scholarly journals Age-Related Changes in Vasomotor Reflex Control of Calf Venous Capacitance Response to Lower Body Negative Pressure in Humans.

2002 ◽  
Vol 52 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Qi Fu ◽  
Satoshi Iwase ◽  
Yuki Niimi ◽  
Astunori Kamiya ◽  
Daisaku Michikami ◽  
...  
Keyword(s):  
Negative Pressure ◽  
Lower Body Negative Pressure ◽  
Lower Body ◽  
Venous Capacitance ◽  
Age Related ◽  
Reflex Control ◽  
Vasomotor Reflex ◽  
Capacitance Response ◽  
Age Related Changes

Cardiovascular Responses to Maximal Graded and Acute Lower Body Negative Pressure

2010 ◽  
Vol 18 (1) ◽  
pp. 27-42 ◽  
Author(s):  
Juliane P. Hernandez ◽  
Kristin Roever ◽  
Tonya Seed
Keyword(s):  
Heart Rate ◽  
Negative Pressure ◽  
Orthostatic Intolerance ◽  
Lower Body Negative Pressure ◽  
Cardiovascular Responses ◽  
Tolerance Index ◽  
Lower Body ◽  
Age Related ◽  
Per Se ◽  
Blood Pressure Responses

This investigation attempted to determine whether heart-rate and blood pressure responses to maximal acute lower body negative pressure (LBNP) are exacerbated compared with maximal graded LBNP in active older (n= 9, 70 ± 7 yr) and endurance-trained younger (n= 10, 23 ± 3 yr) individuals. Heart rate increased earlier during graded LBNP in the younger group (−40 mm Hg vs. tolerance) and was significantly higher than that of the older adults at the point of tolerance. Mean arterial pressure (MAP) decreased more in the older than the younger individuals during graded LBNP. LBNP-tolerance index was significantly greater in the younger group (309 ± 52 vs. 255.6 ± 48 mm Hg/min). Acute doses of LBNP elicited slower heart-rate responses in the older group. Despite these age-related differences, MAP responses were not different between groups with acute LBNP, so age per se does not appear to predispose individuals to orthostatic intolerance.

Association of sex and age with responses to lower-body negative pressure

1988 ◽  
Vol 65 (4) ◽  
pp. 1752-1756 ◽  
Author(s):  
M. A. Frey ◽  
G. W. Hoffler
Keyword(s):  
Heart Rate ◽  
Negative Pressure ◽  
Lower Body Negative Pressure ◽  
Peripheral Resistance ◽  
Older Men ◽  
Lower Body ◽  
Fluid Shift ◽  
Arterial Blood ◽  
Age Related ◽  
Older Subjects

Responses of 21 women and 29 men (29-56 yr of age) to -50 Torr lower body negative pressure (LBNP) were examined for differences due to sex or age. Responses to LBNP were normal, including fluid shift from thorax to lower body, increased heart rate and peripheral resistance, and decreased stroke volume, cardiac output, and Heather index of ventricular function. Mean arterial blood pressure did not change. Comparison of responses of the women to responses of an age-matched subset of the men (n = 26) indicated the men had larger relative increases in calf circumference and greater increases in peripheral resistance during LBNP than the women, whereas the women experienced greater increases in thoracic impedance and heart rate. Analyses of responses of the 29 men for age-related differences indicated older subjects had greater increases in peripheral resistance and less heart rate elevation in response to LBNP (P less than 0.05 for all differences, except sex-related heart rate difference, where P less than 0.10). Based on these data and the data of other investigators, we hypothesize the age-related circulatory differences in response to LBNP are due to a reduction in vagal response and a switch to predominant sympathetic nervous system influence in older men. We cannot exclude the possibility that diminished responsiveness in the afferent arm of the baroreceptor reflex also plays a role in the attenuated heart rate response of older men to LBNP.

Reflex Responses of Venous Capacitance Vessels in Patients with Hypertrophic Cardiomyopathy

1998 ◽  
Vol 94 (4) ◽  
pp. 339-346 ◽  
Author(s):  
Helen L. Thomson ◽  
Jayne Morris-Thurgood ◽  
John Atherton ◽  
William J McKenna ◽  
Michael P. Frenneaux
Keyword(s):  
Hypertrophic Cardiomyopathy ◽  
Negative Pressure ◽  
Lower Body Negative Pressure ◽  
Percentage Reduction ◽  
Lower Body ◽  
Venous Capacitance ◽  
History Of ◽  
Venous Volume ◽  
Exercise Induced ◽  
Blood Pressure Responses

1. The aim of this study was to determine if there is impaired reflex venoconstriction in patients with hypertrophic cardiomyopathy and whether this is related to a history of syncope or exercise hypotension. 2. Thirty percent of patients with hypertrophic cardiomyopathy have exercise-induced hypotension associated with a failure of arteriolar constriction. Impaired venoconstriction could exacerbate this situation. 3. We evaluated 43 patients with hypertrophic cardiomyopathy and 24 controls. Nuclear venous plethysmography was used to measure forearm venous capacitance during lower body negative pressure, splenic venous volume changes during bicycle exercise and blood pressure responses to treadmill exercise. We assessed any association between abnormal reflex venous control and a history of syncope and exercise hypotension. 4. The percentage reduction in unstressed forearm venous volume during lower body negative pressure was similar in patients and controls (8.9 ± 7.1% versus 9.7 ± 5.9%, P not significant). Patients with a history of syncope demonstrated a less marked percentage reduction in volume than those without (−2.1 ± 6.9% versus −10.6 ± 6.0%, P = 0.001). In three patients with a history of syncope there was a paradoxical increase in forearm venous volume during lower body negative pressure. During exercise there was a substantially smaller decrease in splenic venous volume in patients compared with controls (−20.1 ± 14.0% and −42.6 ± 12.6% respectively, P = 0.0001). Furthermore, there was an association between attenuated splenic venoconstriction or venodilation and exercise hypotension in patients (P = 0.005). 5. Abnormal reflex control of venous capacitance beds in patients with hypertrophic cardiomyopathy was associated with both syncope and exercise hypotension.

Neurohormonal responses to oscillatory lower body negative pressure in healthy subjects

2021 ◽  
Author(s):  
Akanksha Singh ◽  
Shival Srivastav ◽  
Kavita Yadav ◽  
Dinu S. Chandran ◽  
Ashok Kumar Jaryal ◽  
...  
Keyword(s):  
Negative Pressure ◽  
Healthy Subjects ◽  
Lower Body Negative Pressure ◽  
Lower Body

Reduced venous compliance in lower limbs of aging humans and its importance for capacitance function

1998 ◽  
Vol 275 (3) ◽  
pp. H878-H886 ◽  
Author(s):  
Henrik Olsen ◽  
Toste Länne
Keyword(s):  
Muscle Tissue ◽  
Negative Pressure ◽  
Lower Body Negative Pressure ◽  
Subcutaneous Tissue ◽  
Lower Limbs ◽  
Venous Compliance ◽  
Reduced Pressure ◽  
Pressure Transmission ◽  
Circulatory Stress ◽  
Capacitance Response

Venous compliance in the calf of humans and its importance for capacitance function in relation to age were studied with the aid of 22, 44, and 59 mmHg lower body negative pressure (LBNP). Negative pressure transmission to the calf as well as changes in calf volume were studied, and venous compliance was calculated [change in volume with pressure change (dV/dP)]. The change in capacitance response of the calf with age (20–70 yr) was evaluated during LBNP 44 mmHg. Transmission of negative pressure to the subcutaneous tissue was almost full without any changes with age (92%). However, it was reduced to 80% in the underlying muscle tissue, irrespective of depth. Venous compliance in the young was 0.051 ml ⋅ 100 ml−1 ⋅ mmHg−1and was reduced by 45% to 0.029 ml ⋅ 100 ml−1 ⋅ mmHg−1in the old ( P < 0.05). Accordingly, the capacitance response was reduced by 0.015 ml ⋅ 100 ml−1 ⋅ yr−1( P < 0.005). Furthermore, the hemodynamic response to hypovolemic circulatory stress was attenuated with age. The reduced pressure transmission in muscle tissue is probably due to restriction of the muscle fascia envelope. The reduced venous compliance with age and the concomitant reduction in capacitance response during LBNP have implications for both the sympathetic reflex responses as well as the capacitance response during acute hypovolemic circulatory stress, which might be defected in aging humans.

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