scholarly journals Carotid baroreflex control of blood pressure to simulated hypotension in young and older women

2012 ◽  
Vol 26 (S1) ◽  
Author(s):  
Areum Kim ◽  
James P Fisher ◽  
Paul J Fadel
Keyword(s):  
Blood Pressure ◽  
Older Women ◽  
Baroreflex Control ◽  
Carotid Baroreflex

scholarly journals Cardiac and vasomotor components of the carotid baroreflex control of arterial blood pressure during isometric exercise in humans

2006 ◽  
Vol 572 (3) ◽  
pp. 869-880 ◽  
Author(s):  
James P. Fisher ◽  
Shigehiko Ogoh ◽  
Ellen A. Dawson ◽  
Paul J. Fadel ◽  
Niels H. Secher ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Isometric Exercise ◽  
Baroreflex Control ◽  
Arterial Blood ◽  
Carotid Baroreflex ◽  
Exercise In Humans

scholarly journals Carotid baroreflex control of arterial blood pressure at rest and during dynamic exercise in aging humans

2010 ◽  
Vol 299 (5) ◽  
pp. R1241-R1247 ◽  
Author(s):  
James P. Fisher ◽  
Areum Kim ◽  
Colin N. Young ◽  
Paul J. Fadel
Keyword(s):  
Blood Pressure ◽  
Response Curve ◽  
Dynamic Exercise ◽  
Baroreflex Control ◽  
Stimulus Response ◽  
Arterial Blood ◽  
Carotid Baroreflex ◽  
Older Subjects ◽  
Maximal Gain ◽  
Neck Pressure

The arterial baroreflex is fundamental for evoking and maintaining appropriate cardiovascular adjustments to exercise. We sought to investigate how aging influences carotid baroreflex regulation of blood pressure (BP) during dynamic exercise. BP and heart rate (HR) were continuously recorded at rest and during leg cycling performed at 50% HR reserve in 15 young (22 ± 1 yr) and 11 older (61 ± 2 yr) healthy subjects. Five-second pulses of neck pressure and neck suction from +40 to −80 Torr were applied to determine the full carotid baroreflex stimulus response curve and examine baroreflex resetting during exercise. Although the maximal gain of the modeled stimulus response curve was similar in both groups at rest and during exercise, in older subjects the operating point (OP) was located further away from the centering point (CP) and toward the reflex threshold, both at rest (OP minus CP; −10 ± 3 older vs. 0 ± 2 young mmHg, P < 0.05) and during exercise (OP minus CP; −10 ± 2 older vs. 1 ± 3 young mmHg, P < 0.05). In agreement, older subjects demonstrated a reduced BP response to neck pressure (simulated carotid hypotension) and a greater BP response to neck suction (simulated carotid hypertension). In addition, the magnitude of the upward and rightward resetting of the carotid baroreflex-BP stimulus response curve with exercise was ∼40% greater in older individuals. These data indicate that despite a maintained maximal gain, the ability of the carotid baroreflex to defend against a hypotensive challenge is reduced, whereas responses to hypertensive stimuli are greater with advanced age, both at rest and during exercise.

Progressive attenuation of the carotid baroreflex control of blood pressure and heart rate during exercise

1987 ◽  
Vol 114 (4) ◽  
pp. 765-772 ◽  
Author(s):  
Jan Staessen ◽  
Roberto Fiocchi ◽  
Robert Fagard ◽  
Peter Hespel ◽  
Antoon Amery
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Baroreflex Control ◽  
Carotid Baroreflex

Exercise intensity influences cardiac baroreflex function at the onset of isometric exercise in humans

2007 ◽  
Vol 103 (3) ◽  
pp. 941-947 ◽  
Author(s):  
James P. Fisher ◽  
Shigehiko Ogoh ◽  
Colin N. Young ◽  
David M. Keller ◽  
Paul J. Fadel
Keyword(s):  
Blood Pressure ◽  
Exercise Intensity ◽  
Isometric Exercise ◽  
Voluntary Contraction ◽  
Isometric Handgrip ◽  
Baroreflex Control ◽  
Cardiac Responses ◽  
Carotid Baroreflex ◽  
Exercise Onset ◽  
Exercise In Humans

We sought to examine the influence of exercise intensity on carotid baroreflex (CBR) control of heart rate (HR) and mean arterial pressure (MAP) at the onset of exercise in humans. To accomplish this, eight subjects performed multiple 1-min bouts of isometric handgrip (HG) exercise at 15, 30, 45 and 60% maximal voluntary contraction (MVC), while breathing to a metronome set at eupneic frequency. Neck suction (NS) of −60 Torr was applied for 5 s at end expiration to stimulate the CBR at rest, at the onset of HG (<1 s), and after ∼40 s of HG. Beat-to-beat measurements of HR and MAP were recorded throughout. Cardiac responses to NS at onset of 15% (−12 ± 2 beats/min) and 30% (−10 ± 2 beats/min) MVC HG were similar to rest (−10 ± 1 beats/min). However, HR responses to NS were reduced at the onset of 45% and 60% MVC HG (−6 ± 2 and −4 ± 1 beats/min, respectively; P < 0.001). In contrast to HR, MAP responses to NS were not different from rest at exercise onset. Furthermore, both HR and MAP responses to NS applied at ∼40s of HG were similar to rest. In summary, CBR control of HR was transiently blunted at the immediate onset of high-intensity HG, whereas MAP responses were preserved demonstrating differential baroreflex control of HR and blood pressure at exercise onset. Collectively, these results suggest that carotid-cardiac baroreflex control is dynamically modulated throughout isometric exercise in humans, whereas carotid baroreflex regulation of blood pressure is well-maintained.

scholarly journals Cardiac and vasomotor components of the carotid baroreflex control of arterial blood pressure during isometric exercise in humans

2006 ◽  
Vol 20 (4) ◽  
Author(s):  
James P Fisher ◽  
Shigehiko Ogoh ◽  
Ellen A Dawson ◽  
Paul J Fadel ◽  
Niels H Secher ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Isometric Exercise ◽  
Baroreflex Control ◽  
Arterial Blood ◽  
Carotid Baroreflex ◽  
Exercise In Humans

scholarly journals Effect of aging on carotid baroreflex control of blood pressure and leg vascular conductance in women

2014 ◽  
Vol 306 (10) ◽  
pp. H1417-H1425 ◽  
Author(s):  
Daniel P. Credeur ◽  
Seth W. Holwerda ◽  
Leryn J. Boyle ◽  
Lauro C. Vianna ◽  
Areum K. Jensen ◽  
...  
Keyword(s):  
Older Women ◽  
Young Women ◽  
Vascular Changes ◽  
Vascular Conductance ◽  
Response Latencies ◽  
Baroreflex Control ◽  
Age Related ◽  
Carotid Baroreflex ◽  
Duplex Doppler ◽  
Neck Pressure

Recent work suggests that β-adrenergic vasodilation offsets α-adrenergic vasoconstriction in young women, but this effect is lost after menopause. Given these age-related vascular changes, we tested the hypothesis that older women would exhibit a greater change in vascular conductance following baroreflex perturbation compared with young women. In 10 young (21 ± 1 yr) and 10 older (62 ± 2 yr) women, mean arterial pressure (MAP; Finometer), heart rate (HR), cardiac output (CO; Modelflow), total vascular conductance (TVC), and leg vascular conductance (LVC, duplex-Doppler ultrasound) were continuously measured in response to 5-s pulses of neck suction (NS; −60 Torr) and neck pressure (NP; +40 Torr) to simulate carotid hypertension and hypotension, respectively. Following NS, decreases in MAP were similar between groups; however, MAP peak response latency was slower in older women ( P < 0.05). Moreover, at the time of peak MAP, increases in LVC (young, −11.5 ± 3.9%LVC vs. older, +19.1 ± 7.0%LVC; P < 0.05) and TVC were greater in older women, whereas young women exhibited larger decreases in HR and CO (young, −10 ± 3% CO vs. older, +0.8 ± 2% CO; P < 0.05). Following NP, increases in MAP were blunted (young, +14 ± 1 mmHg vs. older, +8 ± 1 mmHg; P < 0.05) in older women, whereas MAP response latencies were similar. Interestingly, decreases in LVC and TVC were similar between groups, but HR and CO (young, +7.0 ± 2% CO vs. older, −4.0 ± 2% CO; P < 0.05) responses were attenuated in older women. These findings suggest that older women have greater reliance on vascular conductance to modulate MAP via carotid baroreflex, whereas young women rely more on cardiac responsiveness. Furthermore, older women demonstrate a blunted ability to increase MAP to hypotensive stimuli.

Carotid baroreflex control of leg vascular conductance at rest and during exercise

2003 ◽  
Vol 94 (2) ◽  
pp. 542-548 ◽  
Author(s):  
David M. Keller ◽  
Wendy L. Wasmund ◽  
D. Walter Wray ◽  
Shigehiko Ogoh ◽  
Paul J. Fadel ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Vascular Tone ◽  
Knee Extension ◽  
Vascular Conductance ◽  
Baroreflex Control ◽  
Carotid Baroreflex ◽  
Neck Pressure ◽  
Induced Changes ◽  
Knee Extension Exercise ◽  
Rest And Exercise

We sought to test the hypothesis that the carotid baroreflex (CBR) alters mean leg blood flow (LBF) and leg vascular conductance (LVC) at rest and during exercise. In seven men and one woman, 25 ± 2 (SE) yr of age, CBR control of LBF and LVC was determined at rest and during steady-state one-legged knee extension exercise at ∼65% peak O2 uptake. The application of 5-s pulses of +40 Torr neck pressure and −60 Torr neck suction significantly altered mean arterial pressure (MAP) and LVC both at rest and during exercise. CBR-mediated changes in MAP were similar between rest and exercise ( P > 0.05). However, CBR-mediated decreases in LVC (%change) to neck pressure were attenuated in the exercising leg (16.4 ± 1.6%) compared with rest (33 ± 2.1%) and the nonexercising leg (23.7 ± 1.9%) ( P < 0.01). These data suggest CBR control of blood pressure is partially mediated by changes in leg vascular tone both at rest and during exercise. Furthermore, despite alterations in CBR-induced changes in LVC during exercise, CBR control of blood pressure was well maintained.

scholarly journals Impaired carotid baroreflex control of arterial blood pressure in multiple sclerosis

2016 ◽  
Vol 116 (1) ◽  
pp. 81-87 ◽  
Author(s):  
Mu Huang ◽  
Dustin R. Allen ◽  
David M. Keller ◽  
Paul J. Fadel ◽  
Elliot M. Frohman ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Blood Pressure ◽  
Heart Rate ◽  
Cardiovascular Responses ◽  
Vascular Conductance ◽  
Baroreflex Control ◽  
Arterial Blood ◽  
Carotid Baroreflex ◽  
Relapsing Remitting ◽  
Neck Pressure

Multiple sclerosis (MS), a progressive neurological disease, can lead to impairments in the autonomic control of cardiovascular function. We tested the hypothesis that individuals with relapsing-remitting MS ( n = 10; 7 females, 3 males; 13 ± 4 yr from diagnosis) exhibit impaired carotid baroreflex control of blood pressure and heart rate compared with sex, age, and body weight-matched healthy individuals (CON: n = 10; 7 females, 3 males). At rest, 5-s trials of neck pressure (NP; +40 Torr) and neck suction (NS; −60 Torr) were applied to simulate carotid hypotension and hypertension, respectively, while mean arterial pressure (MAP; finger photoplethysmography), heart rate (HR), cardiac output (CO; Modelflow), and total vascular conductance (TVC) were continuously measured. In response to NP, there was a blunted increase in peak MAP responses (MS: 5 ± 2 mmHg) in individuals with MS compared with healthy controls (CON: 9 ± 3 mmHg; P = 0.005), whereas peak HR responses were not different between groups. At the peak MAP response to NP, individuals with MS demonstrated an attenuated decrease in TVC (MS, −10 ± 4% baseline vs. CON, −15 ± 4% baseline, P = 0.012), whereas changes in CO were similar between groups. Following NS, all cardiovascular responses (i.e., nadir MAP and HR and percent changes in CO and TVC) were not different between MS and CON groups. These data suggest that individuals with MS have impaired carotid baroreflex control of blood pressure via a blunted vascular conductance response resulting in a diminished ability to increase MAP in response to a hypotensive challenge.

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