scholarly journals Active forearm blood flow adjustments to handgrip exercise in young and older healthy men.

1994 ◽  
Vol 474 (2) ◽  
pp. 353-360 ◽  
Author(s):  
J L Jasperse ◽  
D R Seals ◽  
R Callister
Keyword(s):  
Blood Flow ◽  
Forearm Blood Flow ◽  
Handgrip Exercise ◽  
Healthy Men

Vasodilation contributes to the rapid hyperemia with rhythmic contractions in humans

1998 ◽  
Vol 76 (4) ◽  
pp. 418-427 ◽  
Author(s):  
J K Shoemaker ◽  
M E Tschakovsky ◽  
R L Hughson
Keyword(s):  
Blood Flow ◽  
Forearm Blood Flow ◽  
Perfusion Pressure ◽  
Blood Velocity ◽  
Pulsed Doppler ◽  
Contraction Rate ◽  
Handgrip Exercise ◽  
Arterial Diameter ◽  
Exercise Tests ◽  
Rhythmic Contractions

The hypothesis that the rapid increases in blood flow at the exercise onsetare exclusively due to the mechanical effects of the muscle pump was tested in six volunteersduring dynamic handgrip exercise. While supine, each subject completed a series of eightdifferent exercise tests in which brachial artery blood pressure (BP) was altered by25–30 mmHg (1 mmHg = 133.3 Pa) by positioning the arm above or below the heart.Two different weights, corresponding to 4.9 and 9.7% of maximal voluntary isometriccontraction, were raised and lowered at two different contraction rate schedules (1s:1s and 2s:2swork–rest) each with a 50% duty cycle. Beat-by-beat measures of mean blood velocity (MBV)(pulsed Doppler) were obtained at rest and for 5 min following step increases in work ratewith emphasis on the first 24 s. MBV was increased 50–100% above rest following the firstcontraction in both arm positions (p < 0.05). The increase in MBV from rest was greaterin the below position compared with above, and this effect was observed following the first andsubsequent contractions (p < 0.05). However, the positional effect on the increase inMBV could not be explained entirely by the ~40% greater BP in this position. Also, the greaterworkload resulted in greater increases in MBV as early as the first contraction, compared withthe light workload (p < 0.05) despite similar reductions in forearm volume followingsingle contractions. MBV was greater with faster contraction rate tests by 8 s of exercise. Itwas concluded that microvascular vasodilation must act in concert with a reduction in venouspressure to increase forearm blood flow within the initial 2–4 s of exercise.Key words: Doppler, mean blood velocity, arterial diameter,handgrip exercise, perfusion pressure.

Forearm Vasoreactivity in Type I Diabetic Subjects

2001 ◽  
Vol 26 (1) ◽  
pp. 34-43 ◽  
Author(s):  
Jason D. Allen ◽  
Michael Welsch ◽  
Nikki Aucoin ◽  
Robert Wood ◽  
Matt Lee ◽  
...  
Keyword(s):  
Risk Factors ◽  
Blood Flow ◽  
Vascular Function ◽  
Forearm Blood Flow ◽  
Reactive Hyperemia ◽  
Arterial Occlusion ◽  
Type I ◽  
Handgrip Exercise ◽  
Blood Flows

This study compared forearm vasoreactivity in 15 Type 1 diabetic subjects with 15 healthy controls. The groups were matched for age, exercise capacity, and the absence of other cardiovascular risk factors. Vasoreactivity was measured using strain gauge plethysmography, at rest, after arterial occlusion (OCC), and following OCC coupled with handgrip exercise (ROCC). Forearm blood flows were significantly elevated between conditions 2.58 ± 0.37 ml/100mltissue at rest to 26.80 ± 6.56 after OCC and 32.80 ± 8.26ml/100mltissue following ROCC in Type 1 diabetic subjects. There were no differences in forearm blood flow between groups for any of the conditions. These data indicate the degree of forearm blood flow is directly related to the intensity of the vasodilatory stimulus. However, our study did not reveal evidence of impaired vasodilatory capacity in Type 1 diabetic subjects compared to controls in the absence of other risk factors. Key words: IDDM, vascular function, exercise, fitness, and reactive hyperemia

Acute effects of felodipine and nifedipine on hepatic and forearm blood flow in healthy men

1990 ◽  
Vol 38 (6) ◽  
pp. 529-533 ◽  
Author(s):  
B. Bengtsson-Hasselgren ◽  
O. R�nn ◽  
L. -O. Blychert ◽  
B. Edgar ◽  
S. Raner
Keyword(s):  
Blood Flow ◽  
Forearm Blood Flow ◽  
Acute Effects ◽  
Healthy Men

Reproducibility of haemodynamic and plasma catecholamine responses to isometric exercise and mental arithmetic in normo- and hyper-tensive subjects

1988 ◽  
Vol 75 (6) ◽  
pp. 615-619 ◽  
Author(s):  
Jacques Lenders ◽  
Harry Houben ◽  
Rudolf Van Valderen ◽  
Jacques Willemsen ◽  
Theo Thien
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Forearm Blood Flow ◽  
Mental Arithmetic ◽  
Pharmacological Intervention ◽  
Handgrip Exercise ◽  
Single Observation ◽  
Plasma Adrenaline ◽  
Normotensive Subjects

1. To determine the reproducibility of a mental arithmetic stress test and a handgrip exercise test, we studied the responses of blood pressure, heart rate, forearm blood flow and plasma catecholamines on two occasions, with an interval of at least 1 week, in 24 normotensive and 22 hypertensive subjects. 2. The se of a single observation of the percentage changes of blood pressure ranged from 3.9 to 9.3% in normotensive subjects and from 3.9 to 7.4% in hypertensive subjects in both tests. For heart rate, these values were 4.9–12.3% in the normotensive subjects and 4.8–5.7% in the hypertensive subjects. However, there was a wide individual scatter of these haemodynamic responses during both tests. The forearm blood flow, only measured during mental arithmetic, had an se of a single observation of 33.7%. 3. In 10 normotensive subjects the se of a single observation of the change in plasma noradrenaline was 0.16 nmol/l during handgrip exercise and 0.09 nmol/l during mental arithmetic. The corresponding values for plasma adrenaline were 0.04 and 0.05 nmol/l. 4. In conclusion, although both tests showed a rather low se of a single observation for the blood pressure and heart rate responses in normo- and hyper-tensive subjects, there was a considerable individual variability. If related to the mean forearm blood flow responses, the se of a single observation of the forearm blood flow response was of similar magnitude. The limited intra-individual reproducibility of both tests should be borne in mind when interpreting pharmacological intervention studies or studies evaluating sympathoadrenal reactivity in cardiovascular disorders.

Forearm blood flow responses to fatiguing isometric contractions in women and men

2007 ◽  
Vol 293 (1) ◽  
pp. H805-H812 ◽  
Author(s):  
Benjamin C. Thompson ◽  
Tanvi Fadia ◽  
Danny M. Pincivero ◽  
Barry W. Scheuermann
Keyword(s):  
Blood Flow ◽  
Forearm Blood Flow ◽  
Vascular Occlusion ◽  
Exercise Duration ◽  
Handgrip Exercise ◽  
Isometric Handgrip ◽  
Isometric Handgrip Exercise ◽  
Target Force ◽  
The Subject ◽  
Voluntary Contractions

Previous studies suggest that women experience less vascular occlusion than men when generating the same relative contractile force. This study examined forearm blood flow (FBF) in women and men during isometric handgrip exercise requiring the same relative force. Thirty-eight subjects [20 women and 18 men, 22.8 ± 0.6 yrs old (means ± SE)] performed low- and moderate-force handgrip exercise on two occasions. Subjects performed five maximum voluntary contractions (MVC) before exercise to determine 20% and 50% MVC target forces. Time to task failure (TTF) was determined when the subject could not maintain force within 5% of the target force. Mean blood velocity was measured in the brachial artery with the use of Doppler ultrasonography. Arterial diameter was measured at rest and used to calculate absolute FBF (FBFa; ml/min) and relative FBF (FBFr; ml·min−1·100 ml−1). Women generated less ( P < 0.05) absolute maximal force (208 ± 10 N) than men (357 ± 17 N). The TTF was longer ( P < 0.05) at 20% MVC for women (349 ± 32 s) than for men (230 ± 23 s), but no difference between the sexes was observed at 50% MVC (women: 69 ± 5 s; men: 71 ± 8 s). FBFa and FBFr increased ( P < 0.05) from rest to TTF in both women and men during 20% and 50% MVC trials. FBFr was greater in women than in men at ≥30% TTF during 50% MVC. At exercise durations ≥60% of TTF, FBFa was lower ( P < 0.05) in women than in men during handgrip at 20% MVC. Despite the longer exercise duration for women at the lower contraction intensity, FBFr was similar between the sexes, suggesting that muscle perfusion is matched to the exercising muscle mass independent of sex.

Comparison of Static and Placebo Magnets on Resting Forearm Blood Flow in Young, Healthy Men

2002 ◽  
Vol 32 (10) ◽  
pp. 518-524 ◽  
Author(s):  
Gregory F. Martel ◽  
Steven C. Andrews ◽  
Christopher G. Roseboom
Keyword(s):  
Blood Flow ◽  
Forearm Blood Flow ◽  
Healthy Men

scholarly journals Sympathetic activation increases NO release from eNOS but neither eNOS nor nNOS play an essential role in exercise hyperemia in the human forearm

2013 ◽  
Vol 304 (9) ◽  
pp. H1225-H1230 ◽  
Author(s):  
Husain Shabeeh ◽  
Michael Seddon ◽  
Sally Brett ◽  
Narbeh Melikian ◽  
Barbara Casadei ◽  
...  
Keyword(s):  
Blood Flow ◽  
Negative Pressure ◽  
Essential Role ◽  
Forearm Blood Flow ◽  
Lower Body Negative Pressure ◽  
No Synthase ◽  
Lower Body ◽  
Sympathetic Activation ◽  
Handgrip Exercise ◽  
No Release

Nitric oxide (NO) release from endothelial NO synthase (eNOS) and/or neuronal NO synthase (nNOS) could be modulated by sympathetic nerve activity and contribute to increased blood flow after exercise. We examined the effects of brachial-arterial infusion of the nNOS selective inhibitor S-methyl-l-thiocitrulline (SMTC) and the nonselective NOS inhibitor NG-monomethyl-l-arginine (l-NMMA) on forearm arm blood flow at rest, during sympathetic activation by lower body negative pressure, and during lower body negative pressure immediately after handgrip exercise. Reduction in forearm blood flow by lower body negative pressure during infusion of SMTC was not significantly different from that during vehicle (−28.5 ± 4.02 vs. −34.1 ± 2.96%, respectively; P = 0.32; n = 8). However, l-NMMA augmented the reduction in forearm blood flow by lower body negative pressure (−44.2 ± 3.53 vs. −23.4 ± 5.71%; n = 8; P < 0.01). When lower body negative pressure was continued after handgrip exercise, there was no significant effect of either l-NMMA or SMTC on forearm blood flow immediately after low-intensity exercise ( P = 0.91 and P = 0.44 for l-NMMA vs. saline and SMTC vs. saline, respectively; each n = 10) or high-intensity exercise ( P = 0.46 and P = 0.68 for l-NMMA vs. saline and SMTC vs. saline, respectively; each n = 10). These results suggest that sympathetic activation increases NO release from eNOS, attenuating vasoconstriction. Dysfunction of eNOS could augment vasoconstrictor and blood pressure responses to sympathetic activation. However, neither eNOS nor nNOS plays an essential role in postexercise hyperaemia, even in the presence of increased sympathetic activation.

Evaluation of muscle metaboreflex function through graded reduction in forearm blood flow during rhythmic handgrip exercise in humans

2011 ◽  
Vol 301 (2) ◽  
pp. H609-H616 ◽  
Author(s):  
Masashi Ichinose ◽  
Stephane Delliaux ◽  
Kazuhito Watanabe ◽  
Naoto Fujii ◽  
Takeshi Nishiyasu
Keyword(s):  
Blood Flow ◽  
Forearm Blood Flow ◽  
Pressor Response ◽  
Muscle Blood Flow ◽  
Voluntary Contraction ◽  
Open Loop ◽  
Handgrip Exercise ◽  
Hemodynamic Responses ◽  
Muscle Metaboreflex ◽  
Arterial Blood

Hypoperfusion of active skeletal muscle elicits a reflex pressor response termed the muscle metaboreflex. Our aim was to determine the muscle metaboreflex threshold and gain in humans by creating an open-loop relationship between active muscle blood flow and hemodynamic responses during a rhythmic handgrip exercise. Eleven healthy subjects performed the exercise at 5 or 15% of maximal voluntary contraction (MVC) in random order. During the exercise, forearm blood flow (FBF), which was continuously measured using Doppler ultrasound, was reduced in five steps by manipulating the inner pressure of an occlusion cuff on the upper arm. The FBF at each level was maintained for 3 min. The initial reductions in FBF elicited no hemodynamic changes, but once FBF fell below a threshold, mean arterial blood pressure (MAP) and heart rate (HR) increased and total vascular conductance (TVC) decreased in a linear manner. The threshold FBF during the 15% MVC trial was significantly higher than during the 5% MVC trial. The gain was then estimated as the slope of the relationship between the hemodynamic responses and FBFs below the threshold. The gains for the MAP and TVC responses did not differ between workloads, but the gain for the HR response was greater in the 15% MVC trial. Our findings thus indicate that increasing the workload shifts the threshold for the muscle metaboreflex to higher blood flows without changing the gain of the reflex for the MAP and TVC responses, whereas it enhances the gain for the HR response.

Acute haemodynamic effects of lipolysis-induced increase of free fatty acids in healthy men

2002 ◽  
Vol 102 (5) ◽  
pp. 495-500 ◽  
Author(s):  
Mark T. KEARNEY ◽  
Philip J. CHOWIENCZYK ◽  
Sally E. BRETT ◽  
Angela SUTCLIFFE ◽  
James M. RITTER ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Fatty Acids ◽  
Blood Flow ◽  
Free Fatty Acids ◽  
Arterial Blood Pressure ◽  
Lipid Emulsion ◽  
Forearm Blood Flow ◽  
Haemodynamic Effects ◽  
Healthy Men ◽  
Arterial Blood

Circulating free fatty acids (FFA) are elevated in subjects with insulin resistance and Type II diabetes, and increase during myocardial ischaemia, but their haemodynamic effects are incompletely understood. During an investigation of the effects of FFA on endothelial function, we administered lipid emulsion (150mgċmin-1 of soybean oil) with heparin (0.2 unitċkg-1ċmin-1) intravenously to eight healthy men for 2h. This increased circulating FFA to 3.1±0.5mmol/l. Forearm blood flow was measured by venous occlusion plethysmography during brachial artery infusions of saline, acetylcholine and nitroprusside before, and at 1 and 2h. Lipid/heparin infusion had no significant effect on vasodilation to nitroprusside but progressively increased responses to acetylcholine (from 6.3±2.0 during 30μgċmin-1 before-lipid infusion to 7.9±1.3 at 1h and 12.2±1.1mlċmin-1ċ100ml-1 at 2h, P < 0.001). Basal flow increased from 2.7±0.7 to 4.7±0.8mlċmin-1ċ100ml-1 from 0 to 2h. We performed a second study to clarify this effect on basal blood flow. Healthy men (n = 8) received, on separate occasions, 4h intravenous infusions of lipid emulsion with heparin and, as a control, saline with heparin. Lipid with heparin increased mean arterial blood pressure (maximum increment 8.2±2.7mmHg, P < 0.01 compared with saline/heparin control) and forearm blood flow (from 1.7±0.2 to 2.9±0.3mlċmin-1ċ100ml-1, P < 0.01) without a significant effect on heart rate, and reduced calculated forearm vascular resistance (from 49.1±5.4 to 31.3±3.9 arbitrary units, P < 0.01). In conclusion, acute elevation of FFA in healthy men increases arterial blood pressure and reduces vascular resistance. These haemodynamic changes could be clinically relevant.

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