This question is very basic. I have yet to receive one single reply as to why varicose veins shrink when the head of the bed is raised to +5 degree to the horizontal and flat bedrest is avoided for 4 weeks? If you are working in the Health Industry then you should want to know more about this and you should want to question why it is not mentioned in any literature.
If you don't have an answer then you should say "I don't have an answer" To ignore this question is not an option because I will continue to badger everyone until I get a statisfactory answer..
What happens when we sleep the opposite way round with our head down?
F. Louisy1 , C. Gaudin1, J. M. Oppert1 , A. Güell2 and C. Y. Guezennec1
(1) C.E.R.M.A. = Centre d'Etudes et de Recherches de Médecine Aérospatiale, Base d'Essais en vol, F-91228 Brétigny-sur-Orge Cedex, France
(2) Centre National d'Etudes Spatiales, Toulouse, France
(3) CNES-NASA = Centre National d'Etudes, Spatiales, National Aéronautics and Space Agency, France
Accepted: 18 April 1990
Summary Venous distensibility of the lower limbs was assessed in six healthy men who were submitted twice successively to 1 month of –6° head-down bedrest, with and without lower body negative pressure (LBNP) (LBNP subjects and control subjects, respectively). Venous capacity ( V v,max, in ml·100 ml–1) of the legs was determined by mercury strain gauge plethysmography with venous occlusion. Plethysmographic measurements were made on each subject before (Dc), during (D6 and D20) and after (5th day of recovery, D+5) bedrest. During bedrest, LBNP was applied daily, several times a day to the subjects submitted to this procedure. Results showed a gradual increase in V v,max (ml·100 ml–1) throughout the bedrest, both in the control group [ V v,max = 2.11 SD 0.54 at Dc, 2.69 SD 0.29 at D6, 4.39 SD 2.08 at D20, 2.39 SD 0.69 at D+5, P<0.001 (ANOVA)] and in the LBNP group [ V v,max = 2.07 SD 0.71 at Dc, 2.85 SD 1.19 at D6, 3.75 SD 1.74 at D20, 2.43 SD 0.94 at D+5, P<0.001 (ANOVA)], without significant LBNP effect. These increases were of the same order as those encountered during spaceflight. It is concluded that –6° head-down bedrest is a good model to simulate the haemodynamic changes induced by exposure to weightlessness and that LBNP did not seem to be a good technique to counteract the adverse effects of weightlessness on the capacitance vessels of the lower limbs. This latter conclusion raises the question of the role and magnitude of leg venous capacitance in venous return and cardiac regulation.
Key words Vein haemodynamics - Bedrest - Lower body negative pressure - Venous return
This study was part of a joint CNES — NASA project designed to evaluate the efficiency of periodic lower body negative pressure exposures to prevent microgravity effects on certain physiological parameters (orthostatic tolerance, work capacity, muscle changes, etc....
in order to prepare the future manned space missions Hermes and Colombus.