Effects of Dietary Sodium Supplement on Blood Volume, Orthostatic Tolerance and Baroreceptor Sensitivity

1995 ◽  
Vol 88 (s32) ◽  
pp. 19P-19P
Author(s):  
H. El-Sayed ◽  
R. Hainsworth
Keyword(s):  
Blood Volume ◽  
Dietary Sodium ◽  
Orthostatic Tolerance ◽  
Baroreceptor Sensitivity

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

Alterations in Cardiac Function and Cardiopulmonary Blood Volume in Chronic Sodium Depletion in Dogs

1980 ◽  
Vol 59 (s6) ◽  
pp. 393s-395s ◽  
Author(s):  
M. P. Lynn ◽  
F. Fouad ◽  
S. A. Cook ◽  
Carmen A. Napoli ◽  
C. M. Ferrario
Keyword(s):  
Cardiac Output ◽  
Blood Volume ◽  
Pressor Response ◽  
Vagal Afferents ◽  
Dietary Sodium ◽  
Total Blood Volume ◽  
Sodium Depletion ◽  
Vagus Nerves ◽  
Total Blood ◽  
Ventricular Performance

1. Chronic sodium depletion in dogs is associated with a blunting of the pressor response to carotid occlusion. After section of the vagus nerves this pressor response reverts to normal although atropine is without effect, suggesting a possible role for increased activity of cardiopulmonary vagal afferents in suppressing sympathetic outflow. Since increases in central blood volume stimulate vagal afferents, cardiopulmonary haemodynamics were studied by radioisotope dilution before and after 3 and 4 weeks of dietary sodium restriction together with frusemide. 2. Sodium depletion was associated with significant decreases in cardiac output, ejection fraction and total blood volume; the cardiopulmonary blood volume increased but the change was not statistically significant (P<0.2). These changes were accompanied by a significant increase in the ratio cardiopulmonary blood volume/total blood volume and a decrease in the ratio cardiac output/cardiopulmonary blood volume. 3. Results indicate that sodium depletion may be accompanied by a paradoxical translocation of blood to the cardiopulmonary region in part due to depressed ventricular performance.

Renin, Blood Volume and Response to Saralasin in Patients on Chronic Haemodialysis: Evidence against Volume- and Renin-‘Dependent’ Hypertension

1978 ◽  
Vol 54 (3) ◽  
pp. 305-312
Author(s):  
B. P. McGrath ◽  
J. G. G. Ledingham
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Plasma Renin Activity ◽  
Blood Volume ◽  
Plasma Renin ◽  
Renin Activity ◽  
Mean Blood Pressure ◽  
Dietary Sodium ◽  
Chronic Haemodialysis ◽  
Plasma Angiotensin

1. No significant relationship was found between blood pressure and blood volume, sulphate space or plasma angiotensin II concentration in 59 non-nephrectomized haemodialysis patients, of whom 42 were hypertensive. Supine mean blood pressure was only weakly correlated with plasma renin activity and the correlation was not improved when blood pressure was related to expressions combining renin and volume. 2. Changes in supine mean blood pressure during saralasin infusion were related to pre-infusion plasma renin activity (P < 0·001) or plasma angiotensin II (P < 0·02) but also to blood volume (P < 0·001) or sulphate space (P < 0·001). A fall of more than 10% in mean blood pressure during saralasin infusion was observed in only 12 patients (one normotensive), in five of whom there was evidence of volume depletion. 3. Thirteen patients (nine hypertensive) were studied at two levels of dietary sodium: 100 mmol/day and < 20 mmol/day. Supine mean blood pressure in hypertensive patients was lower during the period of higher salt intake despite increased volumes. 4. Hypertension in haemodialysis patients cannot be adequately explained by abnormalities either in volume homeostasis and/or in the renin—angiotensin system.

Sign in / Sign up

Export Citation Format

Share Document