scholarly journals Blood flow and muscle oxygen uptake at the onset and end of moderate and heavy dynamic forearm exercise

2001 ◽  
Vol 280 (6) ◽  
pp. R1741-R1747 ◽  
Author(s):  
Mireille C. P. Van Beekvelt ◽  
J. Kevin Shoemaker ◽  
Michael E. Tschakovsky ◽  
Maria T. E. Hopman ◽  
Richard L. Hughson
Keyword(s):  
Blood Flow ◽  
Oxygen Uptake ◽  
Venous Blood ◽  
Recovery Period ◽  
Dynamic Exercise ◽  
Moderate Intensity ◽  
Moderate Exercise ◽  
Muscle Oxygen ◽  
Forearm Exercise ◽  
Muscle Oxygen Uptake

We hypothesized that forearm blood flow (FBF) during moderate intensity dynamic exercise would meet the demands of the exercise and that postexercise FBF would quickly recover. In contrast, during heavy exercise, FBF would be inadequate causing a marked postexercise hyperemia and sustained increase in muscle oxygen uptake (V˙o 2musc). Six subjects did forearm exercise (1-s contraction/relaxation, 1-s pause) for 5 min at 25 and 75% of peak workload. FBF was determined by Doppler ultrasound, and O2 extraction was estimated from venous blood samples. In moderate exercise, FBF andV˙o 2musc increased within 2 min to steady state. Rapid recovery to baseline suggested adequate O2supply during moderate exercise. In contrast, FBF was not adequate during heavy dynamic exercise. Immediately postexercise, there was an ∼50% increase in FBF. Furthermore, we observed for the first time in the recovery period an increase inV˙o 2musc above end-exercise values. During moderate exercise, O2 supply met requirements, but with heavy forearm exercise, inadequate O2 supply during exercise caused accumulation of a large O2 deficit that was repaid during recovery.

Low blood flow at onset of moderate-intensity exercise does not limit muscle oxygen uptake

2010 ◽  
Vol 298 (3) ◽  
pp. R843-R848 ◽  
Author(s):  
Michael Nyberg ◽  
Stefan P. Mortensen ◽  
Bengt Saltin ◽  
Ylva Hellsten ◽  
Jens Bangsbo
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Oxygen Uptake ◽  
Oxygen Delivery ◽  
Initial Phase ◽  
Muscle Blood Flow ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Muscle Oxygen ◽  
Muscle Oxygen Uptake

The effect of low blood flow at onset of moderate-intensity exercise on the rate of rise in muscle oxygen uptake was examined. Seven male subjects performed a 3.5-min one-legged knee-extensor exercise bout (24 ± 1 W, mean ± SD) without (Con) and with (double blockade; DB) arterial infusion of inhibitors of nitric oxide synthase ( NG-monomethyl-l-arginine) and cyclooxygenase (indomethacin) to inhibit the synthesis of nitric oxide and prostanoids, respectively. Leg blood flow and leg oxygen delivery throughout exercise was 25–50% lower ( P < 0.05) in DB compared with Con. Leg oxygen extraction (arteriovenous O2 difference) was higher ( P < 0.05) in DB than in Con (5 s: 127 ± 3 vs. 56 ± 4 ml/l), and leg oxygen uptake was not different between Con and DB during exercise. The difference between leg oxygen delivery and leg oxygen uptake was smaller ( P < 0.05) during exercise in DB than in Con (5 s: 59 ± 12 vs. 262 ± 39 ml/min). The present data demonstrate that muscle blood flow and oxygen delivery can be markedly reduced without affecting muscle oxygen uptake in the initial phase of moderate-intensity exercise, suggesting that blood flow does not limit muscle oxygen uptake at the onset of exercise. Additionally, prostanoids and/or nitric oxide appear to play important roles in elevating skeletal muscle blood flow in the initial phase of exercise.

scholarly journals Muscle oxygen uptake and energy turnover during dynamic exercise at different contraction frequencies in humans

2001 ◽  
Vol 536 (1) ◽  
pp. 261-271 ◽  
Author(s):  
Richard A. Ferguson ◽  
Derek Ball ◽  
Peter Krustrup ◽  
Per Aagaard ◽  
Michael Kjær ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Dynamic Exercise ◽  
Energy Turnover ◽  
Muscle Oxygen ◽  
Muscle Oxygen Uptake

scholarly journals Slowed muscle oxygen uptake kinetics with raised metabolism are not dependent on blood flow or recruitment dynamics

2014 ◽  
Vol 592 (8) ◽  
pp. 1857-1871 ◽  
Author(s):  
Rob C. I. Wüst ◽  
James R. McDonald ◽  
Yi Sun ◽  
Brian S. Ferguson ◽  
Matthew J. Rogatzki ◽  
...  
Keyword(s):  
Blood Flow ◽  
Oxygen Uptake ◽  
Oxygen Uptake Kinetics ◽  
Uptake Kinetics ◽  
Muscle Oxygen ◽  
Muscle Oxygen Uptake

scholarly journals Impact of combined NO and PG blockade on rapid vasodilation in a forearm mild-to-moderate exercise transition in humans

2005 ◽  
Vol 288 (1) ◽  
pp. H214-H220 ◽  
Author(s):  
Natasha R. Saunders ◽  
Frank A. Dinenno ◽  
Kyra E. Pyke ◽  
Anna M. Rogers ◽  
Michael E. Tschakovsky
Keyword(s):  
Blood Flow ◽  
Steady State ◽  
Control Treatment ◽  
Moderate Intensity ◽  
Saline Control ◽  
Moderate Exercise ◽  
Early Increase ◽  
Forearm Vascular Conductance ◽  
Forearm Exercise ◽  
Pg Release

We tested the hypothesis that nitric oxide (NO) and prostaglandins (PGs) contribute to the rapid vasodilation that accompanies a transition from mild to moderate exercise. Nine healthy volunteers (2 women and 7 men) lay supine with forearm at heart level. Subjects were instrumented for continuous brachial artery infusion of saline (control condition) or combined infusion of NG-nitro-l-arginine methyl ester (l-NAME) and ketorolac (drug condition) to inhibit NO synthase and cyclooxygenase, respectively. A step increase from 5 min of steady-state mild (5.4 kg) rhythmic, dynamic forearm handgrip exercise (1 s of contraction followed by 2 s of relaxation) to moderate (10.9 kg) exercise for 30 s was performed. Steady-state forearm blood flow (FBF; Doppler ultrasound) and forearm vascular conductance (FVC) were attenuated in drug compared with saline (control) treatment: FBF = 196.8 ± 30.8 vs. 281.4 ± 34.3 ml/min and FVC = 179.3 ± 29.4 vs. 277.8 ± 34.8 ml·min−1·100 mmHg−1 (both P < 0.01). FBF and FVC increased from steady state after release of the initial contraction at the higher workload in saline and drug conditions: ΔFBF = 72.4 ± 8.7 and 52.9 ± 7.8 ml/min, respectively, and ΔFVC = 66.3 ± 7.3 and 44.1 ± 7.0 ml·min−1·100 mmHg−1, respectively (all P < 0.05). The percent ΔFBF and ΔFVC were not different during saline infusion or combined inhibition of NO and PGs: ΔFBF = 27.2 ± 3.1 and 28.1 ± 3.8%, respectively ( P = 0.78) and ΔFVC = 25.7 ± 3.2 and 26.0 ± 4.0%, respectively ( P = 0.94). The data suggest that NO and vasodilatory PGs are not obligatory for rapid vasodilation at the onset of a step increase from mild- to moderate-intensity forearm exercise. Additional vasodilatory mechanisms not dependent on NO and PG release contribute to the immediate and early increase in blood flow in an exercise-to-exercise transition.

Effect of changes in blood flow, norepinephrine, and pH on oxygen uptake by resting skeletal muscle

1980 ◽  
Vol 58 (1) ◽  
pp. 93-96 ◽  
Author(s):  
C. K. Chapler ◽  
W. N. Stainsby ◽  
L. B. Gladden
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Oxygen Uptake ◽  
Muscle Blood Flow ◽  
Sampling Period ◽  
Low Flow ◽  
Muscle Oxygen ◽  
Norepinephrine Infusion ◽  
Infusion Of Norepinephrine ◽  
Muscle Oxygen Uptake

The purpose of this study was to examine the effects of norepinephrine infusion alone and during alkalosis on oxygen uptake in the dog gastrocnemius-plantaris muscle group under conditions of constant muscle blood flow. The animals were not cold acclimatized. Blood flow was pump controlled, alkalosis was produced by hyperventilation, and norepinephrine was infused intravenously at a rate of 1–1.5 μg/kg per minute. Alkalosis had no effect either alone or in combination with changes in blood flow. Similarly, changing blood flow from a low (0.10 ± 0.02 mL/g muscle per minute (mean ± SE)) to a high (0.34 ± 0.04 mL/g muscle per minute) rate did not alter resting oxygen uptake. Norepinephrine caused an average increase of about 30% in resting muscle oxygen uptake which was sustained for the 15-min sampling period during low flow - norepinephrine infusion and during the low and high blood flow - norepinephrine - alkalosis sampling periods. Norepinephrine infusion during the period of high muscle blood flow without alkalosis resulted in a transient increase followed by a decrease in muscle oxygen uptake. The data demonstrated that infusion of norepinephrine increased skeletal muscle oxygen uptake in "non-cold-acclimatized" dogs at low constant muscle blood flow. Further, without alkalosis, the norepinephrine effect at high flow was transient.

Skeletal muscle blood flow and oxygen uptake at rest and during exercise in humans: a pet study with nitric oxide and cyclooxygenase inhibition

2011 ◽  
Vol 300 (4) ◽  
pp. H1510-H1517 ◽  
Author(s):  
Heinonen Ilkka ◽  
Saltin Bengt ◽  
Kemppainen Jukka ◽  
Hannu T. Sipilä ◽  
Oikonen Vesa ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Skeletal Muscle ◽  
Blood Flow ◽  
Oxygen Uptake ◽  
Muscle Blood Flow ◽  
Arterial Infusion ◽  
Skeletal Muscle Blood Flow ◽  
Muscle Oxygen ◽  
Resting Muscle ◽  
Muscle Oxygen Uptake

The aim of the present study was to determine the effect of nitric oxide and prostanoids on microcirculation and oxygen uptake, specifically in the active skeletal muscle by use of positron emission tomography (PET). Healthy males performed three 5-min bouts of light knee-extensor exercise. Skeletal muscle blood flow and oxygen uptake were measured at rest and during the exercise using PET with H2O15 and 15O2 during: 1) control conditions; 2) nitric oxide synthase (NOS) inhibition by arterial infusion of NG-monomethyl-l-arginine (l-NMMA), and 3) combined NOS and cyclooxygenase (COX) inhibition by arterial infusion of l-NMMA and indomethacin. At rest, inhibition of NOS alone and in combination with indomethacin reduced ( P < 0.05) muscle blood flow. NOS inhibition increased ( P < 0.05) limb oxygen extraction fraction (OEF) more than the reduction in muscle blood flow, resulting in an ∼20% increase ( P < 0.05) in resting muscle oxygen consumption. During exercise, muscle blood flow and oxygen uptake were not altered with NOS inhibition, whereas muscle OEF was increased ( P < 0.05). NOS and COX inhibition reduced ( P < 0.05) blood flow in working quadriceps femoris muscle by 13%, whereas muscle OEF and oxygen uptake were enhanced by 51 and 30%, respectively. In conclusion, by specifically measuring blood flow and oxygen uptake by the use of PET instead of whole limb measurements, the present study shows for the first time in humans that inhibition of NO formation enhances resting muscle oxygen uptake and that combined inhibition of NOS and COX during exercise increases muscle oxygen uptake.

scholarly journals Eight weeks of nitrate supplementation improves blood flow and reduces the exaggerated pressor response during forearm exercise in peripheral artery disease

2018 ◽  
Vol 315 (1) ◽  
pp. H101-H108 ◽  
Author(s):  
Nicholas T. Kruse ◽  
Kenichi Ueda ◽  
William E. Hughes ◽  
Darren P. Casey
Keyword(s):  
Blood Flow ◽  
Peripheral Artery Disease ◽  
Pressor Response ◽  
Treated Group ◽  
Moderate Intensity ◽  
Peripheral Artery ◽  
Pressor Responses ◽  
Nitrate Supplementation ◽  
Artery Disease ◽  
Forearm Exercise

Peripheral artery disease (PAD) is characterized by a reduced blood flow (BF) and an elevated blood pressure (pressor) response during lower extremity exercise. Although PAD is evident in the upper extremities, no studies have determined BF and pressor responses during upper extremity exercise in PAD. Emerging evidence suggests that inorganic nitrate supplementation may serve as an alternative dietary strategy to boost nitric oxide bioavailability, improving exercising BF and pressor responses during exercise. The present study investigated 1) BF and pressor responses to forearm exercise in patients with PAD ( n = 21) relative to healthy age-matched control subjects ( n = 16) and 2) whether 8 wk of NaNO3 supplementation influenced BF and pressor responses to forearm exercise in patients with PAD. Patients with moderate to severe PAD were randomly assigned to a NaNO3 (1 g/day, n = 13)-treated group or a placebo (microcrystalline cellulose, n = 8)-treated group. Brachial artery forearm BF (FBF; via Doppler) and blood pressure (via finger plethysmography) were measured during mild-intensity (~3.5-kg) and moderate-intensity (~7-kg) handgrip exercise. The absolute change (from baseline) in FBF was reduced (except in the 3.5-kg condition) and BP responses were increased in patients with PAD compared with healthy control subjects in 3.5- and 7-kg conditions (all P < 0.05). Plasma nitrate and nitrite were elevated, exercising (7-kg) ΔFBF was improved (from 141 ± 17 to 172 ± 20 ml/min), and mean arterial pressure response was reduced (from 13 ± 1 to 9 ± 1 mmHg, P < 0.05) in patients with PAD that received NaNO3 supplementation for 8 wk relative to those that received placebo. These results suggest that the BF limitation and exaggerated pressor response to moderate-intensity forearm exercise in patients with PAD are improved with 8 wk of NaNO3 supplementation. NEW & NOTEWORTHY Peripheral artery disease (PAD) results in an exaggerated pressor response and reduced blood flow during lower limb exercise; however, the effect of PAD in the upper limbs has remained unknown. These results suggest that 8 wk of inorganic nitrate supplementation improves the blood flow limitation and exaggerated pressor response to moderate-intensity forearm exercise in PAD.

Effect of stimulation of hepatic nerves on hepatic O2 uptake and blood flow

1977 ◽  
Vol 232 (6) ◽  
pp. H652-H656
Author(s):  
W. W. Lautt
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Oxygen Uptake ◽  
Portal Vein ◽  
Hepatic Artery ◽  
Venous Blood ◽  
Neurogenic Vasoconstriction ◽  
Pressure Changes ◽  
Hepatic Nerves ◽  
Stimulation Of

Acute denervation of the liver did not result in changes of oxygen uptake or hemodynamics in the intact liver of the cat. Stimulation of the hepatic nerves resulted in a marked reduction of vascular conductance of the hepatic artery and portal vein (intrahepatic) resulting in almost complete cessation of arterial flow and increased portal blood pressure. The hepatic artery showed a more complete escape from the neurogenic vasoconstriction than did the portal vein. During the stable "escape phase" oxygen delivery was 86% of control, but hepatic extraction of oxygen increased so that oxygen uptake was not altered from control values. The return of oxygen consumption to normal during nerve stimulation suggests that redistribution of hepatic blood flow did not occur. In spite of arterial and portal venous blood pressure changes and changes in gut conductance, oxygen extraction of the gut did not change.

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