To examine whether the so-called musculovenous pump counteracts the development of @entity4 in the lower extremities of @entity1 in the upright position, the volume changes in the @entity291 which occurred during twenty minutes of rhythmic muscular exercise were measured in twenty-three subjects by impedance-plethysmography. The results were compared with the volume increase found during quiet relaxed standing for the same length of time. Contrary to the hypothesis, and @entity4 -protective effect of the musculovenous pump could only be shown in about half the number of the subjects. In the others, muscular exercise led to increases in @entity291 volume which were higher than those measured in the normal upright position. These results show that the @entity291 muscle pump does not generally have a @entity4 -protective effect but rather that muscle contractions also activate mechanisms which stimulate the extravasation of fluid. In a second test-series with twenty subjects, changes in @entity291 volume were measured during the course of the day. In nearly all cases, the @entity291 volume was greater in the evening than in the morning. It could be shown that the volume increases in the evening are caused by an increase in extravascular fluid. Compared to the increase in extravascular volume occurring during twenty minutes, in a normal upright position, the accumulation of extravascular fluid during the day is, however, remarkably low. Although it is still unknown how @entity4 in @entity1 's lower extremities is prevented during the day, these findings lead to the hypothesis that the @entity4 -preventing mechanisms, for instance the muscle-lymphpump, do not become maximally effective until a certain volume has accumulated in the interstitial space.

On physiological XXXX in @entity1 's lower extremity.

@entity1 :: ('9606', 'Species') :: ['man'] @entity4 :: ('MESH:D004487', 'Disease') :: ['interstitial edema', 'edema'] @entity291 :: ('9913', 'Species') :: ['calf']
@entity4 :: (MESH:D004487,Disease) :: ['edema']
