Local and central circulatory responses to sustained contractions and the effect of free or restricted arterial inflow on post‐exercise hyperaemia

Lind, A. R.; McNicol, G. W.

doi:10.1113/jphysiol.1967.sp008318

Cited by 91 publications

(60 citation statements)

References 12 publications

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“…2 the test forearm contracted at 10 % MVC. In the present experiments, as elsewhere reported (Lind & McNicol, 1967) the blood flow through the forearm at this tension reaches a steady state, from which it may be assumed that the blood flow is adequate for the metabolic activity of the muscles; in these circumstances it seems inconceivable that there is 606 CARDIOVASCULAR RESPONSES 607 a further dilatation due to a further increased production of metabolites (Barcroft, 1964). It seems more probable that the increased flow results from the increased perfusion pressure to the muscle which arises when another group of muscles contracts at an appropriately higher comparative tension.…”

Section: Discussionmentioning

confidence: 59%

Circulatory responses to sustained hand‐grip contractions performed during other exercise, both rhythmic and static

Lind¹,

McNicol²

1967

The Journal of Physiology

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181

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SUIMMARY1. The cardiovascular responses to sustained hand-grip contractions at 20, 30 and 50 % maximal voluntary contraction (MVC) were measured in subjects who were engaged in treadmill walking at three different rates with oxygen intakes of 11, 1-7 and 2-8 1./min. The increments in heart rate and blood pressure at tensions of 20 and 30 % MVC were similar at all rates of walking, but the response to a contraction at 50 % MVC was lower at the hardest work rate than at the two easier rates.2. When two or more muscle groups contracted at the same relative tension, the increments in heart rate and blood pressure were the same, whether they contracted separately or together.3. When two or more muscle groups contracted simultaneously at different relative tensions, the increments in heart rate and blood pressure were the same as when the muscle group, at the higher relative tension, contracted separately at that tension.4. The blood flow to a muscle engaged in sustained contraction was increased when a second muscle group contracted at a higher relative tension.

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Section: Discussionmentioning

confidence: 59%

Circulatory responses to sustained hand‐grip contractions performed during other exercise, both rhythmic and static

Lind¹,

McNicol²

1967

The Journal of Physiology

Self Cite

181

View full text Add to dashboard Cite

show abstract

“…In normal man mechanisms which are mainly local cause an increase in blood flow within a second in contracting muscles which lasts as long as the muscle contraction, usually increases further in the immediate postcontraction period and therefore returns to normal slowly (Koroxenidis & Shepherd, 1961;Brandon, Cooper, Fewings, Walsh & Whelan, 1966;Lind & McNicol, 1967). With short periods of muscle contraction the blood flow in non-contracting muscles and in the hand usually decreases in spite of an increased perfusion pressure and the veins constrict (Bevegard & Shepherd, 1965) these responses being the result of a reflex increase in sympathetic constrictor tone (Shepherd, 1967).…”

Section: Resultsmentioning

confidence: 99%

Cardiovascular changes associated with skeletal muscle spasm in tetraplegic man

Corbett¹,

Frankel²,

Harris³

1971

The Journal of Physiology

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SUMMARY1. A study has been made of the effect of spontaneous and induced muscle spasms on blood pressure, heart rate, hand blood flow, calf blood flow and occluded vein pressure in the hand and foot in non-bedridden patients with chronic, closed, complete, localized transaction of the cervical spinal cord.2. Both types of spasm produced a similar response consisting of an increase in blood pressure and occluded vein pressure and a decrease in heart rate and hand and calf blood flow. The changes commenced within 2-3 see and usually reached maxima in 20-30 sec. On some occasions there was a temporary initial increase in heart rate and calf blood flow.3. The changes occurred independently of changes in bladder pressure. 4. It is concluded that the changes in peripheral blood vessels result from a spinal sympathetic reflex to somatic afferents associated with muscular contraction.

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“…Exercise endurance varied in these untrained subjects. Supine exercise lasted [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] minutes (mean 17.5) and upright exercise 9-18 minutes (mean 13.5).…”

Section: Bicycle Exercisementioning

confidence: 99%

Echocardiographic evaluation of left ventricular size and performance during handgrip and supine and upright bicycle exercise.

Crawford¹,

White²,

Amon³

1979

Circulation

136

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SUMMARY We used M-mode echocardiography to measure left ventricular dimensions in diastole (Dd) and systole (Ds) and to assess ventricular performance by computing the percent dimensional shortening (%AD) and the normalized rate of dimensional shortening (Vd) during isometric and isotonic exercise in normal subjects. In 27 subjects, isometric handgrip exercise at 50% of maximum grip until fatigue produced a significant increase in Ds (33 ± 3.4 (SD) vs 30.6 i 3.7 mm, p < 0.001), and a reduction in %AD (34 ± 4 vs 39 ± 5%,p < 0.001) and Vd (1.15 ± 0.15 vs 1.28 0.19 sec-',p < 0.001). Handgrip exercise at 15% of maximum grip produced similar but less marked changes in the 27 subjects, and acute pressure loading with phenylephrine caused similar but more marked changes in 10 of the subjects. In the 20 subjects who performed at least 12 minutes of supine bicycle exercise, Ds decreased significantly (25.6 ± 4.0 vs 31.7 ± 2.8 mm, p < 0.001) and %AD increased (49 ± 6 vs 36 ± 5%,p < 0.001). We observed similar results in the 12 subjects also studied during upright bicycle exercise. Dd was smaller in the upright position but unchanged during either isometric or isotonic exercise. We conclude that: 1) end-diastolic left ventricular size is maintained during isometric exercise and moderate dynamic exercise, even in the upright position; 2) isometric exercise leads to a mild decrease in left ventricular shortening, whereas dynamic exercise results in marked increases in shortening; this difference may be related to the relatively greater increase in blood pressure than in heart rate during isometric exercise; and 3) M-mode echocardiography can be successfully accomplished in selected subjects during various forms of exercise. M-MODE ECHOCARDIOGRAPHY is an accurateand reproducible technique for assessing resting left ventricular size and performance in normal-sized hearts without segmental myocardial disease.'14 The sensitivity of this technique for detecting changes in left ventricular dynamics has been shown in studies evaluating the response to upright tilting,', the Valsalva maneuver,7 8 ventricular premature depolarizations,9 normal phasic respiration'0 and acute pharmacologic interventions with agents such as amyl nitrite, nitroglycerin, atropine and phenylephrine. 1" 12 One advantage of echocardiography is the ability to measure left ventricular diameters intermittently or continuously before, during and after an intervention without risk or discomfort to the subject and without affecting the normal response to the test conditions. Accordingly, we used echocardiography to measure left ventricular size and performance in normal subjects during isometric handgrip exercise and dynamic bicycle exercise in the supine and upright positions. MethodsThe study population consisted of 27 normal subjects who were selected from a group of twice as many because of excellent echocardiograms in the supine position at rest. There were 23 men and four women, ages 19-36 years. Physical fitness varied from subject

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Local and central circulatory responses to sustained contractions and the effect of free or restricted arterial inflow on post‐exercise hyperaemia

Cited by 91 publications

References 12 publications

Circulatory responses to sustained hand‐grip contractions performed during other exercise, both rhythmic and static

Circulatory responses to sustained hand‐grip contractions performed during other exercise, both rhythmic and static

Cardiovascular changes associated with skeletal muscle spasm in tetraplegic man

Echocardiographic evaluation of left ventricular size and performance during handgrip and supine and upright bicycle exercise.

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