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Sponsors and Collaborators: |
Centre Hospitalier Universitaire de Saint Etienne Ministry of Health, France |
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Information provided by: | Centre Hospitalier Universitaire de Saint Etienne |
ClinicalTrials.gov Identifier: | NCT00515645 |
Head down tilt (HDT) was widely used to simulate microgravity effects on cardiovascular system. HDT could be a suitable model of water immersion (WI) which is also used to simulate the cardiovascular effects of microgravity and which is not easy to study in laboratory. To define the possibility to simulate immersion by HDT, a comparison between these models is required. A comparison between WI and few angles during HDT seems necessary to understand which angle is more adapt. The immersion induces an increase of the central blood volume. This increase is caused by a redistribution of blood from peripheral portions of the body to the intrathoracic circulation. It seems to load cardiopulmonary and arterial baroreceptors. These baroreceptors bring into play autonomic nervous system (ANS) activation and induce a bradycardia. HDT induces an increase in central blood volume as supported by the central venous pressure and cardiac volume increase and in return, MSNA and heart rate decrease. These cardiovascular effects seem to be the same as the thermoneutral immersion and suggest that the ANS activation is the same during HDT and WI.
Nevertheless, a few previous studies about ANS in HDT indicate some discordant results: a sympathetic decrease was reported but several results show an increase of parasympathetic activity linked with a trend of increase of arterial baroreflex. The aim of this study is to assess ANS activity in HDT on different angles (-6° and -15°) and WI. The investigators suppose an increase of parasympathetic activity during WI corresponding to parasympathetic activation during HDT especially at -6°.
Condition | Intervention |
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Healthy |
Other: Head-down tilt and immersion |
Study Type: | Interventional |
Study Design: | Basic Science, Non-Randomized, Open Label, Uncontrolled, Single Group Assignment, Efficacy Study |
Official Title: | Cardiac Autonomic Functions During Head-Out Immersion and During Head Down Tilt |
Estimated Enrollment: | 25 |
Study Start Date: | April 2008 |
Estimated Study Completion Date: | September 2009 |
Estimated Primary Completion Date: | September 2009 (Final data collection date for primary outcome measure) |
Arms | Assigned Interventions |
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1: Experimental |
Other: Head-down tilt and immersion
Head-down tilt -6° at inclusion, head-down tilt -15° at week one and Water Immersion at week two
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Ages Eligible for Study: | 18 Years to 40 Years |
Genders Eligible for Study: | Male |
Accepts Healthy Volunteers: | Yes |
Inclusion Criteria:
Exclusion Criteria:
Contact: Frédéric Roche, MD PhD | +33 (0)477828300 | frederic.roche@univ-st-etienne.fr |
Contact: Jean Claude Barthelemy, MD PhD | +33 (0)477828300 | JC.Barthelemy@univ-st-etienne.fr |
France | |
Centre Hospitalier de Saint-Etienne | Recruiting |
Saint-Etienne, France, 42055 | |
Contact: Fréderic Roche, MD PhD +33 (0)477828300 frederic.roche@univ-st-etienne.fr | |
Contact: Florian Chouchou, CRA +33 (0)477828300 florianchouchou@hotmail.fr | |
Sub-Investigator: Jean Claude Barthelemy, MD PhD | |
Sub-Investigator: Frédéric Costes, MD PhD |
Principal Investigator: | Frédéric Roche, MD PhD | Centre Hospitalier de Saint-Etienne |
Responsible Party: | Centre Hospitalier Universitaire de Saint Etienne ( Clément CAILLAUX ) |
Study ID Numbers: | 0708061, 2007-A00727-46 |
Study First Received: | August 13, 2007 |
Last Updated: | June 9, 2009 |
ClinicalTrials.gov Identifier: | NCT00515645 History of Changes |
Health Authority: | France: Ministry of Health; France: French Data Protection Authority |
Autonomic nervous system Immersion Heart rate variability Head-down tilt Healthy volunteers |
Healthy |