Progressive lower-body negative pressure (0 to -40 mmHg) revealed sex-dependent compensation, with lower-body resistance rising markedly in males but remaining near baseline in females.
Does lower-body negative pressure induce sex-dependent regional cardiovascular compensation strategies in healthy adults?
Computational modeling of human hemodynamic data reveals that males and females employ distinct regional vascular resistance strategies to compensate for central hypovolemia.
Lower-body negative pressure (LBNP) induces controlled central hypovolemia, yet the regional mechanisms of cardiovascular compensation remain difficult to resolve experimentally. This study presents a computational framework for estimating regional parameter changes consistent with observed hemodynamic responses to progressive LBNP using a refined lumped-parameter model calibrated to experimental data. Hemodynamic responses to graded LBNP (0 to −40 mmHg) and recovery were obtained from a previously published experimental study in 35 healthy adults (17 females, 18 males), including heart rate, cardiac output, arterial pressure, total peripheral resistance, and ultrasound-derived internal jugular and portal venous flow. The model was structurally refined by separating head and arm circulations, enabling explicit modeling of cerebral venous outflow and jugular vein dynamics, and calibrated using a sensitivity- and correlation-guided identification strategy. Baseline calibration revealed distinct vascular architectures, with males exhibiting higher arterial compliance and dominant lower-body resistance, and females showing greater splanchnic and renal tone. During progressive LBNP, the identified splanchnic resistance increased monotonically in both sexes, whereas lower-body resistance rose markedly in males but remained near baseline in females, indicating sex-dependent compensation strategies. The calibrated model quantifies regional vascular resistance changes and venous blood volume redistribution during hypovolemia, providing a model-based interpretation of possible regulatory mechanisms into sex-specific cardiovascular regulation that cannot be directly measured in vivo.
Bergauer et al. (Fri,) conducted a other in Healthy adults (n=35). Lower-body negative pressure (LBNP) vs. Males vs Females was evaluated on Regional vascular resistance changes and venous blood volume redistribution. Progressive lower-body negative pressure (0 to -40 mmHg) revealed sex-dependent compensation, with lower-body resistance rising markedly in males but remaining near baseline in females.