Cardiovascular responses to stimulation of carotid baroreceptors in healthy subjects

1988 ◽  
Vol 75 (2) ◽  
pp. 159-165 ◽  
Author(s):  
R. Hainsworth ◽  
Y. M. H. Al-Shamma
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Cardiovascular Responses ◽  
Pulse Interval ◽  
Healthy Population ◽  
Control Value ◽  
Carotid Baroreceptors ◽  
Single Breath ◽  
Arterial Blood ◽  
Blood Pressures

1. Carotid baroreceptors were stimulated by application of a subatmospheric pressure to a chamber fitted round the anterior and lateral aspects of the subject's neck (neck suction). Pulse interval and heart rate were determined from an electrocardiogram, cardiac output by a single-breath method and arterial blood pressure by an automatic sphygmomanometer. 2. The maximal prolongation of the pulse interval, determined during held expiration, occurred within 2–3 s from the onset of the neck suction. All the measured variables were in steady states between 2 and 3 min from the start of neck suction. 3. Neck suction at − 10 mmHg resulted only in an immediate change in pulse interval. All variables changed approximately linearly with the magnitude of the neck suction between − 10 and − 40 mmHg. 4. The reproducibilities of the responses to neck suction at − 30 mmHg, expressed as two standard deviations of the differences between responses on two occasions, were (mean responses in parentheses): immediate pulse interval, ± 32 (+ 236) ms; steady-state heart rate, ± 2.5 (− 6.5) beats/min; cardiac output ± 0.14 (− 0.59) 1/min; systolic and diastolic blood pressures, ± 10.0 (− 16.9) and ± 5.4 (− 10.1) mmHg, respectively. 5. Control values and responses to neck suction at − 30 mmHg were compared in subjects grouped in four age bands between 19 and 80 years. With increasing age, the control value of cardiac index (cardiac output divided by calculated body surface area) decreased, systolic and diastolic pressures increased, and the responses of all the measured variables to neck suction decreased. These results, obtained from a healthy population, provide reference values for comparison with those of individuals who may have abnormal baroreceptor reflexes.

Cardiovascular responses to upright tilting in healthy subjects

1988 ◽  
Vol 74 (1) ◽  
pp. 17-22 ◽  
Author(s):  
R. Hainsworth ◽  
Y. M. H. Al-Shamma
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Diastolic Pressure ◽  
Age Groups ◽  
Cardiovascular Responses ◽  
Healthy Population ◽  
Healthy Human ◽  
Arterial Blood ◽  
Postural Responses

1. The cardiovascular responses to passive upright tilting were determined in healthy human subjects of various ages using entirely ‘non-invasive’ techniques. Cardiac output was determined by a single breath method and arterial blood pressure by an automatic sphygmomanometer. 2. Steady-state responses were achieved within 4–6 min from the onset of the tilt and were maintained for at least 15 min. 3. The reproducibilities of the responses to tilting by 60°, expressed as two standard deviations of the differences between responses on two occasions (mean responses in parentheses), were: cardiac output ±0.70 (−1.41) litre/min, heart rate ±7.6 (+ 14.7) beats/min, systolic blood pressure ± 15.5 (+ 1.0), and diastolic blood pressure μ13.1 (+ 13.6)mmHg. 4. Tilting by 20° resulted in no significant responses but between 20° and 60° responses were linearly related to the angle of tilt. 5. Supine values and responses to tilting by 60° were compared in subjects in four age groups between 20 and 80 years. With increasing age, the supine values of cardiac output declined and those of arterial blood pressures increased. Responses of heart rate, cardiac output and diastolic pressure declined by increasing age. These results, obtained from a healthy population, provide reference values for comparison with individuals who may have deficient postural responses.

Diurnal patterns of hemodynamic performance in nonhuman primates

1987 ◽  
Vol 253 (5) ◽  
pp. R779-R785
Author(s):  
B. T. Engel ◽  
M. I. Talan
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Diastolic Pressure ◽  
Peripheral Resistance ◽  
Diurnal Patterns ◽  
Arterial Blood ◽  
Blood Pressures ◽  
Hemodynamic Performance ◽  
Lower Cardiac Output

Heart rate, stroke volume, and intra-arterial blood pressures were monitored continuously in each of four monkeys for 18 consecutive hours, 5 days/wk, for several weeks. Mean heart rate, stroke volume, cardiac output, systolic and diastolic pressure, and total peripheral resistance were calculated each minute, and these averages were analyzed further to yield hourly means and intercorrelations. The main findings from the analyses of mean levels were that cardiac output fell throughout the night and that peripheral resistance rose during the same interval so that arterial pressure fell only slightly; the highest levels of peripheral resistance and lowest levels of cardiac output were recorded between 0500 and 0700. Furthermore, the levels of these responses during the remainder of the morning were higher (peripheral resistance) and lower (cardiac output) than those recorded in the evening.

scholarly journals Fructose ingestion acutely elevates blood pressure in healthy young humans

2008 ◽  
Vol 294 (3) ◽  
pp. R730-R737 ◽  
Author(s):  
Clive M. Brown ◽  
Abdul G. Dulloo ◽  
Gayathri Yepuri ◽  
Jean-Pierre Montani
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Energy Expenditure ◽  
Total Peripheral Resistance ◽  
Peripheral Resistance ◽  
Cardiovascular Responses ◽  
Health Concern ◽  
Arterial Blood ◽  
Glucose Ingestion

Overconsumption of fructose, particularly in the form of soft drinks, is increasingly recognized as a public health concern. The acute cardiovascular responses to ingesting fructose have not, however, been well-studied in humans. In this randomized crossover study, we compared cardiovascular autonomic regulation after ingesting water and drinks containing either glucose or fructose in 15 healthy volunteers (aged 21–33 yr). The total volume of each drink was 500 ml, and the sugar content 60 g. For 30 min before and 2 h after each drink, we recorded beat-to-beat heart rate, arterial blood pressure, and cardiac output. Energy expenditure was determined on a minute-by-minute basis. Ingesting the fructose drink significantly increased blood pressure, heart rate, and cardiac output but not total peripheral resistance. Glucose ingestion resulted in a significantly greater increase in cardiac output than fructose but no change in blood pressure and a concomitant decrease in total peripheral resistance. Ingesting glucose and fructose, but not water, significantly increased blood pressure variability and decreased cardiovagal baroreflex sensitivity. Energy expenditure increased by a similar amount after glucose and fructose ingestion, but fructose elicited a significantly greater increase in respiratory quotient. These results show that ingestion of glucose and fructose drinks is characterized by specific hemodynamic responses. In particular, fructose ingestion elicits an increase in blood pressure that is probably mediated by an increase in cardiac output without compensatory peripheral vasodilatation.

A Comparison of the Acute Haemodynamic Effects of Propranolol and Pindolol at Rest and during Supine Exercise in Man

1980 ◽  
Vol 59 (s6) ◽  
pp. 465s-468s ◽  
Author(s):  
T. L. Svendsen ◽  
J. E. Carlsen ◽  
O. Hartling ◽  
A. McNair ◽  
J. Trap-Jensen
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Pulmonary Artery ◽  
Pulmonary Artery Pressure ◽  
Response Curves ◽  
Receptor Blocking ◽  
Artery Pressure ◽  
Arterial Blood ◽  
Β Receptor

1. Dose-response curves for heart rate, cardiac output, arterial blood pressure and pulmonary artery pressure were obtained in 16 male patients after intravenous administration of three increasing doses of pindolol, propranolol or placebo. All patients had an uncomplicated acute myocardial infarction 6–8 months earlier. 2. The dose-response curves were obtained at rest and during repeated bouts of supine bicycle exercise. The cumulative dose amounted to 0.024 mg/kg body weight for pindolol and to 0.192 mg/kg body weight for propranolol. 3. At rest propranolol significantly reduced heart rate and cardiac output by 12% and 15% respectively. Arterial mean blood pressure was reduced by 9.2 mmHg. Mean pulmonary artery pressure increased significantly by 2 mmHg. Statistically significant changes in these variables were not seen after pindolol or placebo. 4. During exercise pindolol and propranolol both reduced cardiac output, heart rate and arterial blood pressure to the same extent. After propranolol mean pulmonary artery pressure was increased significantly by 3.6 mmHg. Pindolol and placebo did not change pulmonary artery pressure significantly. 5. The study suggests that pindolol may offer haemodynamic advantages over β-receptor-blocking agents without intrinsic sympathomimetic activity during low activity of the sympathetic nervous system, and may be preferable in situations where the β-receptor-blocking effect is required only during physical or psychic stress.

Ascending pathways mediating somatoautonomic reflexes in exercising dogs

1987 ◽  
Vol 62 (3) ◽  
pp. 1186-1191 ◽  
Author(s):  
J. W. Kozelka ◽  
G. W. Christy ◽  
R. D. Wurster
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Surgical Techniques ◽  
Arterial Occlusion ◽  
Cardiovascular Responses ◽  
Spinal Pathways ◽  
Arterial Blood ◽  
Bilateral Carotid ◽  
Dorsolateral Funiculus ◽  
Carotid Arterial

The ascending spinal pathways mediating somatocardiovascular reflexes during exercise were studied in unanesthetized dogs by placing lesions in the lumbar spinal cord. After training to run on a treadmill with hindlimbs only, 20 dogs were anesthetized and instrumented using sterile surgical techniques. To chronically record heart rate and arterial blood pressure, the aorta was cannulated via the omocervical artery. To test the intactness of descending spinal sympathetic pathways, reflex pressor responses to baroreceptor hypotension were produced by bilateral carotid arterial occlusion using pneumatic vessel occluders placed around the common carotid arteries. To generate transient ischemic exercise (120 s), a pneumatic occluder was placed around the left iliac artery. Eight to 10 days after instrumentation, blood pressure and heart rate were monitored at rest and during hindlimb running with and without simultaneous iliac arterial occlusion. The modest pressor response and tachycardia elicited by hindlimb exercise were markedly augmented by simultaneous hindlimb ischemia (i.e., iliac arterial occlusion). Lesion placement in the dorsolateral sulcus area and the dorsolateral funiculus at L2 significantly reduced the blood pressure and heart rate responses to simultaneous exercise occlusion. The cardiovascular responses to nonischemic exercise and bilateral carotid arterial occlusion were not altered by such spinal sections. It is concluded that in the dog the ascending spinal pathways mediating cardiovascular responses to ischemic exercise are located in the lateral funiculus, including the dorsolateral sulcus area and dorsolateral funiculus.

scholarly journals Acute Hemodynamic Changes Associated with Zumba and ZOCA Dance Exercises among Females of Selected Gyms in Lusaka, Zambia

2020 ◽  
Vol 2 (1) ◽  
pp. 84-91
Author(s):  
Chanda Grace Chisunka ◽  
◽  
Gibson Sijumbila ◽  
Fastone Goma ◽  
◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Systolic Blood Pressure ◽  
Hemodynamic Changes ◽  
Aerobic Dance ◽  
Arterial Blood ◽  
Effective Dynamic ◽  
Blood Pressure Monitors ◽  
Blood Pressures

Background: Dynamic exercises are known to elicit hemodynamic changes such as an increase in arterial blood pressure and heart rate. Zumba and ZOCA are part of a fast growing group of dance fitness programmes designed to provide a cardiovascular dynamic workout. Despite their growing popularity, very few studies have been done to provide knowledge regarding the hemodynamic changes associated with these exercises. Methods: Case study in which 27 females took part in either a Zumba or ZOCA class. Using digital blood pressure monitors, recordings of blood pressure and heart rate were taken, firstly, before commencement of the exercise, secondly, after 30 minutes after exercise and thirdly, at the end of the class.Results: Mean baseline blood pressures were 118 (SD = 14) mmHg and 77 (SD = 7) mmHg, systolic and diastolic blood pressures, respectively. After 30 minutes of dancing, mean systolic blood pressure increased to 130 (SD = 19) mmHg (p˂ 0.05) while diastolic blood pressureonly rose to an average of 80 (SD = 8) mmHg (p˃ 0.05). At the end of the class (after the cool down phase) mean systolic blood pressure reduced to 109 (SD = 13) mmHg (p˂0.05) while diastolic blood pressure reduced to 74(SD = 12) mmHg (p˂ 0.05). Conclusions: Zumba and ZOCA elicited significant hemodynamic changes that can be attributed to these exercises stimulating the cardiovascular regulatory mechanisms (e.g central command and exercise-pressor) sufficiently and hence resulting in autonomic adjustmentsthat were concurrent with effective dynamic exercise. Keywords: Blood Pressure, Heart Rate, Aerobic, Dance Exercise

scholarly journals Role of nitric oxide-containing factors in the ventilatory and cardiovascular responses elicited by hypoxic challenge in isoflurane-anesthetized rats

2014 ◽  
Vol 116 (11) ◽  
pp. 1371-1381 ◽  
Author(s):  
James P. Mendoza ◽  
Rachael J. Passafaro ◽  
Santhosh M. Baby ◽  
Alex P. Young ◽  
James N. Bates ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Heart Rate ◽  
Cardiovascular Responses ◽  
Vital Role ◽  
Initial Increase ◽  
Ventilatory Responses ◽  
Arterial Blood ◽  
Anesthetized Rats ◽  
Before And After

Exposure to hypoxia elicits changes in mean arterial blood pressure (MAP), heart rate, and frequency of breathing (fr). The objective of this study was to determine the role of nitric oxide (NO) in the cardiovascular and ventilatory responses elicited by brief exposures to hypoxia in isoflurane-anesthetized rats. The rats were instrumented to record MAP, heart rate, and fr and then exposed to 90 s episodes of hypoxia (10% O2, 90% N2) before and after injection of vehicle, the NO synthase inhibitor NG-nitro-l-arginine methyl ester (l-NAME), or the inactive enantiomer d-NAME (both at 50 μmol/kg iv). Each episode of hypoxia elicited a decrease in MAP, bidirectional changes in heart rate (initial increase and then a decrease), and an increase in fr. These responses were similar before and after injection of vehicle or d-NAME. In contrast, the hypoxia-induced decreases in MAP were attenuated after administration of l-NAME. The initial increases in heart rate during hypoxia were amplified whereas the subsequent decreases in heart rate were attenuated in l-NAME-treated rats. Finally, the hypoxia-induced increases in fr were virtually identical before and after administration of l-NAME. These findings suggest that NO factors play a vital role in the expression of the cardiovascular but not the ventilatory responses elicited by brief episodes of hypoxia in isoflurane-anesthetized rats. Based on existing evidence that NO factors play a vital role in carotid body and central responses to hypoxia in conscious rats, our findings raise the novel possibility that isoflurane blunts this NO-dependent signaling.

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.

Supine exercise restores arterial blood pressure and skin blood flow despite dehydration and hyperthermia

1999 ◽  
Vol 277 (2) ◽  
pp. H576-H583 ◽  
Author(s):  
José González-Alonso ◽  
Ricardo Mora-Rodríguez ◽  
Edward F. Coyle
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Arterial Blood Pressure ◽  
Blood Volume ◽  
Plasma Catecholamines ◽  
Central Blood Volume ◽  
Vascular Conductance ◽  
Arterial Blood ◽  
Cutaneous Vascular Conductance

We determined whether the deleterious effects of dehydration and hyperthermia on cardiovascular function during upright exercise were attenuated by elevating central blood volume with supine exercise. Seven trained men [maximal oxygen consumption (V˙o 2 max) 4.7 ± 0.4 l/min (mean ± SE)] cycled for 30 min in the heat (35°C) in the upright and in the supine positions (V˙o 2 2.93 ± 0.27 l/min) while maintaining euhydration by fluid ingestion or while being dehydrated by 5% of body weight after 2 h of upright exercise. When subjects were euhydrated, esophageal temperature (Tes) was 37.8–38.0°C in both body postures. Dehydration caused equal hyperthermia during both upright and supine exercise (Tes = 38.7–38.8°C). During upright exercise, dehydration lowered stroke volume (SV), cardiac output, mean arterial pressure (MAP), and cutaneous vascular conductance and increased heart rate and plasma catecholamines [30 ± 6 ml, 3.0 ± 0.7 l/min, 6 ± 2 mmHg, 22 ± 8%, 14 ± 2 beats/min, and 50–96%, respectively; all P < 0.05]. In contrast, during supine exercise, dehydration did not cause significant alterations in MAP, cutaneous vascular conductance, or plasma catecholamines. Furthermore, supine versus upright exercise attenuated the increases in heart rate (7 ± 2 vs. 9 ± 1%) and the reductions in SV (13 ± 4 vs. 21 ± 3%) and cardiac output (8 ± 3 vs. 14 ± 3%) (all P< 0.05). These results suggest that the decline in cutaneous vascular conductance and the increase in plasma norepinephrine concentration, independent of hyperthermia, are associated with a reduction in central blood volume and a lower arterial blood pressure.

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