scholarly journals Acute ascorbic acid ingestion increases skeletal muscle blood flow and oxygen consumption via local vasodilation during graded handgrip exercise in older adults

2015 ◽  
Vol 309 (2) ◽  
pp. H360-H368 ◽  
Author(s):  
Jennifer C. Richards ◽  
Anne R. Crecelius ◽  
Dennis G. Larson ◽  
Frank A. Dinenno
Keyword(s):  
Older Adults ◽  
Skeletal Muscle ◽  
Blood Flow ◽  
Ascorbic Acid ◽  
Oxygen Consumption ◽  
Lower Body Negative Pressure ◽  
Muscle Blood Flow ◽  
Voluntary Contraction ◽  
Handgrip Exercise ◽  
Forearm Vascular Conductance

Human aging is associated with reduced skeletal muscle perfusion during exercise, which may be a result of impaired endothelium-dependent dilation and/or attenuated ability to blunt sympathetically mediated vasoconstriction. Intra-arterial infusion of ascorbic acid (AA) increases nitric oxide-mediated vasodilation and forearm blood flow (FBF) during handgrip exercise in older adults, yet it remains unknown whether an acute oral dose can similarly improve FBF or enhance the ability to blunt sympathetic vasoconstriction during exercise. We hypothesized that 1) acute oral AA would improve FBF (Doppler ultrasound) and oxygen consumption (V̇o2) via local vasodilation during graded rhythmic handgrip exercise in older adults ( protocol 1), and 2) AA ingestion would not enhance sympatholysis in older adults during handgrip exercise ( protocol 2). In protocol 1 ( n = 8; 65 ± 3 yr), AA did not influence FBF or V̇o2 during rest or 5% maximal voluntary contraction (MVC) exercise, but increased FBF (199 ± 13 vs. 248 ± 16 ml/min and 343 ± 24 vs. 403 ± 33 ml/min; P < 0.05) and V̇o2 (26 ± 2 vs. 34 ± 3 ml/min and 43 ± 4 vs. 50 ± 5 ml/min; P < 0.05) at both 15 and 25% MVC, respectively. The increased FBF was due to elevations in forearm vascular conductance (FVC). In protocol 2 ( n = 10; 63 ± 2 yr), following AA, FBF was similarly elevated during 15% MVC (∼20%); however, vasoconstriction to reflex increases in sympathetic activity during −40 mmHg lower-body negative pressure at rest (ΔFVC: −16 ± 3 vs. −16 ± 2%) or during 15% MVC (ΔFVC: −12 ± 2 vs. −11 ± 4%) was unchanged. Our collective results indicate that acute oral ingestion of AA improves muscle blood flow and V̇o2 during exercise in older adults via local vasodilation.

scholarly journals Effect of vitamin C on hyperoxia-induced vasoconstriction in exercising skeletal muscle

2014 ◽  
Vol 117 (10) ◽  
pp. 1207-1211 ◽  
Author(s):  
Sushant M. Ranadive ◽  
Michael J. Joyner ◽  
Branton G. Walker ◽  
Jennifer L. Taylor ◽  
Darren P. Casey
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Vitamin C ◽  
Muscle Blood Flow ◽  
Maximum Voluntary Contraction ◽  
Voluntary Contraction ◽  
Ros Generation ◽  
Forearm Vascular Conductance ◽  
Forearm Exercise ◽  
Induced Changes

Hyperoxia can cause substantial reductions in peripheral and coronary blood flow at rest and during exercise, which may be caused by reactive oxygen species (ROS) generated during hyperoxia. The aim of this study was to investigate the role of ROS in hyperoxia-induced reductions in skeletal muscle blood flow during forearm exercise. We hypothesized that infusion of vitamin C would abolish the effects of hyperoxia on the forearm blood flow (FBF) responses to exercise. Twelve young healthy adults performed rhythmic forearm handgrip exercise (10% of maximum voluntary contraction for 5 min) during normoxia and hyperoxia. For each condition, two trials were conducted with intra-arterial administration of saline or vitamin C. FBF was measured using Doppler ultrasound. During hyperoxia with saline, FBF and forearm vascular conductance (FVC) were 86.3 ± 5.1 and 86.8 ± 5.2%, respectively, of the normoxic values (100%) ( P < 0.05). During vitamin C, hyperoxic FBF and FVC responses were 90.9 ± 4.2 and 90.9 ± 4.1%, respectively, of the normoxic values ( P = 0.57 and 0.59). Subjects were then divided into three subgroups based on their percent decrease in FBF (>20, 10–20, and <10%) during hyperoxia. In the subgroup that demonstrated the greatest hyperoxia-induced changes (>20%), FBF and FVC during hyperoxia were 67.1 ± 4.0 and 66.8 ± 3.6%, respectively, of the normoxic values. Vitamin C abolished these effects on FBF and FVC with values that were 102.0 ± 5.2 and 100.8 ± 6.1%, respectively. However, vitamin C had no effect in the other two subgroups. This analysis is consistent with the idea that ROS generation blunts the FBF responses to exercise in the subjects most affected by hyperoxia.

scholarly journals Sex-Related Differences in Rapid-Onset Vasodilation: Impact of Aging

2020 ◽  
Author(s):  
Brady E. Hanson ◽  
Michael J. Joyner ◽  
Darren P. Casey
Keyword(s):  
Blood Flow ◽  
Older Women ◽  
Muscle Blood Flow ◽  
Rapid Onset ◽  
Young Group ◽  
Voluntary Contraction ◽  
Single Muscle ◽  
Vasodilatory Response ◽  
Age Related ◽  
Forearm Vascular Conductance

Rapid-onset vasodilation (ROV) in response to a single muscle contraction is attenuated with aging. Moreover, sex-related differences in muscle blood flow and vasodilation during dynamic exercise have been observed in young and older adults. The purpose of the present study was to explore if sex-related differences in ROV exist in young (n=36, 25±1 yr) and older (n=32, 66±1 yr) adults. Subjects performed single forearm contractions at 10%, 20%, and 40% maximal voluntary contraction. Brachial artery blood velocity and diameter were measured with Doppler ultrasound, and forearm vascular conductance (ml·min-1·100 mmHg-1) was calculated from blood flow (ml·min-1) and mean arterial pressure (mmHg) and used as a measure of ROV. Peak ROV was attenuated in women across all relative intensities in the young and older groups (P<0.05). In a subset of subjects with similar absolute workloads (~5 kg and ~11kg), age-related differences in ROV were observed among both women and men (P<0.05). However, only older women demonstrated an attenuated peak ROV compared to men (91±6 vs. 121±11 ml·min-1·100 mmHg-1, P<0.05), a difference not observed in the young group (134±8 vs. 154±11 ml·min-1·100 mmHg-1, P=0.15). Additionally, examining the slope of peak ROV across contraction intensities indicated a blunted response in older women compared to their young counterparts (P<0.05), with no differences observed between older and young men (P=0.38). Our data suggest that sex-related differences in the rapid vasodilatory response to single muscle contractions exist in older but not young adults, such that older women have a blunted response compared to older men.

Skeletal muscle blood flow and vascular conductance are enhanced in humans with high‐affinity hemoglobin during handgrip exercise in severe hypoxia

2020 ◽  
Vol 34 (S1) ◽  
pp. 1-1
Author(s):  
Chad C. Wiggins ◽  
Paolo B. Dominelli ◽  
Jonathon W. Senefeld ◽  
John R.A. Shepherd ◽  
Sarah E. Baker ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Muscle Blood Flow ◽  
Severe Hypoxia ◽  
Handgrip Exercise ◽  
Vascular Conductance ◽  
Skeletal Muscle Blood Flow ◽  
High Affinity

Is postexercise hypotension related to excess postexercise oxygen consumption through changes in leg blood flow?

2005 ◽  
Vol 98 (4) ◽  
pp. 1463-1468 ◽  
Author(s):  
Jay T. Williams ◽  
Mollie P. Pricher ◽  
John R. Halliwill
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Oxygen Consumption ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Muscle Blood Flow ◽  
Causal Link ◽  
Skeletal Muscle Blood Flow ◽  
Leg Blood Flow ◽  
Postexercise Hypotension

After a single bout of aerobic exercise, oxygen consumption remains elevated above preexercise levels [excess postexercise oxygen consumption (EPOC)]. Similarly, skeletal muscle blood flow remains elevated for an extended period of time. This results in a postexercise hypotension. The purpose of this study was to explore the possibility of a causal link between EPOC, postexercise hypotension, and postexercise elevations in skeletal muscle blood flow by comparing the magnitude and duration of these postexercise phenomena. Sixteen healthy, normotensive, moderately active subjects (7 men and 9 woman, age 20–31 yr) were studied before and through 135 min after a 60-min bout of upright cycling at 60% of peak oxygen consumption. Resting and recovery V̇o2 were measured with a custom-built dilution hood and mass spectrometer-based metabolic system. Mean arterial pressure was measured via an automated blood pressure cuff, and femoral blood flow was measured using ultrasound. During the first hour postexercise, V̇o2 was increased by 11 ± 2%, leg blood flow was increased by 51 ± 18%, leg vascular conductance was increased by 56 ± 19%, and mean arterial pressure was decreased by 2.2 ± 1.0 mmHg (all P < 0.05 vs. preexercise). At the end of the protocol, V̇o2 remained elevated by 4 ± 2% ( P < 0.05), whereas leg blood flow, leg vascular conductance, and mean arterial pressure returned to preexercise levels (all P > 0.7 vs. preexercise). Taken together, these data demonstrate that EPOC and the elevations in skeletal muscle blood flow underlying postexercise hypotension do not share a common time course. This suggests that there is no causal link between these two postexercise phenomena.

scholarly journals Functional sympatholysis is preserved in healthy young Black men during rhythmic handgrip exercise

2020 ◽  
Vol 319 (3) ◽  
pp. R323-R328
Author(s):  
Thales C. Barbosa ◽  
Benjamin E. Young ◽  
Brandi Y. Stephens ◽  
Damsara Nandadeva ◽  
Jasdeep Kaur ◽  
...  
Keyword(s):  
Black Men ◽  
Lower Body Negative Pressure ◽  
White Men ◽  
Voluntary Contraction ◽  
Moderate Intensity ◽  
Handgrip Exercise ◽  
Sympathetic Vasoconstriction ◽  
Functional Sympatholysis ◽  
Forearm Vascular Conductance ◽  
Underlying Mechanisms

Black men have attenuated increases in forearm vascular conductance (FVC) and forearm blood flow (FBF) during moderate- and high-intensity rhythmic handgrip exercise compared with White men, but the underlying mechanisms are unclear. Here, we tested for the first time the hypothesis that functional sympatholysis (i.e., attenuation of sympathetic vasoconstriction in the exercising muscles) is impaired in Black men compared with White men. Thirteen White and 14 Black healthy young men were studied. FBF (duplex Doppler ultrasound) and mean arterial pressure (MAP; Finometer) were measured at rest and during rhythmic handgrip exercise at 30% maximal voluntary contraction. FVC was calculated as FBF/MAP. Sympathetic activation was induced via lower body negative pressure (LBNP) at −20 Torr for 2 min at rest and from the 3rd to the 5th min of handgrip. Sympathetic vasoconstriction was assessed as percent reductions in FVC during LBNP. The groups presented similar resting FVC, FBF, and MAP. During LBNP at rest, reductions in FVC were not different between White (−35 ± 10%) and Black men (−32 ± 14%, P = 0.616), indicating similar reflex-induced sympathetic vasoconstriction. During handgrip exercise, there were minimal reductions in FVC with LBNP in either group (White: −1 ± 7%; Black: +1 ± 8%; P = 0.523), indicating functional sympatholysis in both groups. Thus, contrary to our hypothesis, our findings indicate a preserved functional sympatholysis in healthy young Black men compared with White men, suggesting that this mechanism does not appear to contribute to reduced exercise hyperemia during moderate-intensity rhythmic handgrip in this population.

Reliability of NIRS Derived Measurements of Skeletal Muscle Blood Flow and Oxygen Consumption During Exercise

2016 ◽  
Vol 48 ◽  
pp. 1031
Author(s):  
Adam A. Lucero ◽  
Gifty Addae ◽  
Wayne Lawrence ◽  
Beemnet Neway ◽  
Daniel Credeur ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Oxygen Consumption ◽  
Muscle Blood Flow ◽  
Skeletal Muscle Blood Flow

scholarly journals Nitric oxide, but not vasodilating prostaglandins, contributes to the improvement of exercise hyperemia via ascorbic acid in healthy older adults

2010 ◽  
Vol 299 (5) ◽  
pp. H1633-H1641 ◽  
Author(s):  
Anne R. Crecelius ◽  
Brett S. Kirby ◽  
Wyatt F. Voyles ◽  
Frank A. Dinenno
Keyword(s):  
Nitric Oxide ◽  
Older Adults ◽  
Blood Flow ◽  
Ascorbic Acid ◽  
Steady State ◽  
Muscle Blood Flow ◽  
Dynamic Exercise ◽  
Healthy Older Adults ◽  
Group 2 ◽  
Group 1

Acute ascorbic acid (AA) administration increases muscle blood flow during dynamic exercise in older adults, and this is associated with improved endothelium-dependent vasodilation. We directly tested the hypothesis that increase in muscle blood flow during AA administration is mediated via endothelium-derived vasodilators nitric oxide (NO) and prostaglandins (PGs). In 14 healthy older adults (64 ± 3 yr), we measured forearm blood flow (FBF; Doppler ultrasound) during rhythmic handgrip exercise at 10% maximum voluntary contraction. After 5-min steady-state exercise with saline, AA was infused via brachial artery catheter for 10 min during continued exercise, and this increased FBF ∼25% from 132 ± 16 to 165 ± 20 ml/min ( P < 0.05). AA was infused for the remainder of the study. Next, subjects performed a 15-min exercise bout in which AA + saline was infused for 5 min, followed by 5 min of the nitric oxide synthase (NOS) inhibitor NG-monomethyl-l-arginine (l-NMMA) and then 5 min of the cyclooxygenase inhibitor ketorolac ( group 1). The order of inhibition was reversed in eight subjects ( group 2). In group 1, independent NOS inhibition reduced steady-state FBF by ∼20% ( P < 0.05), and subsequent PG inhibition had no impact on FBF (Δ 3 ± 5%). Similarly, in group 2, independent PG inhibition had little effect on FBF (Δ −4 ± 4%), whereas subsequent NO inhibition significantly decreased FBF by ∼20% ( P < 0.05). In a subgroup of five subjects, we inhibited NO and PG synthesis before AA administration. In these subjects, there was a minimal nonsignificant improvement in FBF with AA infusion (Δ 7 ± 3%; P = nonsignificant vs. zero). Together, our data indicate that the increase in muscle blood flow during dynamic exercise with acute AA administration in older adults is mediated primarily via an increase in the bioavailability of NO derived from the NOS pathway.

Dietary nitrate does not acutely enhance skeletal muscle blood flow and vasodilation in the lower limbs of older adults during single-limb exercise

2020 ◽  
Vol 120 (6) ◽  
pp. 1357-1369
Author(s):  
William E. Hughes ◽  
Nicholas T. Kruse ◽  
Kenichi Ueda ◽  
Andrew J. Feider ◽  
Satoshi Hanada ◽  
...  
Keyword(s):  
Older Adults ◽  
Skeletal Muscle ◽  
Blood Flow ◽  
Muscle Blood Flow ◽  
Lower Limbs ◽  
Skeletal Muscle Blood Flow ◽  
Dietary Nitrate ◽  
Limb Exercise

scholarly journals Influence of α-adrenergic vasoconstriction on the blunted skeletal muscle contraction-induced rapid vasodilation with aging

2012 ◽  
Vol 113 (8) ◽  
pp. 1201-1212 ◽  
Author(s):  
Darren P. Casey ◽  
Michael J. Joyner
Keyword(s):  
Older Adults ◽  
Skeletal Muscle ◽  
Muscle Contraction ◽  
Lower Body Negative Pressure ◽  
Brachial Artery Diameter ◽  
Younger Adults ◽  
Age Related ◽  
Skeletal Muscle Contraction ◽  
Adrenergic Antagonist ◽  
Forearm Vascular Conductance

We tested the hypothesis that elevated sympathetic tone is responsible for lower peak vasodilation after single muscle contractions in older adults. Young ( n = 13, 7 men and 6 women, age: 27 ± 1 yr) and older ( n = 13, 7 men and 6 women, age: 69 ± 2 yr) adults performed single forearm contractions at 10%, 20%, and 40% of maximum during 1) control, 2) sympathetic activation via lower body negative pressure (LBNP; −20 mmHg), and 3) intra-arterial infusion of phentolamine (α-adrenergic antagonist). Brachial artery diameter and velocities were measured via Doppler ultrasound, and forearm vascular conductance (FVC; in ml·min−1·100 mmHg−1) was calculated from blood flow (in ml/min) and blood pressure (in mmHg). Peak vasodilator responses [change in (Δ) FVC from baseline] were attenuated in older adults at 20% and 40% of maximum ( P < 0.05). LBNP reduced peak ΔFVC at 10% (98 ± 17 vs. 70 ± 12 ml·min−1·100 mmHg−1), 20% (144 ± 12 vs. 98 ± 3 ml·min−1·100 mmHg−1), and 40% (209 ± 20 vs. 161 ± 21 ml·min−1·100 mmHg−1, P < 0.01 vs. control) in younger adults but not in older adults (71 ± 11 vs. 68 ± 11, 107 ± 13 vs. 106 ± 16, and 161 ± 22 vs. 144 ± 22 ml·min−1·100 mmHg−1, respectively, P = 0.22–0.99). With phentolamine, peak ΔFVC was enhanced in older adults at each contraction intensity (100 ± 14, 147 ± 22, and 200 ± 26 ml·min−1·100 mmHg−1, respectively, P < 0.01 vs. control) but not in younger adults (94 ± 13, 153 ± 13, and 224 ± 27 ml·min−1·100 mmHg−1, respectively, P = 0.30–0.81 vs. control). Our data indicate that α-adrenergic vasoconstriction and/or blunted functional sympatholysis might contribute to the age-related decreases in skeletal muscle contraction-induced rapid vasodilation in humans.

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