Physical fitness and cardiovascular response to lower body negative pressure

Raven, Peter B.; Rohm-Young, Debbie; Blomqvist, C. Gunnar

doi:10.1152/jappl.1984.56.1.138

Cited by 58 publications

(31 citation statements)

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“…Moreover, it should be noted that the leg O&S induced ϳ0.9% increase in circumference at the mid-calf and an estimated increase in volume of ϳ1.8%. This increase in leg volume was similar with the volume change seen previously with Ϫ32 to Ϫ40 mmHg of LBNP (22). Thus, calf vascular distension seen with leg O&S in the present study is comparable to those seen with orthostatic stress.…”

Section: Perspectives and Significancesupporting

confidence: 92%

Limb suction evoked during arterial occlusion causes systemic sympathetic activity in humans

Cui

Blaha

Herr

et al. 2015

American Journal of Physiology-Regulatory, Integrative and Comp

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-Venous saline infusions in an arterially occluded forearm evokes reflex increases in muscle sympathetic nerve activity (MSNA) and blood pressure (BP). We hypothesized that the application of suction to the human limbs would activate this venous distension reflex and raise sympathetic outflow. We placed airtight pressure tanks and applied 100 mmHg negative pressure to an arterially occluded limb (occlusion and suction, O&S) to induce tissue deformation without fluid translocation. BP, heart rate (HR), and MSNA were assessed in 19 healthy subjects during 2 min of arm or leg O&S. Occlusion without suction served as a control. During a separate visit, saline (5% forearm volume) was infused into veins of the arterially occluded arm (n ϭ 13). The O&S increased limb circumference, MSNA burst rate (arm: ⌬6.7 Ϯ 0.7; leg: ⌬6.8 Ϯ 0.7 bursts/min), and total activity (arm: ⌬199 Ϯ 14; leg: ⌬172 Ϯ 22 units/min) and BP (arm: ⌬4.3 Ϯ 0.3; leg: ⌬9.4 Ϯ 1.4 mmHg) from the baseline. The MSNA and BP responses during arm O&S correlated with those during leg O&S. Occlusion alone had no effect on MSNA and BP. MSNA (r ϭ 0.607) responses during arm O&S correlated with those evoked by the saline infusion into the arm. These correlations suggest that sympathetic activation during limb O&S is likely, at least partially, to be evoked via the venous distension reflex. These data suggest that suction of an occluded limb evokes sympathetic activation and that the limb venous distension reflex exists in arms and legs of normal humans.autonomic; blood pressure regulation; vessel PRIOR STUDIES HAVE SHOWN THAT the distension of abdominal veins increases sympathetic efferent activity in rabbits (2) and dogs (12). Limb venous ligation evokes vasoconstriction in both the occluded and contralateral extremities in dogs (5). Evidence in animals suggests that afferent nerve endings in peripheral veins may sense regional blood volume changes and, in turn, contribute to the blood pressure (BP) regulation via a reflex response in cats (11, 21), rabbits (2), and dogs (12). Venous distension increases the discharge of group III and IV afferent nerves in cat hindlimbs (18).Our recent reports (7-10) have shown that volume infusion (saline or albumin solution, 5% forearm volume, ϳ50 ml) into the veins of an occluded forearm evokes reflex increases in muscle sympathetic nerve activity (MSNA) and BP in human subjects. The magnitude of the MSNA and BP responses depends on the volume and the rate of the infusate during arm vein distension (8). When lidocaine is added to the forearm infusate, the MSNA and BP responses to venous distension are abolished (9). These observations clearly suggest that limb venous distension evokes a sympathoexcitatory reflex (termed venous distension reflex) and, thus, increases BP in humans. Of note, a recent report by Yamauchi et al. (33) has shown this reflex is also present in rats. Additionally, we have shown that venous infusion of albumin evokes a larger and more sustained increase in MSNA and BP than those with infusion of equal vo...

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Section: Perspectives and Significancesupporting

confidence: 92%

Limb suction evoked during arterial occlusion causes systemic sympathetic activity in humans

Cui

Blaha

Herr

et al. 2015

American Journal of Physiology-Regulatory, Integrative and Comp

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“…Regarding this finding, Levine and colleagues (Levine et al 1991;Levine, 1993) suggested that endurance training induced cardiac remodelling; greater ventricular diastolic chamber compliance and distensibility on the steeper part of the Frank-Starling cardiac function curve may be a mechanical, non-autonomic cause of orthostatic intolerance. In addition, an attenuation of arterial baroreflex function is a contributory factor for the increased predisposition to orthostatic hypotension in endurance-trained individuals (Raven et al 1984;Smith et al 1988;Stevens et al 1992;Ogoh et al 2003). Likewise, Cooper & Hainsworth (2002) demonstrated that patients with posturally related syncope fail to enhance carotid baroreflex sensitivity during orthostatic stress.…”

Section: Discussionmentioning

confidence: 99%

“…The systemic cardiovascular regulatory system is exquisitely adapted for maintaining an adequate cerebral circulation to prevent syncope (Raven et al 1984;Smith et al 1988;Stevens et al 1992;Cooper & Hainsworth, 2001, 2002Ogoh et al 2003), but the contribution of the systemic cardiovascular regulatory system to orthostatic tolerance is unknown. Another considerable physiological factor that determines orthostatic tolerance is cerebral blood flow (CBF) or its regulation, because CBF is reduced immediately after orthostatic stimulation, e.g.…”

Section: Introductionmentioning

confidence: 99%

Blood flow in internal carotid and vertebral arteries during graded lower body negative pressure in humans

Ogoh

Sato

Okazaki

et al. 2015

Experimental Physiology

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New Findings r What is the central question of this study?Recently, the heterogeneity of the cerebral arterial circulation has been argued. Orthostatic tolerance may be associated with an orthostatic stress-induced change in blood flow in vertebral arteries rather than in internal carotid arteries, because vertebral arteries supply blood to the medulla oblongata, which is the location of important cardiac, vasomotor and respiratory control centres. r What is the main finding and its importance?The effect of graded orthostatic stress on vertebral artery blood flow is different from that on internal carotid artery blood flow. This response allows for the possibility that orthostatic tolerance may be associated with haemodynamic changes in posterior rather than anterior cerebral blood flow.Recently, the heterogeneity of the cerebral arterial circulation has been argued, but the characteristics of vertebral artery (VA) and internal carotid artery (ICA) blood flow during graded orthostatic stress remain unknown. We hypothesized that the change in blood flow in VA is not similar to that in ICA blood flow during graded orthostatic stress. We measured blood flows in both ICA and VA during graded lower body negative pressure (LBNP; −20, −35 and −50 mmHg) by using two colour-coded ultrasound systems. The effect of graded orthostatic stress on the VA blood flow was different from that on the ICA blood flow (LBNP × artery, P = 0.006). The change in ICA blood flow was associated with the level of LBNP (r = 0.287, P = 0.029), and a reduction in ICA blood flow from pre-LBNP was observed during −50 mmHg LBNP (from 411 ± 35 to 311 ± 40 ml min −1 , P = 0.044) without symptoms of presyncope. In contrast, VA blood flow was unchanged during graded LBNP compared with the baseline (P = 0.597) relative to the reduction in ICA blood flow and thus there was no relationship between VA blood flow and the level of LBNP (r = 0.167, P = 0.219). These findings suggest that the change in ICA blood flow is due to the level of LBNP during graded orthostatic stress, but the change in VA blood flow is different from that in ICA blood flow across the different levels of LBNP. These findings provide the possibility that posterior cerebral blood flow decreases only during severe orthostatic stress and is therefore more likely to be linked with orthostatic tolerance.

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“…On the day of the experiment, the subjects were placed in a supine position within a custom-designed LBNP chamber [13,16,27,40]. The individual's lower body was sealed with a polypropylene skirt fitted snugly around the iliac crest.…”

Section: Protocolmentioning

confidence: 99%

Aging and Arterial Blood Pressure Variability during Orthostatic Challenge

et al. 2003

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Background: It has been demonstrated that a decrease in vagal cardiac function compromises arterial blood pressure (ABP) stability during orthostatic challenge. Augmentations in low-frequency (LF) ABP oscillations are indicative of this change in autonomic hemodynamic control. Aging is associated with diminished arterial baroreflex sensitivity and vagal cardiac dysfunction. However, the effect of aging on the stability of ABP during an orthostatic challenge remains to be elucidated. Objective: The purpose of this study was to investigate ABP stability with aging during central hypovolemia induced by lower-body negative pressure (LBNP). Methods: Graded LBNP up to –40 mm Hg was applied in 16 older (65 ± 3 years of age) and 16 younger (25 ± 3 years of age) healthy adults. ABP variability was analyzed by fast Fourier transform. LF spectral density (0.04–0.15 Hz) was extracted to provide an index of vasomotor responsiveness. Results: Both LF systolic blood pressure (SBP) variability and diastolic blood pressure variability were augmented with LBNP. The rate of increase in LF SBP variability was augmented significantly greater in older as compared with younger subjects (p = 0.049). In addition, LF SBP variability was inversely correlated with decreases in pulse pressure in both age groups (r = –0.84, p = 0.01). The magnitude of the decreases in SBP and pulse pressure during LBNP was significantly affected by age, with the largest changes occurring in older subjects. The altered ABP response that manifested in older individuals was associated with a significant diminution in the reflex tachycardiac response elicited by LBNP. Conclusions: Induction of central hypovolemia via graded LBNP augments LF ABP variability. This increased ABP variability is significantly greater in older individuals. Our data suggest that aging is associated with ABP instability during orthostatic challenge.

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Physical fitness and cardiovascular response to lower body negative pressure

Cited by 58 publications

References 0 publications

Limb suction evoked during arterial occlusion causes systemic sympathetic activity in humans

Limb suction evoked during arterial occlusion causes systemic sympathetic activity in humans

Blood flow in internal carotid and vertebral arteries during graded lower body negative pressure in humans

Aging and Arterial Blood Pressure Variability during Orthostatic Challenge

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