scholarly journals Acute beetroot juice supplementation on sympathetic nerve activity: a randomized, double-blind, placebo-controlled proof-of-concept study

2017 ◽  
Vol 313 (1) ◽  
pp. H59-H65 ◽  
Author(s):  
Karambir Notay ◽  
Anthony V. Incognito ◽  
Philip J. Millar
Keyword(s):  
Nitric Oxide ◽  
Blood Pressure ◽  
Sympathetic Outflow ◽  
Beetroot Juice ◽  
Proof Of Concept ◽  
Burst Frequency ◽  
Double Blind ◽  
Dietary Nitrate ◽  
Nitrate Supplementation ◽  
Central Sympathetic Outflow

Acute dietary nitrate ([Formula: see text]) supplementation reduces resting blood pressure in healthy normotensives. This response has been attributed to increased nitric oxide bioavailability and peripheral vasodilation, although nitric oxide also tonically inhibits central sympathetic outflow. We hypothesized that acute dietary [Formula: see text] supplementation using beetroot (BR) juice would reduce blood pressure and muscle sympathetic nerve activity (MSNA) at rest and during exercise. Fourteen participants (7 men and 7 women, age: 25 ± 10 yr) underwent blood pressure and MSNA measurements before and after (165–180 min) ingestion of 70ml high-[Formula: see text] (~6.4 mmol [Formula: see text]) BR or [Formula: see text]-depleted BR placebo (PL; ~0.0055 mmol [Formula: see text]) in a double-blind, randomized, crossover design. Blood pressure and MSNA were also collected during 2 min of static handgrip (30% maximal voluntary contraction). The changes in resting MSNA burst frequency (−3 ± 5 vs. 3 ± 4 bursts/min, P = 0.001) and burst incidence (−4 ± 7 vs. 4 ± 5 bursts/100 heart beats, P = 0.002) were lower after BR versus PL, whereas systolic blood pressure (−1 ± 5 vs. 2 ± 5 mmHg, P = 0.30) and diastolic blood pressure (4 ± 5 vs. 5 ± 7 mmHg, P = 0.68) as well as spontaneous arterial sympathetic baroreflex sensitivity ( P = 0.95) were not different. During static handgrip, the change in MSNA burst incidence (1 ± 8 vs. 8 ± 9 bursts/100 heart beats, P = 0.04) was lower after BR versus PL, whereas MSNA burst frequency (6 ± 6 vs. 11 ± 10 bursts/min, P = 0.11) as well as systolic blood pressure (11 ± 7 vs. 12 ± 8 mmHg, P = 0.94) and diastolic blood pressure (11 ± 4 vs. 11 ± 4 mmHg, P = 0.60) were not different. Collectively, these data provide proof of principle that acute BR supplementation can decrease central sympathetic outflow at rest and during exercise. Dietary [Formula: see text] supplementation may represent a novel intervention to target exaggerated sympathetic outflow in clinical populations. NEW & NOTEWORTHY The hemodynamic benefits of dietary nitrate supplementation have been attributed to nitric oxide-mediated peripheral vasodilation. Here, we provide proof of concept that acute dietary nitrate supplementation using beetroot juice can decrease muscle sympathetic outflow at rest and during exercise in a normotensive population. These results have applications for targeting central sympathetic overactivation in disease.

scholarly journals Effect of acute dietary nitrate supplementation on sympathetic vasoconstriction at rest and during exercise

2019 ◽  
Vol 127 (1) ◽  
pp. 81-88 ◽  
Author(s):  
Christopher J. de Vries ◽  
Darren S. DeLorey
Keyword(s):  
Nitric Oxide ◽  
Blood Pressure ◽  
Skeletal Muscle ◽  
Beetroot Juice ◽  
Total Plasma ◽  
Dietary Nitrate ◽  
Arterial Blood ◽  
Sympathetic Vasoconstriction ◽  
Nitrate Supplementation ◽  
Healthy Males

Dietary nitrate ([Formula: see text]) supplementation has been shown to reduce resting blood pressure. However, the mechanism responsible for the reduction in blood pressure has not been identified. Dietary [Formula: see text] supplementation may increase nitric oxide (NO) bioavailability, and NO has been shown to inhibit sympathetic vasoconstriction in resting and contracting skeletal muscle. Therefore, the purpose of this study was to investigate the hypothesis that acute dietary [Formula: see text] supplementation would attenuate sympathetic vasoconstrictor responsiveness at rest and during exercise. In a double-blind randomized crossover design, 12 men (23 ± 5 yr) performed a cold-pressor test (CPT) at rest and during moderate- and heavy-intensity alternate-leg knee-extension exercise after consumption of [Formula: see text] rich beetroot juice (~12.9 mmol [Formula: see text]) or a [Formula: see text]-depleted placebo (~0.13 mmol [Formula: see text]). Venous blood was sampled before and 2.5 h after the consumption of beetroot juice for the measurement of total plasma nitrite/[Formula: see text] [NOx]. Beat-by-beat blood pressure was measured by Finometer. Leg blood flow was measured at the femoral artery via Doppler ultrasound, and leg vascular conductance (LVC) was calculated. Sympathetic vasoconstrictor responsiveness was calculated as the percentage decrease in LVC in response to the CPT. Total plasma [NOx] was greater ( P < 0.001) in the [Formula: see text] (285 ± 120 µM) compared with the placebo (65 ± 30 µM) condition. However, mean arterial blood pressure and plasma catecholamines were not different ( P > 0.05) between [Formula: see text] and placebo conditions at rest or during moderate- and heavy-intensity exercise. Sympathetic vasoconstrictor responsiveness (Δ% LVC) was not different ( P > 0.05) between [Formula: see text] and placebo conditions at rest ([Formula: see text]: −33 ± 10%; placebo: −35 ± 11%) or during moderate ([Formula: see text]: −18 ± 8%; placebo: −20 ± 10%)- and heavy ([Formula: see text]: −12 ± 8%; placebo: −11 ± 9%)-intensity exercise. These data demonstrate that acute dietary [Formula: see text] supplementation does not alter sympathetic vasoconstrictor responsiveness at rest or during exercise in young healthy males. NEW & NOTEWORTHY Dietary nitrate may increase nitric oxide bioavailability, and nitric oxide has been shown to attenuate sympathetic vasoconstriction in resting and contracting skeletal muscle and enhance functional sympatholysis. However, the effect of dietary nitrate on sympathetic vasoconstrictor responsiveness is unknown. Acute dietary nitrate supplementation did not alter blood pressure or sympathetic vasoconstrictor responsiveness at rest or during exercise in young healthy males.

scholarly journals No Effect of Beetroot Juice Supplementation on 100-m and 200-m Swimming Performance in Moderately Trained Swimmers

2019 ◽  
Vol 14 (6) ◽  
pp. 706-710 ◽  
Author(s):  
Ozcan Esen ◽  
Ceri Nicholas ◽  
Mike Morris ◽  
Stephen J. Bailey
Keyword(s):  
Blood Pressure ◽  
Swimming Performance ◽  
Time Trial ◽  
Upper Body ◽  
Beetroot Juice ◽  
Nitrite Concentration ◽  
Double Blind ◽  
Dietary Nitrate ◽  
Nitrate Supplementation ◽  
Plasma Nitrite

Purpose: Dietary nitrate supplementation has been reported to improve performance in kayaking and rowing exercise, which mandate significant recruitment of the upper-body musculature. Because the effect of dietary nitrate supplementation on swimming performance is unclear, the purpose of this study was to assess the effect of dietary nitrate supplementation on 100-m and 200-m swimming freestyle time-trial (TT) performance. Methods: In a double-blind, randomized crossover design, 10 moderately trained swimmers underwent 2 separate 3-d supplementation periods, with a daily dose of either 140 mL nitrate-rich (∼800 mg/d nitrate) or nitrate-depleted (PLA) beetroot juice (BRJ). After blood sampling on day 3, the swimmers performed both 200-m and 100-m freestyle swimming TTs, with 30 min recovery between trials. Results: Plasma nitrite concentration was greater after BRJ relative to PLA consumption (432 [203] nmol/L, 111 [56] nmol/L, respectively, P = .001). Systolic blood pressure was lowered after BRJ compared with PLA supplementation (114 [10], 120 [10] mm Hg, respectively P = .001), but time to complete the 200-m (BRJ 152.6 [14.1] s, PLA 152.5 [14.1] s) and 100-m (BRJ 69.5 [7.2] s, PLA 69.4 [7.4] s) freestyle swimming TTs was not different between BRJ and PLA (P > .05). Conclusions: Although 3 d of BRJ supplementation increased plasma nitrite concentration and lowered blood pressure, it did not improve 100-m and 200-m swimming TT performance. These results do not support an ergogenic effect of nitrate supplementation in moderately trained swimmers, at least for 100-m and 200-m freestyle swimming performance.

scholarly journals The Effect of Dietary Nitrate Supplementation on Physiology and Performance in Trained Cyclists

2017 ◽  
Vol 12 (5) ◽  
pp. 684-689 ◽  
Author(s):  
Joseph A. McQuillan ◽  
Deborah K. Dulson ◽  
Paul B. Laursen ◽  
Andrew E. Kilding
Keyword(s):  
Time Trial ◽  
Crossover Design ◽  
Moderate Intensity ◽  
Beetroot Juice ◽  
Double Blind ◽  
Dietary Nitrate ◽  
Performance Time ◽  
Exercise Economy ◽  
Nitrate Supplementation ◽  
And Performance

Purpose:To determine the effect of dietary nitrate (NO3 –) supplementation on physiology and performance in well-trained cyclists after 6–8 d of NO3 – supplementation.Methods:Eight competitive male cyclists (mean ± SD age 26 ± 8 y, body mass 76.7 ± 6.9 kg, VO2peak 63 ± 4 mL · kg–1 · min–1) participated in a double-blind, placebo-controlled, crossover-design study in which participants ingested 70 mL of beetroot juice containing ~4 mmol NO3 – (NIT) or a NO3 –-depleted placebo (PLA), each for 8 d. Replicating pretreatment measures, participants undertook an incremental ramp assessment to determine VO2peak and first (VT1) and second (VT2) ventilatory thresholds on d 6 (NIT6 and PLA6), moderate-intensity cycling economy on d 7 (NIT7 and PLA7), and a 4-km time trial (TT) on d 8 (NIT8 and PLA8).Results:Relative to PLA, 6 d of NIT supplementation produced unclear effects for VO2peak (mean ± 95% confidence limit: 1.8% ± 5.5%) and VT1 (3.7% ± 12.3%) and trivial effects for both VT2 (–1.0% ± 3.0%) and exercise economy on d 7 (–1.0% ± 1.6%). However, effects for TT performance time (–0.7% ± 0.9%) and power (2.4% ± 2.5%) on d 8 were likely beneficial.Conclusions:Despite mostly unclear outcomes for standard physiological determinants of performance, 8 d of NO3 – supplementation resulted in likely beneficial improvements to 4-km TT performance in well-trained male endurance cyclists.

scholarly journals Oral nitrate supplementation to enhance pulmonary rehabilitation in COPD: ON-EPIC a multicentre, double-blind, placebo-controlled, randomised parallel group study

Thorax ◽  
2020 ◽  
Vol 75 (7) ◽  
pp. 547-555
Author(s):  
Matthew J Pavitt ◽  
Rebecca Jayne Tanner ◽  
Adam Lewis ◽  
Sara Buttery ◽  
Bhavin Mehta ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Active Treatment ◽  
Treatment Effect ◽  
Pulmonary Rehabilitation ◽  
Activity Level ◽  
Double Blind ◽  
Dietary Nitrate ◽  
Double Blind Placebo ◽  
Parallel Group ◽  
Nitrate Supplementation

RationaleDietary nitrate supplementation has been proposed as a strategy to improve exercise performance, both in healthy individuals and in people with COPD. We aimed to assess whether it could enhance the effect of pulmonary rehabilitation (PR) in COPD.MethodsThis double-blind, placebo-controlled, parallel group, randomised controlled study performed at four UK centres, enrolled adults with Global Initiative for Chronic Obstructive Lung Disease grade II–IV COPD and Medical Research Council dyspnoea score 3–5 or functional limitation to undertake a twice weekly 8-week PR programme. They were randomly assigned (1:1) to either 140 mL of nitrate-rich beetroot juice (BRJ) (12.9 mmol nitrate), or placebo nitrate-deplete BRJ, consumed 3 hours prior to undertaking each PR session. Allocation used computer-generated block randomisation.MeasurementsThe primary outcome was change in incremental shuttle walk test (ISWT) distance. Secondary outcomes included quality of life, physical activity level, endothelial function via flow-mediated dilatation, fat-free mass index and blood pressure parameters.Results165 participants were recruited, 78 randomised to nitrate-rich BRJ and 87 randomised to placebo. Exercise capacity increased more with active treatment (n=57) than placebo (n=65); median (IQR) change in ISWT distance +60 m (10, 85) vs +30 m (0, 70), estimated treatment effect 30 m (95% CI 10 to 40); p=0.027. Active treatment also impacted on systolic blood pressure: treatment group −5.0 mm Hg (−5.0, –3.0) versus control +6.0 mm Hg (−1.0, 15.5), estimated treatment effect −7 mm Hg (95% CI 7 to −20) (p<0.0005). No significant serious adverse events or side effects were reported.ConclusionsDietary nitrate supplementation appears to be a well-tolerated and effective strategy to augment the benefits of PR in COPD.Trial registration numberISRCTN27860457.

scholarly journals ACUTE DIETARY NITRATE SUPPLEMENTATION FAILS TO IMPROVE EXERCISE ECONOMY IN ELDERLY

2017 ◽  
pp. 1-4
Author(s):  
M. Driller ◽  
L. Thompson ◽  
J. McQuillan ◽  
R. Masters
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Perceived Exertion ◽  
Double Blind ◽  
Walking Test ◽  
Dietary Nitrate ◽  
Exercise Economy ◽  
Nitrate Supplementation ◽  
Walking Economy ◽  
Experimental Trials

Objective: Improvements in exercise economy following dietary nitrate (NO3-) supplementation in young, athletic populations has been well documented, but little research has focused on whether these same benefits translate to elderly populations. Design: Participants completed two experimental trials in a double-blind, randomized, crossover design. Setting: University laboratory. Participants: Twenty-one elderly participants >65 yr (10 male/11 female, mean ± SD; age: 72 ± 6 yr). Intervention: Each trial consisted of participants ingesting a 70ml dose of either NO3- rich (NIT; 5.0mmol.L-1) or NO3- depleted (PLA; 0.003mmol.L-1) beetroot juice two hours prior to reporting to the laboratory. Measurements: On arrival at the laboratory, blood pressure was assessed followed by a five minute walking economy test on a treadmill (3km.h-1 and 1% gradient). VO2, heart rate and RPE were monitored during the walking test. Results: There were no significant differences (p > 0.05) between NIT and PLA trials for any of the measured variables during the walking test. Furthermore, no differences were found for blood pressure between trials. All results were associated with trivial or unclear effect sizes. Conclusion: Despite recent reports of improved exercise economy in young, athletic populations following NO3- supplementation, the current study did not find any benefit to sub-maximal VO2, heart rate, perceived exertion or blood pressure in elderly participants when performing a 5-minute walk following NO3- supplementation.

scholarly journals Acute dietary nitrate supplementation does not augment submaximal forearm exercise hyperemia in healthy young men

2015 ◽  
Vol 40 (2) ◽  
pp. 122-128 ◽  
Author(s):  
Jin-Kwang Kim ◽  
David J. Moore ◽  
David G. Maurer ◽  
Daniel B. Kim-Shapiro ◽  
Swati Basu ◽  
...  
Keyword(s):  
Blood Flow ◽  
Brachial Artery ◽  
Young Men ◽  
Evidence Base ◽  
Beetroot Juice ◽  
Double Blind ◽  
Brachial Artery Diameter ◽  
Dietary Nitrate ◽  
Nitrate Supplementation ◽  
Forearm Exercise

Despite the popularity of dietary nitrate supplementation and the growing evidence base of its potential ergogenic and vascular health benefits, there is no direct information about its effects on exercising limb blood flow in humans. We hypothesized that acute dietary nitrate supplementation from beetroot juice would augment the increases in forearm blood flow, as well as the progressive dilation of the brachial artery, during graded handgrip exercise in healthy young men. In a randomized, double-blind, placebo-controlled crossover study, 12 young (22 ± 2 years) healthy men consumed a beetroot juice (140 mL Beet-It Sport, James White Juice Company) that provided 12.9 mmol (0.8 g) of nitrate or placebo (nitrate-depleted Beet-It Sport) on 2 study visits. At 3 h postconsumption, brachial artery diameter, flow, and blood velocity were measured (Doppler ultrasound) at rest and during 6 exercise intensities. Nitrate supplementation raised plasma nitrate (19.5-fold) and nitrite (1.6-fold) concentrations, and lowered resting arterial pulse wave velocity (PWV) versus placebo (all p < 0.05), indicating absorption, conversion, and a biological effect of this supplement. The supplement-associated lowering of PWV was also negatively correlated with plasma nitrite (r = –0.72, p = 0.0127). Despite these systemic effects, nitrate supplementation had no effect on brachial artery diameter, flow, or shear rates at rest (all p ≥ 0.28) or during any exercise workload (all p ≥ 0.18). These findings suggest that acute dietary nitrate supplementation favorably modifies arterial PWV, but does not augment blood flow or brachial artery vasodilation during nonfatiguing forearm exercise in healthy young men.

scholarly journals Dose-response effect of dietary nitrate on muscle contractility and blood pressure in older subjects

2020 ◽  
Author(s):  
Edgar J. Gallardo ◽  
Derrick A. Gray ◽  
Richard L. Hoffman ◽  
Brandon A. Yates ◽  
Ranjani N. Moorthi ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Pressure ◽  
Contractile Function ◽  
Knee Extensor ◽  
High Dose ◽  
Older Individuals ◽  
Muscle Contractility ◽  
Double Blind ◽  
Dietary Nitrate ◽  
Older Subjects

AbstractPurposeWe have recently demonstrated that dietary nitrate, a source of nitric oxide via the enterosalivary pathway, can improve muscle contractile function in healthy older men and women. Nitrate ingestion has also been shown to reduce blood pressure in some, but not all, studies of older individuals. However, the optimal dose for eliciting these beneficial effects is unknown.MethodsA randomized, double-blind, placebo-controlled crossover study was performed to determine the effects of ingesting 3.3 mL/kg of concentrated beetroot juice (BRJ) containing 0, 200, or 400 µmol/kg of nitrate in nine healthy older subjects (one man, eight women; mean age 70±1 y). Maximal knee extensor power (Pmax) and speed (Vmax) were measured 2 h after BRJ ingestion using isokinetic dynamometry. Blood pressure was monitored periodically throughout each study.ResultsPmax (in W/kg) was higher (P< 0.05) after the low dose (3.9±0.4) compared to the placebo (3.7±0.4) or high dose (3.7±0.4). Vmax (in rad/s) also tended higher (P = 0.08) in the low (11.9±0.7) compared to the placebo (10.8±0.8) or high dose (11.2±0.8) trials. Eight out of nine subjects achieved a higher Pmax and Vmax after the lower vs. the higher dose. These dose-related changes in muscle contractility paralleled changes in nitric oxide (NO) bioavailability, as reflected by changes in breath NO and plasma 3-nitrotyrosine levels. No significant changes were found in systolic, diastolic, or mean arterial pressure.ConclusionsVarying doses of dietary nitrate have differential effects on muscle function and blood pressure in older individuals. A moderate dose of nitrate increases muscle speed and power, but these improvements are lost at a higher dose. Blood pressure, on the other hand, is not reduced even with a higher dose.

scholarly journals Dietary nitrate restores compensatory vasodilation and exercise capacity in response to a compromise in oxygen delivery in the noncompensator phenotype

2017 ◽  
Vol 123 (3) ◽  
pp. 594-605 ◽  
Author(s):  
Robert F. Bentley ◽  
Jeremy J. Walsh ◽  
Patrick J. Drouin ◽  
Aleksandra Velickovic ◽  
Sarah J. Kitner ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Exercise Capacity ◽  
Perfusion Pressure ◽  
Beetroot Juice ◽  
Local Pressure ◽  
Dietary Nitrate ◽  
Arterial Blood ◽  
Nitrate Supplementation ◽  
Plasma Nitrite

Recently, dietary nitrate supplementation has been shown to improve exercise capacity in healthy individuals through a potential nitrate-nitrite-nitric oxide pathway. Nitric oxide has been shown to play an important role in compensatory vasodilation during exercise under hypoperfusion. Previously, we established that certain individuals lack a vasodilation response when perfusion pressure reductions compromise exercising muscle blood flow. Whether this lack of compensatory vasodilation in healthy, young individuals can be restored with dietary nitrate supplementation is unknown. Six healthy (21 ± 2 yr), recreationally active men completed a rhythmic forearm exercise. During steady-state exercise, the exercising arm was rapidly transitioned from an uncompromised (below heart) to a compromised (above heart) position, resulting in a reduction in local pressure of −31 ± 1 mmHg. Exercise was completed following 5 days of nitrate-rich (70 ml, 0.4 g nitrate) and nitrate-depleted (70 ml, ~0 g nitrate) beetroot juice consumption. Forearm blood flow (in milliliters per minute; brachial artery Doppler and echo ultrasound), mean arterial blood pressure (in millimeters of mercury; finger photoplethysmography), exercising forearm venous effluent (ante-cubital vein catheter), and plasma nitrite concentrations (chemiluminescence) revealed two distinct vasodilatory responses: nitrate supplementation increased (plasma nitrite) compared with placebo (245 ± 60 vs. 39 ± 9 nmol/l; P < 0.001), and compensatory vasodilation was present following nitrate supplementation (568 ± 117 vs. 714 ± 139 ml ⋅ min−1 ⋅ 100 mmHg−1; P = 0.005) but not in placebo (687 ± 166 vs. 697 ± 171 min−1 ⋅ 100 mmHg−1; P = 0.42). As such, peak exercise capacity was reduced to a lesser degree (−4 ± 39 vs. −39 ± 27 N; P = 0.01). In conclusion, dietary nitrate supplementation during a perfusion pressure challenge is an effective means of restoring exercise capacity and enabling compensatory vasodilation. NEW & NOTEWORTHY Previously, we identified young, healthy persons who suffer compromised exercise tolerance when exercising muscle perfusion pressure is reduced as a result of a lack of compensatory vasodilation. The ability of nitrate supplementation to restore compensatory vasodilation in such noncompensators is unknown. We demonstrated that beetroot juice supplementation led to compensatory vasodilation and restored perfusion and exercise capacity. Elevated plasma nitrite is an effective intervention for correcting the absence of compensatory vasodilation in the noncompensator phenotype.

Sign in / Sign up

Export Citation Format

Share Document