Comparison of hemodynamic responses to static and dynamic exercise

1982 ◽  
Vol 53 (6) ◽  
pp. 1589-1593 ◽  
Author(s):  
G. R. Bezucha ◽  
M. C. Lenser ◽  
P. G. Hanson ◽  
F. J. Nagle
Keyword(s):  
Arterial Pressure ◽  
Pressor Response ◽  
Peripheral Resistance ◽  
Bicycle Ergometer ◽  
Open Circuit ◽  
Dynamic Exercise ◽  
Arm Cranking ◽  
Hemodynamic Responses ◽  
Leg Extension ◽  
Leg Cycling

Eight healthy male adults (25–34 yr) were studied to compare hemodynamic responses to static exercise (30% MVC in leg extension), static-dynamic exercise (one-arm cranking, 66 and 79% VO2 max-arm), and dynamic exercise (two-leg cycling, 58 and 82% VOmax-legs). Leg extension (LE) strength was measured by a spring scale. Cranking and cycling were performed on a Quinton bicycle ergometer. VO2 was measured using an automated open-circuit system. Heart rate (HR) was monitored from a CM-5 ECG lead, and arterial pressure (Pa) was measured from an indwelling brachial artery catheter. Cardiac output (Q) was measured using a CO2-rebreathing procedure. Total peripheral resistance (TPR) was calculated using the mean arterial pressure (Pa) as the systemic pressure gradient. In 30% LE, a significant (P less than 0.05) Pa increase occurred (pressor response) mediated primarily by an increase in Q. One-arm cranking and two-leg cycling at similar relative VO2 demands resulted in nearly identical increases in Pa due to different contributions of Q and TPR. Q and the arteriovenous O2 difference varied as a function of VO2 regardless of the mode of exercise (static or dynamic). On the other hand, the HR response, which accounted for increased Q in the exercises containing a static component, and Pa varied with mode of exercise. Any generalized scheme of cardiovascular control during exercise must account for the potential influence of dynamic and static components of the exercise.

scholarly journals Postexercise hypotension is mediated by reductions in sympathetic nerve activity

1999 ◽  
Vol 276 (1) ◽  
pp. H27-H32 ◽  
Author(s):  
Jennifer M. Kulics ◽  
Heidi L. Collins ◽  
Stephen E. DiCarlo
Keyword(s):  
Arterial Pressure ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Peripheral Resistance ◽  
Dynamic Exercise ◽  
Nerve Activity ◽  
Spontaneously Hypertensive ◽  
Before And After ◽  
Postexercise Hypotension ◽  
Carotid Arterial

Mean arterial pressure (MAP), the product of cardiac output (CO) and total peripheral resistance (TPR), is reduced below preexercise levels after a single bout of mild to moderate dynamic exercise. Thus acute, dynamic exercise may be used as a safe, therapeutic approach to reduce MAP. However, the mechanisms responsible for the postexercise hypotension (PEH) are unknown. We tested the hypothesis that PEH is associated with reductions in TPR and sympathetic nerve activity (SNA). Two experimental protocols were designed to test this hypothesis in male spontaneously hypertensive rats (SHR). In protocol 1( n = 9), CO and TPR were determined before, during, and after exercise. In protocol 2 ( n = 7), lumbar SNA (LSNA) was recorded before and after exercise. Rats in protocol 1 were chronically instrumented with left carotid arterial catheters and ascending aortic Doppler ultrasonic flow probes. Rats in protocol 2 were chronically instrumented with left carotid arterial catheters and electrodes around the lumbar sympathetic trunk. Dynamic treadmill exercise (9–12 m/min, 10% grade for 40 min) resulted in a postexercise reduction in MAP (from 143 ± 5 to 128 ± 4 mmHg, P < 0.05). Associated with the PEH was a reduction in TPR (from 28 ± 3 to 19 ± 2 mmHg/kHz; P < 0.05) and an elevation in CO (from 5.7 ± 0.4 to 7.2 ± 0.5 kHz; P < 0.05). The reductions in arterial pressure and TPR were associated with a decrease in LSNA (from 98 ± 3 to 49 ± 6%; P < 0.05). These results suggest that PEH is mediated by reductions in TPR and SNA.

PGE2 does not act at carotid sinus to raise arterial pressure in conscious sheep

1983 ◽  
Vol 245 (6) ◽  
pp. H1007-H1012
Author(s):  
B. A. Breuhaus ◽  
J. E. Chimoskey
Keyword(s):  
Carotid Artery ◽  
Arterial Pressure ◽  
Carotid Sinus ◽  
Pressor Response ◽  
Direct Action ◽  
Peripheral Resistance ◽  
External Carotid Artery ◽  
External Carotid ◽  
Conscious Sheep ◽  
Female Sheep

Conscious chronically instrumented adult female sheep were used to determine whether direct action of prostaglandin E2 (PGE2) on the carotid sinus baroreceptors contributes to the pressor response observed during infusion of PGE2 into the common carotid artery (CCA). During infusion of PGE2 into the CCA caudal to an intact carotid sinus, into the CCA caudal to a denervated carotid sinus, and into the external carotid artery, mean arterial pressure (MAP) rose 17, 22, and 17 mmHg, respectively (P less than 0.01). Heart rate (HR) rose 6, 6, and 8 beats/min, respectively (P less than 0.05). Cardiac output (CO) was also measured by indicator dilution using indocyanine green. In these experiments with infusion of PGE2 into the external carotid artery, MAP rose 15 mmHg (P less than 0.01), HR increased 6 beats/min (P less than 0.05), CO did not change, and total peripheral resistance (TPR) increased 23% (P less than 0.01). With infusion of PGE2 past a denervated carotid sinus, MAP rose 20 mmHg (P less than 0.01), HR rose 4 beats/min (P less than 0.05), CO did not change, and TPR increased 29% (P less than 0.01). There were no statistically significant differences in MAP or HR responses when PGE2 was infused past an intact carotid sinus, past a denervated carotid sinus, or beyond the carotid sinus. There is no evidence that direct action of PGE2 on carotid sinus baroreceptors either augments or inhibits the observed pressor effect of intracarotid PGE2. Intracarotid PGE2 acts rostral to the carotid sinus to increase MAP, HR, and TPR in conscious sheep.

Cardiorespiratory deconditioning with static and dynamic leg exercise during bed rest

1976 ◽  
Vol 41 (6) ◽  
pp. 905-909 ◽  
Author(s):  
R. W. Stremel ◽  
V. A. Convertino ◽  
E. M. Bernauer ◽  
J. E. Greenleaf
Keyword(s):  
Heart Rate ◽  
Plasma Volume ◽  
Rest Period ◽  
Bed Rest ◽  
Bicycle Ergometer ◽  
Dynamic Exercise ◽  
Maximal Heart Rate ◽  
Leg Extension ◽  
Ergometer Exercise ◽  
Extension Force

Bed rest deconditioning was assessed in seven healthy men (19–22 yr) following three 14-day periods of controlled activity during recumbencyby measuring submaximal and maximal oxygen uptake (VO2), ventilation (VE), heart rate, and plasma volume. Exercise regimens were performed in the supine position and included a) two 30-min periods daily of intermittent staticexercise at 21% of maximal leg extension force, and b) two 30-min periods of dynamic bicycle ergometer exercise daily at 68% of VO2max. No prescribed exercise was performed during the third bed rest period. Compared with their respective pre-bed rest control values, VO2max decreased (P less than 0.05) under all exercise conditions; -12.3% with no exercise, -9.2% with dynamic exercise, but only -4.8% with static exercise. Maximal heart rate was increased by 3.3% to 4.9% (P less than 0.05) under the three exercise conditions, while plasma volume decreased (P less than 0.05) -15.1% with no exercise and -10.1% with static, but only -7.8% (NS) with dynamic exercise. Sinceneither the static nor dynamic exercise training regimes minimized the changes in all the variables studied, some combination of these two types of exercise may be necessary for maximum protection from the effects of the bed deconditioning.

Hemodynamic effects of angiotensin, norepinephrine, and bradykinin continuously measured in unanesthetized dogs

1961 ◽  
Vol 201 (1) ◽  
pp. 92-96 ◽  
Author(s):  
Irvine H. Page ◽  
Frederick Olmsted
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Arterial Pressure ◽  
Stroke Volume ◽  
Diastolic Pressure ◽  
Pressor Response ◽  
Peripheral Resistance ◽  
Partial Recovery ◽  
Slight Rise ◽  
Abrupt Rise

Cardiac output, arterial pressure, heart rate and the derived functions, peripheral resistance and stroke volume, were registered continuously from intact, unanesthetized, unrestrained dogs. Isoleucyl5- or valyl5-angiotensin octapeptide caused output, heart rate and stroke volume to fall sharply when peripheral resistance rose. When infused for an hour, systolic and diastolic pressure remained elevated with unchanged infusion rate. Heart rate decreased in most animals, stroke volume and cardiac output fell, while peripheral resistance rose. Pentobarbital anesthesia increased somewhat the pressor response and decreased the bradycardia. Norepinephrine elicited, first, an abrupt rise in pressure and peripheral resistance, slight rise in heart rate and stroke volume. Arterial pressure then tended to stabilize, followed by a slow decrease associated with continued depression of cardiac output. Bradykinin caused fall in pressure, partial recovery, then further fall. Heart rate slowed, then rose. Cardiac output rose sharply during the initial fall in arterial pressure and remained elevated during the hypotensive response. Stroke volume was reduced during the initial fall but was reduced less during the rest of the response. Peripheral resistance was decreased sharply.

Reduced stroke volume during exercise in postural tachycardia syndrome

2007 ◽  
Vol 103 (4) ◽  
pp. 1128-1135 ◽  
Author(s):  
Shizue Masuki ◽  
John H. Eisenach ◽  
William G. Schrage ◽  
Christopher P. Johnson ◽  
Niki M. Dietz ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Arterial Pressure ◽  
Stroke Volume ◽  
Peripheral Resistance ◽  
Cardiovascular Regulation ◽  
Open Circuit ◽  
Exercise Intolerance ◽  
Postural Tachycardia Syndrome ◽  
Cycle Exercise ◽  
Postural Tachycardia

Postural tachycardia syndrome (POTS) is characterized by excessive tachycardia without hypotension during orthostasis. Most POTS patients also report exercise intolerance. To assess cardiovascular regulation during exercise in POTS, patients ( n = 13) and healthy controls ( n = 10) performed graded cycle exercise at 25, 50, and 75 W in both supine and upright positions while arterial pressure (arterial catheter), heart rate (HR; measured by ECG), and cardiac output (open-circuit acetylene breathing) were measured. In both positions, mean arterial pressure, cardiac output, and total peripheral resistance at rest and during exercise were similar in patients and controls ( P > 0.05). However, supine stroke volume (SV) tended to be lower in the patients than controls at rest (99 ± 5 vs. 110 ± 9 ml) and during 75-W exercise (97 ± 5 vs. 111 ± 7 ml) ( P = 0.07), and HR was higher in the patients than controls at rest (76 ± 3 vs. 62 ± 4 beats/min) and during 75-W exercise (127 ± 3 vs. 114 ± 5 beats/min) (both P < 0.01). Upright SV was significantly lower in the patients than controls at rest (57 ± 3 vs. 81 ± 6 ml) and during 75-W exercise (70 ± 4 vs. 94 ± 6 ml) (both P < 0.01), and HR was much higher in the patients than controls at rest (103 ± 3 vs. 81 ± 4 beats/min) and during 75-W exercise (164 ± 3 vs. 131 ± 7 beats/min) (both P < 0.001). The change (upright − supine) in SV was inversely correlated with the change in HR for all participants at rest ( R2= 0.32), at 25 W ( R2= 0.49), 50 W ( R2= 0.60), and 75 W ( R2= 0.32) ( P < 0.01). These results suggest that greater elevation in HR in POTS patients during exercise, especially while upright, was secondary to reduced SV and associated with exercise intolerance.

The Effect of Disuse Muscular Atrophy on the Forces Generated in Dynamic Exercise

1977 ◽  
Vol 53 (2) ◽  
pp. 183-188 ◽  
Author(s):  
A. J. Sargeant ◽  
C. T. M. Davies
Keyword(s):  
Muscle Atrophy ◽  
Muscular Atrophy ◽  
Work Rate ◽  
Dynamic Exercise ◽  
Peak Force ◽  
Similar Reduction ◽  
Leg Extension ◽  
Leg Cycling ◽  
Continuous Dynamic ◽  
Prolonged Immobilization

1. Six patients were studied after prolonged immobilization of an injured leg resulting in muscle atrophy. 2. The forces exerted by the atrophied and normal legs during continuous dynamic exercise (one- and two-leg cycling) were examined by a specially adapted ergometer. 3. In one-leg cycling the peak force exerted on the crank at a given work rate, the net work rate performed on the crank, and the proportion of work rate performed in leg extension and flexion phases of the cycle were the same whether the atrophied or normal limb was used. 4. Despite these similarities there was an unexplained reduction in efficiency when using the atrophied leg to perform one-leg cycling. 5. In two-leg cycling the peak force exerted at a given work rate by the atrophied leg was reduced by about 40% as compared with the normal leg, which reflected a similar reduction in the contribution of that leg to the total net work rate. Possible reasons and implications for this disproportionate sharing of work between the normal and atrophied leg are discussed.

Selected Contribution: Gender differences in cardiovascular regulation during recovery from exercise

2001 ◽  
Vol 91 (4) ◽  
pp. 1902-1907 ◽  
Author(s):  
Robert Carter ◽  
Donald E. Watenpaugh ◽  
Michael L. Smith
Keyword(s):  
Heart Rate ◽  
Arterial Pressure ◽  
Orthostatic Hypotension ◽  
Peripheral Resistance ◽  
Cardiovascular Regulation ◽  
Dynamic Exercise ◽  
Exercise Heart Rate ◽  
Active Recovery ◽  
Maximum Heart Rate ◽  
Increased Risk

Are women more susceptible to acute postexercise orthostatic hypotension compared with men? We hypothesized that decreases in arterial pressure during recovery from dynamic exercise are greater in women compared with men. We studied 8 men and 11 women during inactive and active recovery from cycling exercise. Heart rate, stroke volume (SV), cardiac output, mean arterial pressure (MAP), and total peripheral resistance (TPR) were measured during and after 3 min of exercise at 60% of calculated maximum heart rate. At 1 min after exercise, MAP decreased less ( P < 0.05) during inactive recovery in men (−18 ± 2 mmHg) compared with women (−30 ± 2 mmHg). This difference was due to greater decreases in SV and less increase in TPR during inactive recovery from exercise in women compared with men. These differences persisted for 5 min after exercise. MAP decreased less during active recovery in men compared with women. These findings suggest that women may have increased risk of postexercise orthostatic hypotension and that active recovery from exercise may reduce this risk.

Forces applied to cranks of a bicycle ergometer during one- and two-leg cycling

1977 ◽  
Vol 42 (4) ◽  
pp. 514-518 ◽  
Author(s):  
A. J. Sargeant ◽  
C. T. Davies
Keyword(s):  
Work Load ◽  
Bicycle Ergometer ◽  
Normal Cycle ◽  
Leg Extension ◽  
Significant Difference ◽  
Leg Cycling ◽  
Leg Exercise ◽  
The Mean ◽  
The Right ◽  
Work Done

An examination was made of the comparability of one- and two-leg exercise performed pedaling a stationary bicycle ergometer. The pattern of force exerted on both cranks was examined by means of a specially adapted ergometer which is described. The mean of the peak force in each cycle (MPF) was linearly related to work load (W) in both forms of exercise, and if account was taken of the doubled work output in two-leg cycling there was no significant difference between the MPF/W relationships; these are given by the equations one-leg: MPF (kg) = 11.23 + 0.065 (W in kpm/min) two-leg MPF (kg) = 10.76 + 0.032 (W in kpm/min). Calculation from the force records of the work performed on the cranks (WCR net) showed good agreement (r = 0.98, P less than 0.001) with the work load set on the ergometer. Analysis of the proportion of work done in leg extension and flexion phases of cycling revealed no differences between one- and two-leg exercise or between the right and left legs. The majority (approximately 80%) of Wer net being performed in leg extension is described by: Wer net (extension)) = 10.6 +/- 0.8 (W cr net total). In one-leg exercise (W greater than 900 kpm/min) the variation in rotation speed during a normal cycle ranged from +20 to --30% of the mean speed compared with +/- 10% in two-leg exercise.

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