Limb blood flow and muscle oxygenation responses during handgrip exercise above vs. below critical force

2020 ◽  
Vol 131 ◽  
pp. 104002
Author(s):  
Shane M. Hammer ◽  
Andrew M. Alexander ◽  
Kaylin D. Didier ◽  
Lillie M. Huckaby ◽  
Thomas J. Barstow
Keyword(s):  
Blood Flow ◽  
Critical Force ◽  
Muscle Oxygenation ◽  
Handgrip Exercise ◽  
Limb Blood Flow

scholarly journals Limb blood flow and muscle oxygenation responses to rhythmic exercise below and above critical force

2020 ◽  
Vol 34 (S1) ◽  
pp. 1-1
Author(s):  
Shane M. Hammer ◽  
Andrew M. Alexander ◽  
Kaylin D. Didier ◽  
Lillie M. Huckaby ◽  
Thomas J. Barstow
Keyword(s):  
Blood Flow ◽  
Critical Force ◽  
Muscle Oxygenation ◽  
Limb Blood Flow ◽  
Rhythmic Exercise

scholarly journals Effect of dietary nitrate supplementation on conduit artery blood flow, muscle oxygenation, and metabolic rate during handgrip exercise

2018 ◽  
Vol 125 (2) ◽  
pp. 254-262 ◽  
Author(s):  
Jesse C. Craig ◽  
Ryan M. Broxterman ◽  
Joshua R. Smith ◽  
Jason D. Allen ◽  
Thomas J. Barstow
Keyword(s):  
Blood Flow ◽  
Muscle Mass ◽  
Muscle Blood Flow ◽  
Muscle Oxygenation ◽  
Moderate Intensity ◽  
Handgrip Exercise ◽  
Exercise Tests ◽  
Dietary Nitrate ◽  
Positive Effects ◽  
Nitrate Supplementation

Dietary nitrate supplementation has positive effects on mitochondrial and muscle contractile efficiency during large muscle mass exercise in humans and on skeletal muscle blood flow (Q̇) in rats. However, concurrent measurement of these effects has not been performed in humans. Therefore, we assessed the influence of nitrate supplementation on Q̇ and muscle oxygenation characteristics during moderate- (40 %peak) and severe-intensity(85% peak) handgrip exercise in a randomized, double-blind, crossover design. Nine healthy men (age: 25 ± 2 yr) completed four constant-power exercise tests (2/intensity) randomly assigned to condition [nitrate-rich (nitrate) or nitrate-poor (placebo) beetroot supplementation] and intensity (40 or 85% peak). Resting mean arterial pressure was lower after nitrate compared with placebo (84 ± 4 vs. 89 ± 4 mmHg, P < 0.01). All subjects were able to sustain 10 min of exercise at 40% peak in both conditions. Nitrate had no effect on exercise tolerance during 85% peak (nitrate: 358 ± 29; placebo: 341 ± 34 s; P = 0.3). Brachial artery Q̇ was not different after nitrate at rest or any time during exercise. Deoxygenated [hemoglobin + myoglobin] was not different for 40% peak ( P > 0.05) but was elevated throughout 85% peak ( P < 0.05) after nitrate. The metabolic cost (V̇o2) was not different at the end of exercise; however, the V̇o2 primary amplitude at the onset of exercise was elevated after nitrate for the 85% peak work rate (96 ± 20 vs. 72 ± 12 ml/min, P < 0.05) and had a faster response. These findings suggest that an acute dose of nitrate reduces resting blood pressure and speeds V̇o2 kinetics in young adults but does not augment Q̇ or reduce steady-state V̇o2 during small muscle mass handgrip exercise. NEW & NOTEWORTHY We show that acute dietary nitrate supplementation via beetroot juice increases the amplitude and speed of local muscle V̇o2 on kinetics parameters during severe- but not moderate-intensity handgrip exercise. These changes were found in the absence of an increased blood flow response, suggesting that the increased V̇o2 was attained via improvements in fractional O2 extraction and/or spatial distribution of blood flow within the exercising muscle.

scholarly journals Human muscle length-dependent changes in blood flow

2012 ◽  
Vol 112 (4) ◽  
pp. 560-565 ◽  
Author(s):  
John McDaniel ◽  
Stephen J. Ives ◽  
Russell S. Richardson
Keyword(s):  
Blood Flow ◽  
Knee Joint ◽  
Joint Angle ◽  
Muscle Blood Flow ◽  
Muscle Length ◽  
Limb Blood Flow ◽  
Knee Joint Angle ◽  
Femoral Blood Flow ◽  
Femoral Blood ◽  
Cyclic Changes

Although a multitude of factors that influence skeletal muscle blood flow have been extensively investigated, the influence of muscle length on limb blood flow has received little attention. Thus the purpose of this investigation was to determine if cyclic changes in muscle length influence resting blood flow. Nine healthy men (28 ± 4 yr of age) underwent a passive knee extension protocol during which the subjects' knee joint was passively extended and flexed through 100–180° knee joint angle at a rate of 1 cycle per 30 s. Femoral blood flow, cardiac output (CO), heart rate (HR), stroke volume (SV), and mean arterial pressure (MAP) were continuously recorded during the entire protocol. These measurements revealed that slow passive changes in knee joint angle did not have a significant influence on HR, SV, MAP, or CO; however, net femoral blood flow demonstrated a curvilinear increase with knee joint angle ( r2 = 0.98) such that blood flow increased by ∼90% (125 ml/min) across the 80° range of motion. This net change in blood flow was due to a constant antegrade blood flow across knee joint angle and negative relationship between retrograde blood flow and knee joint angle ( r2 = 0.98). Thus, despite the absence of central hemodynamic changes and local metabolic factors, blood flow to the leg was altered by changes in muscle length. Therefore, when designing research protocols, researchers need to be cognizant of the fact that joint angle, and ultimately muscle length, influence limb blood flow.

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.

Cardiac Output Changes in Newborns With Hyperbilirubinemia Treated With Phototherapy

PEDIATRICS ◽  
1985 ◽  
Vol 76 (6) ◽  
pp. 918-921
Author(s):  
Frans J. Walther ◽  
Paul Y. K. Wu ◽  
Bijan Siassi
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Skin Blood Flow ◽  
Peripheral Blood ◽  
Cardiovascular Effects ◽  
Tissue Perfusion ◽  
Peripheral Blood Flow ◽  
Limb Blood Flow ◽  
Term Infants

Phototherapy is known to increase peripheral blood flow in neonates, but information on the associated cardiovascular effects is not available. Using pulsed Doppler echocardiography we evaluated cardiac output and stroke volume in 12 preterm and 13 term neonates during and after phototherapy. We concomitantly measured arterial limb blood flow by strain gauge plethysmography and skin blood flow by photoplethysmography. Cardiac output decreased by 6% due to reduced stroke volume during phototherapy, whereas total limb blood flow and skin blood flow increased by 38% and 41%, respectively. Peripheral blood flow increments tended to be higher in the preterm than in the term infants. The reduced stroke volume during phototherapy may be an expression of reduced activity of the newborn during phototherapy. For healthy neonates the reduction in cardiac output is minimal, but for sick infants with reduced cardiac output, this reduction may further aggravate the decrease in tissue perfusion.

Limb blood flow and tissue perfusion during exercise with blood flow restriction

2018 ◽  
Vol 119 (2) ◽  
pp. 377-387 ◽  
Author(s):  
Matthew A. Kilgas ◽  
John McDaniel ◽  
Jon Stavres ◽  
Brandon S. Pollock ◽  
Tyler J. Singer ◽  
...  
Keyword(s):  
Blood Flow ◽  
Tissue Perfusion ◽  
Blood Flow Restriction ◽  
Limb Blood Flow ◽  
Flow Restriction

scholarly journals Stimulatory effect of insulin on creatine accumulation in human skeletal muscle

1998 ◽  
Vol 275 (6) ◽  
pp. E974-E979 ◽  
Author(s):  
G. R. Steenge ◽  
J. Lambourne ◽  
A. Casey ◽  
I. A. Macdonald ◽  
P. L. Greenhaff
Keyword(s):  
Blood Flow ◽  
Human Skeletal Muscle ◽  
Insulin Infusion ◽  
Forearm Blood Flow ◽  
Dry Mass ◽  
Limb Blood Flow ◽  
Time Points ◽  
Creatine Transport ◽  
Total Creatine ◽  
Muscle Creatine

This study investigated the effect of insulin on plasma and muscle creatine accumulation and limb blood flow in humans after creatine administration. Seven men underwent a 300-min euglycemic insulin clamp combined with creatine administration on four separate occasions. Insulin was infused at rates of 5, 30, 55, or 105 mU ⋅ m−2 ⋅ min−1, and on each occasion 12.4 g creatine was administered. During infusion of insulin at rates of 55 and 105 mU ⋅ m−2 ⋅ min−1, muscle total creatine concentration increased by 4.5 ± 1.4 ( P < 0.05) and 8.3 ± 1.0 mmol/kg dry mass ( P < 0.05), and plasma creatine concentrations were lower at specific time points compared with the 5 mU ⋅ m−2 ⋅ min−1infusion rate. The magnitude of increase in calf blood flow (plethysmography) was the same irrespective of the rate of insulin infusion, and forearm blood flow increased to the same extent as the three highest infusion rates. These findings demonstrate that insulin can enhance muscle creatine accumulation in humans but only when present at physiologically high or supraphysiological concentrations. This response is likely to be the result of an insulin-mediated increase in muscle creatine transport rather than creatine delivery.

Effects of prior heavy-intensity exercise during single-leg knee extension on v̇o2 kinetics and limb blood flow

2005 ◽  
Vol 99 (4) ◽  
pp. 1462-1470 ◽  
Author(s):  
Nicole D. Paterson ◽  
John M. Kowalchuk ◽  
Donald H. Paterson
Keyword(s):  
Blood Flow ◽  
Phase Ii ◽  
Time Course ◽  
Muscle Blood Flow ◽  
Knee Extension ◽  
Phase Iii ◽  
Limb Blood Flow ◽  
Heavy Exercise ◽  
Pulsed Wave Doppler ◽  
Young Subjects

The effects of prior heavy-intensity exercise on O2 uptake (V̇o2) kinetics of a second heavy exercise may be due to vasodilation (associated with metabolic acidosis) and improved muscle blood flow. This study examined the effect of prior heavy-intensity exercise on femoral artery blood flow (Qleg) and its relationship with V̇o2 kinetics. Five young subjects completed five to eight repeats of two 6-min bouts of heavy-intensity one-legged, knee-extension exercise separated by 6 min of loadless exercise. V̇o2 was measured breath by breath. Pulsed-wave Doppler ultrasound was used to measure Qleg. V̇o2 and blood flow velocity data were fit using a monoexponential model to identify phase II and phase III time periods and estimate the response amplitudes and time constants (τ). Phase II V̇o2 kinetics was speeded on the second heavy-intensity exercise [mean τ (SD), 29 ( 10 ) s to 24 ( 10 ) s, P < 0.05] with no change in the phase II (or phase III) amplitude. Qleg was elevated before the second exercise [1.55 (0.34) l/min to 1.90 (0.25) l/min, P < 0.05], but the amplitude and time course [τ, 25 ( 13 ) s to 35 ( 13 ) s] were not changed, such that throughout the transient the Qleg (and ΔQleg/ΔV̇o2) did not differ from the prior heavy exercise. Thus V̇o2 kinetics were accelerated on the second exercise, but the faster kinetics were not associated with changes in Qleg. Thus limb blood flow appears not to limit V̇o2 kinetics during single-leg heavy-intensity exercise nor to be the mechanism of the altered V̇o2 response after heavy-intensity prior exercise.

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