OBSERVATIONS ON THE INDIVIDUAL EFFECTS OF SMOKING ON THE BLOOD PRESSURE, HEART RATE, STROKE VOLUME AND CARDIAC OUTPUT OF HEALTHY YOUNG ADULTS

1956 ◽  
Vol 44 (5) ◽  
pp. 874 ◽  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Young Adults ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Individual Effects ◽  
The Individual

Effect of sympathetic blockade on diurnal variation of hemodynamic patterns

1989 ◽  
Vol 256 (3) ◽  
pp. R778-R785 ◽  
Author(s):  
M. I. Talan ◽  
B. T. Engel
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Total Peripheral Resistance ◽  
Peripheral Resistance ◽  
Base Line ◽  
Sympathetic Blockade ◽  
Selective Blockade ◽  
Arterial Blood

Heart rate, stroke volume, and intra-arterial blood pressure were monitored continuously in each of four monkeys, 18 consecutive h/day for several weeks. The mean heart rate, stroke volume, cardiac output, systolic and diastolic blood pressure, and total peripheral resistance were calculated for each minute and reduced to hourly means. After base-line data were collected for approximately 20 days, observation was continued for equal periods of time under conditions of alpha-sympathetic blockade, beta-sympathetic blockade, and double sympathetic blockade. This was achieved by intra-arterial infusion of prazosin, atenolol, or a combination of both in concentration sufficient for at least 75% reduction of response to injection of agonists. The results confirmed previous findings of a diurnal pattern characterized by a fall in cardiac output and a rise in total peripheral resistance throughout the night. This pattern was not eliminated by selective blockade, of alpha- or beta-sympathetic receptors or by double sympathetic blockade; in fact, it was exacerbated by sympathetic blockade, indicating that the sympathetic nervous system attenuates these events. Because these findings indicate that blood volume redistribution is probably not the mechanism mediating the observed effects, we have hypothesized that a diurnal loss in plasma volume may mediate the fall in cardiac output and that the rise in total peripheral resistance reflects a homeostatic regulation of arterial pressure.

Leg crossing improves orthostatic tolerance in healthy subjects: a placebo-controlled crossover study

2006 ◽  
Vol 291 (4) ◽  
pp. H1768-H1772 ◽  
Author(s):  
C. T. Paul Krediet ◽  
Johannes J. van Lieshout ◽  
Lysander W. J. Bogert ◽  
Rogier V. Immink ◽  
Yu-Sok Kim ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Crossover Study ◽  
Healthy Subjects ◽  
Lower Body Negative Pressure ◽  
Vasovagal Syncope ◽  
Orthostatic Tolerance ◽  
Healthy Human

Vasovagal syncope is the most common cause of transient loss of consciousness, and recurrent vasovagal fainting has a profound impact on quality of life. Physical countermaneuvers are applied as a means of tertiary prevention but have so far only proven useful at the onset of a faint. This placebo-controlled crossover study tested the hypothesis that leg crossing increases orthostatic tolerance. Nine naïve healthy subjects [6 females, median age 25 yr (range 20–41 yr), mean body mass index 23 (SD 2)] were subjected to passive head-up tilt combined with a graded lower body negative pressure challenge (20, 40, and 60 mmHg) determining orthostatic tolerance thrice, in randomized order: 1) control, 2) with leg crossing, and 3) with oral placebo. Blood pressure (Finometer), heart rate, and changes in thoracic blood volume (impedance), stroke volume, and cardiac output (Modelflow) were followed during orthostatic stress. Primary outcome was time to presyncope (systolic blood pressure ≤85 mmHg, heart rate ≥140 beats/min). With leg crossing, orthostatic tolerance increased from 26 ± 2 to 34 ± 2 min (placebo 23 ± 3 min, P < 0.001). During leg crossing, mean arterial pressure (81 vs. 81 mmHg) and cardiac output (95 vs. 94% supine) remained unchanged; heart rate increase was lower (13 vs. 18 beats/min, P < 0.05); stroke volume was higher (79 vs. 74% supine, P < 0.05); and there was a trend toward lower thoracic impedance. Leg crossing increases orthostatic tolerance in healthy human subjects. As a measure of prevention, it is a worthwhile addition to the management of vasovagal syncope.

scholarly journals The Peculiarities of Heart Rate Variability in Student Athletes

2021 ◽  
Vol 11 (2) ◽  
pp. 169-172
Author(s):  
Andrew Martusevich ◽  
Ivan Bocharin ◽  
Natalia Ronzhina ◽  
Solomon Apoyan ◽  
Levon Dilenyan ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Optimal Level ◽  
Track And Field ◽  
Testing System ◽  
Integral Criterion ◽  
Age Range

The aim of this research was to study the peculiarities of heart rate variability (HRV) and microcirculation in students, depending on their sport specialization. Methods and Results: Our study included the results of a survey of 96 students from 18 to 21 years of age who were the members of the national teams of their universities in athletics (n=49) and floorball (n=47). For ECG registration and analysis of hemodynamic findings, including those characterizing the HRV, we used the “Medical Soft” sports testing system (“MS FIT Pro”). For monitoring, we used the standard hemodynamic patterns (blood pressure, HR, stroke volume, cardiac output, and others), statistical and spectral indicators of the HRV, as well as an integral criterion of the state of microcirculation. The studied HRV parameters in most students generally were within the age range. At the same time, track and field athletes have large adaptive resources and, consequently, a more optimal level of myocardial fitness, in comparison with floorball players. Conclusion: The orientation of sports training among students affects heart condition.

Cardiovascular changes during acceleration stress in dogs

1960 ◽  
Vol 15 (6) ◽  
pp. 1065-1068 ◽  
Author(s):  
Edward J. Hershgold ◽  
Sheldon H. Steiner
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Technical Assistance ◽  
Peripheral Resistance ◽  
Cardiovascular Changes ◽  
Positive Acceleration ◽  
Acceleration Stress ◽  
Circulatory Disturbances

Dogs were accelerated on the Wright-Patterson AFB human centrifuge in positive and transverse vectors. Cardiac output, blood pressure and heart rate were measured, and stroke volume and peripheral resistance calculated. In positive (headward) acceleration, the cardiac output and stroke volume were reduced; the peripheral resistance was increased. In the transverse vectors, the cardiac output was stable or increased; stroke volume was stable, and peripheral resistance was reduced. The results suggest that the circulatory disturbances associated with positive acceleration may limit tolerance to acceleration and that these may be avoided in transverse acceleration. Note: (With the Technical Assistance of Peter Grenell) Submitted on December 3, 1959

Autonomic Cardiovascular Dysregulation at Rest and During Stress in Chronically Low Blood Pressure

2019 ◽  
Vol 33 (1) ◽  
pp. 39-53 ◽  
Author(s):  
Stefan Duschek ◽  
Alexandra Hoffmann ◽  
Casandra I. Montoro ◽  
Gustavo A. Reyes del Paso
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Total Peripheral Resistance ◽  
Baroreflex Sensitivity ◽  
Peripheral Resistance ◽  
Control Group ◽  
Low Blood Pressure

Abstract. Chronic low blood pressure (hypotension) is accompanied by symptoms such as fatigue, reduced drive, faintness, dizziness, cold limbs, and concentration difficulties. The study explored the involvement of aberrances in autonomic cardiovascular control in the origin of this condition. In 40 hypotensive and 40 normotensive subjects, impedance cardiography, electrocardiography, and continuous blood pressure recordings were performed at rest and during stress induced by mental calculation. Parameters of cardiac sympathetic control (i.e., stroke volume, cardiac output, pre-ejection period, total peripheral resistance), parasympathetic control (i.e., heart rate variability), and baroreflex function (i.e., baroreflex sensitivity) were obtained. The hypotensive group exhibited markedly lower stroke volume, heart rate, and cardiac output, as well as higher pre-ejection period and baroreflex sensitivity than the control group. Hypotension was furthermore associated with a smaller blood pressure response during stress. No group differences arose in total peripheral resistance and heart rate variability. While reduced beta-adrenergic myocardial drive seems to constitute the principal feature of the autonomic impairment that characterizes chronic hypotension, baroreflex-related mechanisms may also contribute to this state. Insufficient organ perfusion due to reduced cardiac output and deficient cardiovascular adjustment to situational requirements may be involved in the manifestation of bodily and mental symptoms.

Effects of reserpine on circulation of the rat after microwave irradiation

1962 ◽  
Vol 202 (6) ◽  
pp. 1171-1174 ◽  
Author(s):  
Theodore Cooper ◽  
Teresa Pinakatt ◽  
Max Jellinek ◽  
Alfred W. Richardson
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Continuous Wave ◽  
Peripheral Resistance ◽  
Thermal Response ◽  
Cardiac Response ◽  
Tissue Temperature ◽  
White Rats

Hyperthermia of 40.5 C was induced in anesthetized white rats by microwave exposure (2,450-Mc continuous wave, .08 w/cm2). Thermal response was accompanied by increased cardiac output, stroke volume, cardiac work, and heart rate. Blood pressure and total peripheral resistance decreased. Administration of reserpine as a single dose of 2.5 mg/kg body wt. 1 day before the experiment depleted the myocardial norepinephrine, but did not eliminate the accelerated heart rate and increase of cardiac output during hyperthermia. Hyperthermia after reserpine did not alter significantly the stroke volume and blood pressure, and the peripheral resistance decreased. These data suggest that the circulatory adaptation to microwave hyperthermia is mediated not only through the sympathetic nervous system, but by other mechanisms such as direct cardiac response to the increased tissue temperature.

Treatment of Hypotension after Hyperbaric Tetracaine Spinal Anesthesia 

1997 ◽  
Vol 86 (4) ◽  
pp. 797-805 ◽  
Author(s):  
Robert F. Brooker ◽  
John F. IV Butterworth ◽  
Dalane W. Kitzman ◽  
Jeffrey M. Berman ◽  
Hillel I. Kashtan ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Systolic Blood Pressure ◽  
Spinal Anesthesia ◽  
Adrenergic Agonist ◽  
Induced Hypotension ◽  
Alpha Adrenergic Agonist ◽  
Hyperbaric Tetracaine

Background Despite many advantages, spinal anesthesia often is followed by undesirable decreases in blood pressure, for which the ideal treatment remains controversial. Because spinal anesthesia-induced sympathectomy and management with a pure alpha-adrenergic agonist can separately lead to bradycardia, the authors hypothesized that epinephrine, a mixed alpha- and beta-adrenergic agonist, would more effectively restore arterial blood pressure and cardiac output after spinal anesthesia than phenylephrine, a pure alpha-adrenergic agonist. Methods Using a prospective, double-blind, randomized, cross-over study design, 13 patients received sequential infusions of epinephrine and phenylephrine to manage hypotension after hyperbaric tetracaine (10 mg) spinal anesthesia. Blood pressure, heart rate, and stroke volume (measured by Doppler echocardiography using the transmitral time-velocity integral) were recorded at baseline, 5 min after injection of tetracaine, and before and after management of hypotension with epinephrine and phenylephrine. Cardiac output was calculated by multiplying stroke volume x heart rate. Results Five min after placement of a hyperbaric tetracaine spinal anesthesia, significant decrease in systolic (from 143 +/- 6 mmHg to 125 +/- 5 mmHg; P &lt; 0.001), diastolic (from 81 +/- 3 to 71 +/- 3; P &lt; 0.001), and mean (from 102 +/- 4 to 89 +/- 3; P &lt; 0.001) arterial pressures occurred. Heart rate (75 +/- 4 beats/min to 76 +/- 4 beat/min; P = 0.9), stroke volume (115 +/- 17 to 113 +/- 13; P = 0.9), and cardiac output (8.0 +/- 1 l/m to 8.0 +/- 1l/m; P = 0.8) did not change significantly after spinal anesthesia. Phenylephrine was effective at restoring systolic blood pressure after spinal anesthesia (120 +/- 6 mmHg to 144 +/- 5 mmHg; P &lt; 0.001) but was associated with a decrease in heart rate from 80 +/- 5 beats/min to 60 +/- 4 beats/min (P &lt; 0.001) and in cardiac output from 8.6 +/- 0.7 l/m to 6.2 +/- 0.7 l/m (P &lt; 0.003). Epinephrine was effective at restoring systolic blood pressure after spinal anesthesia (119 +/- 5 mmHg to 139 +/- 6 mmHg; P &lt; 0.001) and was associated with an increase in stroke volume from 114 +/- 12 ml to 142 +/- 17 (P &lt; 0.001) and cardiac output from 7.8 +/- 0.6 l/m to 10.8 +/- 1.1 l/m (P &lt; 0.001). Conclusions Epinephrine management of tetracaine spinal-induced hypotension increases heart rate and cardiac output and restores systolic arterial pressure but does not restore mean and diastolic blood pressure. Phenylephrine management of tetracaine spinal-induced hypotension decreases heart rate and cardiac output while restoring systolic, mean, and diastolic blood pressure.

Cardiovascular and Metabolic Responses to On-Water Upwind Sailing in Optimist Sailors

2016 ◽  
Vol 11 (5) ◽  
pp. 615-622
Author(s):  
Santiago Lopez ◽  
Jan G. Bourgois ◽  
Enrico Tam ◽  
Paolo Bruseghini ◽  
Carlo Capelli
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Steady State ◽  
Exercise Intensity ◽  
Peripheral Resistance ◽  
Peak Oxygen Uptake ◽  
Metabolic Responses ◽  
Arterial Blood ◽  
The Individual

Purpose:To explore the cardiovascular and metabolic responses of 9 Optimist sailors (12.7 ± 0.8 y, 153 ± 9 cm, 41 ± 6 kg, sailing career 6.2 ± 1 y, peak oxygen uptake [V̇O2peak] 50.5 ± 4.5 mL · min−1 · kg−1) during on-water upwind sailing with various wind intensities (W).Methods:In a laboratory session, peak V̇O2, beat-by-beat cardiac output (Q̇), mean arterial blood pressure (MAP), and heart rate (fH) were measured using a progressive cycle ramp protocol. Steady-state V̇O2, Q̇, MAP, and fH at 4 submaximal workloads were also determined. During 2 on-water upwind sailing tests (constant course and with tacks), W, Q̇, MAP, and fH were measured for 15 min. On-water V̇O2 was estimated on the basis of steady-state fH measured on water and of the individual ΔV̇O2/ΔfH relationship obtained in the laboratory.Results:V̇O2, fH, and Q̇ expressed as percentage of the corresponding peak values were linearly related with W; exercise intensity during on-water sailing corresponded to 46–48% of V̇O2peak. MAP and total vascular peripheral resistance (TPR = MAP/Q̇) were larger (P < .005) during on-water tests (+39% and +50%, respectively) than during cycling, and they were correlated with W. These responses were responsible for larger values of the double (DP) and triple (TP) products of the heart during sailing than during cycling (P < .005) (+37% and +32%, respectively).Conclusions:These data indicate that the cardiovascular system was particularly stressed during upwind sailing even though the exercise intensity of this activity was not particularly high.

Cardiovascular changes associated with thermal polypnea in the chicken

1964 ◽  
Vol 207 (6) ◽  
pp. 1349-1353 ◽  
Author(s):  
G. C. Whittow ◽  
P. D. Sturkie ◽  
G. Stein
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Respiratory Rate ◽  
Peripheral Resistance ◽  
Flow Through ◽  
Skin Temperatures ◽  
Increased Blood Flow

The effect of hyperthermia on the respiratory rate, cardiac output, blood pressure, arterial hematocrit, and the skin temperatures of the extremities of unanesthetized hens has been investigated. During hyperthermia, the respiratory rate increased to a maximal value and then declined. There was also an increase in cardiac output, followed by a decrease, but the peak cardiac output occurred at a rectal temperature which was significantly higher than that at which the peak respiratory rate was recorded. The increase in cardiac output was the result of an increase in both stroke volume and heart rate. The diminution of cardiac output seemed to be related to a decrease in the stroke volume at high levels of heart rate. The decrease in blood pressure and total peripheral resistance was attributed partly to an increased blood flow through the extremities.

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