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

Notay, Karambir; Incognito, Anthony V.; Millar, Philip J.

doi:10.1152/ajpheart.00163.2017

Cited by 72 publications

(67 citation statements)

References 50 publications

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“…Also, evidence exists that acute nitrate supplementation is effective at reducing muscle sympathetic nerve activity at rest (Notay et al . ).…”

Section: Discussionmentioning

confidence: 97%

“…This is plausible considering that past work finds chronic Cit increases urinary excretion of cyclic GMP (Schwedhelm et al 2008), a byproduct of NO-stimulated guanylyl cyclase in smooth muscle that results in vasodilatation. Also, evidence exists that acute nitrate supplementation is effective at reducing muscle sympathetic nerve activity at rest (Notay et al 2017).…”

Section: Effect Of L-citrulline On Blood Pressurementioning

confidence: 99%

See 1 more Smart Citation

Does l‐citrulline supplementation improve exercise blood flow in older adults?

Gonzales

Raymond

Ashley

et al. 2017

Experimental Physiology

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New Findings r What is the central question of this study?Does short-term supplementation with l-citrulline in order to increase l-arginine improve exercise blood flow and peripheral dilatation responses to exercise in older adults? r What is the main finding and its importance? l-Citrulline increased femoral blood flow by 11% and vascular conductance by 14% during lower-limb exercise in older men, whereas no changes were observed in older women. This modest improvement in bulk muscle blood flow in older men has implications for altering muscle metabolism that may result in enhanced exercise tolerance in older adults.l-Citrulline (Cit) increases l-arginine (Arg), the primary substrate for nitric oxide biosynthesis. We tested the hypothesis that muscle blood flow during exercise would be enhanced by Cit supplementation in older adults. Femoral artery blood flow was measured during calf exercise using Doppler ultrasound, and vascular conductance (FVC) was calculated in 25 older adults (13 women and 12 men) before and after 14 days of Cit (6 g day −1 ) and placebo (maltodextrin) in a randomized, double-blind, crossover study. Plasma [Arg] and resting blood pressure were also measured before and after each condition. Women and men were analysed separately because of significant sex-by-condition interactions for the change in exercise blood flow and FVC. Plasma [Arg] was increased by 30 and 35% after Cit (P < 0.01) in women and men, respectively, with no change after placebo. Citrulline lowered diastolic blood pressure in men (75 ± 9 versus 71 ± 6 mmHg, P = 0.02), but this variable remained unchanged in women. Blood flow and FVC during exercise at higher workloads were increased after Cit in men (flow, 521 ± 134 versus 584 ± 166 ml min −1 , P = 0.04; FVC, 5.0 ± 1.5 versus 5.8 ± 1.7 m, min mmHg −1 , P = 0.01) but were not different after placebo. These variables were not altered by Cit in women. Adjusting for baseline diastolic blood pressure removed (P = 0.10) the difference in FBF and FVC following Cit in men. These results indicate that l-citrulline has a modest effect of improving muscle blood flow during submaximal exercise in older men.

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“…Also, evidence exists that acute nitrate supplementation is effective at reducing muscle sympathetic nerve activity at rest (Notay et al . ).…”

Section: Discussionmentioning

confidence: 97%

Section: Effect Of L-citrulline On Blood Pressurementioning

confidence: 99%

Does l‐citrulline supplementation improve exercise blood flow in older adults?

Gonzales

Raymond

Ashley

et al. 2017

Experimental Physiology

View full text Add to dashboard Cite

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“…2009; Notay et al . 2017). However, no change in plasma nitrite levels were previously reported in healthy subjects during a 60 min inhalation of 25 ppm iNO (Westfelt et al .…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, we did not observe a significant relationship between the change in S pO 2 and change in MSNA (r = −0.16, P = 0.61) in the present study. Finally, whilst any NO that enters the circulation is rapidly inactivated (Rimar & Gillis, 1993), an increased central NO bioavailability, via the nitrate-nitrite-NO pathway, may have influenced the MSNA response (Owlya et al 1997;Young et al 2009;Notay et al 2017). However, no change in plasma nitrite levels were previously reported in healthy subjects during a 60 min inhalation of 25 ppm iNO (Westfelt et al 1995).…”

Section: Sympathetic Neural Activation By Pulmonary Arterial Barorecementioning

confidence: 96%

Evidence for a physiological role of pulmonary arterial baroreceptors in sympathetic neural activation in healthy humans

Simpson

Meah

Steele

et al. 2020

The Journal of Physiology

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Key points In an anaesthetised animal model, independent stimulation of baroreceptors in the pulmonary artery elicits reflex sympathoexcitation. In humans, pulmonary arterial pressure is positively related to basal muscle sympathetic nerve activity (MSNA) under conditions where elevated pulmonary pressure is evident (e.g. high altitude); however, a causal link is not established. Using a novel experimental approach, we demonstrate that reducing pulmonary arterial pressure lowers basal MSNA in healthy humans. This response is distinct from the negative feedback reflex mediated by aortic and carotid sinus baroreceptors when systemic arterial pressure is lowered. Afferent input from pulmonary arterial baroreceptors may contribute to sympathetic neural activation in healthy lowland natives exposed to high altitude. Abstract In animal models, distension of baroreceptors located in the pulmonary artery induces a reflex increase in sympathetic outflow; however, this has not been examined in humans. Therefore, we investigated whether reductions in pulmonary arterial pressure influenced sympathetic outflow and baroreflex control of muscle sympathetic nerve activity (MSNA). Healthy lowlanders (n = 13; 5 females) were studied 4–8 days following arrival at high altitude (4383 m; Cerro de Pasco, Peru), a setting that increases both pulmonary arterial pressure and sympathetic outflow. MSNA (microneurography) and blood pressure (BP; photoplethysmography) were measured continuously during ambient air breathing (Amb) and a 6 min inhalation of the vasodilator nitric oxide (iNO; 40 ppm in 21% O2), to selectively lower pulmonary arterial pressure. A modified Oxford test was performed under both conditions. Pulmonary artery systolic pressure (PASP) was determined using Doppler echocardiography. iNO reduced PASP (24 ± 3 vs. 32 ± 5 mmHg; P < 0.001) compared to Amb, with a similar reduction in MSNA total activity (1369 ± 576 to 994 ± 474 a.u min−1; P = 0.01). iNO also reduced the MSNA operating point (burst incidence; 39 ± 16 to 33 ± 17 bursts·100 Hb−1; P = 0.01) and diastolic operating pressure (82 ± 8 to 80 ± 8 mmHg; P < 0.001) compared to Amb, without changing heart rate (P = 0.6) or vascular–sympathetic baroreflex gain (P = 0.85). In conclusion, unloading of pulmonary arterial baroreceptors reduced basal sympathetic outflow to the skeletal muscle vasculature and reset vascular–sympathetic baroreflex control of MSNA downward and leftward in healthy humans at high altitude. These data suggest the existence of a lesser‐known reflex input involved in sympathetic activation in humans.

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“…There are also studies that do not show any BP reduction after nitrate-rich BRJ supplementation de Vries and DeLorey 2019;Notay, Incognito, and Millar 2017;Perez et al 2019). de Vries & DeLorey (2019) found that sympathetic vasoconstrictor responsiveness was not altered, not in rest not after exercise, after a single dose of BRJ consumption compared to placebo (de Vries and DeLorey 2019).…”

Section: Effect On Blood Pressurementioning

confidence: 99%

The benefits and risks of beetroot juice consumption: a systematic review

Zamani

Joode

Hossein

et al. 2020

Critical Reviews in Food Science and Nutrition

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Beetroot juice (BRJ) has become increasingly popular amongst athletes aiming to improve sport performances. BRJ contains high concentrations of nitrate, which can be converted into nitric oxide (NO) after consumption. NO has various functions in the human body, including a vasodilatory effect, which reduces blood pressure and increases oxygen-and nutrient delivery to various organs. These effects indicate that BRJ may have relevant applications in prevention and treatment of cardiovascular disease. Furthermore, the consumption of BRJ also has an impact on oxygen delivery to skeletal muscles, muscle efficiency, tolerance and endurance and may thus have a positive impact on sports performances. Aside from the beneficial aspects of BRJ consumption, there may also be potential health risks. Drinking BRJ may easily increase nitrate intake above the acceptable daily intake, which is known to stimulate the endogenous formation of N-nitroso compounds (NOC's), a class of compounds that is known to be carcinogenic and that may also induce several other adverse effects. Compared to studies on the beneficial effects, the amount of data and literature on the negative effects of BRJ is rather limited, and should be increased in order to perform a balanced risk assessment.

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

Cited by 72 publications

References 50 publications

Does l‐citrulline supplementation improve exercise blood flow in older adults?

Does l‐citrulline supplementation improve exercise blood flow in older adults?

Evidence for a physiological role of pulmonary arterial baroreceptors in sympathetic neural activation in healthy humans

The benefits and risks of beetroot juice consumption: a systematic review

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