Dietary nitrate supplementation reduces the O2cost of walking and running: a placebo-controlled study

2011 ◽  
Vol 110 (3) ◽  
pp. 591-600 ◽  
Author(s):  
Katherine E. Lansley ◽  
Paul G. Winyard ◽  
Jonathan Fulford ◽  
Anni Vanhatalo ◽  
Stephen J. Bailey ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Physiological Responses ◽  
Dietary Supplementation ◽  
Moderate Intensity ◽  
Controlled Study ◽  
Time To Exhaustion ◽  
Exercise Tests ◽  
Positive Effects ◽  
Severe Intensity ◽  
Per Se

Dietary supplementation with beetroot juice (BR) has been shown to reduce resting blood pressure and the O2cost of submaximal exercise and to increase tolerance to high-intensity cycling. We tested the hypothesis that the physiological effects of BR were consequent to its high NO3−content per se, and not the presence of other potentially bioactive compounds. We investigated changes in blood pressure, mitochondrial oxidative capacity (Qmax), and physiological responses to walking and moderate- and severe-intensity running following dietary supplementation with BR and NO3−-depleted BR [placebo (PL)]. After control (nonsupplemented) tests, nine healthy, physically active male subjects were assigned in a randomized, double-blind, crossover design to receive BR (0.5 l/day, containing ∼6.2 mmol of NO3−) and PL (0.5 l/day, containing ∼0.003 mmol of NO3−) for 6 days. Subjects completed treadmill exercise tests on days 4 and 5 and knee-extension exercise tests for estimation of Qmax(using31P-magnetic resonance spectroscopy) on day 6 of the supplementation periods. Relative to PL, BR elevated plasma NO2−concentration (183 ± 119 vs. 373 ± 211 nM, P < 0.05) and reduced systolic blood pressure (129 ± 9 vs. 124 ± 10 mmHg, P < 0.01). Qmaxwas not different between PL and BR (0.93 ± 0.05 and 1.05 ± 0.22 mM/s, respectively). The O2cost of walking (0.87 ± 0.12 and 0.70 ± 0.10 l/min in PL and BR, respectively, P < 0.01), moderate-intensity running (2.26 ± 0.27 and 2.10 ± 0.28 l/min in PL and BR, respectively, P < 0.01), and severe-intensity running (end-exercise O2uptake = 3.77 ± 0.57 and 3.50 ± 0.62 l/min in PL and BL, respectively, P < 0.01) was reduced by BR, and time to exhaustion during severe-intensity running was increased by 15% (7.6 ± 1.5 and 8.7 ± 1.8 min in PL and BR, respectively, P < 0.01). In contrast, relative to control, PL supplementation did not alter plasma NO2−concentration, blood pressure, or the physiological responses to exercise. These results indicate that the positive effects of 6 days of BR supplementation on the physiological responses to exercise can be ascribed to the high NO3−content per se.

Beetroot juice and exercise: pharmacodynamic and dose-response relationships

2013 ◽  
Vol 115 (3) ◽  
pp. 325-336 ◽  
Author(s):  
Lee J. Wylie ◽  
James Kelly ◽  
Stephen J. Bailey ◽  
Jamie R. Blackwell ◽  
Philip F. Skiba ◽  
...  
Keyword(s):  
Dose Response ◽  
Cardiovascular Health ◽  
Physiological Responses ◽  
Moderate Intensity ◽  
Dependent Manner ◽  
Beetroot Juice ◽  
Moderate Intensity Exercise ◽  
Exercise Tests ◽  
Severe Intensity ◽  
Plasma Nitrite

Dietary supplementation with beetroot juice (BR), containing approximately 5–8 mmol inorganic nitrate (NO3−), increases plasma nitrite concentration ([NO2−]), reduces blood pressure, and may positively influence the physiological responses to exercise. However, the dose-response relationship between the volume of BR ingested and the physiological effects invoked has not been investigated. In a balanced crossover design, 10 healthy men ingested 70, 140, or 280 ml concentrated BR (containing 4.2, 8.4, and 16.8 mmol NO3−, respectively) or no supplement to establish the effects of BR on resting plasma [NO3−] and [NO2−] over 24 h. Subsequently, on six separate occasions, 10 subjects completed moderate-intensity and severe-intensity cycle exercise tests, 2.5 h postingestion of 70, 140, and 280 ml BR or NO3−-depleted BR as placebo (PL). Following acute BR ingestion, plasma [NO2−] increased in a dose-dependent manner, with the peak changes occurring at approximately 2–3 h. Compared with PL, 70 ml BR did not alter the physiological responses to exercise. However, 140 and 280 ml BR reduced the steady-state oxygen (O2) uptake during moderate-intensity exercise by 1.7% ( P = 0.06) and 3.0% ( P < 0.05), whereas time-to-task failure was extended by 14% and 12% (both P < 0.05), respectively, compared with PL. The results indicate that whereas plasma [NO2−] and the O2 cost of moderate-intensity exercise are altered dose dependently with NO3−-rich BR, there is no additional improvement in exercise tolerance after ingesting BR containing 16.8 compared with 8.4 mmol NO3−. These findings have important implications for the use of BR to enhance cardiovascular health and exercise performance in young adults.

scholarly journals The Prophylactic Antiemetic Efficacy of Prochlorperazine and Ondansetron in Nasal Septal Surgery: A Randomized Double-Blind Comparison

1996 ◽  
Vol 24 (5) ◽  
pp. 538-545 ◽  
Author(s):  
A. A. Van Den Berg
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiovascular Effects ◽  
Controlled Study ◽  
Postoperative Vomiting ◽  
Double Blind ◽  
Septal Surgery ◽  
Postoperative Headache ◽  
Per Se ◽  
Blind Comparison

A prospective, randomized placebo-controlled study was undertaken to compare the effects on heart rate and blood pressure during surgery and on the incidence of nausea, vomiting and headache after surgery of IM prochlorperazine 0.2 mg.kg-1, IV prochlorperazine 0.1 mg.kg-1 and IV ondansetron 0.06 mg.kg-1 given at induction of general anaesthesia to patients undergoing septorhinoplasty. The effects of the test drugs after administration on heart rate and blood pressure were similar, as were the incidences of retching and vomiting in the recovery ward after each test drug. Postoperatively, compared with placebo (7%), nausea per se was most frequent in those given IV prochlorperazine (25%, P<0.01), and less frequent in those given IM prochlorperazine (2%) and IV ondansetron (15%). Vomiting per se was reduced from 24% to 7% (P<0.025) by IV prochlorperazine and to 4% (P<0.0005) by IV ondansetron. The incidence of nausea with vomiting was reduced from 35% to 15% (P<0.025), 16% (P<0.05) and 11% (P<0.005) by IM prochlorperazine, IV prochlorperazine and IV ondansetron respectively. IM prochlorperazine and IV ondansetron increased the frequency (from 35% to 64%, P<0.0005 and to 71%, P<0.0005, respectively) of those experiencing no PONV and delayed the onset of PONV, but only IM prochlorperazine reduced the severity of postoperative vomiting. Headache was frequent in the control (69%), IV prochlorperazine (62%) and IV ondansetron (69%) groups, and least frequent after IM prochlorperazine (53%; P<0.05 versus IV ondansetron). It is concluded that these drugs have no adverse cardiovascular effects within 10 minutes of administration, IM prochlorperazine and IV ondansetron reduce PONV more effectively than IV prochlorperazine and postoperative headache after septorhinoplasty occurs less frequently in those given IM prochlorperazine than in those given IV ondansetron.

The Effect of Prior Moderate- and Heavy-Intensity Running on the VO2 Response to Exhaustive Severe-Intensity Running

2006 ◽  
Vol 1 (4) ◽  
pp. 361-374 ◽  
Author(s):  
Stephen B. Draper ◽  
Dan M. Wood ◽  
Jo Corbett ◽  
David V.B. James ◽  
Christopher R. Potter
Keyword(s):  
Oxygen Uptake ◽  
Slow Component ◽  
Maximum Oxygen Uptake ◽  
Moderate Intensity ◽  
Time To Exhaustion ◽  
Heavy Exercise ◽  
Square Wave ◽  
Severe Intensity ◽  
The Difference ◽  
Trained Runners

We tested the hypothesis that prior heavy-intensity exercise reduces the difference between asymptotic oxygen uptake (VO2) and maximum oxygen uptake (VO2max) during exhaustive severe-intensity running lasting ≍2 minutes. Ten trained runners each performed 2 ramp tests to determine peak VO2 (VO2peak) and speed at venti-latory threshold. They performed exhaustive square-wave runs lasting ≍2 minutes, preceded by either 6 minutes of moderate-intensity running and 6 minutes rest (SEVMOD) or 6 minutes of heavy-intensity running and 6 minutes rest (SEVHEAVY). Two transitions were completed in each condition. VO2 was determined breath by breath and averaged across the 2 repeats of each test; for the square-wave test, the averaged VO2 response was then modeled using a monoexponential function. The amplitude of the VO2 response to severe-intensity running was not different in the 2 conditions (SEVMOD vs SEVHEAVY; 3925 ± 442 vs 3997 ± 430 mL/min, P = .237), nor was the speed of the response (τ; 9.2 ± 2.1 vs 10.0 ± 2.1 seconds, P = .177). VO2peak from the square-wave tests was below that achieved in the ramp tests (91.0% ± 3.2% and 92.0% ± 3.9% VO2peak, P < .001). There was no difference in time to exhaustion between conditions (110.2 ± 9.7 vs 111.0 ± 15.2 seconds, P = .813). The results show that the primary VO2 response is unaffected by prior heavy exercise in running performed at intensities at which exhaustion will occur before a slow component emerges.

Exercise intensity dependent relevance of protective textile properties for human thermo-physiology

2016 ◽  
Vol 87 (12) ◽  
pp. 1425-1434 ◽  
Author(s):  
Piero Fontana ◽  
Fabio Saiani ◽  
Marc Grütter ◽  
Jean-Philippe Croset ◽  
André Capt ◽  
...  
Keyword(s):  
Functional Properties ◽  
Exercise Intensity ◽  
Human Subject ◽  
Core Body Temperature ◽  
Physiological Responses ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Exercise Tests ◽  
Physiological Relevance ◽  
Low Intensity Exercise

During firefighting, thermoregulation is challenged due to a combination of harsh environmental conditions, high metabolic rates and personal protective clothing (PPC). Consequently, investigations of thermoregulation in firefighters should not only consider climate and exercise intensity, but technical properties of textiles too. Therefore, laboratory textile performance simulations may provide additional insights into textile-dependent thermoregulatory responses to exercise. In order to investigate the thermo-physiological relevance of textile properties and to test how different garments affect thermoregulation at different exercise intensities, we analyzed the results of a standard laboratory test and human subject trials by relating functional properties of textiles to thermo-physiological responses. Ten professional, healthy, male firefighters (age: 43 ± 6 y, weight: 84.3 ± 10.3kg, height: 1.79 ± 0.05m) performed low and moderate intensity exercise wearing garments previously evaluated with a sweating torso system to characterize thermal and evaporative properties. Functional properties of PPC and the control garment differed markedly. Consequently, skin temperature was higher using PPC at both exercise intensities (low: 36.27 ± 0.32 versus 36.75 ± 0.15℃, P < 0.05; moderate: 36.53 ± 0.34 versus 37.18 ± 0.23℃, P < 0.001), while core body temperature was only higher for PPC at moderate (37.54 ± 0.24 versus 37.83 ± 0.27℃, P < 0.05), but not low-intensity exercise (37.26 ± 0.21 versus 37.21 ± 0.19, P = 0.685). Differences in thermal and evaporative properties between textiles are reflected in thermo-physiological responses during human subject trials. However, an appropriate exercise intensity has to be chosen in order to challenge textile performance during exercise tests.

scholarly journals Effects of combined endurance and resistance training in Amyotrophic Lateral Sclerosis: A pilot, randomized, controlled study

2018 ◽  
Vol 28 (1) ◽  
Author(s):  
Antonio Merico ◽  
Marianna Cavinato ◽  
Caterina Gregorio ◽  
Alessandra Lacatena ◽  
Elisabetta Gioia ◽  
...  
Keyword(s):  
Muscle Power ◽  
Objective Evaluation ◽  
Exercise Programme ◽  
Functional Independence ◽  
Moderate Intensity ◽  
Controlled Study ◽  
Specific Exercise ◽  
Moderate Intensity Exercise ◽  
Positive Effects ◽  
Als Patients

Based on available evidence, muscle strengthening and cardiovascular exercises can help maintain function and not adversely affect the progression of disease in patients with ALS. However, this evidence is not sufficiently detailed to recommend a specific exercise prescription. The purpose of this project was to assess clinical outcomes of a combined exercise programme to increase knowledge of rehabilitation in ALS patients. 38 ALS patients were assigned randomly to two groups: one group underwent a specific exercise programme (ALS-EP) based on a moderate aerobic workout and isometric contractions, and the second group followed a standard neuromotor rehabilitation treatment. Objective evaluation consisted of cardiovascular measures, muscle strength and fatigue. Some positive effects of physical activity on ALS patients were found. Among the benefits, an overall improvement of functional independence in all patients, independently of the type of exercise conducted was seen. In addition, improvements in muscle power, oxygen consumption and fatigue were specifically observed in the ALS-EP group, all hallmarks of a training effect for the specific exercises. In conclusion, moderate intensity exercise is beneficial in ALS, helping in avoiding deconditioning and muscle atrophy resulting from progressive inactivity.

Dietary nitrate supplementation: effects on plasma nitrite and pulmonary O2 uptake dynamics during exercise in hypoxia and normoxia

2014 ◽  
Vol 307 (7) ◽  
pp. R920-R930 ◽  
Author(s):  
James Kelly ◽  
Anni Vanhatalo ◽  
Stephen J. Bailey ◽  
Lee J. Wylie ◽  
Christopher Tucker ◽  
...  
Keyword(s):  
Exercise Tolerance ◽  
Moderate Intensity ◽  
Beetroot Juice ◽  
Moderate Intensity Exercise ◽  
Exercise Tests ◽  
Double Blind ◽  
Dietary Nitrate ◽  
Severe Intensity ◽  
Rate Of Decline ◽  
Plasma Nitrite

We investigated the effects of dietary nitrate (NO3−) supplementation on the concentration of plasma nitrite ([NO2−]), oxygen uptake (V̇o2) kinetics, and exercise tolerance in normoxia (N) and hypoxia (H). In a double-blind, crossover study, 12 healthy subjects completed cycle exercise tests, twice in N (20.9% O2) and twice in H (13.1% O2). Subjects ingested either 140 ml/day of NO3−-rich beetroot juice (8.4 mmol NO3; BR) or NO3−-depleted beetroot juice (PL) for 3 days prior to moderate-intensity and severe-intensity exercise tests in H and N. Preexercise plasma [NO2−] was significantly elevated in H-BR and N-BR compared with H-PL ( P < 0.01) and N-PL ( P < 0.01). The rate of decline in plasma [NO2−] was greater during severe-intensity exercise in H-BR [−30 ± 22 nM/min, 95% confidence interval (CI); −44, −16] compared with H-PL (−7 ± 10 nM/min, 95% CI; −13, −1; P < 0.01) and in N-BR (−26 ± 19 nM/min, 95% CI; −38, −14) compared with N-PL (−1 ± 6 nM/min, 95% CI; −5, 2; P < 0.01). During moderate-intensity exercise, steady-state pulmonary V̇o2 was lower in H-BR (1.91 ± 0.28 l/min, 95% CI; 1.77, 2.13) compared with H-PL (2.05 ± 0.25 l/min, 95% CI; 1.93, 2.26; P = 0.02), and V̇o2 kinetics was faster in H-BR (τ: 24 ± 13 s, 95% CI; 15, 32) compared with H-PL (31 ± 11 s, 95% CI; 23, 38; P = 0.04). NO3− supplementation had no significant effect on V̇o2 kinetics during severe-intensity exercise in hypoxia, or during moderate-intensity or severe-intensity exercise in normoxia. Tolerance to severe-intensity exercise was improved by NO3− in hypoxia (H-PL: 197 ± 28; 95% CI; 173, 220 vs. H-BR: 214 ± 43 s, 95% CI; 177, 249; P = 0.04) but not normoxia. The metabolism of NO2− during exercise is altered by NO3− supplementation, exercise, and to a lesser extent, hypoxia. In hypoxia, NO3− supplementation enhances V̇o2 kinetics during moderate-intensity exercise and improves severe-intensity exercise tolerance. These findings may have important implications for individuals exercising at altitude.

Effects of interval and continuous training on O2 uptake kinetics during severe-intensity exercise initiated from an elevated metabolic baseline

2014 ◽  
Vol 116 (8) ◽  
pp. 1068-1077 ◽  
Author(s):  
Mariasole Da Boit ◽  
Stephen J. Bailey ◽  
Steven Callow ◽  
Fred J. DiMenna ◽  
Andrew M. Jones
Keyword(s):  
Exercise Performance ◽  
Performance Test ◽  
Moderate Intensity ◽  
Sprint Training ◽  
Continuous Training ◽  
Exercise Tests ◽  
Repeated Sprint ◽  
Severe Intensity ◽  
O2 Uptake Kinetics ◽  
Before And After

The purpose of this study was to test the hypothesis that V̇o2 kinetics would be speeded to a greater extent following repeated sprint training (RST), compared with continuous endurance training (ET), in the transition from moderate- to severe-intensity exercise. Twenty-three recreationally active subjects were randomly assigned to complete six sessions of ET (60–110 min of moderate-intensity cycling) or RST (four to seven 30-s all-out Wingate tests) over a 2-wk period. Subjects completed three identical work-to-work cycling exercise tests before and after the intervention period, consisting of baseline cycling at 20 W followed by sequential step increments to moderate- and severe-intensity work rates. The severe-intensity bout was continued to exhaustion on one occasion and was followed by a 60-s all-out sprint on another occasion. Phase II pulmonary V̇o2 kinetics were speeded by a similar magnitude in both the lower (ET pre, 28 ± 4; ET post, 22 ± 4 s; RST pre, 25 ± 8; RST post, 20 ± 7 s) and upper (ET pre, 50 ± 10; ET post, 39 ± 11 s; RST pre, 54 ± 7; RST post, 40 ± 11 s) steps of the work-to-work test following ET and RST ( P < 0.05). The tolerable duration of exercise and the total amount of sprint work completed in the exercise performance test were also similarly enhanced by ET and RST ( P < 0.05). Therefore, ET and RST provoked comparable improvements in V̇o2 kinetics and exercise performance in the transition from an elevated baseline work rate, with RST being a more time-efficient approach to elicit these adaptations.

Acute l-arginine supplementation reduces the O2 cost of moderate-intensity exercise and enhances high-intensity exercise tolerance

2010 ◽  
Vol 109 (5) ◽  
pp. 1394-1403 ◽  
Author(s):  
Stephen J. Bailey ◽  
Paul G. Winyard ◽  
Anni Vanhatalo ◽  
Jamie R. Blackwell ◽  
Fred J. DiMenna ◽  
...  
Keyword(s):  
Exercise Tolerance ◽  
Slow Component ◽  
Moderate Intensity ◽  
Time To Exhaustion ◽  
Moderate Intensity Exercise ◽  
Double Blind ◽  
Healthy Humans ◽  
Severe Intensity ◽  
Component Amplitude ◽  
Plasma Nitrite

It has recently been reported that dietary nitrate (NO3−) supplementation, which increases plasma nitrite (NO2−) concentration, a biomarker of nitric oxide (NO) availability, improves exercise efficiency and exercise tolerance in healthy humans. We hypothesized that dietary supplementation with l-arginine, the substrate for NO synthase (NOS), would elicit similar responses. In a double-blind, crossover study, nine healthy men (aged 19–38 yr) consumed 500 ml of a beverage containing 6 g of l-arginine (Arg) or a placebo beverage (PL) and completed a series of “step” moderate- and severe-intensity exercise bouts 1 h after ingestion of the beverage. Plasma NO2− concentration was significantly greater in the Arg than the PL group (331 ± 198 vs. 159 ± 102 nM, P < 0.05) and systolic blood pressure was significantly reduced (123 ± 3 vs. 131 ± 5 mmHg, P < 0.01). The steady-state O2 uptake (V̇o2) during moderate-intensity exercise was reduced by 7% in the Arg group (1.48 ± 0.12 vs. 1.59 ± 0.14 l/min, P < 0.05). During severe-intensity exercise, the V̇o2 slow component amplitude was reduced (0.58 ± 0.23 and 0.76 ± 0.29 l/min in Arg and PL, respectively, P < 0.05) and the time to exhaustion was extended (707 ± 232 and 562 ± 145 s in Arg and PL, respectively, P < 0.05) following consumption of Arg. In conclusion, similar to the effects of increased dietary NO3− intake, elevating NO bioavailability through dietary l-Arg supplementation reduced the O2 cost of moderate-intensity exercise and blunted the V̇o2 slow component and extended the time to exhaustion during severe-intensity exercise.

scholarly journals Gardening Intervention as a Low- to Moderate-Intensity Physical Activity for Improving Blood Lipid Profiles, Blood Pressure, Inflammation, and Oxidative Stress in Women over the Age of 70: A Pilot Study

HortScience ◽  
2017 ◽  
Vol 52 (1) ◽  
pp. 200-205 ◽  
Author(s):  
Sin-Ae Park ◽  
A-Young Lee ◽  
Hee-Geun Park ◽  
Ki-Cheol Son ◽  
Dae-Sik Kim ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Physical Activity ◽  
Blood Pressure ◽  
Blood Lipid ◽  
Lipid Profiles ◽  
Moderate Intensity ◽  
Community Center ◽  
Moderate Physical Activity ◽  
Positive Effects ◽  
And Oxidative Stress

The objective of this study was to investigate the effects of a gardening intervention as a physical activity in women aged over 70 years. Twenty-one women aged over 70 years were recruited from the community in Seoul, South Korea. Eleven subjects at a senior community center participated in a 15-session gardening program (twice a week, average 50 minutes per session) from Sept. to Nov. 2015. The rest of the subjects who were recruited from another senior community center acted as the control group. Blood lipid profiles, blood pressure, inflammation in peripheral-blood mononuclear cells (PBMC), and oxidative stress were assessed by a blood test before and after the 15-session gardening intervention. The results showed that the subjects in the gardening intervention as a low- to moderate-physical activity had a significant improvement in their high-density lipoprotein (HDL) level, systolic and diastolic blood pressures, and the variables related to immunity such as tumor necrosis factor-α (TNF-α) for inflammation in blood and receptor for advanced glycation end products (RAGE) expression for oxidative stress. The results of this study suggested that the 15-session gardening intervention as a low- to moderate-physical activity led to positive effects on the blood lipid profiles, blood pressure, level of inflammatory markers in blood, and oxidative stress of women aged over 70 years.

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.

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