Related Experiment Videos
Adaptations to a 7-day head-down bed rest with thigh cuffs
C Millet1, M A Custaud, A M Allevard
1Laboratoire de Physiologie de L'Environnement, Faculté de Médecine Lyon Grange-Blanche, France. gharib@cismsun.univ-lyon1.fr
Medicine and Science in Sports and Exercise
|October 20, 2000
Summary
Thigh cuffs limited fluid shift during head-down bed rest, reducing plasma volume decrease. However, they did not improve orthostatic tolerance, indicating limited effectiveness as a countermeasure.
Area of Science:
- Space physiology
- Human physiology
- Cardiovascular research
Background:
- Head-down bed rest (HDBR) induces fluid shifts and orthostatic intolerance.
- Thigh cuffs are proposed to limit cephalad fluid migration.
Purpose of the Study:
- To investigate the effects of thigh cuffs on hormonal and plasma volume responses.
- To assess the impact of thigh cuffs on orthostatic tolerance during 7-day HDBR.
Main Methods:
- Eight healthy men underwent 7 days of -6° HDBR.
- Thigh cuffs were applied for 10 hours daily.
- Measurements included orthostatic tolerance, plasma volume, total body water, hormones, and electrolytes.
Main Results:
- Thigh cuffs attenuated the decrease in plasma volume (-5.85% vs. -9.09% in control, P<0.05).
- No significant changes in total body water were observed.
- Hormonal responses and orthostatic intolerance symptoms were not significantly affected by thigh cuffs.
Conclusions:
- Thigh cuffs partially mitigated plasma volume loss during HDBR but did not improve orthostatic tolerance.
- Thigh cuffs are not a completely effective countermeasure against HDBR-induced deconditioning.
- Hypovolemia is necessary but not sufficient for orthostatic intolerance post-HDBR.