Abstract

Capillary filtration rate, venous compliance and blood flow in arms and legs were measured during bed rest. Furthermore orthostatic tolerance to lower body suction was recorded. 6 young healthy males and 3 young healthy females participated in the 20 days bed rest study. Neither arm nor leg blood flow was changed by bed rest. Capillary filtration rate tended to decrease in the arms and there was a tendency to an increase in filtration rate in legs but both of these changes had recovered from day 10 on. There was a steady state in venous compliance of the forearm during the first two weeks of the bed rest period but the values tended to increase at days 16 and 19, respectively, while leg venous compliance showed a transient tendency to increase at day 3 to attain control values from day 5. Orthostatic intolerance measured during lower body suction decreased in the present subjects. This has been described before after bed rest. However, the present results did not indicate that the vascular bed of the legs contributed hereto. Previous results published showed that the hepatosplanchnic area might play a more significant role. An interesting finding was that the capillary filtration rate of the legs increased transiently in the beginning of the 20 days bed rest period (days 3-5) and the same seemed to be the case for the arms at the end of the period (day 16). This might indicate that the unloading of gravitational forces has a sudden effect in the lower extremities while adjustements take longer in the upper extremities. Verf.-Referat