Relative effects of fat-, carbohydrate- and protein-containing liquid diets on cardiac output in healthy adult subjects

1992 ◽  
Vol 83 (4) ◽  
pp. 483-487 ◽  
Author(s):  
Susan K. Hawley ◽  
Kevin S. Channer
Keyword(s):  
Blood Pressure ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Pulse Rate ◽  
Healthy Adult ◽  
Nutritional Composition ◽  
Significant Rise ◽  
Mean Blood Pressure ◽  
Carbohydrate Diet ◽  
Liquid Meal

1. Nine healthy adult subjects consumed four types of proprietary liquid diet of similar volume and calorific value but of different nutritional composition. The effects on resting cardiac output, mean blood pressure and pulse rate were measured. 2. A significant rise in cardiac output occurred with the balanced, protein and carbohydrate diets but not with the fat diet. The greatest rise was seen with the balanced diet. Water alone had no effect on cardiac output. 3. The average time taken to reach peak cardiac output was shortest with the carbohydrate diet and longest with the fat diet. 4. The increases in cardiac output resulted from a rise in both pulse rate and stroke volume. The carbohydrate diet produced the most sustained rise in pulse rate but the least sustained elevation in stroke volume. 5. No significant changes were seen in mean blood pressure when each liquid meal was compared with water. 6. Our data show that the increase in cardiac output with liquid ingestion is related to the dietary components. These effects are additive.

Dynamics of Circulatory Adjustments to Head-Up Tilt and Tilt-Back in Healthy and Sympathetically Denervated Subjects

1998 ◽  
Vol 94 (4) ◽  
pp. 347-352 ◽  
Author(s):  
W. Wieling ◽  
J. J. Van Lieshout ◽  
A. D. J. Ten Harkel
Keyword(s):  
Blood Pressure ◽  
Cardiac Output ◽  
Arterial Pressure ◽  
Stroke Volume ◽  
Systemic Vascular Resistance ◽  
Vascular Resistance ◽  
Healthy Subjects ◽  
Mean Blood Pressure ◽  
Head Up Tilt ◽  
Change In Mean

1. The initial circulatory adjustments induced by head-up tilt and tilt-back were investigated in six healthy subjects (aged 30–58 years) and six patients with orthostatic hypotension due to pure autonomic failure (aged 33–65 years). 2. Continuous responses of finger arterial pressure and heart rate were recorded by Finapres. A pulse contour algorithm applied to the arterial pressure waveform was used to compute stroke volume responses. 3. In the healthy subjects, head-up tilt induced gradual circulatory adjustments. After 1 min upright stroke volume and cardiac output had decreased by 39 ± 9% and 26 ± 10% respectively. Little change in mean blood pressure at heart level (+1 ± 7 mmHg) indicated that systemic vascular resistance had increased by 39 ± 24%. The gradual responses to head-up tilt contrasted with the pronounced and rapid circulatory responses upon tilt-back. After 2–3 s a rapid increase in stroke volume (from 62 ± 8% to 106 ± 10%) and cardiac output (from 81 ± 11% to 118 ± 20%) was observed with an overshoot of mean arterial pressure above supine control values of 16 ± 3 mmHg at 7 s. In the patients a progressive fall in blood pressure on head-up tilt was observed. After 1 min upright mean blood pressure had decreased by 59 ± 8 mmHg. No change in systemic vascular resistance and a larger decrease in stroke volume (60 ± 7%) and cardiac output (53 ± 8%) were found. On tilt-back a gradual recovery of blood pressure was observed. 4. In healthy humans upon head-up tilt neural compensatory mechanisms are very effective in maintaining arterial pressure at heart level. The gradual circulatory adjustments to head-up tilt in healthy subjects contrast with the pronounced and abrupt circulatory changes on tilt-back. In patients with a lack of neural circulatory reflex adjustments, gradual blood pressure decreases to head-up tilt and gradual increases to tilt-back are observed.

Effects of Leg Muscle Pumping and Tensing on Orthostatic Arterial Pressure: A Study in Normal Subjects and Patients with Autonomic Failure

1994 ◽  
Vol 87 (5) ◽  
pp. 553-558 ◽  
Author(s):  
A. D. J. Ten Harkel ◽  
J. J. Van Lieshout ◽  
W. Wieling
Keyword(s):  
Blood Pressure ◽  
Cardiac Output ◽  
Arterial Pressure ◽  
Stroke Volume ◽  
Healthy Subjects ◽  
Healthy Adult ◽  
Autonomic Failure ◽  
Contour Method ◽  
Orthostatic Blood Pressure ◽  
Leg Muscle

1. The effects of leg muscle pumping (tiptoeing) and tensing (leg-crossing) on orthostatic blood pressure were investigated in six healthy adult subjects (aged 28–34 years) and in seven patients with severe hypoadrenergic orthostatic hypotension (aged 20–65 years). 2. Finger arterial pressure was monitored. Relative changes in left ventricular stroke volume were computed by a pulse contour method. 3. Tiptoeing increased mean arterial pressure (7 ± 5 mmHg) in the healthy subjects, but not in the patients, whereas cardiac output increased in both groups, although by more in the healthy adults than in the patients (35 ± 10% versus 20 ± 11%, P < 0.05). Systemic vascular resistance decreased substantially in both groups while tiptoeing. Leg-crossing did not affect arterial pressure in the healthy subjects, although stroke volume had increased. In contrast, in the patients an increase in cardiac output (16 ± 12%) and mean blood pressure (13 ± 13 mmHg) was observed. 4. Tiptoeing and leg-crossing have different effects on orthostatic blood pressure in healthy adult subjects and in patients with autonomic failure. In normal humans, tiptoeing increases arterial pressure, whereas leg-crossing has little effect. In the patients, in contrast, tiptoeing has little effect, whereas leg-crossing increases arterial pressure considerably. Patients with autonomic failure should be instructed to apply leg-crossing to combat orthostatic dizziness.

Finger Arterial versus Intrabrachial Pressure and Continuous Cardiac output during Head-up Tilt Testing in Healthy Subjects

1996 ◽  
Vol 91 (2) ◽  
pp. 193-200 ◽  
Author(s):  
Wilbert T. Jellema ◽  
Ben P. M. Imholz ◽  
Jeroen Van Goudoever ◽  
Karel H. Wesseling ◽  
Johannes J. Van Lieshout
Keyword(s):  
Blood Pressure ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Healthy Subjects ◽  
Pulse Contour Analysis ◽  
Pulse Contour ◽  
Mean Blood Pressure ◽  
Contour Analysis ◽  
Head Up Tilt ◽  
The Difference

1. The aims of this study were to determine the clinical feasibility of continuous, non-invasive Finapres recordings as a replacement for intrabrachial pressure during a 30 min head-up tilt, and the reliability of continuous cardiac output computation by pulse contour analysis from the finger arterial versus the brachial waveform. 2. In eight healthy subjects a 30 min 70° passive head-up tilt was performed. Finger arterial (FINAP) and intrabrachial (IAP) pressures were measured simultaneously. Beat-to-beat changes in stroke volume were computed using a pulse contour algorithm. 3. Accuracy (the group-averaged FINAP—IAP difference) and precision (the SD of the difference) of Finapres measurements were 4 and 9 mmHg for systolic blood pressure, −5 and 9 mmHg for mean blood pressure and −5 and 9 mmHg for diastolic blood pressure. 4. The time course of the FINAP—IAP differences during head-up tilt showed a linear trend (P < 0.001 for all pressure levels). Averaged for the group, the difference increased 7 mmHg for mean blood pressure. The difference in stroke volume computed from FINAP and IAP was 0.3 ± 5% (mean ± SD), and independent of the duration of the tilt (P > 0.05). This difference did not change at low blood pressure levels (0.5 ± 6%). 5. The qualitative performance of the Finapres allows it to be used in the clinical setting as a monitor of sudden changes in blood pressure induced by a 30 min head-up tilt. Relative changes in stroke volume, as obtained by pulse contour analysis of the finger arterial waveform, closely follow intrabrachial values during long-duration head-up tilt and associated arterial hypotension.

MECHANISMS OF ADAPTATION OF THE LEFT VENTRICLE TO MUSCULAR EXERCISE

PEDIATRICS ◽  
1963 ◽  
Vol 32 (4) ◽  
pp. 660-670
Author(s):  
Jere H. Mitchell
Keyword(s):  
Cardiac Output ◽  
Left Ventricle ◽  
Stroke Volume ◽  
Pulse Rate ◽  
Individual Factors ◽  
Normal Male ◽  
Oxygen Intake ◽  
Mechanisms Of Adaptation ◽  
Male Subjects ◽  
Oxygen Difference

THE mechanisms of adaptation of the left ventricle to the demands of muscular exercise have intrigued cardiovascular physiologists for many years. Although highly complex, these adaptive mechanisms are more and more susceptible to analysis and quantification. In this presentation I will attempt to identify some of the individual factors which appear to be important in the response of the left ventricle to exercise, beginning with data obtained from experiments on conscious normal male subjects and proceeding to experiments performed on dog preparations in which individual factors were controlled and analyzed. The changes in oxygen intake, cardiac output, estimated arteriovenous oxygen difference, pulse rate and estimated mean stroke volume were determined in 15 normal male subjects during rest in the standing position and during treadmill exercise at the maximal oxygen intake level. Oxygen intake was obtained from the volume and composition of expired air, cardiac output by the dye dilution technique, and pulse rate from the electrocardiogram. Estimated arteriovenous oxygen difference was obtained by dividing the oxygen intake by the cardiac output (Fick principle) and estimated mean stroke volume by dividing the cardiac output by the heart rate. The data are shown in Figure 1. Oxygen intake increased from a mean value of 0.34 at rest to a maximal value of 3.22 L./min. The corresponding mean values for cardiac output were 5.4 and 23.4 L./min. and for arteriovenous oxygen difference were 6.5 and 14.3 ml./100 ml. Thus, as oxygen intake increased 9.5 times, the cardiac output increased 4.3 times and the arterio venous oxygen difference 2.2 times.

Long-term hemodynamic actions of atrial natriuretic factor (99-126) in conscious sheep

1988 ◽  
Vol 254 (4) ◽  
pp. H811-H815 ◽  
Author(s):  
D. G. Parkes ◽  
J. P. Coghlan ◽  
J. G. McDougall ◽  
B. A. Scoggins
Keyword(s):  
Blood Pressure ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Blood Volume ◽  
Total Peripheral Resistance ◽  
Atrial Natriuretic Factor ◽  
Peripheral Resistance ◽  
Natriuretic Factor ◽  
Atrial Natriuretic

The hemodynamic and metabolic effects of long-term (5 day) infusion of human atrial natriuretic factor (ANF) were examined in conscious chronically instrumented sheep. Infusion of ANF at 20 micrograms/h, a rate below the threshold for an acute natriuretic effect, decreased blood pressure by 9 +/- 1 mmHg on day 5, associated with a fall in calculated total peripheral resistance. On day 1, ANF reduced cardiac output, stroke volume, and blood volume, effects that were associated with an increase in heart rate and calculated total peripheral resistance and a small decrease in blood pressure. On days 4 and 5 there was a small increase in urine volume and sodium excretion. On day 5 an increase in water intake and body weight was observed. No change was seen in plasma concentrations of renin, arginine vasopressin, glucose, adrenocorticotropic hormone, or protein. This study suggests that the short-term hypotensive effect of ANF results from a reduction in cardiac output associated with a fall in both stroke volume and effective blood volume. However, after 5 days of infusion, ANF lowers blood pressure via a reduction in total peripheral resistance.

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.

Base-line effects on response of stroke volume to leg exercise in the supine position

1964 ◽  
Vol 19 (4) ◽  
pp. 639-643 ◽  
Author(s):  
M. H. Frick ◽  
Timo Somer
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Normal Subjects ◽  
Significant Rise ◽  
Base Line ◽  
Horizontal Position ◽  
Volume Data ◽  
Leg Exercise ◽  
Low Levels

Cardiac output was measured with dye dilution in normal subjects at rest in horizontal position, at rest supine with the legs on the pedals, and during increasing work loads. Experiments were designed to clarify the effect of leg raising on comparisons of stroke volume at various levels of exercise. Leg raising evoked a 19% increase in stroke volume and a decrease in heart rate. Oxygen uptake and A-V O2 difference remained unaltered. In comparing stroke volume at mild exercise with leg-raised resting position, no change occurred contrasting the significant rise when compared with horizontal position. At mild exercise cardiac output response was relatively flat, whereas A-V O2 difference rose sharply. At heavier exercise cardiac output rose more steeply and approximately linear to oxygen consumed. Stroke volumes at these loads were significantly higher than levels in both of the resting positions. Ignorance of the effect of leg raising results in misinterpretation of the stroke volume data at low levels of supine exercise when greatly enhanced tissue extraction of oxygen allows smaller blood flow increments. base line in exercise; exercise stroke volume; stroke volume, exercise; stroke volume, base line; supine exercise Submitted on December 13, 1963

Systemic hemodynamic determinants of blood pressure in women: age, physical activity, and hormone replacement

1997 ◽  
Vol 273 (2) ◽  
pp. H777-H785 ◽  
Author(s):  
B. E. Hunt ◽  
K. P. Davy ◽  
P. P. Jones ◽  
C. A. DeSouza ◽  
R. E. Van Pelt ◽  
...  
Keyword(s):  
Physical Activity ◽  
Blood Pressure ◽  
Cardiac Output ◽  
Oxygen Consumption ◽  
Stroke Volume ◽  
Hormone Replacement ◽  
Systemic Hemodynamic ◽  
Arterial Blood ◽  
Age Related ◽  
Hemodynamic Determinants

We tested the hypothesis that the age-related changes in systemic hemodynamic determinants of arterial blood pressure in healthy women are related to physical activity and hormone replacement status. We studied 66 healthy, normotensive premenopausal (21-35 yr) and postmenopausal (50-72 yr) sedentary and endurance-trained women under supine resting conditions. Mean blood pressure was 7 mmHg higher in sedentary post- compared with premenopausal women, which was associated with an 11-mmHg higher systolic blood pressure, a 25% lower stroke volume and cardiac output, and a 50% higher systemic vascular resistance (all P < 0.05). Absolute (ml) levels of total blood volume did not differ across age, but resting oxygen consumption was approximately 35% lower in the postmenopausal women (P < 0.05). The elevations in mean and systolic blood pressures with age were similar in endurance-trained runners, but, in contrast to the sedentary women, the elevations were not associated with significant age-related differences in cardiac output, stroke volume, or oxygen consumption, and only a modest (15%) increase in systemic vascular resistance (P = 0.06). Postmenopausal swimmers demonstrated the same systemic hemodynamic profile as that of postmenopausal runners, indicating a nonspecific influence of the endurance-trained state. Blood pressure and its systemic hemodynamic determinants did not differ in postmenopausal users compared with those of nonusers of hormone replacement therapy. Resting oxygen consumption was the strongest physiological correlate of cardiac output in the overall population (r = 0.65, P < 0.001). We conclude that 1) the increases in arterial blood pressure at rest with age in healthy normotensive women are not obviously related to habitual physical activity status; 2) the systemic hemodynamic determinants of the age-related elevations in blood pressure are fundamentally different in sedentary vs. active women, possibly due, in part, to an absence of decline in resting oxygen consumption in the latter; and 3) systemic hemodynamics at rest are not different in healthy normotensive postmenopausal users vs. nonusers of estrogen-based hormone replacement.

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