Hormonal, metabolic, and cardiovascular responses to static exercise in humans: influence of epidural anesthesia

1991 ◽  
Vol 261 (2) ◽  
pp. E214-E220 ◽  
Author(s):  
M. Kjaer ◽  
N. H. Secher ◽  
F. W. Bach ◽  
H. Galbo ◽  
D. R. Reeves ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Epidural Anesthesia ◽  
Pressor Response ◽  
Plasma Concentrations ◽  
Cardiovascular Responses ◽  
Knee Extension ◽  
Voluntary Contraction ◽  
Static Exercise ◽  
Exercise In Humans

To determine the role of reflex neural mechanisms for hormonal, metabolic, heart rate (HR), and blood pressure (MABP) changes during static exercise, seven health young males performed 10-min periods of two-legged static knee extension both during control and during epidural anesthesia. Comparisons were made at identical absolute (29 Nm) and relative [15% maximal voluntary contraction (MVC)] force. Afferent nerve blockade was verified by hypesthesia below T10-T12 and attenuated postexercise ischemic pressor response. Leg strength was reduced to 67 +/- 5% of control. At same relative force, increases in MABP and HR occurred more rapidly without than with epidural anesthesia (P less than 0.05). This difference was diminished during identical absolute force. Changes in plasma concentrations of catecholamines followed the pattern of HR and MABP responses, with differences between epidural and control experiments being most pronounced early in the work period. Plasma beta-endorphin was elevated only after control exercise. No response at 15% MVC was found for growth hormone, adrenocorticotropic hormone, insulin, glucagon, cortisol, glycerol, free fatty acids, or glucose (P greater than 0.05). In conclusion, during static exercise with large muscle groups and moderate relative force, modest changes in plasma hormones and metabolites take place. Furthermore, afferent nervous feedback from contracting muscles is important in regulation of blood pressure, heart rate, and catecholamine responses during static exercise in humans.

Heart Rate and Blood Pressure Responses to Static Handgrip Exercise of Different Intensities: Reliability and Adult versus Child Differences

2002 ◽  
Vol 14 (1) ◽  
pp. 45-55 ◽  
Author(s):  
Kenneth R. Turley ◽  
D. Eric Martin ◽  
Eric D. Marvin ◽  
Kelley S. Cowley
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Maximal Voluntary Contraction ◽  
Cardiovascular Response ◽  
Isometric Exercise ◽  
Cardiovascular Responses ◽  
Voluntary Contraction ◽  
Static Exercise ◽  
Handgrip Exercise ◽  
Blood Pressure Responses

To determine the reliability of cardiovascular responses to isometric exercise of different intensities, and to compare adult versus child responses, 27 boys (7–9 years old) and 27 men (18–26 years old) performed static handgrip exercise at 10, 20, and 30% of previously determined maximal voluntary contraction (MVC) for three min each on different days, while heart rate (HR) and blood pressure (BP) were measured. HR reliability was moderately high at all intensities in both boys and men ranging from R = 0.52–0.87. BP reliability was moderate in men and boys at 30% MVC while at 10% and 20% MVC reliability was very low for boys and only moderate for men. HR response from pre- to 3-min of static exercise was not different between boys versus men at any intensity. At 30% MVC diastolic (20.2 vs. 29.3 mmHg), systolic (17.4 vs. 36.2 mmHg) and mean (19.2 vs. 31.6 mmHg) BP responses were lower in boys versus men, respectively. At 20% MVC SBP (6.8 vs. 14.3 mmHg) and MBP (8.4 vs. 12.6 mmHg) responses were lower in boys versus men, respectively. In conclusion, the reliability of cardiovascular response to isometric exercise is low at low contraction intensities and moderate at higher contraction intensities. Further, BP response in men at 30% MVC is higher than boys, while responses are similar at lower contraction intensities.

Cardiovascular control during voluntary static exercise in humans with tetraplegia

2004 ◽  
Vol 97 (6) ◽  
pp. 2077-2082 ◽  
Author(s):  
Makoto Takahashi ◽  
Akihiro Sakaguchi ◽  
Kanji Matsukawa ◽  
Hidehiko Komine ◽  
Kotaro Kawaguchi ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Cervical Spinal Cord ◽  
Pressor Response ◽  
Peripheral Resistance ◽  
Voluntary Contraction ◽  
Static Exercise ◽  
Arm Exercise ◽  
Arterial Blood ◽  
Cord Injury

The purpose of the present study was 1) to investigate whether an increase in heart rate (HR) at the onset of voluntary static arm exercise in tetraplegic subjects was similar to that of normal subjects and 2) to identify how the cardiovascular adaptation during static exercise was disturbed by sympathetic decentralization. Mean arterial blood pressure (MAP) and HR were noninvasively recorded during static arm exercise at 35% of maximal voluntary contraction in six tetraplegic subjects who had complete cervical spinal cord injury (C6-C7). Stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR) were estimated by using a Modelflow method simulating aortic input impedance from arterial blood pressure waveform. In tetraplegic subjects, the increase in HR at the onset of static exercise was blunted compared with age-matched control subjects, whereas the peak increase in HR at the end of exercise was similar between the two groups. CO increased during exercise with no or slight decrease in SV. MAP increased approximately one-third above the control pressor response but TPR did not rise at all throughout static exercise, indicating that the slight pressor response is determined by the increase in CO. We conclude that the cardiovascular adaptation during voluntary static arm exercise in tetraplegic subjects is mainly accomplished by increasing cardiac pump output according to the tachycardia, which is controlled by cardiac vagal outflow, and that sympathetic decentralization causes both absent peripheral vasoconstriction and a decreased capacity to increase HR, especially at the onset of exercise.

Mechanisms for increasing stroke volume during static exercise with fixed heart rate in humans

1997 ◽  
Vol 83 (3) ◽  
pp. 712-717 ◽  
Author(s):  
Antonio C. L. Nóbrega ◽  
Jon W. Williamson ◽  
Jorge A. Garcia ◽  
Jere H. Mitchell
Keyword(s):  
Heart Rate ◽  
Stroke Volume ◽  
Knee Extension ◽  
Left Ventricular ◽  
Voluntary Contraction ◽  
Peak Exercise ◽  
Ventricular Contractility ◽  
Static Exercise ◽  
Systolic Volume ◽  
End Diastolic Volume

Nóbrega, Antonio C. L., Jon W. Williamson, Jorge A. Garcia, and Jere H. Mitchell. Mechanisms for increasing stroke volume during static exercise with fixed heart rate in humans. J. Appl. Physiol. 83(3): 712–717, 1997.—Ten patients with preserved inotropic function having a dual-chamber (right atrium and right ventricle) pacemaker placed for complete heart block were studied. They performed static one-legged knee extension at 20% of their maximal voluntary contraction for 5 min during three conditions: 1) atrioventricular sensing and pacing mode [normal increase in heart rate (HR; DDD)], 2) HR fixed at the resting value (DOO-Rest; 73 ± 3 beats/min), and 3) HR fixed at peak exercise rate (DOO-Ex; 107 ± 4 beats/min). During control exercise (DDD mode), mean arterial pressure (MAP) increased by 25 mmHg with no change in stroke volume (SV) or systemic vascular resistance. During DOO-Rest and DOO-Ex, MAP increased (+25 and +29 mmHg, respectively) because of a SV-dependent increase in cardiac output (+1.3 and +1.8 l/min, respectively). The increase in SV during DOO-Rest utilized a combination of increased contractility and the Frank-Starling mechanism (end-diastolic volume 118–136 ml). However, during DOO-Ex, a greater left ventricular contractility (end-systolic volume 55–38 ml) mediated the increase in SV.

Hemodynamic and Catecholamine Responses to Laryngoscopy and Tracheal Intubation in Patients with Complete Spinal Cord Injuries

2001 ◽  
Vol 95 (3) ◽  
pp. 647-651 ◽  
Author(s):  
Kyung Y. Yoo ◽  
JongUn Lee ◽  
Hak S. Kim ◽  
Woong M. Im
Keyword(s):  
Blood Pressure ◽  
Spinal Cord ◽  
Heart Rate ◽  
Tracheal Intubation ◽  
Endotracheal Intubation ◽  
Spinal Cord Injuries ◽  
Plasma Concentrations ◽  
Cardiovascular Responses ◽  
Plasma Catecholamine ◽  
Cord Injury

Background Endotracheal intubation in patients undergoing general anesthesia often causes hypertension and tachycardia, which may be altered when the efferent sympathetic fiber to the cardiovascular system is interrupted. The aim of the current study was to investigate the effects of different levels of spinal cord injury on the cardiovascular responses to intubation. Methods Fifty-four patients with traumatic complete cord injuries requiring tracheal intubation were grouped into quadriplegics (above C7; n = 22), high paraplegics (T1-T4, n = 8), and low paraplegics (below T5, n = 24) according to the level of injury. Twenty patients without spinal injury served as controls. Arterial pressure, heart rate, and rhythm were recorded at intervals for up to 5 min after intubation. Plasma concentrations of catecholamines were also measured. Results The intubation increased the systolic blood pressure similarly in control, high-paraplegic, and low-paraplegic groups (P < 0.05), whereas it did not alter the blood pressure in the quadriplegic group. Heart rate was significantly increased in all groups; however, the magnitude was more pronounced in the high-paraplegic group (67%) than in the control (38%) and quadriplegic (33%) groups. Plasma concentrations of norepinephrine were significantly increased after intubation in all groups; however, values were lower in the quadriplegic group and higher in the low-paraplegic group compared with those in the control group. Incidence of arrhythmias did not differ among groups. Conclusions The cardiovascular and plasma catecholamine changes associated with endotracheal intubation may differ according to the affected level in patients with complete spinal cord injuries.

Role of muscle mass and mode of contraction in circulatory responses to exercise

1985 ◽  
Vol 58 (1) ◽  
pp. 146-151 ◽  
Author(s):  
S. F. Lewis ◽  
P. G. Snell ◽  
W. F. Taylor ◽  
M. Hamra ◽  
R. M. Graham ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Muscle Mass ◽  
Pressor Response ◽  
Cardiovascular Responses ◽  
Knee Extension ◽  
Systemic Resistance ◽  
Static Exercise ◽  
Active Muscle ◽  
Pressor Responses

The roles of the mode of contraction (i.e., dynamic or static) and the active muscle mass as determinants of the cardiovascular responses to exercise were studied. Six healthy men performed static handgrip (SHG), dynamic handgrip (DHG), static two-knee extension (SKE), and dynamic two-knee extension (DKE) to local muscular fatigue in approximately 6 min. Increases in mean arterial pressure were similar for each mode of contraction, 29 +/- 5 and 30 +/- 3 mmHg in SHG and DHG and 56 +/- 2 and 48 +/- 2 mmHg in SKE and DKE (P greater than 0.05) but larger for KE than HG (P less than 0.001). Cardiac output increased more for dynamic than for static exercise and for each mode more for KE than HG (P less than 0.001). Systemic resistance was lower for dynamic than static exercise and fell from resting levels by approximately 1/3 during DKE. The magnitude of the pressor response was related to the active muscle mass but independent of the contraction mode. However, the mode of contraction affected the circulatory changes contributing to the pressor response. Equalization of the pressor responses was achieved by proportionately larger increases in cardiac output during dynamic exercise.

Forearm elevation augments sympathetic activation during handgrip exercise in humans

2002 ◽  
Vol 103 (3) ◽  
pp. 295-301 ◽  
Author(s):  
Daisaku MICHIKAMI ◽  
Atsunori KAMIYA ◽  
Qi FU ◽  
Yuki NIIMI ◽  
Satoshi IWASE ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Muscle Sympathetic Nerve Activity ◽  
Voluntary Contraction ◽  
Sympathetic Activation ◽  
Handgrip Exercise ◽  
Excitatory Effect ◽  
Muscle Metaboreflex ◽  
Forearm Exercise ◽  
Exercise In Humans

Although angina pectoris in patients with coronary heart disease often occurs when their forearms are in an elevated position for a prolonged period, and sympathetic activation is a major cause of this condition, little is known about the physiological effects of forearm elevation on sympathetic activity during forearm exercise. We hypothesized that forearm elevation augments sympathetic activation during the static handgrip exercise in humans. A total of 10 healthy male volunteers performed 2min of static handgrip exercise at 30% of maximal voluntary contraction followed by 2min of post-exercise muscle ischaemia (PEMI; specific activation of the muscle metaboreflex) with two forearm positions: the exercising forearm was elevated 50cm above the heart (forearm-elevated trial) or fixed at the level of the heart (heart-level trial). Muscle sympathetic nerve activity (MSNA), blood pressure and heart rate were monitored. MSNA increased during handgrip exercise in both forearm positions (P<0.001); the increase was 51% greater in the forearm-elevated trial (516±99 arbitrary units) than in the heart-level trial (346±44units; P<0.05). The increase in mean blood pressure was 8.4mmHg greater during exercise in the forearm-elevated trial (P<0.05), while changes in heart rate were similar in both forearm positions. The increase in MSNA during PEMI was 71% greater in the forearm-elevated trial (393±71 arbitrary units/min) than in the heart-level trial (229±29units/min; P<0.05). These results support the hypothesis that forearm elevation augments sympathetic activation during handgrip exercise. The excitatory effect of forearm elevation on exercising MSNA may be mediated primarily by increased activation of the muscle metaboreflex.

scholarly journals Maintenance of Blood Pressure in Emotional Context-based Autonomic Switching by the Central Nucleus of the Amygdala in Rats

2020 ◽  
Author(s):  
Ko Yamanaka ◽  
Hidefumi Waki
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Pressor Response ◽  
Cardiovascular Responses ◽  
Central Nucleus ◽  
Emotional Context ◽  
Neuronal Mechanisms ◽  
Pressor Responses ◽  
Pharmacological Blockade ◽  
Aversive Classical Conditioning

Abstract Proper autonomic control is necessary in making appropriate decisions and actions, but neuronal mechanisms for this function are yet to be determined. Here we show that the amygdala plays a role in autonomic cardiovascular tuning in a dynamically changing environment. We recorded blood pressure and heart rate of head-restrained rats during appetitive and aversive classical conditioning tasks. Rats learned varying associations between conditioned stimuli and unconditioned stimuli in three types of contexts: appetitive, neutral, and aversive blocks. Blood pressure and heart rate in the appetitive block gradually increased after reward-predicting cues, followed by a vigorously increased response to the actual reward. The predictive response was found to be significantly higher than the responses in the neutral and aversive blocks. Blood pressure and heart rate responses to the air puff-predicting cue in the aversive block were significantly lower than that of the responses in the neutral block. Pharmacological blockade of the amygdala has significantly decreased reward-predictive pressor responses in the latter phase, but not in the initial phase of context change. Cardiovascular responses are thus adaptively tuned by positive and negative emotional stimuli, and the central nucleus of the amygdala likely assists in maintaining pressor response tuning based on emotional context.

scholarly journals Regulation of blood pressure by the central nucleus of the amygdala in dynamically changing appetitive and aversive classical conditioning tasks in rats

2021 ◽  
Author(s):  
Ko Yamanaka ◽  
Hidefumi Waki
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Classical Conditioning ◽  
Blood Pressure Response ◽  
Pressor Response ◽  
Cardiovascular Responses ◽  
Central Nucleus ◽  
Conditioned Stimuli ◽  
Neuronal Mechanisms ◽  
Aversive Classical Conditioning

Abstract In an environment of dynamically changing conditions, humans and animals can determine whether a current situation is favorable to them and accordingly select actions. Autonomic cardiovascular tuning is as important as motor control for this function. However, neuronal mechanisms underlying the dynamic adjustments of autonomic cardiovascular responses remain unclear. In this study, we hypothesized that the amygdala plays a role in autonomic cardiovascular tuning in a dynamically changing situation. We recorded the blood pressures and heart rates of head-restrained rats during appetitive and aversive classical conditioning tasks. Rats learned varying associations between conditioned stimuli and unconditioned stimuli in appetitive, neutral, and aversive blocks. Blood pressure and heart rate in the appetitive block gradually increased in response to reward-predicting cue, preceded by a vigorously increased response to the actual reward. The predictive response was significantly higher than the responses in the neutral and aversive condition blocks. Blood pressure and heart rate responses to the air puff-predicting cue in the aversive block were significantly lower than that of the responses in the neutral block. The conditioned blood pressure response rapidly changed through condition switching. Furthermore, bilateral pharmacological inactivation of the central nucleus of the amygdala has significantly decreased reward-predictive pressor responses in the latter phase, but not in the initial phase of block change. These results suggest that blood pressure is adaptively tuned by positive and negative conditioned stimuli and that the central nucleus of the amygdala likely assists in maintaining pressor response in dynamically changing situations.

Blunted blood pressure response to exercise and isolated muscle metaboreflex activation in patients with cirrhosis

2020 ◽  
Author(s):  
Pedro Augusto Carvalho Mira ◽  
Maria Fernanda Almeida Falci ◽  
Janaína Becari Moreira ◽  
Rosa Virginia Diaz Guerrero ◽  
Tarsila Campanha da Rocha Ribeiro ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Pressure Response ◽  
Pressor Response ◽  
Cardiovascular Responses ◽  
Pressure Response ◽  
Isometric Handgrip ◽  
Muscle Metaboreflex ◽  
Cirrhotic Patients ◽  
Response To Exercise

We sought to test the hypothesis that the cardiovascular responses to isolated muscle metaboreflex activation would be blunted in patients with cirrhosis. Eleven patients with cirrhosis and 15 healthy controls were evaluated. Blood pressure (BP, oscillometric method), contralateral forearm blood flow (FBF, venous occlusion plethysmography) and heart rate (HR, electrocardiogram) were measured during baseline, isometric handgrip at 30% of maximal voluntary contraction followed by post-exercise ischemia (PEI). Forearm vascular conductance (FVC) was calculated as follows: (FBF/mean BP) x 100. Changes in HR during handgrip were similar between groups, but tended to be different during PEI (controls: ∆0.5 ± 1.1 bpm vs. cirrhotic patients: ∆3.6 ± 1.0 bpm, P = 0.057). Mean BP response to handgrip (controls: ∆20.9 ± 2.7 mmHg vs. cirrhotic patients: ∆10.6 ± 1.5 mmHg, P = 0.006) and PEI was attenuated in cirrhotic patients (controls: ∆16.1 ± 1.9 mmHg vs. cirrhotic patients: ∆7.2 ± 1.4 mmHg, P = 0.001). In contrast, FBF and FVC increased during handgrip and decreased during PEI similarly between groups. These results indicate that an abnormal muscle metaboreflex activation explained, at least partially, the blunted pressor response to exercise exhibited by cirrhotic patients. Novelty bullets: • Patients with cirrhosis present abnormal muscle metaboreflex activation • Blood pressure response was blunted, but forearm vascular response was preserved • Heart rate response was slightly elevated

Cardiovascular responses to voluntary and nonvoluntary static exercise in humans

1992 ◽  
Vol 73 (5) ◽  
pp. 1982-1985 ◽  
Author(s):  
D. B. Friedman ◽  
C. Peel ◽  
J. H. Mitchell
Keyword(s):  
Neural Mechanism ◽  
Random Order ◽  
Cardiovascular Responses ◽  
Normal Subjects ◽  
Voluntary Contraction ◽  
Central Command ◽  
Static Exercise ◽  
Leg Extension ◽  
Static Contractions ◽  
Exercise In Humans

We have measured the cardiovascular responses during voluntary and nonvoluntary (electrically induced) one-leg static exercise in humans. Eight normal subjects were studied at rest and during 5 min of static leg extension at 20% of maximal voluntary contraction performed voluntarily and nonvoluntarily in random order. Heart rate (HR), mean arterial pressure (MAP), and cardiac output (CO) were determined, and peripheral vascular resistance (PVR) and stroke volume (SV) were calculated. HR increased from approximately 65 +/- 3 beats/min at rest to 80 +/- 4 and 78 +/- 6 beats/min (P < 0.05), and MAP increased from 83 +/- 6 to 103 +/- 6 and 105 +/- 6 mmHg (P < 0.05) during voluntary and nonvoluntary contractions, respectively. CO increased from 5.1 +/- 0.7 to 6.0 +/- 0.8 and 6.2 +/- 0.8 l/min (P < 0.05) during voluntary and nonvoluntary contractions, respectively. PVR and SV did not change significantly during voluntary or nonvoluntary contractions. Thus the cardiovascular responses were not different between voluntary and electrically induced contractions. These results suggest that the increases in CO, HR, SV, MAP, and PVR during 5 min of static contractions can be elicited without any contribution from a central neural mechanism (central command). However, central command could still have an important role during voluntary static exercise.

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