Blood volume primarily determines orthostatic tolerance in women

2021 ◽  
Author(s):  
Candela Diaz‐Canestro ◽  
David Montero
Keyword(s):  
Blood Volume ◽  
Orthostatic Tolerance

Delayed vasoconstrictor response to venous pooling in the calf is associated with high orthostatic tolerance to LBNP

2010 ◽  
Vol 109 (4) ◽  
pp. 996-1001 ◽  
Author(s):  
T. Hachiya ◽  
M. L. Walsh ◽  
M. Saito ◽  
A. P. Blaber
Keyword(s):  
Blood Volume ◽  
Negative Pressure ◽  
Near Infrared ◽  
Lower Body Negative Pressure ◽  
Orthostatic Stress ◽  
Orthostatic Tolerance ◽  
Lower Body ◽  
High Tolerance ◽  
Venous Pooling ◽  
Vasoconstrictor Response

Central blood volume loss to venous pooling in the lower extremities and vasoconstrictor response are commonly viewed as key factors to distinguish between individuals with high and low tolerance to orthostatic stress. In this study, we analyzed calf vasoconstriction as a function of venous pooling during simulated orthostatic stress. We hypothesized that high orthostatic tolerance (OT) would be associated with greater vasoconstrictor responses to venous pooling compared with low OT. Nineteen participants underwent continuous stepped lower body negative pressure at −10, −20, −30, −40, −50, and −60 mmHg each for 5 min or until exhibiting signs of presyncope. Ten participants completed the lower body negative pressure procedure without presyncope and were categorized with high OT; the remaining nine were categorized as having low OT. Near-infrared spectroscopy measurements of vasoconstriction (Hachiya T, Blaber A, Saito M. Acta Physiologica 193: 117–127, 2008) in calf muscles, along with heart rate (HR) responses for each participant, were evaluated in relation to calf blood volume, estimated by plethysmography. The slopes of this relationship between vasoconstriction and blood volume were not different between the high- and low-tolerance groups. However, the onset of vasoconstriction in the high-tolerance group was delayed. Greater HR increments in the low-tolerance group were also observed as a function of lower limb blood pooling. The delayed vasoconstriction and slower HR increments in the high-tolerance group to similar venous pooling in the low group may suggest a greater vascular reserve and possible delayed reduction in venous return.

scholarly journals Sex Differences in Orthostatic Tolerance Are Mainly Explained by Blood Volume and Oxygen Carrying Capacity

2022 ◽  
Vol 4 (1) ◽  
pp. e0608
Author(s):  
Candela Diaz-Canestro ◽  
Brandon Pentz ◽  
Arshia Sehgal ◽  
David Montero
Keyword(s):  
Sex Differences ◽  
Blood Volume ◽  
Carrying Capacity ◽  
Orthostatic Tolerance ◽  
Oxygen Carrying Capacity

Effect of Localized Exercise on Blood Volume and Orthostatic Tolerance

2015 ◽  
Vol 47 ◽  
pp. 748
Author(s):  
Taylor L. Payne ◽  
Morgan Gibson ◽  
Cristyn Pawluk ◽  
John E. Davis
Keyword(s):  
Blood Volume ◽  
Orthostatic Tolerance

Blood-volume studies in cardiac-surgery patients

JAMA ◽  
1966 ◽  
Vol 195 (5) ◽  
pp. 356-361 ◽  
Author(s):  
J. B. McClenahan
Keyword(s):  
Cardiac Surgery ◽  
Blood Volume

Repeated Blood Volume Determinations in Bleeding Peptic Ulcer

1952 ◽  
Vol 21 (4) ◽  
pp. 516-524 ◽  
Author(s):  
Sam Kruger ◽  
Lester Baker ◽  
William D. Mosiman
Keyword(s):  
Peptic Ulcer ◽  
Blood Volume ◽  
Bleeding Peptic Ulcer

Letter: Whole blood volume determinations

1974 ◽  
Vol 134 (1) ◽  
pp. 181b-181
Author(s):  
R. E. Willard
Keyword(s):  
Blood Volume ◽  
Whole Blood
Sign in / Sign up

Export Citation Format

Share Document