Influence of dietary nitrate supplementation on local sweating and cutaneous vascular responses during exercise in a hot environment

Amano, Tsuyoshi; Okushima, Dai; Breese, Brynmor C.; Bailey, Stephen J.; Koga, Shunsaku

doi:10.1007/s00421-018-3889-9

Cited by 16 publications

(26 citation statements)

References 55 publications

(84 reference statements)

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“…While a study containing incremental doses and multiple measurement points is indeed more comprehensive, it would reduce feasibility and complicate statistical analysis. However, it should be noted that the increases in plasma [nitrate] and [nitrite] observed in the current study (eight weeks, 8.5mM) are similar to other studies utilizing shorter supplementation periods (314 days) and similar doses (8.0–8.4mM) of inorganic nitrate in various populations (3, 4, 13, 19). Second, the smaller sample size of our study is also worth noting given our a priori power analysis proposing 15 subjects per group.…”

Section: Discussionsupporting

confidence: 89%

Inorganic nitrate supplementation enhances functional capacity and lower-limb microvascular reactivity in patients with peripheral artery disease

et al. 2018

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Peripheral artery disease (PAD) is characterized by functional and vascular impairments as well as elevated levels of inflammation which are associated with reduced nitric oxide (NO) bioavailability. Inorganic nitrate supplementation boosts NO bioavailability potentially improving functional and vasodilatory capacities and may reduce inflammation. Twenty-one patients with PAD were randomly assigned to sodium nitrate (NaNO) or placebo supplementation groups for eight-weeks. Outcome measures included a 6-min walk test (6 MWT), blood flow and vasodilator function in the forearm and calf, as well as plasma inflammatory and adhesion biomarker concentrations. NaNO elevated plasma nitrate (32.3 ± 20.0 to 379.8 ± 204.6 μM) and nitrite (192.2 ± 51.8 to 353.1 ± 134.2 nM), improved 6 MWT performance (387 ± 90 to 425 ± 82 m), peak calf blood flow (BF; 11.6 ± 4.9 to 14.1 ± 5.1 mL/dL tissue/min), and peak calf vascular conductance (VC; 11.1 ± 4.3 to 14.2 ± 4.9 mL/dL tissue/min/mmHg) (p < 0.05 for all). Improvements in calf BF (r = 0.70, p < 0.05) and VC (r = 0.61, p < 0.05) correlated with changes in 6 MWT distance. Placebo supplementation did not change plasma nitrate or nitrite, 6 MWT, calf BF, or calf VC. Forearm vascular function nor inflammatory and adhesion biomarker concentrations changed in either group. Eight-weeks of NaNO supplementation improves vasodilatory capacity in the lower-limbs of patients with PAD, which correlated with improvement in functional capacity.

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Section: Discussionsupporting

confidence: 89%

Inorganic nitrate supplementation enhances functional capacity and lower-limb microvascular reactivity in patients with peripheral artery disease

et al. 2018

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“…An increased cutaneous vascular conductance with dietary nitrate could account for the elevated cerebral O 2 Hb during normoxic TT. It should be acknowledged that, dietary nitrate supplementation does not appear to influence forearm cutaneous vascular conductance response to exercise in heat ( Amano et al, 2018 ), nor alter cutaneous reactive hyperaemic response ( Wong et al, 2017 ). Moreover, the use of a source-detector distance of 41 mm in our setup reduces the extracranial influence on prefrontal NIRS signals.…”

Section: Discussionmentioning

confidence: 99%

Oral Nitrate Supplementation Differentially Modulates Cerebral Artery Blood Velocity and Prefrontal Tissue Oxygenation During 15 km Time-Trial Cycling in Normoxia but Not in Hypoxia

et al. 2018

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Background: Nitrate is a precursor of nitric oxide (NO), an important regulator of cerebral perfusion in normoxic and hypoxic conditions. Nitrate supplementation could be used to improve cerebral perfusion and oxygenation during exercise in hypoxia. The effects of dietary nitrate supplementation on cerebral haemodynamics during exercise in severe hypoxia (arterial O2 saturation < 70%) have not been explored.Methods: In twelve trained male cyclists, we measured blood pressure (BP), middle cerebral artery blood velocity (MCAv), cerebrovascular resistance (CVR) and prefrontal oxyhaemoglobin and deoxyhaemoglobin concentration (O2Hb and HHb, respectively) during 15 km cycling time trials (TT) in normoxia and severe hypoxia (11% inspired O2, peripheral O2 saturation ∼66%) following 3-day oral supplementation with placebo or sodium nitrate (0.1 mmol/kg/day) in a randomised, double-blinded manner. We tested the hypothesis that dietary nitrate supplementation increases MCAv and cerebral O2Hb during TT in severe hypoxia.Results: During TT in normoxia, nitrate supplementation lowered MCAv by ∼2.3 cm/s and increased cerebral O2Hb by ∼6.8 μM and HHb by ∼2.1 μM compared to normoxia placebo (p ≤ 0.01 for all), while BP tended to be lowered (p = 0.06). During TT in severe hypoxia, nitrate supplementation elevated MCAv (by ∼2.5 cm/s) and BP (by ∼5 mmHg) compared to hypoxia placebo (p < 0.01 for both), while it had no effect on cerebral O2Hb (p = 0.98), HHb (p = 0.07) or PETCO2 (p = 0.12). Dietary nitrate had no effect of CVR during TT in normoxia or hypoxia (p = 0.19).Conclusion: Our findings indicate that during normoxic TT, the modulatory effect of dietary nitrate on regional and global cerebral perfusion is heterogeneous. Meanwhile, the lack of major changes in cerebral perfusion with dietary nitrate during hypoxic TT alludes to an exhausted cerebrovascular reserve.

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“…An animal study with rats also showed an increase in muscle blood flow, but only using high doses of nitrate (Ferguson et al 2014). However, Amano et al (2018) showed that BRJ intake, 140 ml for 3 days, does not affect skin blood flow (Amano et al 2018).…”

Section: Effect On Blood Flow and Endothelial Functionmentioning

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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Influence of dietary nitrate supplementation on local sweating and cutaneous vascular responses during exercise in a hot environment

Abstract: These results suggest that inorganic [Formula: see text] supplementation, which increases the potential for O-independent NO production, does not affect local sweating and cutaneous vascular responses, but attenuates blood pressure in young healthy subjects exercising in a hot environment.

Cited by 16 publications

References 55 publications

Inorganic nitrate supplementation enhances functional capacity and lower-limb microvascular reactivity in patients with peripheral artery disease

Inorganic nitrate supplementation enhances functional capacity and lower-limb microvascular reactivity in patients with peripheral artery disease

Oral Nitrate Supplementation Differentially Modulates Cerebral Artery Blood Velocity and Prefrontal Tissue Oxygenation During 15 km Time-Trial Cycling in Normoxia but Not in Hypoxia

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

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