title: Study protocol, implementation, and verification of a short versatile upright exercise regime during 5 days of bed rest.
abstract: OBJECTIVE
  This work provides a reference for future papers originating from this study by providing basic results on body mass, urine volume, and hemodynamic changes to 5 days of bed rest (BR) and by describing acute cardio-respiratory/mechanographic responses to a short versatile upright exercise battery.
  
  
  METHODS
  Ten male subjects (mean ± SEM age: 29.4 ± 1.5 years; height: 178.8 ± 1.5 cm; body mass: 77.7 ± 1.5 kg) performed, in random order, 5 days of 6° head-down tilt (HDT) BR with no exercise (CON), or BR with daily 25 minutes of quiet upright standing (STA) or upright locomotion replacement training (LRT).
  
  
  RESULTS
  Plasma volume, exercise capacity and orthostatic tolerance decreased similarly between interventions following 5 days of BR. Upright heart rate during LRT and STA increased throughout BR; from 137 ± 4 bpm to 146 ± 4 bpm for LRT (P<0.01); and from 90 ± 3 bpm to 102 ± 6 bpm (P<0.001) for STA.
  
  
  CONCLUSIONS
  the overall similarity in the response to BR, and increase in upright heart rate during the LRT sessions suggest early and advancing cardiovascular deconditioning during 5 days of BR bed rest, which was not prevented by the versatile exercise regime.
authors.affiliation: Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Mulder
authors.forename: P
authors.initials: P
authors.lastname: Frings-Meuthen
authors.forename: M
authors.initials: M
authors.lastname: von der Wiesche
authors.forename: G
authors.initials: G
authors.lastname: Clément
authors.forename: D
authors.initials: D
authors.lastname: Linnarsson
authors.forename: W H
authors.initials: WH
authors.lastname: Paloski
authors.forename: F L
authors.initials: FL
authors.lastname: Wuyts
authors.forename: J
authors.initials: J
authors.lastname: Zange
authors.forename: J
authors.initials: J
authors.lastname: Rittweger
mesh_terms: D000328:Adult; D001510:Bed Rest / Q000009:adverse effects*; D018493:Cardiovascular Deconditioning; D018592:Cross-Over Studies; D015444:Exercise / Q000502:physiology*; D018475:Head-Down Tilt / Q000009:adverse effects*; D006801:Humans; D008297:Male; D018474:Weightlessness Simulation / Q000009:adverse effects*