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gerBöhmer, Andreas BenedictGerzer, RupertEinfluss simulierter Mikrogravitation und variabler Kochsalzzufuhr auf arteriellen Blutdruck, Hämodynamik und Orthostasetoleranz gesunder Probandeninfo:eu-repo/classification/ddc/610Langzeit-BlutdruckmessungMikrogravitationKochsalzOrthostaseBlutdruckMedizinblood pressuresodiumnormotensiveorthostatic tolerancemicrogravityThe human cardiovascular system is continuously influenced by external factors. Especially gravitation on earth means a constant challenge. By the loss of gravitational stress, e.g. during simulated microgravity or spaceflight the human cardiovascular system is modulated in a way which promotes different problems when gravitation reaffects human body: reduced hemodynamic adaptiveness and orthostatic tolerance is the consequence. High dosage of salt tablets given directly after residence in microgravity has been shown to be an appropriate measure to ameliorate orthostatic tolerance. Effects of continuously high resp. low salt diet on orthostatic tolerance are unknown yet. As well as the influences of different salt diets on the cardiovascular system of young healthy men have not been described in detail, the coincidence of salt ingestion and hypertension disease is still object of controversial health care discussion. The aim of our study was to investigate the effect of high vs. low salt diet during simulated microgravity on the cardiovascular system of young healthy normotensive men. We measured 24 hrs blood pressure before and after 14 day head-down tilt bed rest and furthermore examined hemodynamic response and orthostatic tolerance by tilt table testing. Our results showed an increase of blood pressure and development of a “non-dipper” pattern especially for the diastolic component under low salt diet, while blood pressure is barely influenced by high salt diet. Orthostatic tolerance is altered by microgravity; continuous salt ingestion shows no benefit on its related hemodynamics. Basic aldosterone plasma concentration increases under low salt conditions and declines under high salt diet. Its head up tilt response turns out more distinctive under low salt ingestion while norepinephrine levels have been unaltered by salt diet. Our findings indicate that continuously altered salt diet is less effective to improve orthostatic tolerance after simulated microgravity than single administration. Activation of hormonal feed back control mechanisms, especially of renin-angiotensin-aldosterone-system could wash out the short-term benefit of salt ingestion. We could show that low salt diet combined with microgravity have an enormous effect of blood pressure pattern. Results of blood pressure measurement suggest relevant blood pressure regulation agents in young normotensives that vary significantly from the presumed mechanisms found in some groups of hypertensive patients. Investigation of blood pressure regulation of young normotensives should be taken into account to get a deeper understanding of the basical mechanisms of the human cardiovascular system. Because natriuretic peptide and renin-angiotensin-aldosterone-system activity are possible useful surrogate markers in diagnostics and therapy of cardiosvascular diseases, scientific advance in this area becomes more and more important.Aachen : Publikationsserver der RWTH Aachen University 84 S. : graph. Darst. (2009). = Aachen, Techn. Hochsch., Diss., 2009info:eu-repo/semantics/doctoralThesisinfo:eu-repo/semantics/publishedVersionPublikationsserver der RWTH Aachen University2009info:eu-repo/semantics/openAccessDEhttps://publications.rwth-aachen.de/record/51115https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-113431%22StudentsStudent Financial Aid ProvidersTeachersResearchersinfo:eu-repo/semantics/altIdentifier/urn/urn:nbn:de:hbz:82-opus-27528