Age- and fitness-related differences in limb venous compliance do not affect tolerance to maximal lower body negative pressure in men and women

2004 ◽  
Vol 97 (3) ◽  
pp. 925-929 ◽  
Author(s):  
J. P. Hernandez ◽  
W. D. Franke
Keyword(s):  
Exercise Training ◽  
Negative Pressure ◽  
Lower Body Negative Pressure ◽  
Cuff Pressure ◽  
The Elderly ◽  
Venous Occlusion ◽  
Lower Body ◽  
Chronic Exercise ◽  
Venous Compliance ◽  
Men And Women

Aging and chronic exercise training influence leg venous compliance. Venous compliance affects responses to an orthostatic stress; its effect on tolerance to maximal lower body negative pressure (LBNP) in the elderly is unknown. The purpose of this study was to determine the influence of age and fitness, a surrogate measure of exercise training, on calf venous compliance and tolerance to maximal LBNP in men and women. Forty participants, 10 young fit (YF; age = 22.6 ± 0.5 yr, peak oxygen uptake = 57.1 ± 2.0 ml·kg−1·min−1), 10 young unfit (YU; 23.1 ± 1.0 yr, 41.1 ± 2.0 ml·kg−1·min−1), 10 older fit (OF; 73.9 ± 2.0 yr, 39.0 ± 2.0 ml·kg−1·min−1), and 10 older unfit (OU; 70.9 ± 1.6 yr, 27.1 ± 2.0 ml·kg−1·min−1), underwent graded LBNP to presyncope or 4 min at −100 mmHg. By utilizing venous occlusion plethysmography, calf venous compliance was determined by using the first derivative of the pressure-volume relation during cuff pressure reduction. We found that the more fit groups had greater venous compliance than their unfit peers ( P < 0.05) as did the young groups compared with their older peers ( P < 0.05) such that OU < YU = OF < YF. LBNP tolerance did not differ between groups. In conclusion, these data suggest that aging reduces, and chronic exercise increases, venous compliance. However, these data do not support a significant influence of venous compliance on LBNP tolerance.

The impact of menopausal status on cardiac responses to exercise training and lower body negative pressure

Maturitas ◽  
2017 ◽  
Vol 103 ◽  
pp. 91
Author(s):  
Amanda Q.X. Nio ◽  
Eric J. Stöhr ◽  
Samantha Rogers ◽  
Rachel Mynors-Wallis ◽  
Jane M. Black ◽  
...  
Keyword(s):  
Exercise Training ◽  
Negative Pressure ◽  
Lower Body Negative Pressure ◽  
Menopausal Status ◽  
Lower Body ◽  
Cardiac Responses ◽  
The Impact

Gender affects calf venous compliance at rest and during baroreceptor unloading in humans

2004 ◽  
Vol 286 (3) ◽  
pp. H895-H901 ◽  
Author(s):  
Kevin D. Monahan ◽  
Chester A. Ray
Keyword(s):  
Lower Body Negative Pressure ◽  
Cuff Pressure ◽  
Cold Pressor ◽  
Orthostatic Tolerance ◽  
Sympathetic Outflow ◽  
Lower Body ◽  
Venous Compliance ◽  
Supine Posture ◽  
Volume Relation ◽  
Cold Pressor Testing

Leg venous compliance is a determinant of peripheral venous pooling during orthostatic stress such that high venous compliance could contribute to reduced orthostatic tolerance. We tested the hypotheses that 1) calf venous compliance is reduced during baroreceptor unloading, and 2) calf venous compliance is greater in women than men. Twelve men (27 ± 2 yr) and 12 women (25 ± 2 yr) were studied in the supine posture. Calf venous compliance was determined by inflating a thigh venous collecting cuff to 60 mmHg for 8 min and then decreasing cuff pressure at a rate of 1 mmHg/s to 0 mmHg. The slope of the pressure-compliance relation (compliance = β1 + 2·β2·cuff pressure), which is the first derivative of the quadratic pressure-volume relation [(Δlimb volume) = β0 + β1·(cuff pressure) + β2·(cuff pressure)2] during the reduction in collecting cuff pressure, was used to assess venous compliance at baseline and during one-legged lower body negative pressure (LBNP; —50 mmHg). At baseline, calf venous compliance was 48% lower ( P < 0.001) in women than men and decreased in men (Δ—25 ± 8%; P < 0.05) but not women (Δ1 ± 11%) during LBNP. Rhythmic ischemic handgrip (Δ6 ± 9%) and cold pressor testing (Δ—9 ± 7%) did not alter calf venous compliance in a subgroup of men ( n = 6). These data indicate gender-dependent effects on calf venous compliance under conditions associated with low sympathetic outflow (i.e., rest) and high sympathetic outflow (i.e., LBNP). However, they cannot explain gender-associated differences in orthostatic tolerance.

scholarly journals Differentiating compensatory mechanisms associated with low tolerance to central hypovolemia in women

2019 ◽  
Vol 316 (3) ◽  
pp. H609-H616 ◽  
Author(s):  
Taylor Elyse Schlotman ◽  
Kevin S. Akers ◽  
Shawn C. Nessen ◽  
Victor A. Convertino
Keyword(s):  
Blood Volume ◽  
Negative Pressure ◽  
Lower Body Negative Pressure ◽  
Reduction Rate ◽  
Lower Body ◽  
Men And Women ◽  
Compensatory Responses ◽  
Arterial Blood ◽  
Compensatory Reserve ◽  
Lower Tolerance

Women generally display lower tolerance to acute central hypovolemia than men. The measurement of compensatory reserve (CRM) is a novel metric that provides information about the sum total of all mechanisms that together work to compensate for the relative blood volume deficit. Hemodynamic decompensation occurs with depletion of the CRM (i.e., 0% CRM). In the present study, we hypothesized that the lower tolerance to progressive central hypovolemia reported in women can be explained by a faster reduction rate in CRM compared with men rather than sex differences in absolute integrated compensatory responses. Continuous, noninvasive measures of CRM were collected from 208 healthy volunteers (107 men and 85 women) who underwent progressive stepwise central hypovolemia induced by lower body negative pressure to the point of presyncope. Comparisons revealed shorter ( P < 0.01) times in female participants compared with male participants to reach 30% and 0% CRM. Similarly, the lower body negative pressure level, represented by the cumulative stress index, was less at 30% and 0% CRM in women compared with men ( P < 0.01). Changes in hemodynamic responses and frequency-domain data (oscillations in cerebral blood flow velocity and mean arterial blood pressure) were similar between men and women at 0% CRM ( P > 0.05). We conclude that compensatory responses to central hypovolemia in women were similar to men but were depleted at a faster rate compared with men. The earlier depletion of the compensatory reserve in women appears to be influenced by failure to maintain adequate cerebral oxygen delivery. NEW & NOTEWORTHY We compared hemodynamic and metabolic responses in men and women to experimentally controlled reductions in central blood volume at physiologically equivalent levels of compensatory reserve. We corroborated previous findings that females have lower tolerance to central hypovolemia than males but demonstrated for the first time that compensatory responses are similar. Our findings suggest lower tolerance to central hypovolemia in women results from reaching critical cerebral delivery of oxygen faster than men.

scholarly journals The influence of combined lower body negative pressure and mental stress on cerebral blood flow in men and women

2013 ◽  
Vol 27 (S1) ◽  
Author(s):  
Angelea H. Young ◽  
Chelsea R. Strong ◽  
William H. Cooke ◽  
Jason R. Carter ◽  
John J. Durocher
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Negative Pressure ◽  
Mental Stress ◽  
Lower Body Negative Pressure ◽  
Lower Body ◽  
Men And Women

Effects of a 6-mo endurance-training program on venous compliance and maximal lower body negative pressure in older men and women

2005 ◽  
Vol 99 (3) ◽  
pp. 1070-1077 ◽  
Author(s):  
Juliane P. Hernandez ◽  
Warren D. Franke
Keyword(s):  
Training Program ◽  
Endurance Training ◽  
Lower Body Negative Pressure ◽  
Older Men ◽  
Exercise Group ◽  
Control Group ◽  
Lower Body ◽  
Venous Compliance ◽  
Men And Women ◽  
Older Men And Women

Aging and chronic exercise training influence leg venous compliance. Venous compliance affects responses to an orthostatic stress. The extent to which exercise training in a previously sedentary older population will affect venous compliance and tolerance to the simulated orthostatic stress of maximal lower body negative pressure (LBNP) is unknown. The purpose of this investigation is to determine the influence of a 6-mo endurance-training program on calf venous compliance and responses and tolerance to maximal LBNP in older men and women. Twenty participants (exercise group: n = 10, 5 men, 5 women; control group: n = 10, 6 men, 4 women; all >60 yr) underwent graded LBNP to presyncope or 4 min at −100 mmHg before and after a 6-mo endurance-training program. Utilizing venous occlusion plethysmography, calf venous compliance was determined in both groups using the first derivative of the pressure-volume relation during cuff pressure reduction before training, at 3 mo, and at the end of the training program. The exercise group improved their fitness with the 6-mo endurance-training program, whereas the control group did not change (14 ± 3 vs. <1 ± 2%; P < 0.05). LBNP tolerance did not differ between groups or across trials ( P = 0.47). Venous compliance was not different between groups or trials, either initially or after 3 mo of endurance training, but tended to be greater in the exercise group after 6 mo of training ( P = 0.08). These data suggest that a 6-mo endurance-training program may improve venous compliance without affecting tolerance to maximal LBNP in older participants.

Effects of chronic sympathectomy on vascular function in the human forearm

2002 ◽  
Vol 92 (5) ◽  
pp. 2019-2025 ◽  
Author(s):  
John H. Eisenach ◽  
Erin S. Clark ◽  
Nisha Charkoudian ◽  
Frank A. Dinenno ◽  
John L. D. Atkinson ◽  
...  
Keyword(s):  
Negative Pressure ◽  
Vascular Function ◽  
Lower Body Negative Pressure ◽  
Sympathetic Nerves ◽  
Venous Occlusion ◽  
Lower Body ◽  
Response Curves ◽  
Nitric Oxide Synthase Inhibitor ◽  
Thoracic Sympathectomy ◽  
Synthase Inhibitor

To determine whether endothelial function is altered by chronic surgical sympathectomy, we infused ACh, isoproterenol, nitroprusside (NTP), and the nitric oxide synthase inhibitor N G-mono-methyl-l-arginine (l-NMMA) into the brachial arteries of nine patients 5–64 mo after thoracic sympathectomy for hyperhidrosis. Age- and gender-matched controls were also studied. Forearm blood flow (FBF) was measured by venous occlusion plethysmography. Lower body negative pressure was used to assess reflex vasoconstrictor responses. Tyramine, which acts locally and causes norepinephrine release from sympathetic nerves, was also administered via the brachial artery. FBF at rest was 2.5 ± 0.4 ml · dl−1 · min−1 in the patients and 2.5 ± 0.3 ml · dl−1 · min−1 in the controls ( P = 0.95). The normal vasoconstrictor responses to lower body negative pressure were abolished in the patients. By contrast, tyramine produced dose-dependent vasoconstriction in the patients that was identical to that of controls. The dose-response curves to ACh were similar in patients and controls, with maximum values of 19.3 ± 4.4 vs. 25.5 ± 2.8 ml · dl−1 · min−1, respectively. l-NMMA reduced baseline FBF similarly and reduced the maximal FBF response to ACh in both groups (patients 8.9 ± 3.5 vs. controls 9.7 ± 2.5 ml · dl−1 · min−1). The vasodilation to isoproterenol was similar and blunted to the same extent in both groups by l-NMMA. The responses to NTP in patients and controls were similar and not affected byl-NMMA. We conclude that, in humans, chronic surgical sympathectomy does not cause major disruptions in vascular function in the forearm. The normal vasoconstrictor responses to tyramine indicate that there were viable sympathetic nerves in the forearm that were not engaged by LBNP.

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