Influence of Sympatholytic Drugs on the Cardiovascular Response to Isometric Exercise

1981 ◽  
Vol 60 (2) ◽  
pp. 139-143 ◽  
Author(s):  
S. J. Watt ◽  
R. D. Thomas ◽  
P. W. Belfield ◽  
P. W. Goldstraw ◽  
S. H. Taylor
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Healthy Subjects ◽  
Cardiovascular Response ◽  
Pressor Response ◽  
Isometric Exercise ◽  
Systemic Blood Pressure ◽  
Isometric Handgrip ◽  
Systemic Blood ◽  
Oral Doses

1. The effects of single oral doses of various sympatholytic drugs on the heart rate and blood pressure increases during isometric handgrip contraction were studied in six healthy subjects. 2. Bethanidine reduced both the systolic and diastolic increases in pressure. Clonidine reduced the systolic but not the diastolic increase. Oxprenolol alone or in combination with phentolamine or phenyoxybenzamine failed to influence the pressor response. 3. The increase in systemic blood pressure associated with sustained contraction of voluntary muscle appears to be relatively resistant to acute sympathetic adrenoreceptor blockade in man.

Effect of aerobic conditioning on cardiovascular response to isometric exercise

1982 ◽  
Vol 52 (5) ◽  
pp. 1257-1260 ◽  
Author(s):  
B. J. Morgan ◽  
H. L. Brammell ◽  
D. L. Sable ◽  
M. L. Morton ◽  
L. D. Horwitz
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Systolic Blood Pressure ◽  
Cardiovascular Response ◽  
Isometric Exercise ◽  
Adrenergic Blockade ◽  
Isometric Handgrip ◽  
Double Product ◽  
Beta Adrenergic ◽  
Aerobic Conditioning

The response to isometric handgrip exercise (IHE) and isometric quadriceps exercise (IQE) (30% maximum voluntary contraction held 3 min) was studied before and after 5 wk of aerobic training. Training exercises involved only the lower extremities. Seventeen healthy unconditioned males aged 21--35 yr were subjects. During training nine subjects received propranolol in doses that provided a high degree of beta-adrenergic blockade; eight received a placebo. All subjects were tested before training or drug and after training, 3--5 days off drug. With IGE after training, the placebo group had lower maximum heart rate (91 +/- 4 to 79 +/- 5 beats/min, P less than 0.05), systolic blood pressure (151 +/- 5 to 139 +/- 4 mmHg, P less than 0.05), and double product (heart rate x systolic blood pressure) (138 +/- 10 x 10(2) to 110 +/- 7 x 10(2), P less than 0.05). The response to IQE in the propranolol group was unchanged after training. Heart rate, systolic blood pressure, and double product with IHE was unchanged in either group after training. Aerobic conditioning can modify the hemodynamic response to isometric exercise. This effect is specific for the trained muscle group and is prevented by beta-adrenergic blockade.

Effect of an increase in systemic blood pressure on nailfold capillary pressure in humans

1993 ◽  
Vol 265 (3) ◽  
pp. H820-H823 ◽  
Author(s):  
A. C. Shore ◽  
D. D. Sandeman ◽  
J. E. Tooke
Keyword(s):  
Blood Pressure ◽  
Capillary Pressure ◽  
Venous Pressure ◽  
Isometric Exercise ◽  
Systemic Blood Pressure ◽  
Isometric Handgrip ◽  
Systemic Blood ◽  
Protective Mechanisms ◽  
Arterial Blood ◽  
Contralateral Hand

Moderate autoregulation of capillary pressure occurs during changes in arterial and/or venous pressure in animals. Whether an increase in systemic blood pressure is transmitted to capillaries in humans is unknown. Eight healthy volunteers performed isometric handgrip exercise (30% of maximum) while nailfold capillary pressure (CP) and digital arterial blood pressure (DBP) were measured in the contralateral hand. CP was measured for 40 s before exercise and 40-100 s during exercise. Only experiments with no change in pipette position and no artifactual changes in flow were accepted. Basal DBP was stable [91.5 +/- 12.7 mmHg (-40 to -20 s basal) and 91.3 +/- 11.8 mmHg (-20 to 0 s basal)], and isometric exercise increased DBP [100.4 +/- 13.9 mmHg (0-20 s exercise) and 103.1 +/- 15.3 mmHg (20-40 s exercise); P < 0.05]. CP was unchanged during the first 40 s of exercise [18.9 +/- 4.9 mmHg (-40 to 20 s basal), 18.9 +/- 5.2 mmHg (-20 to 0 s basal), 18.4 +/- 4.7 mmHg (0-20 s exercise), and 18.3 +/- 5.3 mmHg (20-40 s exercise)] and remained unchanged for up to 100 s (n = 5), despite a continued elevation of DBP. These data suggest that protective mechanisms minimize the transmission of increases in systemic blood pressure to the capillary bed in humans.

Forearm endurance training attenuates sympathetic nerve response to isometric handgrip in normal humans

1992 ◽  
Vol 72 (3) ◽  
pp. 1039-1043 ◽  
Author(s):  
V. K. Somers ◽  
K. C. Leo ◽  
R. Shields ◽  
M. Clary ◽  
A. L. Mark
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Endurance Training ◽  
Sympathetic Nerve ◽  
Isometric Exercise ◽  
Voluntary Contraction ◽  
Isometric Handgrip ◽  
Nerve Response ◽  
The Right ◽  
Muscle Chemoreflex

Recent evidence indicates that muscle ischemia and activation of the muscle chemoreflex are the principal stimuli to sympathetic nerve activity (SNA) during isometric exercise. We postulated that physical training would decrease muscle chemoreflex stimulation during isometric exercise and thereby attenuate the SNA response to exercise. We investigated the effects of 6 wk of unilateral handgrip endurance training on the responses to isometric handgrip (IHG: 33% of maximal voluntary contraction maintained for 2 min). In eight normal subjects the right arm underwent exercise training and the left arm sham training. We measured muscle SNA (peroneal nerve), heart rate, and blood pressure during IHG before vs. after endurance training (right arm) and sham training (left arm). Maximum work to fatigue (an index of training efficacy) was increased by 1,146% in the endurance-trained arm and by only 40% in the sham-trained arm. During isometric exercise of the right arm, SNA increased by 111 +/- 27% (SE) before training and by only 38 +/- 9% after training (P less than 0.05). Endurance training did not significantly affect the heart rate and blood pressure responses to IHG. We also measured the SNA response to 2 min of forearm ischemia after IHG in five subjects. Endurance training also attenuated the SNA response to postexercise forearm ischemia (P = 0.057). Sham training did not significantly affect the SNA responses to IHG or forearm ischemia. We conclude that endurance training decreases muscle chemoreflex stimulation during isometric exercise and thereby attenuates the sympathetic nerve response to IHG.

scholarly journals Changes in Respiratory Rate, Blood Pressure and Heart Rate Variability in Rabbits during Orthostasis

2006 ◽  
Vol 75 (1) ◽  
pp. 3-12 ◽  
Author(s):  
J. Mokrý ◽  
T. Remeňová ◽  
K. Javorka
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Respiratory Rate ◽  
Supine Position ◽  
Spectral Power ◽  
Systemic Blood Pressure ◽  
Microcomputer System ◽  
Systemic Blood ◽  
Frequency Bands

The purpose of the study was to evaluate the changes of respiratory rate, systemic blood pressure and heart rate variability parameters (HRV) during orthostasis in anaesthetized rabbits. Furthermore, these changes were influenced by affecting the renin-angiotensin-aldosterone (RAA) system and autonomic nervous system (ANS) to study the mechanisms participating in activity of spectral frequency bands of HRV in rabbits. Ten adult rabbits (Chinchilla) were anaesthetized by ketamine and flunitrazepam. The systemic blood pressure, tidal volume and respiratory rate were measured. HRV was evaluated by microcomputer system VariaPulse TF3E. The R-R intervals were derived from the electrocardiogram signal from subcutaneous needle electrodes. The evaluation of HRV in very low (VLF; 0.01-0.05 Hz), low (LF; 0.05-0.15 Hz) and high frequency bands (HF; 0.15-2.0 Hz) was made and parameters of frequency and time analysis were calculated. The measurements were made in horizontal (supine) position, in orthostasis (the angle of 60 °) and again in supine position before and after enalapril (0.5 mg/kg b.w.), metipranolol (0.2 mg/kg b.w.), and after subsequent bilateral cervical vagotomy. The orthostasis in anaesthetized rabbits is accompanied by depression of respiratory rate reversed only by vagotomy. Furthermore, decrease of systemic blood pressure, unchanged heart rate and increased characteristics of heart rate variability were found, with predominant increase of spectral power in LF and VLF bands. This elevation can be eliminated only by complete blockade of ANS. Although the participation of ANS or RAA system in modification of individual HRV frequency bands is not as specific as in humans, we confirmed the participation of RAA system in determination of the VLF band.

Neural mechanism underlying basilar arterial constriction by intracisternal L-NNA in anesthetized dogs

1993 ◽  
Vol 265 (1) ◽  
pp. H103-H107 ◽  
Author(s):  
N. Toda ◽  
K. Ayajiki ◽  
T. Okamura
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cerebral Arteries ◽  
Neural Mechanism ◽  
Systemic Blood Pressure ◽  
Systemic Blood ◽  
Anesthetized Dogs ◽  
Arterial Constriction ◽  
Synthase Inhibitor

Basilar arterial diameters were angiographically measured in anesthetized dogs in which systemic blood pressure and heart rate were also monitored. Injections of NG-nitro-L-arginine (L-NNA), a NO synthase inhibitor, into the cisterna magna produced a significant, persistent decrease in arterial diameter, the effect being reversed by intracisternal injections of L-arginine. The vasoconstrictor effect of L-NNA was diminished in dogs treated with hexamethonium. On the other hand, treatment with phentolamine in a dose sufficient to lower blood pressure to a level similar to that attained with hexamethonium did not inhibit, but rather potentiated, the effect of intracisternal L-NNA. Nicotine injected into the vertebral artery significantly dilated the basilar artery. The effect was abolished by treatment with L-NNA applied intracisternally, the inhibition being reversed by the addition of L-arginine. Systemic blood pressure and heart rate were not altered by intracisternally applied L-NNA and L-arginine. These findings support the hypothesis that basilar arterial constriction caused by intracisternal L-NNA is associated with a suppression of NO synthesis in nitroxidergic nerves innervating the cerebroarterial wall rather than an elimination of basal release of NO from the endothelium. Functional importance of nitroxidergic vasodilator innervation in cerebral arteries in vivo is thus clarified.

scholarly journals Relation of body mass index (BMI) with cardiovascular response to head up tilt in healthy subjects

2020 ◽  
Vol 15 (1) ◽  
pp. 6-10
Author(s):  
Sadia Afrin Rimi ◽  
Shamima Sultana ◽  
Iffat Rezwana ◽  
Sultana Ferdousi
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Systolic Blood Pressure ◽  
Healthy Subjects ◽  
Cardiovascular Response ◽  
Tilt Test ◽  
Tilt Table ◽  
Chi Square ◽  
Female Head ◽  
Head Up Tilt

Background: Tilt table test is used for the last few decades to detect cause in unexplained syncope. The response to tilting may vary physiologically with obesity. Objective: To assess the relationship of BMI to cardiovascular response to tilting. Methods: This experimental study was conducted from March 2019 to Feb 2020 on 90 healthy subjects with different BMI. Fifty one subjects of both gender with BMI 18.5-24.9 kg/m2 were included in the non-obese group and 39 subjects of both gender with BMI of 25-29.9 kg/m2 were included in overweight group and they were further subdivided into male and female. Head up tilting was done for 10 minutes at 600 by using a motorized tilt table. Systolic blood pressure (SBP), diastolic blood pressure (DBP) were recorded by an automatic sphygmomanometer. Heart rate (HR) and peripheral capillary oxygen saturation (SpO2) were measured by a pulse oximeter. For statistical analysis, Independent sample ‘t’ test, Pearson’s correlation test and Chi square tests were applied. Results: Significantly smaller rise of heart rate was observed in overweight males and greater fall of systolic blood pressure was observed in overweight females. Conclusion: This study concluded that over weight is associated with reduced orthostatic tolerance to head up tilt test in both genders. J Bangladesh Soc Physiol. 2020, June; 15(1): 6-10

Baroreceptor influence on postural changes in blood pressure and carotid blood flow

1963 ◽  
Vol 205 (2) ◽  
pp. 360-364 ◽  
Author(s):  
Francis L. Abel ◽  
John H. Pierce ◽  
Warren G. Guntheroth
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Carotid Sinus ◽  
Systemic Blood Pressure ◽  
Systemic Blood ◽  
Carotid Blood Flow ◽  
Postural Changes ◽  
Nembutal Anesthesia

The effects of 30° head-down and head-up tilting on mean systemic blood pressure, carotid blood flow, and heart rate were studied in 16 dogs under morphine and Nembutal anesthesia. The tilting procedure was further repeated after denervation of the carotid sinus and aortic arch baroreceptors and after administration of a dihydrogenated ergot alkaloid mixture (Hydergine). The results indicate that the drop in pressure in the head-down position is primarily due to baroreceptor activity and that the baroreceptors are necessary for compensatory vasoconstriction on head-up tilting. Carotid blood flow decreased in both tilted positions in the control animals; the possible relationship to cerebral blood flow is discussed.

scholarly journals PROGNOSTIC VALUE OF HEART RATE AND SYSTEMIC BLOOD PRESSURE IN PULMONARY ARTERIAL HYPERTENSION

2010 ◽  
Vol 55 (10) ◽  
pp. A154.E1443
Author(s):  
Malcolm M. Bersohn ◽  
Shelley Shapiro ◽  
Michelle P. Turner ◽  
Glenna Traiger ◽  
Adaani E. Frost
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Prognostic Value ◽  
Systemic Blood Pressure ◽  
Systemic Blood ◽  
Pulmonary Arterial
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