4250. HOBOKEN: WILEY. ISSN 1469-7793

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Abstract

Key points The aim of this study was to determine the effect of rotational axis position (RAP and thus g-gradient) during short-arm human centrifugation (SAHC) upon cardiovascular responses, cerebral perfusion and g-tolerance. In 10 male and 10 female participants, 10 min passive SAHC runs were performed with the RAP above the head (P1), at the apex of the head (P2), or at heart level (P3), with foot-level Gz at 1.0 g, 1.7 gand 2.4 g. We hypothesized that movement of the RAP from above the head (the conventional position) towards the heart might reduce central hypovolaemia, limit cardiovascular responses, aid cerebral perfusion, and thus promote g-tolerance. Moving the RAP footward towards the heart decreased the cerebral tissue saturation index, calf circumference and heart rate responses to SAHC, thereby promoting g-tolerance. Our results also suggest that RAP, and thus g-gradient, warrants further investigation as it may support use as a holistic spaceflight countermeasure. Artificial gravity (AG) through short-arm human centrifugation (SAHC) has been proposed as a holistic spaceflight countermeasure. Movement of the rotational axis position (RAP) from above the head towards the heart may reduce central hypovolaemia, aid cerebral perfusion, and thus promote g-tolerance. This study determined the effect of RAP upon cardiovascular responses, peripheral blood displacement (i.e. central hypovolaemia), cerebral perfusion and g-tolerance, and their inter-relationships. Twenty (10 male) healthy participants (26.2 +/- 4.0 years) underwent nine (following a familiarization run) randomized 10 min passive SAHC runs with RAP set above the head (P1), at the apex of the head (P2), or at heart level (P3) with foot-level Gz at 1.0 g, 1.7 gand 2.4 g. Cerebral tissue saturation index (cTSI, cerebral perfusion surrogate), calf circumference (CC, central hypovolaemia), heart rate (HR) and digital heart-level mean arterial blood pressure (MAP) were continuously recorded, in addition to incidence of pre-syncopal symptoms (PSS). Delta CC and Delta HR increases were attenuated from P1 to P3 (Delta CC: 5.46 +/- 0.54 mm to 2.23 +/- 0.42 mm; Delta HR: 50 +/- 4 bpm to 8 +/- 2 bpm,P < 0.05). In addition, Delta cTSI decrements were also attenuated (Delta cTSI: -2.85 +/- 0.48% to -0.95 +/- 0.34%,P < 0.05) and PSS incidence lower in P3 than P1 (P < 0.05). A positive linear relationship was observed between Delta CC and Delta HR with increasing +Gz, and a negative relationship between Delta CC and Delta cTSI, both independent of RAP. Our data suggest that movement of RAP towards the heart (reduced g-gradient), independent of foot-level Gz, leads to improved g-tolerance. Further investigations are required to assess the effect of differential baroreceptor feedback (i.e. aortic-carotid g-gradient).

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Laing, Charles UNSPECIFIED orcid.org/0000-0002-2367-2323 UNSPECIFIED Green, David A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Mulder, Edwin UNSPECIFIED UNSPECIFIED UNSPECIFIED Hinghofer-Szalkay, Helmut UNSPECIFIED UNSPECIFIED UNSPECIFIED Blaber, Andrew P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Rittweger, Joern UNSPECIFIED UNSPECIFIED UNSPECIFIED Goswami, Nandu UNSPECIFIED orcid.org/0000-0002-6704-0723 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-323002
DOI:	10.1113/JP273615
Journal or Publication Title:	J. Physiol.-London
Volume:	598
Number:	19
Page Range:	S. 4237 - 4250
Date:	2020
Publisher:	WILEY
Place of Publication:	HOBOKEN
ISSN:	1469-7793
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language BLOOD-PRESSURE; SPACE; EXERCISE; COUNTERMEASURES; OXYGENATION; IMPAIRMENT; FLOW Multiple languages Neurosciences; Physiology Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/32300