title: Effects of long-term head-down-tilt bed rest and different training regimes on the coagulation system of healthy men.
abstract: Immobility plus preexisting chronic disease or acute trauma can activate the coagulation system, thus increasing the risk for thromboembolic events. The effects of long-term bed-rest immobility and microgravity on the coagulation system of healthy persons (e.g., during crewed Mars missions) have not yet been studied. The main objective of the second Berlin BedRest Study (BBR2-2) "Coagulation Part" was to investigate adaptations of the hemostatic system during long-term bed rest (60 days) under simulated microgravity (6° head-down-tilt [6°HDT]) and after mobilization in three different volunteer groups (randomly assigned to CTR= inactive control group; RE= resistive exercise only group; and RVE= resistive exercise with whole-body vibration group). In 24 males (aged 21-45 years), before, during, and after long-term bed rest, key parameters of coagulation were measured from venous blood samples: D-dimer (DD), thrombin-antithrombin III complex (TAT), and prothrombin fragment F1 + 2 (PT-F1 + 2). Additionally, modified rotational thrombelastometry (ROTEM (®) ) analysis was performed. Times of exploratory analyses were as follows: baseline data collection 2 days before bed rest (BDC-2); eight different days of 6°HDT bed rest (HDT1-HDT60), and two different days after reambulation (R + 3 and R + 6). We found significant changes in DD, TAT, and PT-F1 + 2 over the total time course, but no consistent effect of physical interventions (RE, RVE) on these parameters. Notably, no parameter reached levels indicative of intravascular thrombin formation. All ROTEM® parameters remained within the normal range and no pathological traces were found. Sixty days of 6°HDT bed rest are not associated with pronounced activation of the coagulation system indicative of intravascular thrombus formation in healthy volunteers independent of the training type during the bed rest.
authors.affiliation: Institute for Sports Medicine Alpine, Medicine and Health Tourism UMIT Hall, Austria ; Institute of Veterinary Physiology and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich Zurich, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Haider
authors.affiliation: Department for Physiology and Centre for Space Medicine, Charité University Medicine Berlin, Germany.
authors.forename: Hanns-Christian
authors.initials: HC
authors.lastname: Gunga
authors.affiliation: Institute for Public Health, Medical Decision Making and HTA, UMIT Hall, Austria.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Matteucci-Gothe
authors.affiliation: Central Institute for Med. and Chem. Laboratory Diagnostics, TILAK Innsbruck, Austria.
authors.forename: Elke
authors.initials: E
authors.lastname: Sottara
authors.affiliation: Central Institute for Med. and Chem. Laboratory Diagnostics, TILAK Innsbruck, Austria.
authors.forename: Andrea
authors.initials: A
authors.lastname: Griesmacher
authors.affiliation: Centre for Muscle and Bone Research, Charité University Medicine Berlin, Germany.
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Belavý
authors.affiliation: Centre for Muscle and Bone Research, Charité University Medicine Berlin, Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Felsenberg
authors.affiliation: Department for Physiology and Centre for Space Medicine, Charité University Medicine Berlin, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Werner
authors.affiliation: Institute for Sports Medicine Alpine, Medicine and Health Tourism UMIT Hall, Austria.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schobersberger
keywords: Hemostasis; head-down tilt; immobilization; resistance training; thromboelastography