Hysteresis in response to descending and ascending lower-body negative pressure.

Abstract

We have investigated the pattern of fluid redistribution and cardiovascular responses during graduated orthostatic stress. Twelve men, age 30-39 yr, underwent a 25-min lower-body negative pressure (LBNP) test protocol that involved sequential stages of LBNP at -8 mmHg (1 min), -16 mmHg (1 min), -30 mmHg (3 min), -40 mmHg (5 min), -50 mmHg (5 min), -40 mmHg (5 min), -30 mmHg (3 min), -16 mmHg (1 min), and -8 mmHg (1 min). Data were recorded at the end of each stage. For many measured variables values during the descending phase of LBNP (-8 to -40 mmHg) were significantly different from values during the ascending phase of (-40 to -8 mmHg). These differences appear to be due to a component of fluid translocation that occurs during LBNP and cannot be reversed within the duration of the procedure. We hypothesize that this slowly reversed component is sequestration of fluid in the interstitial and lymphatic compartments. In contrast, venous pooling is a rapidly reversible component of fluid movement during LBNP. A scheme describing fluid and cardiovascular responses to LBNP based on these data and the data of other investigators is presented.

Statistics

0100200'99'01'03'05'07'09'11'13'15'17
Citations per Year

87 Citations

Semantic Scholar estimates that this publication has 87 citations based on the available data.

See our FAQ for additional information.

Cite this paper

@article{Tomaselli1987HysteresisIR, title={Hysteresis in response to descending and ascending lower-body negative pressure.}, author={Clare M. Tomaselli and Mary Anne Bassett Frey and Raymond Kenney and G. Wyckliffe Hoffler}, journal={Journal of applied physiology}, year={1987}, volume={63 2}, pages={719-25} }