Blood pressure regulation XI: overview and future research directions

Raven, Peter B.; Chapleau, Mark W.

doi:10.1007/s00421-014-2823-z

Cited by 36 publications

(36 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…). The mechanism for this observation is the dynamic leg exercise‐induced muscle pump, which is accompanied by an increase in central blood volume and loading of cardiopulmonary baroreceptors (Ray & Saito, ; Fadel & Raven, ; Raven & Chapleau, ; Fisher et al . ).…”

Section: Discussionmentioning

confidence: 99%

“…An appropriate increase in arterial blood pressure (BP) via sympathetic vasomotor outflow is necessary during dynamic exercise to maintain the required blood flow to active muscles. It is well established that central command and the exercise pressor reflex (mechanoreflex and metaboreflex within skeletal muscle) play major roles during the exercise‐induced increase in arterial BP via sympathetic vasomotor outflow (Fadel & Raven, ; Raven & Chapleau, ; Fisher et al . ).…”

Section: Introductionmentioning

confidence: 99%

“…). Indeed, the exercise‐induced increase in muscle sympathetic nerve activity (MSNA) as an index of sympathetic vasomotor outflow is caused by activation of both central command and the exercise pressor reflex (Fadel & Raven, ; Raven & Chapleau, ; Fisher et al . ).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Hypoxia attenuates cardiopulmonary reflex control of sympathetic nerve activity during mild dynamic leg exercise

Katayama

Ishida

Saito

et al. 2016

Experimental Physiology

View full text Add to dashboard Cite

New Findings r What is the central question of this study?The cardiopulmonary baroreflex inhibits adjustment of sympathetic vasomotor outflow during mild-intensity dynamic exercise. However, it is unclear how suppression of sympathetic vasomotor outflow by the cardiopulmonary baroreflex is modulated by a powerful sympatho-excitatory drive from the exercise pressor reflex, central command and/or the arterial chemoreflex. r What is the main finding and its importance?Hypoxia-induced heightened sympathetic nerve activity during dynamic exercise attenuated cardiopulmonary baroreflex control of sympathetic vasomotor outflow. This could facilitate the redistribution of blood flow to the active muscles by sympathetically mediated vasoconstriction of inactive muscles.Muscle sympathetic nerve activity (MSNA) does not increase during mild-intensity dynamic leg exercise in normoxic conditions, despite activation of central command and the exercise pressor reflex. Suppression of MSNA could be caused by muscle pump-induced loading of cardiopulmonary baroreceptors. In contrast, MSNA increases during mild dynamic leg exercise in hypoxic conditions. We hypothesized that hypoxic exercise, which induces a powerful sympatho-excitatory drive from the exercise pressor reflex, central command and/or arterial chemoreflex, attenuates cardiopulmonary reflex control of sympathetic vasomotor outflow. To test this hypothesis, MSNA was recorded during leg cycling in hypoxic conditions and with increased central blood volume by increasing the pedalling frequency to change the cardiopulmonary baroreflex. Subjects performed two leg cycle exercises at different pedal cadences of 60 and 80 r.p.m. (60EX and 80EX trials, respectively) in two (haemodynamic and MSNA) measurement conditions while breathing a hypoxic gas mixture (inspired oxygen fraction = 0.12). Thoracic impedance, stroke volume and cardiac output were measured non-invasively using impedance cardiography. During the MSNA test, MSNA was recorded via microneurography at the right median nerve at the elbow. Changes in thoracic impedance, stroke volume and cardiac output during the 80EX trial were greater than those during the 60EX trial. The MSNA burst frequency during hypoxic exercise in the 80EX trial (39 ± 4 bursts min −1 ) did not differ from that during the 60EX trial (39 ± 3 bursts min −1 ). These results suggest that the cardiopulmonary baroreflex of sympathetic vasomotor outflow during dynamic exercise is modulated by heightened hypoxia-induced sympathetic nerve activity.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Hypoxia attenuates cardiopulmonary reflex control of sympathetic nerve activity during mild dynamic leg exercise

Katayama

Ishida

Saito

et al. 2016

Experimental Physiology

View full text Add to dashboard Cite

show abstract

“…From these findings, it would be expected that loading of cardiopulmonary baroreceptors by a muscle pump‐induced increase in central blood volume would suppress sympathetic vasomotor activity during dynamic leg exercise (Ray et al. ; Ray and Saito ; Fadel and Raven ; Raven and Chapleau ).…”

Section: Discussionmentioning

confidence: 99%

“…; Ray et al. ; Ray and Saito ; Fadel and Raven ; Raven and Chapleau ). The cardiopulmonary baroreflex during dynamic exercise has been but seldom studied, and most representative work is performed by Ray et al.…”

Section: Introductionmentioning

confidence: 99%

Enhanced muscle pump during mild dynamic leg exercise inhibits sympathetic vasomotor outflow

et al. 2014

View full text Add to dashboard Cite

Muscle sympathetic nerve activity (MSNA) is not increased during leg cycling at light and mild intensities, despite activation of central command and the exercise pressor reflex. We determined whether increasing central blood volume and loading the cardiopulmonary baroreceptors modulate sympathetic vasomotor outflow during leg cycling. To this end, we changed the pedaling frequency to enhance skeletal muscle pump. Subjects performed two leg cycle exercises at differential pedal rates of 60 and 80 rpm (60EX and 80EX trials) for two conditions (with and without MSNA measurement). In each trial, subjects completed leg cycling with a differential workload to maintain constant oxygen consumption (VO2). MSNA was recorded via microneurography at the right median nerve of the elbow. Without MSNA measurement, thoracic impedance, stroke volume (SV), and cardiac output (CO) were measured non‐invasively using impedance cardiography. Heart rate and VO2 during exercise did not differ between the 60EX and 80EX trials. Changes in thoracic impedance, SV, and CO during the 80EX trial were greater than during the 60EX trial. MSNA during the 60EX trial was unchanged compared with that at rest (25.8 ± 3.1 [rest] to 28.3 ± 3.4 [exercise] bursts/min), whereas a significant decrease in MSNA was observed during the 80EX trial (25.8 ± 2.8 [rest] to 19.7 ± 2.0 [exercise] bursts/min). These results suggest that a muscle pump‐induced increase in central blood volume, and thereby loading of cardiopulmonary baroreceptors, could inhibit sympathetic vasomotor outflow during mild dynamic leg exercise, despite activation of central command and the exercise pressor reflex.

show abstract