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.

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 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.

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.

Leg oxygen uptake in the initial phase of intense exercise is slowed by a marked reduction in oxygen delivery

2013 ◽  
Vol 305 (3) ◽  
pp. R313-R321 ◽  
Author(s):  
Peter M. Christensen ◽  
Michael Nyberg ◽  
Stefan P. Mortensen ◽  
Jens Jung Nielsen ◽  
Niels H. Secher ◽  
...  
Keyword(s):  
Blood Flow ◽  
Oxygen Uptake ◽  
Oxygen Delivery ◽  
Marked Reduction ◽  
Knee Extensor ◽  
Moderate Intensity ◽  
Intense Exercise ◽  
Moderate Intensity Exercise ◽  
Fast Twitch Muscle ◽  
Slow Twitch Fibers

The present study examined whether a marked reduction in oxygen delivery, unlike findings in moderate-intensity exercise, would slow leg oxygen uptake (V̇o2) kinetics during intense exercise (86 ± 3% of incremental test peak power). Seven healthy males (26 ± 1 years, means ± SE) performed one-legged knee-extensor exercise (60 ± 3 W) for 4 min in a control setting (CON) and with arterial infusion of NG-monomethyl-l-arginine and indomethacin in the working leg to reduce blood flow by inhibiting formation of nitric oxide and prostanoids (double blockade; DB). In DB leg blood flow (LBF) and oxygen delivery during the first minute of exercise were 25–50% lower ( P < 0.01) compared with CON (LBF after 10 s: 1.1 ± 0.2 vs. 2.5 ± 0.3 l/min and 45 s: 2.7 ± 0.2 vs. 3.8 ± 0.4 l/min) and 15% lower ( P < 0.05) after 2 min of exercise. Leg V̇o2 in DB was attenuated ( P < 0.05) during the first 2 min of exercise (10 s: 161 ± 26 vs. 288 ± 34 ml/min and 45 s: 459 ± 48 vs. 566 ± 81 ml/min) despite a higher ( P < 0.01) oxygen extraction in DB. Net leg lactate release was the same in DB and CON. The present study shows that a marked reduction in oxygen delivery can limit the rise in V̇o2 during the initial part of intense exercise. This is in contrast to previous observations during moderate-intensity exercise using the same DB procedure, which suggests that fast-twitch muscle fibers are more sensitive to a reduction in oxygen delivery than slow-twitch fibers.

scholarly journals Respiratory muscle blood flow during exercise: Effects of sex and ovarian cycle

2017 ◽  
Vol 122 (4) ◽  
pp. 918-924 ◽  
Author(s):  
Joshua R. Smith ◽  
K. Sue Hageman ◽  
Craig A. Harms ◽  
David C. Poole ◽  
Timothy I. Musch
Keyword(s):  
Blood Flow ◽  
Respiratory Muscle ◽  
Muscle Blood Flow ◽  
Ovarian Cycle ◽  
Transversus Abdominis ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Vascular Conductance ◽  
Blood Flow Control ◽  
Males And Females

Sex and ovarian cycle have been speculated to modify respiratory muscle blood flow control during exercise, but the findings are inconclusive. We tested the hypotheses that females would have higher respiratory muscle blood flow and vascular conductance (VC) compared with males during exercise and that this difference would be accentuated in proestrus vs. ovariectomized (OVA) females. Mean arterial pressure (carotid artery catheter) and respiratory muscle blood flow (radiolabeled microspheres) were measured during moderate-intensity (24 m/min, 10% grade) exercise in male ( n = 9), female ( n = 9), and OVA female ( n = 7) rats and near-maximal (60 m/min, 5% grade) exercise in male ( n = 5) and female ( n = 7) rats. At rest, diaphragm, intercostal, and transversus abdominis blood flow were not different ( P = 0.33) among groups. During moderate-intensity exercise, diaphragm (M: 124 ± 16; F: 140 ± 14; OVA: 140 ± 20 ml·min−1·100 g−1), intercostal (M: 33 ± 5; F: 34 ± 5; OVA: 30 ± 5 ml·min−1·100 g−1), and transversus abdominis blood flow (M: 24 ± 4; F: 35 ± 7; OVA: 35 ± 9 ml·min−1·100 g−1) significantly increased in all groups compared with rest but were not different ( P = 0.12) among groups. From rest to moderate-intensity exercise, diaphragm ( P < 0.03) and transversus abdominis ( P < 0.04) VC increased in all groups, whereas intercostal VC increased only for males and females ( P = 0.01). No differences ( P > 0.13) existed in VC among groups. During near-maximal exercise, diaphragm (M: 304 ± 62; F: 283 ± 17 ml·min−1·100 g−1), intercostal (M: 29 ± 8; F: 40 ± 6 ml·min−1·100 g−1), and transversus abdominis (M: 85 ± 14; F: 86 ± 9 ml·min−1·100 g−1) blood flow and VC were not different ( P > 0.27) between males and females. These data demonstrate that respiratory muscle blood flow and vascular conductance at rest and during exercise are not affected by sex or ovarian cycle in rats. NEW & NOTEWORTHY It has been proposed that sex and ovarian cycle modulate respiratory muscle blood flow control during exercise. We demonstrate herein that neither sex nor ovarian cycle influences respiratory muscle blood flow or vascular conductance at rest or during exercise in rats.

Monitoring muscle oxygenation after eccentric exercise-induced muscle damage using near-infrared spectroscopy

2008 ◽  
Vol 33 (4) ◽  
pp. 743-752 ◽  
Author(s):  
Sirous Ahmadi ◽  
Peter J. Sinclair ◽  
Nasim Foroughi ◽  
Glen M. Davis
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Infrared Spectroscopy ◽  
Oxygen Uptake ◽  
Oxygen Saturation ◽  
Eccentric Exercise ◽  
Near Infrared ◽  
Muscle Blood Flow ◽  
Muscle Oxygenation ◽  
Muscle Oxygen

Eccentric exercise (EE), a common type of muscular activity whereby muscles lengthen and contract simultaneously, is associated with higher levels of force but may also evoke muscle damage. We investigated the hypothesis that unaccustomed EE might impair muscle oxygenation and muscle blood flow in healthy adults. Ten healthy males performed a bout of 70 maximal eccentric contractions of the elbow flexors. Before and after EE on day 1 and over the next 6 days, maximum voluntary isometric torque (MVT), serum creatine kinase (CK), and the changes in muscle oxygen saturation, blood flow, and oxygen uptake (using near-infrared spectroscopy) within the biceps brachii were assessed. MVT decreased, whereas muscle soreness and CK increased after EE (p < 0.05). Mean resting oxygen saturation increased by 22% after acute EE, and remained elevated by 5%–9% for the following 6 days. During isometric contractions, significant decreases were observed in oxygen desaturation and re-saturation kinetics after EE and these declines were also significantly prevalent over the following 6 days. Both muscle blood flow and oxygen uptake increased significantly after acute EE, but recovered on the next day. This study revealed some prolonged alterations in muscle oxygenation at rest and during exercise after EE, which might be due to a decrease in muscle oxygen consumption, an increase in oxygen delivery, and (or) a combination of both. However, both oxygen consumption and blood flow recovered within 24 h after the eccentric exercise session, and therefore, the reason(s) for the changes in tissue oxygen saturation remain unknown.

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

Kinetics of pulmonary oxygen uptake and muscle phosphates during moderate-intensity calf exercise

1996 ◽  
Vol 81 (3) ◽  
pp. 1331-1338 ◽  
Author(s):  
C. R. McCreary ◽  
P. D. Chilibeck ◽  
G. D. Marsh ◽  
D. H. Paterson ◽  
D. A. Cunningham ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Signal To Noise Ratio ◽  
Plantar Flexion ◽  
Respiratory Control ◽  
Dynamic Responses ◽  
Moderate Intensity ◽  
Resonance Spectroscopy ◽  
Moderate Intensity Exercise ◽  
Muscle Oxygen ◽  
Small Muscle

The purpose of this study is to directly compare the dynamic responses of phosphocreatine (PCr) and P(i) to those oxygen uptake (VO2) measured at the lung during transitions to and from moderate-intensity exercise. Changes in PCr and P(i) were measured by 31P-nuclear magnetic resonance spectroscopy, and changes in VO2 were measured breath by breath by mass spectroscopy during transitions to and from moderate-intensity square-wave ankle plantar flexion exercise in 11 subjects (7 men and 4 women; mean age 27 yr). Three repeated transitions were averaged for improvement in signal-to-noise ratio of phosphate data, and 12 transitions were averaged for VO2 measurements. Averaged transitions were fit with a monoexponential curve for determination of the time constant (tau) of the responses. Mean tau values for on transients of PCr, P(i), and phrase 2 VO2 were 47.0, 57.7, and 44.5 s, respectively, whereas means tau values for off transients were 44.8, 42.1, and 33.4 s, respectively. There were no significant differences between tau values for phosphate- and VO2-measured transients or on and off transients. The similarity of on and off kinetics supports linear first-order respiratory control models. Measurement of phase 2 pulmonary VO2 kinetics to and from moderate-intensity small-muscle-mass exercise reflect muscle phosphate kinetics (and muscle oxygen consumption).

scholarly journals Effects of heavy-intensity priming exercise on pulmonary oxygen uptake kinetics and muscle oxygenation in heart failure with preserved ejection fraction

2019 ◽  
Vol 316 (3) ◽  
pp. R199-R209 ◽  
Author(s):  
Natasha G. Boyes ◽  
Janine Eckstein ◽  
Stephen Pylypchuk ◽  
Darcy D. Marciniuk ◽  
Scotty J. Butcher ◽  
...  
Keyword(s):  
Heart Failure ◽  
Steady State ◽  
Ejection Fraction ◽  
Oxygen Uptake ◽  
Oxygen Delivery ◽  
Moderate Intensity ◽  
Preserved Ejection Fraction ◽  
Pulmonary Oxygen Uptake ◽  
Muscle Oxygen ◽  
Priming Exercise

Exercise intolerance is a hallmark feature in heart failure with preserved ejection fraction (HFpEF). Prior heavy exercise (“priming exercise”) speeds pulmonary oxygen uptake (V̇o2p) kinetics in older adults through increased muscle oxygen delivery and/or alterations in mitochondrial metabolic activity. We tested the hypothesis that priming exercise would speed V̇o2p on-kinetics in patients with HFpEF because of acute improvements in muscle oxygen delivery. Seven patients with HFpEF performed three bouts of two exercise transitions: MOD1, rest to 4-min moderate-intensity cycling and MOD2, MOD1 preceded by heavy-intensity cycling. V̇o2p, heart rate (HR), total peripheral resistance (TPR), and vastus lateralis tissue oxygenation index (TOI; near-infrared spectroscopy) were measured, interpolated, time-aligned, and averaged. V̇o2p and HR were monoexponentially curve-fitted. TPR and TOI levels were analyzed as repeated measures between pretransition baseline, minimum value, and steady state. Significance was P < 0.05. Time constant (τ; tau) V̇o2p (MOD1 49 ± 16 s) was significantly faster after priming (41 ± 14 s; P = 0.002), and the effective HR τ was slower following priming (41 ± 27 vs. 51 ± 32 s; P = 0.025). TPR in both conditions decreased from baseline to minimum TPR ( P < 0.001), increased from minimum to steady state ( P = 0.041) but remained below baseline throughout ( P = 0.001). Priming increased baseline ( P = 0.003) and minimum TOI ( P = 0.002) and decreased the TOI muscle deoxygenation overshoot ( P = 0.041). Priming may speed the slow V̇o2p on-kinetics in HFpEF and increase muscle oxygen delivery (TOI) at the onset of and throughout exercise. Microvascular muscle oxygen delivery may limit exercise tolerance in HFpEF.

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